CN107659150B

CN107659150B - DC-DC module automatic switching DC power conversion method and system

Info

Publication number: CN107659150B
Application number: CN201710038932.9A
Authority: CN
Inventors: 张海波; 麦凯; 李盛峰; 柏志彬
Original assignee: SHENZHEN HOTCHIP TECHNOLOGY CO LTD
Current assignee: SHENZHEN HOTCHIP TECHNOLOGY CO LTD
Priority date: 2017-01-19
Filing date: 2017-01-19
Publication date: 2023-05-23
Anticipated expiration: 2037-01-19
Also published as: CN107659150A

Abstract

The direct current electric energy conversion method and system for automatically switching the DCDC modules comprises N DCDC modules which are arranged in parallel, an output voltage detection feedback module and a clock signal module for providing a working clock signal; the control module detects the current output to an external load, calculates the number of DCDC modules to be started to be Q according to the load current, and outputs the enabling and starting control signals of the Q DCDC modules; working clock signals CLK of Q DCDC modules _N Is the same in period of each working clock signal CLK _N The phase difference is 360 degrees divided by Q. The multiple DCDC modules are connected in parallel, so that larger current can be output, and the power consumption of the system is reduced; the multi-channel DCDC modules are all arranged on the same chip, and have good parameter consistency characteristics and good current balance characteristics of all channels; the time-sharing soft start and the phase-shifting time-sharing control avoid overshoot, reduce the ripple of the power supply output voltage and have more stable output characteristics.

Description

DC-DC module automatic switching DC power conversion method and system

Technical Field

The invention belongs to a direct current electric energy conversion circuit and a system; and more particularly to a method and system for dc power conversion in a current mode having a plurality of dc power conversion units.

Background

The prior art is commonly used for switching regulators of direct current power supply, including a BUCK mode switching regulator, a BOOST mode switching regulator and a BUCK-BOOST mode switching regulator, and the switching regulator of any mode usually has only one DCDC conversion circuit, and when the output current is larger, the efficiency is lower, the heating is larger, the output ripple is also larger, and the requirement on the saturated current of the inductor is larger. In the prior art, only one DCDC module is arranged in an electric energy conversion system, when the output current is required to be large, the saturation current of the inductor is required to be large, and the volume requirement of the inductor is also large; it is clearly no longer suitable for portable applications because of space constraints, small inductances are required, the peak currents of which are small, and heating is severe at heavy loads, thus limiting the output power ratio of the individual DCDC modules.

In order to improve the carrying capacity, the invention adopts a mode of connecting a plurality of DCDC conversion modules in parallel to improve the carrying capacity of the whole system, so that the system has the capacity of outputting large current, and the power consumption of the system is reduced by the mode of connecting a plurality of DCDC in parallel; the multiple paths of DCDC modules are all arranged on the same chip, so that the device has good parameter consistency characteristics, and the current balance characteristics of the DCDC modules in each path are good in a stable working state; and through time-sharing soft start and phase-shifting time-sharing control of each DCDC module, overshoot of output voltage or current when a plurality of DCDC are started or closed is avoided, ripple of power supply output voltage is reduced, and output characteristics are more stable.

Due to the fact that the control module is arranged, the system can automatically adjust the number of the started DCDC modules according to the load condition, after the plurality of DCDC modules are started, currents among the DCDC modules can be balanced well, current deviation among phases is small, consistency is good, overall power conversion efficiency is improved, heating is small, and stability and reliability of the whole system are good.

Noun interpretation:

DCDC is an abbreviation for english directcurrentdirectcurent, and chinese meaning that dc voltage is converted to dc voltage;

Current_modeswitchingDCDC means a Current-mode direct Current switching power supply converter; the DCDC referred to herein is a direct current switching power supply converter in current mode, that is, voltage and current are adopted to perform double closed-loop control at the same time, and feedback voltage and feedback current are adopted to perform system control;

EA is the shorthand for error amplifier;

OSC is a shorthand for oscillator, an oscillator;

MCU is the abbreviation of MicroControllerUnit, and Chinese meaning is microcontroller;

the meaning of the BUCK mode switching regulator in the present application is a BUCK DC/DC converter circuit employing BUCK regulator mode;

the meaning of a BOOST-mode switching regulator in this application is a buck DC/DC converter circuit employing BOOST mode;

The meaning of the BUCK-BOOST mode switching regulator in the application is a BUCK-BOOST DC/DC conversion circuit adopting a BUCK-BOOST topology; the non-isolated DC converter has an output voltage which is lower than or higher than the input voltage, but has a polarity opposite to the input voltage.

PWM is an abbreviation for English pulsewidth modulation, and Chinese meaning is pulse width modulation; the Pulse Width Modulation (PWM) switch type voltage stabilizing circuit achieves the purpose of stabilizing output voltage by adjusting the duty ratio of the PWM switch type voltage stabilizing circuit under the condition that the output frequency of the control circuit is unchanged.

Disclosure of Invention

The technical problem to be solved by the invention is to avoid the defects of the prior art, and provide a multiphase automatic switching direct current electric energy conversion system, when a large load current is needed, a necessary number of DCDC modules are started automatically according to the load current, the power consumption of the electric energy conversion system is reduced, the heat is reduced, the system is more stable, and the output ripple is smaller.

The technical scheme adopted for solving the technical problems is a direct current electric energy conversion method for automatically switching a DCDC module, which comprises the following steps: a: setting N DCDC modules for converting an input direct-current voltage Vin into an output voltage Vout in a parallel mode, wherein N is the number of the DCDC modules, and the value range of N is a natural number ranging from 1 to M; an output voltage detection feedback module for detecting and feeding back the output voltage Vout and a clock signal module for simultaneously providing working clock signals CLKN for the N DCDC modules are arranged; b: the output voltage detection feedback module samples output voltage and compares the output voltage with a set output voltage reference value Vref0, and outputs a peak current control signal VC to each DCDC module; the DCDC module adjusts output peak current according to the peak current control signal VC so as to change output voltage Vout; c: the N DCDC modules respectively receive working clock signals CLKN output by the clock signal modules; d: setting control modules for enabling and starting control of N DCDC modules; the control module detects the current ILoadsen output to an external load, calculates the number of DCDC modules to be started to be Q according to the detected load current ILoadsen, and outputs enabling and starting control signals of the corresponding Q DCDC modules; namely, the control module controls the on/off of the DCDC modules with different numbers according to the load current ILoadsen; adapting the output current of the Q DCDC modules to the external load current requirement; e: the periods of the working clock signals CLKN of the Q DCDC modules output by the clock signal module are the same, and the phase difference of each working clock signal CLKN is 360 degrees divided by Q.

The technical scheme adopted for solving the technical problems can also be a direct current electric energy conversion system for automatically switching a DCDC module, comprising: n DCDC modules which are arranged in parallel and used for converting the input direct-current voltage Vin into the output voltage Vout, wherein N is the number of the DCDC modules, and the value range of N is a natural number ranging from 1 to M; the output voltage detection feedback module is used for detecting and feeding back the output voltage Vout; the direct current power conversion system is characterized by further comprising a clock signal module for simultaneously providing working clock signals CLKN for the N DCDC modules; the control module is used for enabling and starting control of the N DCDC modules; the N DCDC modules respectively receive working clock signals CLKN output by the clock signal modules; the control module detects the current ILoadsen output to an external load, calculates the number of DCDC modules to be started to be Q according to the detected load current ILoadsen, and outputs enabling and starting control signals of the corresponding Q DCDC modules; namely, the control module controls the on/off of the DCDC modules with different numbers according to the load current ILoadsen; adapting the output current of the Q DCDC modules to the external load current requirement; the periods of the working clock signals CLKN of the Q DCDC modules output by the clock signal module are the same, and the phase difference of the working clock signals CLKN is 360 degrees divided by Q.

