JP2007143260A - Multi-stage power supply circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption in a standby mode and accelerate transition from the standby mode to a normal operation mode in a multi-stage power supply circuit constructed by connecting power conversion circuits in multiple stages in series. <P>SOLUTION: The multi-stage power supply circuit includes: a rectifying circuit; a first power conversion circuit that subjects a voltage outputted from the rectifying circuit to power conversion by switching; a first control circuit that controls the operation of the first power conversion circuit; a second power conversion circuit that boosts a direct-current voltage outputted from the first power conversion circuit by switching operation; a second control circuit that controls the operation of the second power conversion circuit; and a starting circuit that generates a supply voltage for operating the first control circuit when a control signal is activated. The first power conversion circuit generates a supply voltage for operating at least the second control circuit in association with switching operation. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multistage power supply circuit configured by connecting a plurality of stages of power conversion circuits (converters or inverters) in series.

  In recent years, with the reduction in size and weight of electronic devices, power conversion circuits that perform boosting or the like by a switching operation are widely used as power supply circuits that are small and light and can efficiently extract power. Furthermore, in order to generate a high-voltage power supply, a multistage power supply circuit configured by connecting such power conversion circuits in series over a plurality of stages is also used.

  By the way, in a power supply circuit that operates by receiving an AC voltage, it is desired to improve the power factor and suppress harmonic noise by matching the waveforms and phases of the input voltage and input current. In recent years, the number of devices that have a standby mode has been increasing to save energy, reducing power consumption in the standby mode for the power supply circuit and speedily shifting from the standby mode to the normal operation mode. It is required to stand up.

  As a related technique, the following Patent Document 1 discloses a power supply apparatus in which an active filter (chopper type converter) and a main converter unit (DC-DC converter) for improving the power factor of the power supply apparatus are connected in series. Further, it is disclosed to protect the start circuit of the active filter from being damaged even when the main converter unit is stopped. This active filter is provided between a control circuit for supplying a drive signal to the switching element of the active filter, a transformer winding provided in the main converter section, and a power supply terminal of the control circuit, and is controlled during operation. An auxiliary power supply circuit that supplies driving power to the circuit, an activation circuit that is provided between the input side or output side of the active filter and the power supply terminal of the control circuit, and supplies driving power to the control circuit at the start of operation; And a protection switch circuit for stopping the supply of drive power from the starter circuit to the control circuit when a control signal for stopping the operation of the main converter unit is received.

  Further, in Patent Document 2 below, in a power supply device in which an active filter and a DC-DC converter are connected in series, the active filter and the DC-DC converter can be sequentially activated with a single activation circuit. It is disclosed to reliably prevent a hunting operation when the voltage gradually decreases. This power supply apparatus includes a boost choke coil, an inverter element, an active filter for power factor improvement provided with an active filter control circuit, a DC-DC converter provided with an insulation transformer, an inverter element, and a converter control circuit, and an active filter control circuit. Are connected to a power supply line that supplies operating power to the converter control circuit, and a diode that cuts off the power supply from the active filter control circuit connection point side to the converter control circuit connection point side. A startup circuit that starts by supplying a startup voltage, and an active filter control circuit that starts by supplying the converter control circuit with power rectified from the output of the auxiliary winding of the boost choke coil after the active filter is started, and through the diode To continue operation A first rectifier circuit, and a second rectifier circuit that continuously supplies the converter control circuit with the electric power obtained by rectifying the output of the auxiliary winding of the insulation transformer after the DC-DC converter is activated, The DC-DC converter is sequentially activated.

However, Patent Document 1 and Patent Document 2 specifically describe maintaining the power supply device in a standby state and speeding up the transition from the state where the operation of the DC-DC converter is stopped to the normal operation state. Not.
Japanese Patent Laid-Open No. 10-28372 (page 1-2, FIG. 1) JP 2004-320912 A (page 1-2, FIG. 1)

  Accordingly, in view of the above points, the present invention reduces power consumption in the standby mode and changes from the standby mode to the normal operation mode in a multi-stage power supply circuit configured by connecting a plurality of stages of power conversion circuits in series. The purpose is to speed up the transition to.

