CN100573398C - Be used to improve the device of power supply load regulation rate - Google Patents

Abstract

The invention discloses a kind of device that is used to improve power supply load regulation rate.This device comprises: the adjustable reference voltage source, be connected to the input end in the same way of voltage error amplifier, and the reference voltage that is used for the input end in the same way by the regulation voltage error amplifier is regulated the output voltage V bus of power supply; Output current sampling compensating module is used for output current I to power supply and samples and the signal of sampling is handled the formation compensating signal, and compensating signal is transferred to output voltage sampling feedback module; Output compensating signal filtration module be used for the compensating signal of output current sampling compensating module output is filtered, and the compensating signal after will filtering exports output voltage sampling feedback module to; Output voltage sampling feedback module is connected to the reverse input end of voltage error amplifier, is used for the output voltage V out of the reverse input end of voltage error amplifier is detected in real time; And resistance, be positioned on the outlet line.

Description

Be used to improve the device of power supply load regulation rate

Technical field

The present invention relates to the communications field, relate more specifically to a kind of device that is used to improve power supply load regulation rate.

Background technology

Communication is formed the system of various capacity to electric usually with power supply, different loads has different requirements to the load regulation of power supply, the industry standard of " communication high-frequency switching rectifier " requires load regulation to be no more than O.5%, but the equipment that has is higher to the regulation requirement of power supply.Early stage power supply, when output current surpassed 50A, output terminal reduced output resistance, reduces pressure drop in the mode of bus-bar usually, and load regulation easily satisfies industry requirement; But along with the volume of power supply constantly dwindles, power density improves constantly, the power output end of output 25A to 50A adopts the bus-bar mode to reduce resistance seldom again, reduce because of PCB simultaneously, output Copper Foil width has minimizing to a certain degree, connector has also dwindled volume, can not structurally realize plug more mechanically.On the hot plug control mode of output general adopt by the difference that detects electric power output voltage and busbar voltage control string on output line relay or the switch of MOSFET realize, consider cost and volume, the output line upward wiring pressure drop of power supply, the pressure drop of hot plug element, connector etc. cause all-in resistance bigger, make load regulation descend, serious slightly any standard that is difficult to satisfy industry, more not satisfied load is to power supply load regulation index higher requirement.

Because technology or demand, most of power supplys to not taking measures because of output line part resistance causes the decline of load regulation.But output current is milliampere a level and to the exigent small-power power of load regulation, have by increasing (as shown in Figure 1) that a resistance that is used to compensate improves load regulation, and by introducing compensating resistance R5, when $R5=(R3+R4)\&times;\frac{R1}{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2},$ Output voltage V bus general does not change with the variation of output current I, be that load regulation can be zero in theory, in fact VREF and resistance etc. have discreteness, and error can not be invariable, but can offset the influence of output line resistance largely, improve load regulation (can be approaching zero).

But this circuit has following weak point:

The one, compensating resistance must be positioned at after the output filter circuit, and the electric current that flows through compensating resistance R5 will equate that fully the ripple current and the noise current that flow through sampling resistor simultaneously must lack with output DC stream.As sampling resistor being connected on position as shown in Figure 2; promptly be connected on before the output filtering; contain bigger ripple current and very big noise current in its sample rate current; noise current often is far longer than flip-flop wherein during particularly unloaded and underloading; power supply cisco unity malfunction then, and communication power supply output sampling resistor (shunt) is uploaded to sampling resistor, output overcurrent protection and current-limiting circuit, the current-sharing of monitoring as output current simultaneously or as the sampling resistor of current inner loop.In order better to realize every functional parameter, shunt usually need be connected on the front of output filtering.

The 2nd, as changing output voltage by adjusting the output voltage sampling resistor, the load regulation that then changes the power supply behind the output voltage is with respective change, can not guarantee in the gamut that output voltage changes, to accomplish desirable compensation, adjusting as output, regulation is a theoretical value zero behind the voltage compensation, over-compensation will appear after then heightening output voltage, be that the big more then output voltage of output current can be high more, then can cause undercompensation after turning down output voltage.