An external inductor is connected between the SW pin of the DCDC module and the ground, and the DCDC module and the external inductor form a complete BUCK-BOOST converter, namely a BUCK-BOOST converter which is a non-isolated direct-current converter with output voltage which can be lower than or higher than input voltage, but the polarity of the output voltage is opposite to that of the input voltage.

Of course, the DCDC module may also include a power conversion circuit with other implementation manners, such as a BUCK mode switching regulator or a BOOST mode switching regulator, if a power conversion circuit with a different mode is adopted, the connection manner of the related electronic components will be correspondingly adjusted, and the timing relationship of the corresponding signals will be correspondingly changed, which is not described in detail in the present disclosure.

In an initial state of starting the direct current electric energy conversion system, only the first DCDC module works; when the load current ILoadsen detected by the control module is greater than or equal to a first load current threshold value, the control module outputs an enabling control signal and an opening control signal to the second DCDC module so as to enable the second DCDC module to be opened; the first DCDC module and the second DCDC module obtain respective working clock signals CLK1 and CLK2 from the clock signal module; the phase difference between the working clock signal CLK1 of the first DCDC module and the working clock signal CLK2 of the second DCDC module is 180 degrees; when the load current detected by the control module is smaller than a first load current threshold value, the control module outputs an enabling control signal and an opening control signal to the second DCDC module, so that the second DCDC module is closed.

When the first DCDC module and the second DCDC module work, and the load current ILoadsen detected by the control module is larger than or equal to a second threshold value of the load current, the control module outputs an enabling control signal and an opening control signal to a third direct current power supply conversion module so as to enable the third direct current power supply conversion module to be opened; the first DCDC module, the second DCDC module and the third dc power conversion module obtain respective working clock signals CLK1, CLK2 and CLK3 from the clock signal module; the phase difference between the working clock signal CLK1 of the first DCDC module and the working clock signal CLK2 of the second DCDC module is 120 degrees; the phase difference between the working clock signal CLK2 of the second DCDC module and the clock signal CLK3 obtained by the third DC power supply conversion module is 120 degrees; when the load current ILoadsen detected by the control module is smaller than the second load current threshold value, the control module outputs an enabling control signal and an opening control signal to the third direct current power supply conversion module, so that the third direct current power supply conversion module is closed.

When the first DCDC module and the second DCDC module work, and the load current ILoadsen detected by the control module is larger than or equal to a third load current threshold value, the control module outputs an enabling control signal and an opening control signal to a third direct current power supply conversion module and a fourth direct current power supply conversion module so as to enable the third direct current power supply conversion module and the fourth direct current power supply conversion module to be opened; the first DCDC module, the second DCDC module, the third dc power conversion module, and the fourth dc power conversion module obtain respective working clock signals CLK1, CLK2, CLK3, and CLK4 from the clock signal module; the phase difference between the working clock signal CLK1 of the first DCDC module and the working clock signal CLK2 of the second DCDC module is 90 degrees; the phase difference between the working clock signal CLK2 of the second DCDC module and the working clock signal CLK3 of the third DC power supply conversion module is 90 degrees; the phase difference between the working clock signal CLK3 of the third DC power supply conversion module and the clock signal CLK4 obtained by the fourth DC power supply conversion module is 90 degrees; when the load current detected by the control module is smaller than a third threshold value of the load current, the control module outputs an enabling control signal and an opening control signal to the third direct current power supply conversion module and the fourth direct current power supply conversion module, so that the third direct current power supply conversion module and the fourth direct current power supply conversion module are closed.

The control module comprises a current sampling judging module for sampling and calculating the load current ILoadsen and an enabling and starting control module for enabling and starting control of each DCDC module; the enabling and starting control module outputs enabling control signals for enabling each DCDC module and starting control signals for soft start and soft close control of each DCDC module to each DCDC module; the enabling control signal is a high-low level signal; the starting control signal is a soft starting control signal; the current sampling judgment module obtains a load current signal from an external load; or the current sampling judgment module obtains a load current signal from the DCDC module.

The current sampling judging module comprises a first operational amplifier for comparing and operating load current sampling voltage with input voltage, a current source controlled by an output signal of the first operational amplifier and a first comparator, wherein the first comparator is used for comparing and operating reference voltage signals and outputting an enabling control signal to the enabling and starting control module; an input voltage signal is input from the positive electrode of the first operational amplifier, and a load current sampling voltage signal is input from the negative electrode of the first operational amplifier; the output of the first operational amplifier is used for controlling the current of the current source, the positive electrode of the current source is electrically connected with the voltage input end, and the negative electrode of the current source is grounded through a resistor; the negative electrode of the current source is input to the positive electrode of the first comparator after passing through a low-pass filter network, and the voltage of a negative electrode input signal of the first comparator is a first reference current threshold value; the first comparator outputs a DCDC module selection signal SEL to the enable and start control module for enabling and starting control of each DCDC module.

The enabling and starting control module comprises a voltage follower, a single-pole double-throw switch, a time delay network, a single-pole three-throw switch and an enabling and soft starting logic controller; the single-pole double-throw switch comprises an end A, an end B and an end D, and the single-pole triple-throw switch comprises an end E, an end F, an end G and an end H; the single-pole double-throw switch and the single-pole three-throw switch are controlled by the enabling and soft start logic controller; the input signals of the enable and soft start logic controller comprise an external enable signal EN and a DCDC module selection signal SEL; the output signals of the enabling and soft start logic controller comprise enabling and starting control signals output to the first DCDC module and the second DCDC module; the positive electrode input end of the amplifier of the voltage follower is electrically connected with the output end of the output voltage detection feedback module to obtain a feedback voltage signal; meanwhile, the positive electrode input end of an amplifier of the voltage follower is electrically connected with the E end of the single-pole three-throw switch, and the E end of the single-pole three-throw switch is used as an output terminal of a soft start control signal of the first DCDC module; when the enable and external enable signal EN input by the soft start logic controller is effective and the selection signal SEL is at a low level, the end B and the end D of the single-pole double-throw switch are electrically connected, and the end G and the end H of the single-pole triple-throw switch are electrically connected; the enabling and soft start logic controller outputs enabling and starting control signals of the first DCDC module, and only one DCDC module of the first DCDC module is in a working state; when the enable and external enable signal EN input by the soft start logic controller is effective and the selection signal SEL is at a high level, the end A and the end D of the single-pole double-throw switch are electrically connected, and the end F and the end H of the single-pole triple-throw switch are electrically connected; the enabling and soft start logic controller outputs enabling and starting control signals of the first DCDC module and the second DCDC module; the H end of the single-pole three-throw switch is used as an output terminal of a soft start control signal of the second DCDC module, and the soft start control signal of the second DCDC module is output; when the voltages of the F end and the H end of the single-pole three-throw switch are equal to the voltage of the D end of the single-pole double-throw switch, namely after the soft start of the second DCDC module is completed, the H end and the E end of the single-pole three-throw switch are electrically connected; and the output terminals of the soft start control signals of the first DCDC module and the second DCDC module are used for outputting stable voltage signals. The control module comprises a microcontroller MCU; the control module detects load current output to the outside by the direct current electric energy conversion system, judges the detected load current through the Micro Controller Unit (MCU), calculates the number of DCDC modules to be started, and outputs enabling and starting control signals of the corresponding DCDC modules.

