CN102916571B - Power supply capable of suppressing low-frequency noises - Google Patents
Power supply capable of suppressing low-frequency noises Download PDFInfo
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- CN102916571B CN102916571B CN201210378109.XA CN201210378109A CN102916571B CN 102916571 B CN102916571 B CN 102916571B CN 201210378109 A CN201210378109 A CN 201210378109A CN 102916571 B CN102916571 B CN 102916571B
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Abstract
The invention discloses a power supply capable of suppressing low-frequency noises. The power supply comprises an input filter circuit and a voltage-stabilizing sampling circuit, and is characterized in that the input filter circuit comprises an inductor L1, a resistor R1, a capacitor C1 and a resistor R2, wherein the inductor L1 and the capacitor C1 form a first-stage differential mode filter circuit, the resistor R1 is connected with the inductor L1, and the resistor R2 is connected with the capacitor C2 in series; the voltage-stabilizing sampling circuit comprises a sampling resistor R3, an operational amplifier N1, a compensation loop, a resistor R4 and a capacitor C3, wherein the resistor R4 and the capacitor C3 are in parallel to two ends of the sampling resistor R3 after being connected in parallel, voltage output from a rectifying filter circuit is connected to a reverse input end of the operational amplifier N1 through the sampling resistor R3, and a forward input end of the operational amplifier is connected with reference voltage, while the reverse input end of the operational amplifier is connected with an output end of the operational amplifier through the compensation loop. On the basis of maintaining a power topology structure, reducing complexity degree of circuits and lowering power consumption, suppression capacity of the power supply to low-frequency ripples is improved.
Description
Technical field
The present invention relates to a kind of power supply.
Background technology
Miniaturized microwave receiving electromechanical source is a part for receiver, realizes the voltage isolated variable of primary power source and secondary power supply and stable output.Different from most of electronic equipment, the receiver circuit particularly AC noise (ripple) of local oscillation circuit to supply power voltage is wherein very responsive, and can the amplitude of its AC noise directly determine receiver and possess ultralow clutter modulating performance.
Related data and in the past R&D experience show, after supply power voltage noise amplitude is more than 10mV, the clutter suppression capability of local oscillation circuit just starts to worsen, and+12V output noise the peak-to-peak value of domestic and international conventional DC/DC converter is general all between 30 ~ 75mV.Although at the energization input series connection L-C filter of local oscillation circuit, the noise (100 ~ 500kHz) of the further decaying power supplies switching frequency of energy, then quite limited to the effect of low-frequency noise (< 10kHz).
Usually the low-frequency ripple of electric power output voltage to be reduced mainly by strengthening L-C filtering, adopting the three kinds of measures of current-control type circuit, output series connection linear voltage regulator.
Strengthen the low frequency filtering effect of L-C filter, need the size strengthening inductance, electric capacity, this will cause power volume to become large.
Adopt current-control type circuit to need to design special current sampling circuit, slope compensation circuit etc., circuit relative complex, and actual effect is also by the impact of the factor such as power supply duty ratio and watt level.In addition, according to related data introduction, current-control type control circuit is not suitable for adopting on half bridge circuit.
Series connection linear voltage regulator can improve the rejection ability of low-frequency ripple, but is not enough to solve completely receiver and makes an uproar mutually the problem worsened, and its input-output pressure reduction can produce larger power consumption, can not adopt on all output voltages.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of power supply, not changing power supply topologies, reducing complexity in circuits, reducing on the basis of power consumption, improves the rejection ability of power supply low-frequency ripple.
The present invention includes following technical scheme:
A power supply for low-frequency noise can be suppressed, comprise input filter circuit, half-bridge converter, pulse-width modulation circuit, power transformer, current rectifying and wave filtering circuit and voltage stabilizing sample circuit; It is characterized in that, input filter circuit comprises inductance L 1, resistance R1, electric capacity C1, resistance R2; Wherein inductance L 1, electric capacity C1 form first order differential mode filter circuit, and resistance R1 is in parallel with resistance L1, and resistance R2 connects with electric capacity C1; Voltage stabilizing sample circuit comprises sampling resistor R3, operational amplifier N1, compensation loop, resistance R4 and electric capacity C3; After resistance R4 connects with electric capacity C3, be connected in parallel on sampling resistor R3 two ends; The voltage that current rectifying and wave filtering circuit exports is connected with the reverse input end of operational amplifier N1 by sampling resistor R3, and the positive input of operational amplifier is connected with reference voltage; Meanwhile, the reverse input end of operational amplifier N1 is connected with the output of operational amplifier by compensation loop.
Described input filter circuit also comprises inductance L 2 and electric capacity C2, and inductance L 2 and electric capacity C2 form second level differential mode filter circuit.
Described power supply is microwave receiving electromechanical source.