The 3rd, to resistance R3, R4 and VERF on certain output line,, sometimes compensating resistance there is strict requirement for accomplishing effective compensation, the type selecting difficulty, moreover be to be difficult to directly use existing output current sampling shunt.The general sampling resistor that adopts the shunt of number milliohm or several milliohms at zero point (precision is ± 1%) as output current in the communication power supply of the big electric current of output, and for output voltage being accomplished desirable compensation, load regulation is as far as possible little, as VREF=2.5V, R3+R4=5m Ω, output 53.5V, output compensating resistance R5 when then load regulation is zero should be 0.245m Ω ± 1%, the sampling shunt that is used to improve load regulation must be just passable less than 0.245m Ω, can not directly use output terminal existing be used for the output current sampling but resistance surpasses the shunt that load regulation compensates to zero required resistance value; Resistance low power consumption more is more little, better from reducing unwanted losses, but the too little sampled signal of resistance is too little, useful signal is subject to noise, cause bigger detection error, be difficult to realize the Expected Results that carries out various effective controls after the output current sampling, secondly be in the making of shunt itself and load onto at shunt among the erection welding process of PCB, its precision is to be difficult to control, also can therefore bring too much defective products.

Summary of the invention

In view of above one or more problems, the invention provides a kind of device that is used to improve power supply load regulation rate.

The device that is used to improve power supply load regulation rate according to the present invention comprises: the adjustable reference voltage source, be connected to the input end in the same way of voltage error amplifier, the reference voltage that is used for the input end in the same way by the regulation voltage error amplifier is regulated the output voltage V bus of power supply; Output current sampling compensating module is used for output current I to power supply and samples and the signal of sampling is handled the formation compensating signal, and compensating signal is transferred to output voltage sampling feedback module; Output compensating signal filtration module be used for the compensating signal of output current sampling compensating module output is filtered, and the compensating signal after will filtering exports output voltage sampling feedback module to; Output voltage sampling feedback module is connected to the reverse input end of voltage error amplifier, is used for output voltage V out is detected in real time; And resistance, be positioned on the outlet line.

The device that is used to improve power supply load regulation rate according to the present invention also comprises: filter capacitor, and one end ground connection, the other end is connected to output voltage; Filter inductor is connected to output voltage, is used for output voltage V out is carried out filtering; Commutation diode connects filter inductor, is used for the input alternating voltage before the filtering is carried out rectification.

Wherein, the adjustable reference voltage source is realized by following at least a mode: hardware adjustments mode and software adjustment method.

Wherein, output current sampling compensating module comprises: sampling module is used for output current I is sampled, and sampled signal is sent to signal processing module; And signal processing module, be used for sampled signal is handled with the formation compensating signal, and compensating signal is sent to output voltage sampling feedback module.Wherein, sampling module is a shunt.Signal processing module is decayed sampled signal pro rata to form compensating signal.

The present invention is by introducing sampling compensating circuit and adjustable reference circuit, can the load regulation of the power supply of single output voltage power supply or wide region output voltage be compensated flexibly and effectively, thereby makes load regulation near zero.For having the circuit of output steering device as the output current sampling, then only need several miniwatt resistance of increase and electric capacity can realize very desirable approaching zero load regulation, increase cost less than 0.1 yuan, cost is very little; Circuit for there not being shunt as the current sample of output then increases a shunt again, and the cost of increase is also very low.

Description of drawings

Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, and illustrative examples of the present invention and explanation thereof are used to explain the present invention, do not constitute improper qualification of the present invention.In the accompanying drawings:

Fig. 1 is the circuit that improves load regulation in the prior art;

Fig. 2 is the circuit that shunt is used in output current sampling common in the communication power supply;

Fig. 3 is the circuit structure diagram of device that is used to improve power supply load regulation rate according to the embodiment of the invention;

Fig. 4 is the circuit theory diagrams of device that are used to improve power supply load regulation rate according to the embodiment of the invention; And

Fig. 5 is the circuit diagram of regulating reference voltage source in the embodiment shown in fig. 4 with PWM according to the embodiment of the invention.

Embodiment

Below with reference to accompanying drawing, describe the specific embodiment of the present invention in detail.

Fig. 3 shows the circuit structure diagram of device that is used to improve power supply load regulation rate according to the embodiment of the invention.As shown in Figure 3, this circuit that is used to improve power supply load regulation rate comprises: the resistance 310 on adjustable reference voltage source 302, output current sampling compensating circuit 304, output compensating signal filtering circuit 306, output voltage sampling feedback circuit 308 and the outlet line.This circuit that is used to improve power supply load regulation rate can further include the diode that is used to export rectification, inductance and the filter capacitor that is used to export filtering.