Compared with the prior art, the invention has the beneficial effects that: 1. the parallel connection mode of a plurality of DCDC conversion circuit modules is adopted, so that the overall load carrying capacity of the system is improved, and larger current can be output; 2. the power consumption of the system is reduced by the mode of connecting a plurality of DCDCs in parallel; 3. the multiple paths of DCDC are all arranged on the same chip, so that the device has good parameter consistency characteristics, and the current balance characteristics of each path of DCDC module are good in a stable working state; 4. through time-sharing soft start and phase-shifting time-sharing control of each DCDC module, overshoot of output voltage or current when a plurality of DCDC are started or closed is avoided, ripple of power supply output voltage is reduced, and output characteristics are more stable; 5. the control module is arranged, so that the system can automatically adjust the number of the started DCDC modules according to the load condition, and after a plurality of DCDC modules are started, currents among the DCDC modules can be well balanced, current deviation among phases is small, consistency is good, overall power conversion efficiency is improved, heating is small, and stability and reliability of the whole system are good.

Drawings

FIG. 1 is a system block diagram of one of the preferred embodiments of the present invention;

Fig. 2 is a system block diagram of a second preferred embodiment of the present invention, in which only two DCDC modules 800, namely, a first DCDC module 801 and a second DCDC module 802 are provided;

FIG. 3 is a system block diagram of a third preferred embodiment of the present invention, wherein the control module 900 includes a microcontroller MCU;

FIG. 4 is a system block diagram of one of the preferred embodiments of the DCDC module 800, which includes a load current detection module, an adder for adding the load current feedback signal and the sawtooth wave, a comparator for comparing the adder output and the feedback voltage, the comparator outputting a PWM control signal to a logic controller, the output of the logic controller being input to a power output MOS tube through an output buffer Buff, one end of the power output MOS tube being electrically connected to the positive electrode of the input power supply, while the other pin SW of the power output MOS tube being grounded through an external inductor; meanwhile, the power output MOS tube outputs the converted voltage;

FIG. 5 is a timing diagram of the related signals of FIG. 4, where A in brackets after each signal name indicates that the signal is a current signal in amperes; v in brackets after each signal name indicates that the signal is a voltage signal in volts; wherein IL (A) is SW external inductor current; VSW (V) is a voltage signal of the SW point; VC (V) is a feedback voltage signal obtained from the output voltage detection feedback module 700; PWM (V) is an input control signal of the logic controller; CLK (V) is the clock signal obtained from the clock signal module 300; fig. 6 is a timing diagram of current signals and voltage signals of external inductor pins of the first DCDC module 801 and the second DCDC module 802 when two DCDC modules are included in the dc power conversion system with automatic switching of DCDC modules; the state shown in the figure is that only the first DCDC module 801 is in an operating state, and the second DCDC module 802 is in an unopened state;

Fig. 7 is a second timing diagram of current signals and voltage signals of external inductor pins of the first DCDC module 801 and the second DCDC module 802 when two DCDC modules are included in the dc power conversion system with automatic switching of DCDC modules; the state shown in the figure is that the first DCDC module 801 and the second DCDC module 802 are both in an on state;

FIG. 8 is a schematic block diagram of one embodiment of a clock signal module 300 when two DCDC modules are present in a direct current power conversion system with automatic switching of the DCDC modules; in the figure, an original crystal oscillator unit OSC0 outputs an original clock signal CLK0, and the original clock signal CLK0 outputs two clock signals CLK1 and CLK2 with a phase difference of 180 degrees after being subjected to flip-flop and related logic operation;

FIG. 9 is a timing diagram of the original clock signal CLK0 and two clock signals CLK1 and CLK2 of 180 degrees out of phase in FIG. 8;

fig. 10 is a schematic block diagram of a first current sampling and judging module 951, which is one of specific embodiments of a current sampling and judging module 950 for sampling and calculating a load current ILoadsen when two DCDC modules are included in a dc power conversion system with automatic switching of DCDC modules;

FIG. 11 is a schematic block diagram of a first enabling and starting control module 961, which is one embodiment of the enabling and starting control module 960 for enabling and starting control of each DCDC module 800, when there are two DCDC modules in the direct current power conversion system with automatic switching of the DCDC modules;

FIG. 12 is a timing diagram of the correlation signals of FIG. 11; as can be seen, when the SEL (V) signal goes from low to high, the signal EN2 (V) for enabling the second DCDC module 802 also goes from low to high, becoming an enabled state; meanwhile, the soft start control signal VS2 (V) of the second DCDC module 802 also changes from low to high after a period of time; when the SEL (V) signal goes from high to low, the soft start control signal VS2 (V) of the second DCDC module 802 also goes from high to low after a period of time, and when the soft start control signal VS2 (V) goes low, the signal EN2 (V) for enabling the second DCDC module 802 also goes from high to low, and becomes an enabled inactive state; the soft start signal is a ramp voltage signal that slowly rises about 1 mS; the signal for soft-off is a ramp voltage signal that slowly drops at about 1 mS; for convenience of drawing, only a straight line segment change process is shown in the drawing, and in fact, the process of changing VS2 (V) from low to high or from high to low can be a linear process or a nonlinear exponential change or other characteristic change process; the starting or closing process of the second DCDC module 802 is a slow-changing process, rather than a step process controlled by logic signals, so as to reduce the overshoot of output voltage or current caused by switching the number of DCDC modules;

Fig. 13 is a schematic block diagram of a second current sampling and judging module 952, which is a second embodiment of the current sampling and judging module 950 for sampling and calculating the load current ILoadsen when there are three or four DCDC modules in the dc power conversion system with automatic switching of DCDC modules;

FIG. 14 is a schematic block diagram of a second embodiment of an enable and start control module 960, a second enable and start control module 962, for enabling and starting control of each DCDC module 800 when there are three DCDC modules in the direct current power conversion system with automatic switching of the DCDC modules;

FIG. 15 is a timing diagram of the correlation signals of FIG. 14; compared with the case of turning on two DCDC modules in fig. 11, when a plurality of DCDC modules are turned on in fig. 14, the turn-on timing sequence of each module is controlled to be sequentially soft-started, so as to reduce the overshoot of output voltage or current caused when the number of DCDC modules is switched;

FIG. 16 is a system block diagram of a fourth preferred embodiment of the present invention.

Description of the embodiments

Embodiments of the present invention are described in further detail below with reference to the drawings.