  In order to solve the above problems, a multistage power supply circuit according to one aspect of the present invention is a multistage power supply circuit configured by connecting a plurality of stages of power conversion circuits in series, and an input AC voltage A first rectifying circuit that converts a voltage output from the rectifying circuit into a rectangular wave voltage by switching through an inductance element, and converts the obtained rectangular wave voltage into a DC voltage again A first control circuit that controls the switching operation of the first power conversion circuit, and a DC voltage output from the first power conversion circuit that is boosted or lowered by the switching operation, or converted into an AC voltage. 2, the second control circuit that controls the switching operation of the second power conversion circuit, and the voltage output from the rectifier circuit And an activation circuit for generating a power supply voltage for operating the first control circuit when the control signal is activated, and the first power conversion circuit is at least associated with the switching operation. A power supply voltage for operating the second control circuit is generated.

  According to the present invention, a start-up circuit for generating a power supply voltage for operating the first control circuit when the control signal is activated is provided, and the first power conversion circuit is associated with the switching operation. By generating a power supply voltage for operating at least the second control circuit, it is possible to reduce power consumption in the standby mode and speed up the transition from the standby mode to the normal operation mode. .

The best mode for carrying out the present invention will be described below in detail with reference to the drawings. The same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.
FIG. 1 is a block diagram showing a configuration of a multistage power supply circuit according to the first embodiment of the present invention. This multi-stage power supply circuit has a multi-stage power conversion circuit (converter or inverter) that performs a switching operation using a transistor as a switching element.

  The power conversion circuit 10 in the previous stage is a power conversion circuit that converts an AC voltage into a DC voltage. For example, a rectifier circuit 11 that rectifies an input AC voltage, and a voltage output from the rectifier circuit 11 via an inductance element. When the obtained rectangular wave voltage is converted back to a DC voltage, the power factor controller (power factor controller: PFC) improves the power factor by matching the waveform and phase of the voltage and current. (Rate improvement control) circuit 12 and an auxiliary output voltage generation circuit 13 for generating an auxiliary output voltage. As an input voltage, 100V or 200V is generally used in Japan, and 115V or 230V is used overseas.

  The power conversion circuit 20 in the subsequent stage is a power conversion circuit that boosts or decreases the DC voltage output from the power conversion circuit 10 in the previous stage or converts the DC voltage into an AC voltage by a switching operation, and is a DC / DC converter. A DC / AC inverter may be used. Examples of the DC / AC inverter include an inverter for a motor (compressor) and a high-frequency lighting inverter for a fluorescent lamp. The subsequent power conversion circuit 20 includes an auxiliary output voltage generation circuit 21 that generates an auxiliary output voltage.

Further, the multistage power supply circuit controls the switching operation in the local power supply generation circuit (starting circuit) 30 that generates the local power supply voltage _VLC based on the voltage output from the rectifier circuit 11 and the power conversion circuit 10 in the previous stage. It has the front | former stage control circuit 40, the back | latter stage control circuit 50 which controls the switching operation in the power converter circuit 20 of a back | latter stage, resistance R1, and the diodes D1-D5.

The local power supply generation circuit 30 determines whether the local power supply voltage V _{LC is in} accordance with whether a control signal (external on signal) supplied from the outside in order to indicate one of the standby mode and the normal operation mode is activated. Switch the voltage value of. That is, the local power supply generation circuit 30 outputs the local power supply voltage V _LC having the first voltage value when the control signal is activated, and the first voltage value when the control signal is not activated. The local power supply voltage V _LC having the second voltage value having an absolute value smaller than that is output. In the following, the case where the first and second voltage values are positive values will be described.