The present invention compared with prior art tool has the following advantages:
The present invention, on the basis of existing power source design, finds can improve the rejection ability of power supply low-frequency ripple by the gain of reduction input filter circuit resonance point, the feedback speed of raising voltage stabilizing sampled signal by great many of experiments.The present invention, by input filter circuit damping network in parallel, reduces the gain of resonance point, the input exchange signal near reduction resonance frequency or the amplification degree of noise; The present invention is R-C network in parallel on voltage stabilizing sample circuit, optimizes loop compensation circuit, improves the feedback speed of voltage stabilizing sampled signal.In a word, the present invention is not changing power supply topologies, is reducing complexity in circuits, is reducing on the basis of power consumption, and by reducing the gain of input filter circuit resonance point, the feedback speed of raising voltage stabilizing sampled signal improves the rejection ability of power supply low-frequency ripple.
Accompanying drawing explanation
Fig. 1 is power principle block diagram;
Fig. 2 is existing input filter circuit schematic diagram;
Fig. 3 is input filter circuit schematic diagram of the present invention;
Fig. 4 is existing voltage stabilizing sample circuit schematic diagram;
Fig. 5 is voltage stabilizing sample circuit schematic diagram of the present invention;
Fig. 6 is existing input filter circuit filtering characteristic simulation result schematic diagram;
Fig. 7 is input filter circuit filtering characteristic simulation result schematic diagram of the present invention.
Embodiment
Just by reference to the accompanying drawings the present invention is described further below.
For the power supply of microwave receiver, the present invention will be described below
As shown in Figure 1, microwave receiving electromechanical source comprises the functional module compositions such as input filter circuit, start-up circuit, protective circuit, half-bridge converter, power transformer, PWM pulse-width modulation circuit, voltage stabilizing sample circuit, output rectifier and filter.
At the input inline fuse of power supply, make power supply no matter any fault occur, all can not cause damage to satellite power supply because of the reason such as short circuit, overcurrent.
When power supply receives start-up command, start-up circuit works, produce+12V a voltage to power to pulse width modulator PWM, the square-wave signal producing 300kHz after PWM starts drives half-bridge converter, make it direct voltage be converted to the ac square-wave voltage of 300kHz and be delivered to current rectifying and wave filtering circuit by power transformer, through current rectifying and wave filtering circuit output multi-channel direct voltage.Wherein a road voltage returns alternative start-up circuit and powers to PWM, and provides voltage stabilizing sampled signal by voltage stabilizing sample circuit to PWM.PWM is by the duty ratio of the inner automatic regulation output drive singal of degeneration factor, thus adjustment output voltage, reach the object of voltage stabilizing.
The pulse duration of start-up command is 100mS, and after it terminates, start-up circuit quits work.
When overcurrent, short circuit, the abnormal lower degradation situation of input voltage appear in power supply, power overcurrent protection circuit sends guard signal to PWM, and PWM stops output drive signal, and power supply quits work, and reaches the object of protection shutdown.After power supply receives shutdown command, signal is input to protective circuit, power supply shuts down.
Because start-up command and the instruction loop line of shutdown command and the loop line of power input voltage are isolated, so switching on and shutting down instruction all needs to carry out isolation transmission by light lotus root.
Input filter circuit comprises differential mode filter, differential mode filter comprises two aspect effects, first, it stops switching power supply noise to affect other equipment of satellite by bus, secondly stops alternating current voltage component and noise on bus directly to affect the normal work of mains-powered apparatus (as microwave receiver).Input voltage is connected with half-bridge converter by input filter circuit.
Existing input filter circuit mainly pursues alap cut-off frequency and noise attentuation high as far as possible.Its circuit diagram and simulation result are as shown in Figure 2 and Figure 6.Its resonance point gain reaches 22.4dB/4.6kHZ.This gain is amplified making the low-frequency transduction noise of bus input at this frequency place, and being reflected to power output end is exactly that the low-frequency noise of output voltage is exaggerated, so need under the prerequisite meeting filter overall performance, reduces as far as possible.
As shown in Figure 3, input filter circuit of the present invention comprises inductance L 1, resistance R1, electric capacity C1, resistance R2, inductance L 2 and electric capacity C2; Wherein inductance L 1, electric capacity C1 form first order differential mode filter circuit, inductance L 2, electric capacity C2 composition second level differential mode filter circuit; The positive input terminal of input voltage is connected with one end of inductance L 1, and the other end of inductance L 1 is connected with inductance L 2 with resistance R2; Resistance R1 is in parallel with inductance L 1, and resistance R2 connects with electric capacity C1; Inductance L 2 is connected with electric capacity C2; Electric capacity C1, C2 are connected with the negative input end of input voltage respectively.Late-class circuit in Fig. 3 is the circuit be connected with input filter circuit, corresponding to the half-bridge converter in Fig. 1.The input filter circuit of power supply of the present invention arranges antihunt circuit at first order differential mode filter, and namely the upper series resistance R2 of parallel resistance R1, C1 on L1, makes the gain reduction at filter cutoff frequency place.