The direct current power conversion method for automatically switching the DCDC module shown in fig. 1 comprises the following steps: a: n DCDC modules 800 for converting the input direct-current voltage Vin into the output voltage Vout are arranged in parallel, wherein N is the number of the DCDC modules 800, and the value range of N is a natural number ranging from 1 to M; an output voltage detection feedback module 700 for detecting and feeding back the output voltage Vout and a clock signal module 300 for simultaneously providing the N DCDC modules 800 with the operation clock signal CLKN; the value of M can be any one value between 2 and 100, and the values of M are 2, 3, 4, 6, 8 and 10 which are common; b: the output voltage detection feedback module 700 samples the output voltage and compares the sampled output voltage with a set output voltage reference value Vref0, and outputs a peak current control signal VC to each DCDC module 800; the DCDC module 800 adjusts the output peak current according to the peak current control signal VC to change the output voltage Vout; c: the N DCDC modules 800 respectively receive the working clock signals CLKN output from the clock signal module 300; d: a control module 900 for enabling and starting control of the N DCDC modules 800 is provided; the control module 900 detects the current ILoadsen output to the external load, calculates the number of DCDC modules 800 to be turned on as Q according to the detected load current ILoadsen, and outputs enable and turn-on control signals of the corresponding Q DCDC modules 800; that is, the control module 900 controls the DCDC modules 800 with different numbers to be turned on or off according to the load current ILoadsen; adapting the Q DCDC module 800 output current magnitudes to external load current requirements; q has a value less than or equal to M, and can be even or odd; e: the working clock signals CLKN of the Q DCDC modules 800 output by the clock signal module 300 have the same period, and each working clock signal CLKN has a phase difference of 360 degrees divided by Q.

In the above method, the output voltage detection feedback module 700 samples the output voltage and compares the sampled output voltage with a set output voltage reference value to output a peak current control signal to each DCDC module 800; the DCDC module 800 adjusts the output peak current according to the peak current control signal to change the output voltage. Because a mode that a plurality of DCDC modules are connected in parallel is adopted, the power consumption of the system is effectively reduced, so that the power consumption of the system adopting the direct current electric energy conversion method with the DCDC modules automatically switched is reduced, and the problem of large system heating during heavy load application is solved.

Particularly, when each DCDC module is a plurality of DCDC modules arranged on one chip, the power consumption of the DCDC modules is reduced in a parallel connection mode; the equivalent impedance characteristics of the DCDC modules are good in consistency, so that load current can be uniformly distributed to different DCDC modules; the clock signals with the same period are used as basic signals for the switch control of different DCDC modules 800, each DCDC module 800 can ensure the consistency of the working rhythm, and the output peak current can be more stable and balanced in different time periods of the same period through the phase difference of the clock signals, so that the ripple wave of the output voltage of the system is reduced.

A direct current power conversion system for automatically switching a DCDC module as shown in fig. 1, comprising: n DCDC modules 800 which are arranged in parallel and are used for converting the input direct-current voltage Vin into the output voltage Vout, wherein N is the number of the DCDC modules 800, and the value range of N is a natural number ranging from 1 to M; an output voltage detection feedback module 700 for detecting and feeding back the output voltage Vout; the direct current power conversion system further includes a clock signal module 300 for simultaneously providing the N DCDC modules 800 with the working clock signal CLKN; a control module 900 for enabling and turning on control of the N DCDC modules 800; the N DCDC modules 800 respectively receive the working clock signals CLKN output from the clock signal module 300; the control module 900 detects the current ILoadsen output to the external load, calculates the number of DCDC modules 800 to be turned on as Q according to the detected load current ILoadsen, and outputs enable and turn-on control signals of the corresponding Q DCDC modules 800; that is, the control module 900 controls the DCDC modules 800 with different numbers to be turned on or off according to the load current ILoadsen; adapting the Q DCDC module 800 output current magnitudes to external load current requirements; the working clock signals CLKN of the Q DCDC modules 800 output by the clock signal module 300 have the same period, and the phase difference of each working clock signal CLKN is 360 degrees divided by Q. Wherein the value of M can be any one value between 2 and 100, and the value of M is 2, 3, 4, 6, 8 and 10 which are commonly used; q has a value equal to or less than M, and may be even or odd.

As shown in fig. 2, an external inductor is connected between the SW pin of the DCDC module 800 and the ground, and the DCDC module 800 and the external inductor form a complete BUCK-BOOST converter, i.e., a BUCK-BOOST converter, which is a non-isolated dc converter with an output voltage that can be lower or higher than the input voltage, but with a polarity opposite to the input voltage. In fig. 1 and 3, the external inductance is omitted for simplicity of the drawing.

As shown in fig. 6, in an initial state in which the direct current power conversion system is turned on, only the first DCDC module 801 operates. As shown in fig. 7 to 12, when the load current ILoadsen detected by the control module 900 is greater than or equal to the load current first threshold, the control module 900 outputs an enable control signal and an on control signal to the second DCDC module 802, so that the second DCDC module 802 is turned on. When the load current detected by the control module 900 is less than the first threshold value of the load current, the control module 900 outputs an enable control signal and an on control signal to the second DCDC module 802, so that the second DCDC module 802 is turned off.

As shown in fig. 8 to 9, the first DCDC module 801 and the second DCDC module 802 obtain respective operation clock signals CLK1 and CLK2 from the clock signal module 300; the phase difference between the working clock signal CLK1 of the first DCDC module 801 and the working clock signal CLK2 of the second DCDC module 802 is 180 degrees.

As shown in fig. 13 to 15, when the first DCDC module 801 and the second DCDC module 802 are both operated, when the load current ILoadsen detected by the control module 900 is greater than or equal to the load current second threshold value, the control module 900 outputs an enable control signal and an on control signal to the third dc power conversion module 803, so that the third dc power conversion module 803 is turned on; the first DCDC module 801, the second DCDC module 802, and the third dc power conversion module 803 obtain respective operation clock signals CLK1, CLK2, and CLK3 from the clock signal module 300; the phase difference between the working clock signal CLK1 of the first DCDC module 801 and the working clock signal CLK2 of the second DCDC module 802 is 120 degrees; the phase difference between the working clock signal CLK2 of the second DCDC module 802 and the clock signal CLK3 obtained by the third dc power conversion module 803 is 120 degrees; when the load current ILoadsen detected by the control module 900 is less than the second threshold value of the load current, the control module 900 outputs an enable control signal and an on control signal to the third dc power conversion module 803, so that the third dc power conversion module 803 is turned off.

In some embodiments not shown in the drawings, when the first DCDC module 801 and the second DCDC module 802 are both operating, when the load current ILoadsen detected by the control module 900 is greater than or equal to the third threshold value of the load current, the control module 900 outputs an enable control signal and an on control signal to the third dc power conversion module 803 and the fourth dc power conversion module 804, so that the third dc power conversion module 803 and the fourth dc power conversion module 804 are turned on; the first DCDC module 801, the second DCDC module 802, the third dc power conversion module 803, and the fourth dc power conversion module 804 obtain respective operating clock signals CLK1, CLK2, CLK3, and CLK4 from the clock signal module 300; the phase difference between the working clock signal CLK1 of the first DCDC module 801 and the working clock signal CLK2 of the second DCDC module 802 is 90 degrees; the phase difference between the working clock signal CLK2 of the second DCDC module 802 and the working clock signal CLK3 of the third dc power conversion module 803 is 90 degrees; the phase difference between the working clock signal CLK3 of the third dc power conversion module 803 and the clock signal CLK4 obtained by the fourth dc power conversion module 804 is 90 degrees; when the load current detected by the control module 900 is smaller than the third threshold value of the load current, the control module 900 outputs an enabling control signal and an opening control signal to the third dc power conversion module 803 and the fourth dc power conversion module 804, so that the third dc power conversion module 803 and the fourth dc power conversion module 804 are turned off.

As shown in fig. 1 to 3, the control module 900 includes a current sampling judgment module 950 for sampling and calculating the load current ILoadsen and an enable and start control module 960 for enabling and starting control of each DCDC module 800; the enabling and starting control module 960 outputs an enabling control signal for enabling each DCDC module 800 and a starting control signal for soft start, soft shut-down control of each DCDC module 800 to each DCDC module 800; the enabling control signal is a high-low level signal; the starting control signal is a soft starting control signal; the current sampling judgment module 950 obtains a load current signal from an external load; or the current sample determination module 950 obtains a load current signal from the DCDC module 800.