The local power supply voltage _VLC output from the local power supply generation circuit 30 is supplied to the pre-stage control circuit 40 via the resistor R1. The pre-stage control circuit 40 does not start even when the local power supply voltage V _LC having the second voltage value is supplied, but starts when the local power supply voltage V _LC having the first voltage value is supplied. Control of the switching operation in the power conversion circuit 10 is started.

  Further, when the power conversion circuit 10 in the previous stage starts a switching operation, the auxiliary output voltage generation circuit 13 outputs an AC voltage along with the switching operation. The AC voltage output from the auxiliary output voltage generation circuit 13 is rectified by the diode D1, and the obtained rectified voltage is supplied to the post-stage control circuit 50 via the diode D5. The post-stage control circuit 50 starts when the rectified voltage is supplied, and starts control of the switching operation in the post-stage power conversion circuit 20. If the rectified voltage by the diode D1 is supplied to the pre-stage control circuit 40 via the diode D3, the start-up of the pre-stage control circuit 40 can be stabilized.

  When the subsequent power conversion circuit 20 starts a switching operation, the auxiliary output voltage generation circuit 21 outputs an alternating voltage along with the switching operation. The AC voltage output from the auxiliary output voltage generation circuit 21 is rectified by the diode D2, and the obtained rectified voltage is supplied to the pre-stage control circuit 40 and the post-stage control circuit 50 via the diodes D3 and D5, respectively. Thereby, starting of the front | former stage control circuit 40 and the back | latter stage control circuit 50 can be stabilized further.

Therefore, even when an AC input is input to the power conversion circuit 10 in the previous stage, when the power supply control signal is not activated in the standby mode, the local power supply voltage V _LC having the second voltage value is supplied to the previous control circuit 40. Thus, the pre-stage control circuit 40 does not start. Thereby, current consumption can be reduced in the standby mode. However, since an AC input is input to the power conversion circuit 10 at the preceding stage, a DC voltage is generated at the output of the PFC circuit 12, and this DC voltage is applied to the power conversion circuit 20 at the subsequent stage.

Thereafter, when the control signal is activated in the normal operation mode, the local power supply voltage V _LC having the first voltage value is supplied to the front-stage control circuit 40, the front-stage control circuit 40 is started, and the previous-stage power conversion circuit 10 starts the switching operation. Here, since a DC voltage has already been generated at the output of the PFC circuit 12, the power conversion circuit 10 in the previous stage can start a power conversion operation quickly. In addition, since a DC voltage has already been applied to the subsequent power conversion circuit 20, the subsequent power conversion circuit 20 can quickly start the power conversion operation.

FIG. 2 is a diagram illustrating the configuration of the power conversion circuit and local power generation circuit in the previous stage shown in FIG. As shown in FIG. 2, in the power conversion circuit 10 in the previous stage, the rectifier circuit 11 is configured by a diode bridge. The PFC circuit 12 includes an inductance element 14 that stores magnetic energy generated by a current flowing through the winding, a switching element Q10 that switches the voltage supplied from the rectifier circuit 11 via the inductance element 14, and a pre-stage control circuit 40. The driver 15 that drives the switching element Q10 based on the drive signal V _C1 supplied from (FIG. 1), the diode D10 that rectifies the rectangular wave voltage generated by the switching operation, and the voltage rectified by the diode D10 is smoothed And a capacitor C10 for generating a DC voltage. Here, by using the primary side winding of the transformer as the inductance element 14, the secondary side winding of the transformer can be used as the auxiliary output voltage generation circuit 13 shown in FIG.