In actual design, the resistance R1 Standard resistance range of L1 two ends parallel connection is generally between 1 ~ 10 Ω, and the resistance R2 scope of connecting with C1 is generally between 0.1 ~ 3 Ω.According to requirements such as power supply EMC index, switching frequency, volume weights, more further emulate, debug.In general, R1 is larger, R2 is less, and circuit characteristic is closer to conventional filter, and namely attenuation characteristic is more close to 80dB/10 octave, and resonance peak is larger.Otherwise circuit characteristic is closer to 40dB/10 octave, and resonance peak is less.
In side circuit, the value of two resistance is respectively 3 Ω and 0.33 Ω (3 1 Ω are in parallel).Its simulation result as shown in Figure 7.As can be seen from Figure 7, the gain of this power supply resonance point is reduced to 7.1dB by 22.4dB, substantially reduces the amplification degree of this frequency place input noise.Although the attenuation characteristic of high band slightly declines (slope of curve decreases), to the normal use of receiver enough, filter overall performance be improved significantly.
Existing power supply input filter design wishes that the equivalent series resistance (i.e. ESR) of electric capacity is the smaller the better, but the C1 in input filter of the present invention is because will connect outer meeting resistance, so to ESR without particular/special requirement, the electrochemical capacitor that low price, capacity density are large can be selected.But in the present invention, because satellite is to the highly reliable requirement of product, so what adopt is the Leaded Ceramic Disc Capacitor of highly reliable grade.
As shown in Figure 4, existing voltage stabilizing sample circuit comprises sampling resistor R3, operational amplifier N1 and compensation loop.Usually by debugging compensation loop parameter, suitable phase margin and low-frequency gain is realized.Low-frequency gain is 46.8dB/100Hz, 26.8dB/1kHz, and phase margin is now less, is 30.67 °; If continue to improve gain, power supply likely enters oscillatory regime under external interference.
As shown in Figure 5, voltage stabilizing sample circuit of the present invention, except comprising sampling resistor R3, operational amplifier N1 and compensation loop, also comprises resistance R4 and the electric capacity C3 of series connection.The R-C network of resistance R4, electric capacity C3 composition is connected in parallel on sampling resistor R3 two ends.The voltage that current rectifying and wave filtering circuit exports is connected with the negative input end of operational amplifier N1 by sampling resistor R3, and the positive input terminal of operational amplifier is connected with reference voltage.Meanwhile, the negative input end of operational amplifier is connected with the output of operational amplifier by compensation loop.Adopt said structure, any fluctuation of output voltage can be reflected to the reverse input end of operational amplifier faster, and its response speed is accelerated.Meanwhile, exchange input impedance and reduce, the gain of error amplifier is improved, and power supply strengthens the rejection ability of low-frequency disturbance.Improve the phase margin of power supply simultaneously, improve stability.
In R-C network, the span of resistance R4 is 100 ~ 1000 Ω, and the span of electric capacity C3 is 4000pF ~ 0.03uF.Power supply after improvement, the gain at 100Hz place is increased to 55.3dB by 46.8dB, and the gain at 1kHz place is increased to 38.7dB by 26.8dB, to the rejection ability of low-frequency disturbance be improved significantly.And phase margin is increased to 41.02 ° by 30.67 °, the stability of power supply is also improved.
The present invention by forming antihunt circuit on input filter circuit, R-C network in parallel on the sampling resistor of voltage stabilizing sample circuit, power supply to the rejection ability of low-frequency disturbance be improved significantly, the clutter suppression capability of receiver local oscillator is close to the best level under theoretical case.There is certain intrinsic noise during debugging actual in power supply, oscilloscope is difficult to the low-frequency ripple effectively differentiating below 10mV, is all verified by the clutter recognition of test receiver local oscillator chain so reality improves effect.Actual test result is in table 1.
The clutter suppression capability of receiver local oscillator surveyed by table 1
As can be seen from Table 1, after improvement, clutter modulation in local oscillation circuit 100Hz place brings up to 63dBc/Hz by 47dBc/Hz, and 1kHz place clutter recognition brings up to 86.7dBc/Hz by 70dBc/Hz, and improvement effect is remarkable.
Some other microwave equipment also proposes high requirement to the low-frequency ripple of electric power output voltage as frequency converter, adopts power supply of the present invention and method also can well meet this requirement.
The unspecified part of the present invention belongs to general knowledge as well known to those skilled in the art.