As shown in fig. 10, the current sampling judgment module 950 includes a first operational amplifier 606 for comparing the load current sampling voltage with the input voltage, a current source 607 controlled by the output signal of the first operational amplifier 606, and a first comparator 608, wherein the first comparator 608 is used for comparing the reference voltage signal and outputting an enable control signal to the enable and start control module 960; an input voltage signal is input from the positive electrode of the first operational amplifier 606, and a load current sampling voltage signal is input from the negative electrode of the first operational amplifier 606; the output of the first operational amplifier 606 is used for controlling the current of the current source 607, the anode of the current source 607 is electrically connected with the voltage input end, and the cathode of the current source 607 is grounded through a resistor; the negative electrode of the current source 607 is input to the positive electrode of the first comparator 608 after passing through the low-pass filter network, and the voltage of the negative electrode input signal of the first comparator 608 is the voltage corresponding to the first reference current threshold value; the first comparator 608 outputs a DCDC module 800 selection signal SEL to the enable and start control module 960 for enabling and starting control of each DCDC module 800.

As shown in fig. 11, the enabling and starting control module 960 includes a voltage follower 601, a single pole double throw switch S1, a delay network 605, a single pole triple throw switch S2, and an enabling and soft starting logic controller 602; the single-pole double-throw switch S1 comprises an A end, a B end and a D end, and the single-pole triple-throw switch S2 comprises an E end, an F end, a G end and an H end; the single-pole double-throw switch S1 and the single-pole three-throw switch S2 are controlled by the enabling and soft start logic controller 602; the input signals of the enable and soft start logic controller 602 include an external enable signal EN and a DCDC module 800 select signal SEL; the output signals of the enable and soft start logic controller 602 include enable and turn-on control signals output to the first DCDC module 801 and the second DCDC module 802; the positive input end of the amplifier of the voltage follower 601 is electrically connected with the output end of the output voltage detection feedback module 700 to obtain a feedback voltage signal; meanwhile, the positive input end of the amplifier of the voltage follower 601 is electrically connected with the E end of the single-pole three-throw switch S2, and the E end of the single-pole three-throw switch S2 is used as an output terminal of the soft start control signal of the first DCDC module 801.

When the enable and external enable signal EN input by the soft start logic controller 602 is valid and the selection signal SEL is at a low level, the B terminal and the D terminal of the single-pole double-throw switch S1 are electrically connected, and the G terminal and the H terminal of the single-pole triple-throw switch S2 are electrically connected; the enable and soft start logic controller 602 outputs enable and start control signals of the first DCDC module 801, and only one DCDC module of the first DCDC module 801 is in an operating state.

When the enable and external enable signal EN input by the soft start logic controller 602 is valid and the selection signal SEL is at a high level, the a terminal and the D terminal of the single pole double throw switch S1 are electrically connected, and the F terminal and the H terminal of the single pole triple throw switch S2 are electrically connected; the enable and soft start logic controller 602 outputs enable and start control signals of the first DCDC module 801 and the second DCDC module 802; the H end of the single-pole three-throw switch S2 is used as an output terminal of the soft start control signal of the second DCDC module 802, and outputs the soft start control signal of the second DCDC module 802; when the voltages of the F end and the H end of the single-pole three-throw switch S2 are equal to the voltage of the D end of the single-pole double-throw switch S1, i.e. after the soft start of the second DCDC module 802 is completed, the H end and the E end of the single-pole three-throw switch S2 are electrically connected; so that the output terminals of the soft start control signals of the first DCDC module 801 and the second DCDC module 802 both output a stable voltage signal.

As shown in fig. 3, the control module 900 includes a microcontroller MCU; the control module 900 detects the load current output to the outside by the direct current power conversion system, the control module 900 judges the detected load current through the Micro Controller Unit (MCU), calculates the number of DCDC modules 800 to be turned on, and outputs the enable and turn-on control signals of the corresponding DCDC modules 800.

The first DCDC module 801 shown in fig. 2 includes a power input pin Vin1 for connecting to an external input power supply, a power output pin Vout1 for voltage-converting and outputting, an enable pin EN1 for controlling the enabling of the first DCDC module 801, a soft start voltage control pin VS1 for controlling the soft start of the first DCDC module 801, a clock signal input pin CLK1 for providing a clock signal of the first DCDC module 801, and a voltage control pin VCin1 for controlling the first DCDC module to output a peak current; the second DCDC module 802 shown in fig. 2 includes a power input pin Vin2 for connection to an external input power supply, a power output pin Vout2 for voltage output after voltage conversion, an enable pin EN2 for enabling the second DCDC module 802, a soft start voltage control pin VS2 for controlling soft start of the second DCDC module 802, a clock signal input pin CLK2 for providing a clock signal of the SMPS2, and a voltage control pin VCin2 for controlling the second DCDC module 802 to output a peak current.

The control circuit sub-module (90) as shown in fig. 2 includes a first DCDC module 801 enable control signal output pin EN1, a first DCDC module 801 soft start control voltage output pin VS1; the second DCDC module 802 enables the control signal output pin EN2, and the second DCDC module 802 soft starts the control voltage output pin VS2.

The clock signal module 300 shown in fig. 8 includes two clock signal output pins, namely CLK1 and CLK2, and is respectively connected to the first DCDC module 801 and the second DCDC module 802, clk1, and CLK2 with a phase difference of 180 °, that is, two DCDC with a phase difference of 180 °; by staggering the phase of 180 degrees, the output voltage ripple becomes smaller and the output voltage is more stable. CLK1, CLK2 are generated by dividing a basic clock signal to ensure that the operating frequencies of the two paths are consistent, thereby reducing the state difference between the two paths, matching the two paths, and particularly matching the peak currents of the two paths.

The output voltage detection feedback module 700 shown in fig. 2 feeds the detected output voltage sample value as a voltage feedback signal to one input of the error amplifier EA. The error amplifier EA comprises an output current control pin VC for controlling two paths of output peak currents; one input end of the error amplifier EA is connected with a voltage feedback signal, and the other input end of the error amplifier EA is connected with a preset reference voltage Vref 0. When the absolute value of the output voltage is smaller than the preset reference voltage Vref0, the output voltage VC of the error amplifier EA increases, so that the output current capability of the first DCDC module 801 and the second DCDC module 802 increases to pull the output voltage back to the preset value; conversely, when the absolute value of the output voltage is greater than the preset value, VC decreases, and the output current capability of the first DCDC module 801 and the second DCDC module 802 decreases to pull the output voltage back to the preset value. Because the two paths share the same peak current control signal VC, the peak currents of the two paths are better in matching, namely the peak currents of the inductances of the two paths are better in matching, so that the whole system is more stable, higher in efficiency and higher in reliability.

The power input pins of the first DCDC module 801 and the second DCDC module 802 are connected; the power output pins of the first DCDC module 801 and the second DCDC module 802 are connected; the output current control pins of the two paths of DCDC modules are connected with each other and the output current control pin of the error amplifier EA; the enable pin EN1 of the first DCDC module 801 is connected to the enable control signal output pin of the control module 900; the soft start control pin VS1 of the first DCDC module 801 is connected to the soft start control voltage output pin of the control module 900; the clock signal input pin CLK1 of the first DCDC module 801 is connected to the clock signal output pin of the clock signal module 300 to obtain the clock signal CLK1.