In the local power supply generation circuit 30, the voltage output from the rectifier circuit 11 is supplied to the collector of the NPN transistor Q30 via the resistor R30 and the diode D30. The cathode voltage of the diode D30 is applied to one end of the Zener diodes Z30 and Z31 connected in series and the base of the transistor Q30 via the resistor R31. Since the other ends of the Zener diodes Z30 and Z31 are grounded, the base voltage of the transistor Q30 is equal to the voltage across the Zener diodes Z30 and Z31. Based on this base voltage, the local power supply voltage _VLC is output from the emitter of the transistor Q30. When the PFC circuit 12 starts the switching operation, the diode D1 rectifies the AC voltage output from the auxiliary output voltage generation circuit 13, so that the rectified voltage of the diode D1 becomes the local power supply voltage V via the diode D4. _{Applied to} the output terminal of the _LC .

On the other hand, a control signal supplied from the outside is applied to the base of the PNP transistor Q32 via a resistor R33. The local power supply voltage _VLC is supplied to the emitter of the transistor Q32 via the resistor R32, and the transistor Q32 operates as an emitter follower. The emitter voltage of transistor Q32 is applied to the base of NPN transistor Q31. The collector of the transistor Q31 is connected to a connection point between the Zener diode Z30 and the Zener diode Z31, and the emitter of the transistor Q31 is connected to one end of the Zener diode Z32. The other end of the Zener diode Z32 is grounded.

When the negative logic control signal is activated to the low level, the emitter voltage of the transistor Q32 decreases, so that the transistor Q31 is turned off. Accordingly, the base voltage of the transistor Q30 becomes a value determined by the sum of the Zener voltage of the Zener diode Z30 and the Zener voltage of the Zener diode Z31, and the local power supply voltage V _LC output from the emitter of the transistor Q30 is the first voltage _{VLC. 1} (for example, 15V).

On the other hand, when the control signal is inactivated to high level or open, the emitter voltage of the transistor Q32 rises, so that the transistor Q31 is turned on. Here, assuming that the Zener voltage of the Zener diode Z32 is smaller than the Zener voltage of the Zener diode Z31, the base voltage of the transistor Q30 is a value determined by the sum of the Zener voltage of the Zener diode Z30 and the Zener voltage of the Zener diode Z32. The local power supply voltage V _LC output from the emitter of the transistor Q30 is a second voltage V ₂ (for example, 7 V) lower than the first voltage V ₁ .

Here, the operation of the pre-stage control circuit 40 shown in FIG. 1 will be described with reference to FIG. FIG. 3 is a diagram showing the relationship between the local power supply voltage _VLC and the high level value of the drive signal V _C1 output from the previous control circuit.

When the local power supply voltage V _LC supplied to the pre-stage control circuit 40 shown in FIG. 1 rises from 0 V and becomes larger than a certain voltage value V _A , the pre-stage control circuit 40 starts normal operation, and the drive signal V The high level value of _C1 increases. Therefore, in the present embodiment, the first voltage V ₁ as the local power supply voltage V _LC in the normal operation mode is set to be at least larger than the voltage value V _A described above. Furthermore, when the front control circuit 40 is present coverage by the manufacturer for the local power supply voltage V _LC to work properly, the first voltage V _1, it is desirable to within the coverage.

On the other hand, is lowered from the local power supply voltage V _LC is high voltage, it becomes less than a certain voltage value V _B, front control circuit 40 shown in FIG. 1 is not operating normally. In general, since the relationship between the local power supply voltage V _LC and the high level value of the drive signal V _C 1 has a hysteresis characteristic, a relationship of V _B <V _A exists. Therefore, in the present embodiment, the second voltage V ₂ as the local power supply voltage V _LC in the standby mode is set to be smaller than the voltage value V _A , and preferably, in order to speed up and stabilize the startup, It is set larger than the voltage value V _B and smaller than the voltage value V _A.