Claims (2)
1. a power supply for low-frequency noise be can suppress, input filter circuit, half-bridge converter, pulse-width modulation circuit, power transformer, current rectifying and wave filtering circuit and voltage stabilizing sample circuit comprised; It is characterized in that, the frequency of described low-frequency noise is less than 10kHz;
Input filter circuit comprises inductance L 1, resistance R1, electric capacity C1, resistance R2, inductance L 2 and electric capacity C2; Wherein inductance L 1 and electric capacity C1 form first order differential mode filter circuit, inductance L 2 and electric capacity C2 and form second level differential mode filter circuit; The positive input terminal of input voltage is connected with one end of inductance L 1, and the other end of inductance L 1 is connected with inductance L 2 with resistance R2; Resistance R1 is in parallel with inductance L 1, and resistance R2 connects with electric capacity C1, makes the gain reduction at input filter circuit cut-off frequency place; Inductance L 2 is connected with electric capacity C2; Electric capacity C1, C2 are connected with the negative input end of input voltage respectively; Electric capacity C2 is connected in parallel on half-bridge converter two ends;
Voltage stabilizing sample circuit comprises sampling resistor R3, operational amplifier N1, compensation loop, resistance R4 and electric capacity C3; After resistance R4 connects with electric capacity C3, be connected in parallel on sampling resistor R3 two ends; The voltage that current rectifying and wave filtering circuit exports is connected with the reverse input end of operational amplifier N1 by sampling resistor R3, and the positive input of operational amplifier is connected with reference voltage; Meanwhile, the reverse input end of operational amplifier N1 is connected with the output of operational amplifier by compensation loop.
2. a kind of power supply that can suppress low-frequency noise according to claim 1, is characterized in that, described power supply is microwave receiving electromechanical source.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210378109.XA CN102916571B (en) | 2012-09-29 | 2012-09-29 | Power supply capable of suppressing low-frequency noises |
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| CN201210378109.XA CN102916571B (en) | 2012-09-29 | 2012-09-29 | Power supply capable of suppressing low-frequency noises |
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| CN102916571A CN102916571A (en) | 2013-02-06 |
| CN102916571B true CN102916571B (en) | 2015-04-22 |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103546023B (en) * | 2013-10-31 | 2015-09-30 | 烽火通信科技股份有限公司 | A kind of method suppressing multiple Switching Power Supply beat frequency noise |
| CN111022276B (en) * | 2019-12-27 | 2021-03-12 | 哈尔滨工业大学 | Hall effect thruster low-frequency oscillation suppression outer loop |
| CN112543034A (en) * | 2020-12-10 | 2021-03-23 | 上海移远通信技术股份有限公司 | Low-frequency filter circuit, communication chip module and antenna system based on 9x07 platform |
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| US5606289A (en) * | 1994-06-22 | 1997-02-25 | Carver Corporation | Audio frequency power amplifiers with actively damped filter |
| US5686806A (en) * | 1994-12-19 | 1997-11-11 | Trans-Coil, Inc. | Low-pass filter and electronic speed control system for electric motors |
| CN1736024A (en) * | 2003-01-20 | 2006-02-15 | 沙夫纳Emv股份公司 | Filter network |
| CN101164228A (en) * | 2005-04-20 | 2008-04-16 | Nxp股份有限公司 | A parallel arranged linear amplifier and dc-dc converter |
| CN201054545Y (en) * | 2007-06-01 | 2008-04-30 | 佛山市顺德区瑞德电子实业有限公司 | Middle power multi-channel output thin switch power supply |
| CN102223094A (en) * | 2010-04-16 | 2011-10-19 | 通用电气公司 | Power conversion system and LC circuit damping method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3943524B2 (en) * | 2003-05-14 | 2007-07-11 | 太陽誘電株式会社 | Power supply |
| JP2008067534A (en) * | 2006-09-08 | 2008-03-21 | Yaskawa Electric Corp | Filter and power converter |
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- 2012-09-29 CN CN201210378109.XA patent/CN102916571B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5606289A (en) * | 1994-06-22 | 1997-02-25 | Carver Corporation | Audio frequency power amplifiers with actively damped filter |
| US5686806A (en) * | 1994-12-19 | 1997-11-11 | Trans-Coil, Inc. | Low-pass filter and electronic speed control system for electric motors |
| CN1736024A (en) * | 2003-01-20 | 2006-02-15 | 沙夫纳Emv股份公司 | Filter network |
| CN101164228A (en) * | 2005-04-20 | 2008-04-16 | Nxp股份有限公司 | A parallel arranged linear amplifier and dc-dc converter |
| CN201054545Y (en) * | 2007-06-01 | 2008-04-30 | 佛山市顺德区瑞德电子实业有限公司 | Middle power multi-channel output thin switch power supply |
| CN102223094A (en) * | 2010-04-16 | 2011-10-19 | 通用电气公司 | Power conversion system and LC circuit damping method |
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