The enable pin EN2 of the second DCDC module 802 is connected to the enable control signal output pin of the control module 900; the voltage control pin VS2 of the soft start of the second DCDC module 802 is connected to the soft start control voltage output pin of the control module 900; the clock signal input pin CLK2 of the second DCDC module 802 is connected to the clock signal output pin of the clock signal module 300 to obtain a clock signal CLK2; the two paths of DCDC modules share the same output current peak control signal, and clock signals of the two paths of DCDC modules are derived from the same clock signal generator, so that when the system works simultaneously with the two paths of DCDC modules, the working states of the two paths of DCDC modules are matched as much as possible, the output currents of the two paths of DCDC modules are basically equal, and the whole circuit system is in a relatively optimized working state, so that the efficiency is higher, and the reliability is better.

FIG. 4 is a schematic block diagram of a preferred embodiment of a DCDC module including an adder, a comparator, a logic controller, a drive buffer and a power tube; in addition to this implementation, the DCDC module may be an implementation of other current mode DCDC modules, and is not limited to the schematic block diagram of this DCDC module. Each DCDC module is provided with a current detection signal Isense and a slope compensation signal Vcast which are generated internally, an adder adds the two analog signals to form Vsum, a comparator compares the Vsum with VC, when the Vsum is higher than the VC, the comparator sends out a high-level PWM, if the PWM signal is high, a logic controller outputs a closing signal, and after the PWM signal is enhanced by a drive buffer, a switching tube in a powermos is closed, and then a follow-up tube is opened. Since the switching tube is turned off, the current detection signal Isense becomes 0, so that the PWM signal becomes low; since the differential pressure across the inductor is negative in the freewheel state, the inductor current gradually decreases. When the next clock signal comes, the logic controller outputs an opening signal, and after the driving buffer is enhanced, the freewheel in the powermos is closed, and then the switching tube is opened. Because the switching tube is turned on, the inductor current starts to rise, and Isense has a current detection signal greater than 0, when the inductor current reaches a certain threshold value (the threshold value is determined by VC, and the magnitude of VC is influenced by the input voltage, the output voltage, the load current, etc.), vsum reaches the value of VC, and the comparator 502 sends a PWM high signal to turn off the switching tube in the powermos505 again, and then turns on the shunt tube. The cycle thus forms a DCDC module switching control that automatically adapts to load current variations.

A functional block diagram of the enable and soft start control modules in a particular embodiment is shown in fig. 11. It includes an operational amplifier 601, an enable and logic controller 602, a switch S1 (603), a switch S2604, and an RC filter 605. When the enable signal EN is high and the selection signal SEL is low, i.e. the load is light, en1=1 and en2=0, only the first DCDC module 801 is operated and the second DCDC module 802 is not operated. Vs1=vc, point a voltage va=vc; the voltage at the point B is 0, and the switch S1 is selectively connected with the point B, namely vd=0; the voltage at point E is ve=vc, the voltage at point F is 0,G and the voltage at point 0, the switch S2 selects the connection G point, i.e. vs2=vh=0.

When the enable signal EN is high and the selection signal SEL also jumps high, i.e., the load is a heavy load, en1=1, en2=1; when the D point of the switch S1 selects the connection a point and the H point of the switch S2 selects the connection F point, vd=vc, vs2=vh=vf. Due to the filtering and delay effects of the RC filter 605, VF rises slowly, for example, after a period of time passes, for example, 1ms, VF rises to be equal to VD, that is, vh=vf=vd=va=vc, the enable and logic controller 602 sends a signal to enable the switch S2 to select the connection E point, that is, vs2=vh=ve=vc, and the soft start is completed; both the first DCDC module 801 and the second DCDC module 802 enter a normal operating state.

When EN is high and the selection signal SEL jumps from high to low, en1=1, en2=1 in the initial state, the D point of the switch S1 selects the connection B point, and the H point of the switch S2 selects the connection F point, vd=vb=0, vh=vf. Due to the filtering and delay action of RC filter 605, VF drops slowly, e.g., 1ms, after a period of time, VF drops to 0, i.e., vf=vd=vb=0. The enable and logic controller 602 then signals the H point of switch S2 to select the connection G point, i.e., vs2=vh=vg=0, while simultaneously causing en2=0, soft-off is complete. Only the first DCDC module 801 is then operated and the second DCDC module 802 is not operated.

Fig. 10 is a schematic block diagram of a current sampling judgment module in the embodiment. Which includes an operational amplifier 606, a controlled current source 607 and a comparator 608. The operational amplifier 606 outputs a control signal to control the controlled current source 607 according to the difference between VIN and ILoadsen, and the current of the controlled current source flows through the resistor Rsen and is filtered by RC to obtain Vsen, thereby obtaining a voltage Vsen proportional to the load current. When Vsen < Vref1, the chip is operating in a light load state, sel=0; when Vsen > Vref1, the chip is operating in a heavy state, sel=1. Vref1 is a voltage value associated with the load current first threshold value.

An internal block diagram of an OSC of a particular embodiment is shown in fig. 8. Including a base oscillator OSC0701, a D flip-flop 702, and two and gates. The oscillator OSC0701 continuously emits a pulse clock signal CLK0, and the two signals with opposite phases obtained by frequency division by the D flip-flop 702 are output from Q, QN, and then phase-separated with CLK0 to obtain the required CLK1 and CLK2, and the frequency of CLK1 and CLK2 is identical and the phase difference is 180 degrees because the same clock source is obtained by frequency division. Fig. 9 is a waveform diagram showing internal signals of the OSC module according to the preferred embodiment of the present invention.

As shown in fig. 2 and 6, when the system load is light, i.e., iload < Iref1, the circuit operates in a single-phase variable-voltage output mode, i.e., only one DCDC module operates. At this time, the first DCDC module 801 has normal switching operation to charge and discharge the inductor L1 to provide the output current to the output terminal, the point SW1 is switched between high and low, and the inductor L1 is charged and discharged. The second DCDC module 802 does not operate, the point SW2 is a high resistance point, the inductor L2 is not charged and discharged, and il2=0.

As shown in fig. 2 and 7, when the system is heavily loaded, i.e., iload > Iref1, the circuit operates in a dual phase variable output mode with a 180 degree phase difference between the two DCDC modules. At this time, the first DCDC module 801 and the second DCDC module 802 have normal switching actions to charge and discharge the respective inductors to provide the output current to the output terminal, the point SW1 is switched between high and low, the point L1 has charge and discharge, the point SW2 is switched between high and low, and the point L2 also has charge and discharge.

In an example of application of the two-phase auto-switching power conversion circuit shown in fig. 2, the two DCDC modules are integrated in the same integrated circuit. Furthermore, both DCDC modules and the control module 900 may be integrated in the same integrated circuit. That is, in the above embodiment, the two DCDC modules and the control module 900 are implemented on the same chip, and the two DCDC modules actually share many identical components, so as to further reduce the chip area.

In other embodiments of the power conversion circuitry for automatic switching of DCDC modules as shown in fig. 1 and 3, the DCDC conversion modules DCDC1, DCDC2 through dcdcdcn are independent integrated circuits. The DCDC conversion module may be any voltage converter commercially available. Of course, the multiple DCDC conversion modules DCDC1 and DCDC2 may be integrated into the same chip, so as to share devices and improve the consistency of circuit characteristics.