FIG. 4 is a diagram showing a configuration of the power conversion circuit at the subsequent stage shown in FIG. Here, a case where a DC / DC converter is used as the power conversion circuit in the subsequent stage will be described. As shown in FIG. 4, the power conversion circuit 20 at the subsequent stage includes a transformer 22 that boosts or steps down a primary-side rectangular wave voltage generated by switching and outputs the voltage to the secondary side, and a primary winding of the transformer. A switching element Q20 that is connected in series and conducts a switching operation to pass a current through the primary winding of the transformer, and a switching element Q20 based on a drive signal V _C2 supplied from the post-stage control circuit 50 (FIG. 1). Includes a driver 23 for driving the inverter, a diode D20 for half-wave rectifying the AC voltage generated in the secondary winding of the transformer 22, and a capacitor C20 for generating a DC voltage by smoothing the voltage rectified by the diode D20. It is out. Here, by providing an auxiliary winding in the transformer 22, the auxiliary winding of the transformer 22 can be used as the auxiliary output voltage generation circuit 21 shown in FIG.

  Next, the operation of the multistage power supply circuit according to this embodiment will be described with reference to FIGS. FIG. 5 is a timing chart for explaining the operation of the multistage power supply circuit shown in FIG.

As shown in FIG. 5, at time t _0, when the AC input to the multi-stage power source circuit is turned on, the DC voltage V _PFC output from the PFC circuit 12 of the preceding stage of the power converter circuit 10 is increased. Although stand up local power supply voltage V _LC that is output from the local power generation circuit 30, is still the standby mode, the control signal is deactivated to a high level, the local power supply voltage V _LC is first It is pressed a second voltage _{V 2} is lower than the voltage _{V 1.} Therefore, since the pre-stage control circuit 40 does not operate, the PFC circuit 12 does not perform a boosting operation, and the output voltage V _PFC of the PFC circuit 12 becomes substantially equal to the output voltage of the rectifier circuit 11. Further, the subsequent power conversion circuit (DC / DC converter) 20 does not operate, and the DC output voltage of the subsequent power conversion circuit 20 remains 0V.

At time t ₁ , when the control signal is activated to a low level due to the system shifting from the standby mode to the normal operation mode, the local power supply voltage V _LC output from the local power generation circuit 30 is the second voltage. changes from V ₂ to the first voltage _{V 1.} As a result, the pre-stage control circuit 40 starts operating, and the high level value of the drive signal V _C1 rises. As a result, since the PFC circuit 12 starts the boosting operation, the output voltage V _PFC of the PFC circuit 12 further increases, and the auxiliary output voltage generation circuit 13 starts operating to generate the auxiliary output voltage. The auxiliary output voltage is rectified by the diode D1 and supplied to the pre-stage control circuit 40 and the post-stage control circuit 50 via the diodes D3 and D5, respectively.

As the auxiliary output voltage rises, the post-stage control circuit 50 starts to operate, and the high level value of the drive signal V _C2 rises. As a result, the subsequent power conversion circuit 20 starts operating, and the DC output voltage rises. Thus, according to the present embodiment, when the system shifts from the standby mode to the normal operation mode and the control signal is activated to a low level, the output voltage of the multistage power supply circuit can be quickly raised. .

  Next, a multistage power supply circuit according to a second embodiment of the present invention will be described. FIG. 6 is a block diagram showing a configuration of a multistage power supply circuit according to the second embodiment of the present invention. The multi-stage power supply circuit according to the second embodiment generates a control signal in the multi-stage power supply circuit instead of supplying a control signal indicating one of the standby mode and the normal operation mode from the outside. Yes. Other points are the same as those of the first embodiment shown in FIG.

  As shown in FIG. 6, the multistage power supply circuit further includes a control signal generation circuit 60. The control signal generation circuit 60 includes a delay circuit 61 that delays the voltage output from the rectifier circuit 11 and an inversion circuit 62 that generates a control signal by inverting the delay signal output from the delay circuit 61. . The delay circuit 61 is configured by, for example, a resistor and a capacitor, and the inverting circuit 62 is configured by, for example, an NPN transistor or an inverter.