In other embodiments of a multiphase auto-switching power conversion circuit as shown in fig. 1, the current sampling and judging module 950 of the control module 900 may be a separate current detection and judging module or a sub-module integrated in an integrated circuit; the load detection pin of the current sampling judgment module 950 of the control module 900 may be integrated in the integrated circuit to directly detect the current, or may be connected to the outside of the integrated circuit to detect the current.

In other embodiments of a power conversion circuit for automatically switching DCDC modules as shown in fig. 1, the enabling and soft start control module 960 may be omitted and an additional MCU may be used to control the coordination of multiple DCDC modules. After the change, as shown in fig. 3, the current sampling judgment module 950 detects the load current, then sends a corresponding signal to the MCU, and the MCU controls each path of DCDC module to coordinate the operation of each path of DCDC module.

Even in some application embodiments as shown in fig. 16, since the system is always operating under a large load most of the time, the entire control module 900 may be omitted, and the enable input pins of each DCDC module may be connected to the system enable input or directly to the power input. At this time, the same VC and the same OSC are shared, so that the system can well work under the condition of heavy load, and high-efficiency, stable and high-reliability variable-voltage output is realized.

The invention relates to a direct current electric energy conversion method and system for automatically switching DCDC modules, which comprises N DCDC modules arranged in parallel, an output voltage detection feedback module and a clock signal module for providing working clock signals; the control module detects the current output to an external load, calculates the number of DCDC modules to be started to be Q according to the load current, and outputs the enabling and starting control signals of the Q DCDC modules; the duty clock signals CLKN of the Q DCDC modules have the same period, and each duty clock signal CLKN has a phase difference of 360 degrees divided by Q. The multiple DCDC modules are connected in parallel, so that larger current can be output, and the power consumption of the system is reduced; the multi-channel DCDC modules are all arranged on the same chip, and have good parameter consistency characteristics and good current balance characteristics of all channels; the time-sharing soft start and the phase-shifting time-sharing control avoid overshoot, reduce the ripple of the power supply output voltage and have more stable output characteristics.

The invention relates to a DCDC module automatic switching power supply conversion circuit system, which comprises: the power conversion modules DCDC1 and DCDC2 and … DCDCN for transforming and outputting the input voltage and the control module 900 for controlling each DCDC voltage conversion module are multiplexed. The control circuit submodule (900) outputs control signals to the DCDC1 and DCDC2 … DCDCN voltage conversion modules according to the detected load current ILoadsen, so that when a large load is applied, the two/multiple DCDC conversion modules DCDC1 and DCDC2 … DCN are used for carrying out voltage conversion considering the current balance of each path; when the load is small or zero, only one path of DCDC module is used for voltage conversion; the circuit has the advantages of balancing current of each circuit during heavy load, along with high voltage conversion efficiency, small system heating, small output ripple, high system reliability and low power consumption of the light load time-varying circuit, and is particularly suitable for the output voltage conversion control circuit of the battery. In addition, the negative electrode of the battery or the external power supply is a zero potential point of the circuit, and the potential values of other circuit nodes are relative to the zero potential point; the battery or external power supply voltage is the potential difference between its positive and negative electrodes. For ease of description, some modules are numbered in one, two, etc., and these serial numbers do not represent any positional or sequential limitations, but are for ease of description.

The foregoing description is only an embodiment of the present invention, and the circuit topology described above is only a specific embodiment of the present invention, and is not limited to the patent scope of the present invention, and all equivalent structures or equivalent flow changes made by the description of the invention and the content of the drawings, or direct or indirect application in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A direct current power conversion system for automatic switching of DCDC modules, comprising:

n DCDC modules (800) which are arranged in parallel and are used for converting the input direct-current voltage Vin into the output voltage Vout, wherein N is the number of the DCDC modules (800), and the value range of N is a natural number ranging from 1 to M; an output voltage detection feedback module (700) for detecting and feeding back the output voltage Vout;

the direct current power conversion system is characterized by further comprising a clock signal module (300) for simultaneously providing working clock signals CLKN for N DCDC modules (800); a control module (900) for enabling and turning on control of the N DCDC modules (800); n DCDC modules (800) respectively receive the working clock signals CLKN output by the clock signal module (300);

The control module (900) detects the current ILoadsen output to an external load, calculates the number of DCDC modules (800) to be started to be Q according to the detected load current ILoadsen, and outputs the enabling and starting control signals of the corresponding Q DCDC modules (800); namely, the control module (900) controls the on or off of the DCDC modules (800) with different numbers according to the load current ILoadsen; adapting the Q DCDC module (800) output current magnitudes to external load current requirements;

the periods of the working clock signals CLKN of the Q DCDC modules (800) output by the clock signal module (300) are the same, and the phase difference of each working clock signal CLKN is 360 degrees divided by Q;

the control module (900) comprises a current sampling judgment module (950) for sampling and calculating a load current ILoadsen and an enabling and starting control module (960) for enabling and starting control of each DCDC module (800);

the enabling and starting control module (960) outputs an enabling control signal for enabling each DCDC module (800) and a starting control signal for soft start and soft close control of each DCDC module (800) to each DCDC module (800); the enabling control signal is a high-low level signal; the starting control signal is a soft starting control signal;

The current sampling judgment module (950) obtains a load current signal from an external load; or the current sampling judgment module (950) obtains a load current signal from the DCDC module (800);

the enabling and starting control module (960) comprises a voltage follower (601), a single-pole double-throw switch (S1), a delay network (605), a single-pole three-throw switch (S2) and an enabling and soft-starting logic controller (602); the single-pole double-throw switch (S1) comprises an A end, a B end and a D end, and the single-pole three-throw switch (S2) comprises an E end, an F end, a G end and an H end; the number of the single-pole double-throw switch (S1), the delay network (605) and the single-pole three-throw switch (S2) is N-1 respectively;

the single-pole double-throw switch (S1) and the single-pole three-throw switch (S2) are controlled by the enabling and soft start logic controller (602);

the input signals of the enable and soft start logic controller (602) comprise an external enable signal EN and a DCDC module (800) selection signal SEL; the output signals of the enabling and soft start logic controller (602) comprise enabling and starting control signals output to each DCDC module;

the positive electrode input end of the amplifier of the voltage follower (601) is electrically connected with the output end of the output voltage detection feedback module (700) to obtain a feedback voltage signal; meanwhile, the positive electrode input end of the amplifier of the voltage follower (601) is electrically connected with the E end of the single-pole three-throw switch (S2), and the E end of the single-pole three-throw switch (S2) is used as an output terminal of a soft start control signal of the first DCDC module (801);

When the enable and external enable signal EN input by the soft start logic controller (602) is valid and the selection signal SEL is at a low level, the B end and the D end of the single-pole double-throw switch (S1) are electrically connected, and the G end and the H end of the single-pole triple-throw switch (S2) are electrically connected; the enabling and soft start logic controller (602) outputs enabling and starting control signals of the first DCDC module (801), and only one DCDC module of the first DCDC module (801) is in a working state;

when the enable and external enable signal EN input by the soft start logic controller (602) is valid and the selection signal SEL is at a high level, the A end and the D end of the single-pole double-throw switch (S1) are electrically connected, and the F end and the H end of the single-pole triple-throw switch (S2) are electrically connected; the enabling and soft start logic controller (602) outputs enabling and starting control signals of the first DCDC module (801) and the second DCDC module (802); the H end of the single-pole three-throw switch (S2) is used as an output terminal of soft start control signals of the other DCDC modules, and soft start control signals are output; when the voltages of the F end and the H end of the single-pole three-throw switch (S2) are equal to the voltage of the D end of the single-pole double-throw switch (S1), namely after the soft start of the second DCDC module (802) is finished, the H end and the E end of the single-pole three-throw switch (S2) are electrically connected; so that the output terminals of the soft start control signals of the first DCDC module (801) and the second DCDC module (802) both output stable voltage signals.