  2, when AC input is input to the multistage power supply circuit, an inrush current flows from the rectifier circuit 11 to the capacitor C10 via the inductance element 14 and the diode D10, and the capacitor C10 is pre-charged. Charged. At this time, when the switching element Q10 is turned on, an inrush current flows through the switching element Q10 in addition to the capacitor C10, so that a very large inrush current flows as a whole.

Therefore, in the present embodiment, a delay signal for delaying the operation of the pre-stage control circuit 40 is provided so that the inrush current flows through the switching element Q10 at an interval after the inrush current flows through the capacitor C10. 61. In this embodiment, since this delay signal is positive logic and the control signal is negative logic, an inversion circuit 62 is provided to invert the delay signal to generate the control signal. Therefore, when the delay signal and the control signal have the same logic, it is not necessary to provide the inverting circuit 62.
Note that the operation of the post-stage control circuit 50 can be shifted in time with respect to the operation of the pre-stage control circuit 40 by the control signal generation circuit 60.

  The present invention can be used in a multi-stage power supply circuit configured by connecting a plurality of stages of power conversion circuits in series.

1 is a block diagram showing a configuration of a multistage power supply circuit according to a first embodiment of the present invention. It is a figure which shows the structure of the power converter circuit and local power generation circuit of the front | former stage shown in FIG. It is a view showing the relationship between the high level value of the driving signal V _{C 1} output from the local power supply voltage V _LC and pre-stage control circuit. It is a figure which shows the structure of the power converter circuit of the back | latter stage shown in FIG. 2 is a timing chart for explaining the operation of the multistage power supply circuit shown in FIG. 1. It is a block diagram which shows the structure of the multistage power supply circuit which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Power conversion circuit of the front stage 11 Rectifier circuit 12 PFC circuit 13, 21 Auxiliary output voltage generation circuit 14 Inductance element 15, 23 Driver 22 Transformer 30 Local power generation circuit 40 Pre-stage control circuit 50 Post-stage control circuit 60 Control signal generation circuit 61 Delay circuit 62 Inversion circuit R1, R30 to R33 Resistor D1 to D5, D10, D20 Diode Z30 to Z32 Zener diode C10, C20 Capacitor Q10, Q20 Switching element Q30 to Q32 Transistor

Claims (5)

A multi-stage power supply circuit configured by connecting a power conversion circuit of a plurality of stages to a series,
A rectifier circuit for rectifying the input AC voltage;
A first power conversion circuit that converts the voltage output from the rectifier circuit into a rectangular wave voltage by switching through an inductance element, and converts the obtained rectangular wave voltage into a DC voltage again;
A first control circuit for controlling a switching operation of the first power conversion circuit;
A second power conversion circuit that boosts or lowers a DC voltage output from the first power conversion circuit by a switching operation, or converts the DC voltage into an AC voltage;
A second control circuit for controlling a switching operation of the second power conversion circuit;
A startup circuit that generates a power supply voltage for operating the first control circuit when a control signal is activated using a voltage output from the rectifier circuit;
A multi-stage power supply circuit, wherein the first power conversion circuit generates a power supply voltage for operating at least the second control circuit in accordance with a switching operation.   The first power conversion circuit generates a power supply voltage for operating the first and second control circuits in association with the switching operation, and the second power conversion circuit is in association with the switching operation. The multi-stage power supply circuit according to claim 1, wherein a power supply voltage for operating the first and second control circuits is generated.   The multi-stage power supply circuit according to claim 1 or 2, wherein the control signal supplied to the activation circuit is a signal supplied from the outside in order to indicate one of a standby mode and a normal operation mode.   The multistage power supply circuit according to claim 1, further comprising a control signal generation circuit that generates a control signal supplied to the starter circuit by delaying a voltage output from the rectifier circuit. The starter circuit uses the voltage output from the rectifier circuit to generate a first power supply voltage when the control signal is activated, and the first power supply when the control signal is not activated. The multistage power supply circuit according to any one of claims 1 to 4, wherein a second power supply voltage having an absolute value smaller than the voltage is generated.

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