2. The direct current power conversion system automatically switched by a DCDC module according to claim 1, wherein:

an external inductor is connected between an SW pin of the DCDC module (800) and the ground, and the DCDC module (800) and the external inductor form a complete BUCK-BOOST converter, namely a BUCK-BOOST converter which is a non-isolated direct-current converter with output voltage which can be lower than or higher than input voltage, but the polarity of the output voltage is opposite to that of the input voltage.

3. The direct current power conversion system automatically switched by a DCDC module according to claim 2, wherein:

in an initial state of the direct current electric energy conversion system, only the first DCDC module (801) works; when the load current ILoadsen detected by the control module (900) is greater than or equal to a first load current threshold value, the control module (900) outputs an enabling control signal and an opening control signal to the second DCDC module (802) so as to enable the second DCDC module (802) to be opened; -said first DCDC module (801) and said second DCDC module (802) obtaining respective operating clock signals CLK1 and CLK2 from said clock signal module (300); the phase difference between the working clock signal CLK1 of the first DCDC module (801) and the working clock signal CLK2 of the second DCDC module (802) is 180 degrees;

When the load current detected by the control module (900) is smaller than a first load current threshold value, the control module (900) outputs an enabling control signal and an opening control signal to the second DCDC module (802) so that the second DCDC module (802) is closed.

4. The direct current power conversion system automatically switched by a DCDC module according to claim 3, wherein:

when the first DCDC module (801) and the second DCDC module (802) work, when the load current ILoadsen detected by the control module (900) is greater than or equal to a second load current threshold value, the control module (900) outputs an enabling control signal and an opening control signal to a third direct current power supply conversion module, so that the third direct current power supply conversion module is opened;

the first DCDC module (801), the second DCDC module (802) and the third dc power conversion module obtain respective operating clock signals CLK1, CLK2 and CLK3 from the clock signal module (300); the phase difference between the working clock signal CLK1 of the first DCDC module (801) and the working clock signal CLK2 of the second DCDC module (802) is 120 degrees; the phase difference between the working clock signal CLK2 of the second DCDC module (802) and the clock signal CLK3 obtained by the third DC power supply conversion module is 120 degrees;

When the load current ILoadsen detected by the control module (900) is smaller than the second load current threshold value, the control module (900) outputs an enabling control signal and an opening control signal to the third direct current power supply conversion module, so that the third direct current power supply conversion module is closed.

5. The direct current power conversion system automatically switched by a DCDC module according to claim 4, wherein:

when the first DCDC module (801) and the second DCDC module (802) work, when the load current ILoadsen detected by the control module (900) is greater than or equal to a third load current threshold value, the control module (900) outputs an enabling control signal and an opening control signal to the third direct current power supply conversion module and the fourth direct current power supply conversion module, so that the third direct current power supply conversion module and the fourth direct current power supply conversion module are opened;

the first DCDC module (801), the second DCDC module (802), the third dc power conversion module and the fourth dc power conversion module obtain respective working clock signals CLK1, CLK2, CLK3 and CLK4 from the clock signal module (300); the phase difference between the working clock signal CLK1 of the first DCDC module (801) and the working clock signal CLK2 of the second DCDC module (802) is 90 degrees;

The phase difference between the working clock signal CLK2 of the second DCDC module (802) and the working clock signal CLK3 of the third DC power conversion module is 90 degrees; the phase difference between the working clock signal CLK3 of the third DC power supply conversion module and the clock signal CLK4 obtained by the fourth DC power supply conversion module is 90 degrees; when the load current detected by the control module (900) is smaller than a third threshold value of the load current, the control module (900) outputs an enabling control signal and an opening control signal to the third direct current power supply conversion module and the fourth direct current power supply conversion module, so that the third direct current power supply conversion module and the fourth direct current power supply conversion module are closed.

6. The direct current power conversion system automatically switched by a DCDC module according to claim 1, wherein:

the current sampling judgment module (950) comprises a first operational amplifier (606) for comparing the load current sampling voltage with the input voltage, a current source (607) controlled by the output signal of the first operational amplifier (606) and a first comparator (608); the first comparator (608) is used for comparing and calculating reference voltage signals and outputting an enabling control signal to the enabling and starting control module (960);

An input voltage signal is input from the positive electrode of the first operational amplifier (606), and a load current sampling voltage signal is input from the negative electrode of the first operational amplifier (606); the output of the first operational amplifier (606) is used for controlling the current magnitude of the current source (607), the positive electrode of the current source (607) is electrically connected with the voltage input end, and the negative electrode of the current source (607) is grounded through a resistor; the negative electrode of the current source (607) is input to the positive electrode of the first comparator (608) after passing through a low-pass filter network, and the voltage of the negative electrode input signal of the first comparator (608) is a first reference current threshold value; the first comparator (608) outputs a DCDC module (800) selection signal SEL to the enable and start control module (960) for enabling and starting control of each DCDC module (800).

7. The direct current power conversion system automatically switched by a DCDC module according to claim 1, wherein:

the control module (900) includes a microcontroller MCU (MicroControllerUnit);

the control module (900) detects the load current output to the outside by the direct current electric energy conversion system, judges the detected load current through the micro controller MCU, calculates the number of DCDC modules (800) to be started, and outputs the enabling and starting control signals of the corresponding DCDC modules (800).

8. A DC-DC module automatic switching DC power conversion method,

the direct current power conversion system is characterized in that the direct current power conversion system is automatically switched based on the DCDC module according to any one of claims 1 to 7; the method comprises the following steps:

a: n DCDC modules (800) for converting the input direct-current voltage Vin into the output voltage Vout are arranged in a parallel mode, wherein N is the number of the DCDC modules (800), and the value range of N is a natural number ranging from 1 to M; an output voltage detection feedback module (700) for detecting and feeding back the output voltage Vout and a clock signal module (300) for simultaneously providing the N DCDC modules (800) with an operating clock signal CLKN;

b: the output voltage detection feedback module (700) samples the output voltage and compares the sampled output voltage with a set output voltage reference value Vref0, and outputs a peak current control signal VC to each DCDC module (800); the DCDC module (800) adjusts output peak current according to the peak current control signal VC so as to change output voltage Vout;

c: n DCDC modules (800) respectively receive the working clock signals CLKN output by the clock signal module (300);

d: setting control modules (900) for enabling and starting control of the N DCDC modules (800); the control module (900) detects the current ILoadsen output to an external load, calculates the number of DCDC modules (800) to be started to be Q according to the detected load current ILoadsen, and outputs the enabling and starting control signals of the corresponding Q DCDC modules (800); namely, the control module (900) controls the on or off of the DCDC modules (800) with different numbers according to the load current ILoadsen; adapting the Q DCDC module (800) output current magnitudes to external load current requirements;

E: the periods of the working clock signals CLKN of the Q DCDC modules (800) output by the clock signal module (300) are the same, and the phase difference of each working clock signal CLKN is 360 degrees divided by Q.