Wherein, the adjustable reference voltage source makes power supply guarantee under the rated output voltage under the design object situation of output load regulation near zero or expection at output sample circuit and compensating resistance parameter, remain unchanged, the reference voltage of the input end in the same way by the regulation voltage error amplifier is regulated output voltage, make output voltage satisfy predetermined wide scope of design, the load regulation under simultaneously any output voltage will approach zero substantially.The implementation of adjustable reference voltage source includes but not limited to following two kinds: one, hardware adjustments mode, promptly regulate reference voltage source by the dividing potential drop of regulator potentiometer; Two, software adjustment mode can directly be utilized the given reference voltage source of monitoring, also can utilize PWM to regulate.

Output current sampling compensating circuit is by output current is sampled (sampled signal and output current are linearly proportional), and sampled signal handled to form compensating signal, then compensating signal is given the output voltage sampling feedback circuit, make to increase then by output current output voltage suitably raises, to eliminate the pressure drop that output electronics resistance causes.Its implementation comprises: the sampling shunt of output compensation usefulness; maybe need the signal that compensates less than normal as use the bigger shunt of existing resistance because of need; can be by the sampled signal of shunt being carried out ratio decay sampling; thereby simply, neatly shunt is carried out type selecting, more can directly utilize output terminal to be used for the shunt of other protection (as current limliting, overcurrent etc.) sampling usefulness.

Output compensating signal filtering circuit is used for compensating signal filtering noise, and signal to noise ratio (S/N ratio) is different under the different output current situation.When unloaded and underloading, noise signal is relatively large, and concrete condition is then with the size of the size of the structure of transformer, the determined coupling electric capacity of coiling mode, switch frequency of operation, and outputting inductance big or small or have or not much relations.For the very big situation of noise in the sampled signal, this filtering circuit is necessary, otherwise, the work that power supply can not be normal or stable.

Output voltage sampling feedback circuit comprises the output voltage sampling resistor.By output voltage being taken a sample and feeding back to the reverse input end of voltage error amplifier, can realize real-time detection, thereby can guarantee the stable of output voltage output voltage.

More or less there are certain distance and line between the output voltage sampled point of power supply and the load, so on outlet line, there is resistance.When the voltage constant of output voltage sampled point, this resistance will cause the voltage that outputs in the load to reduce with the increase of output current, thereby cause the reduction of load regulation.Improve load regulation and be under the situation that can not reduce at this resistance by suitable boosted output voltages eliminating the pressure drop that this resistance causes, thereby guarantee voltage in load be constant or change try one's best little of to improve load regulation.

Fig. 4 is circuit theory diagrams according to an embodiment of the invention.Fig. 5 is a circuit diagram of regulating the circuit of reference voltage source in the embodiment shown in fig. 4 with PWM.

As shown in Figure 5, the 1st pin of optocoupler D5 connects pwm signal, the 2nd pin meets pwm signal ground GND1 (GND1 directly can be met power supply ground GND as not isolating then), one end of resistance R 12, one end of resistance R 14, one end of resistance R 13 links to each other with the 4th pin of optocoupler D5, the other end of resistance R 12, the end of adjustable potentiometer RP2, one end of resistance R 24, one end of resistance R 21, one end of capacitor C 5, one end of capacitor C 6, the anode of voltage stabilizer D4, the 3rd pin of the emitter of triode VT1 and optocoupler D5 is connected in power supply ground GND, the other end of resistance R 14 links to each other with the base stage of triode VT1, the other end of resistance R 13, one end of resistance R 17, and an end of resistance R 19 links to each other with power supply VCC, the other end of resistance R 17, the collector of triode VT1, the other end of adjustable potentiometer RP2 and adjustable end link to each other with the end of R16, the other end of resistance R 16, the other end of capacitor C 5 links to each other with an end of resistance R 18, the other end of resistance R 18, the other end of capacitor C 6 links to each other with an end of resistance R 15, the other end of resistance R 15, the other end of resistance R 24, be connected in adjustable reference voltage VREF point with an end of resistance R 23, the other end of resistance R 23, one end of resistance R 20, the negative electrode of the other end of resistance R 19 and voltage stabilizer D4 is connected in VREF1, the other end of resistance R 20, the reference voltage terminal of the other end of resistance R 21 and voltage stabilizer D4 is connected in VREF2.

This circuit is by the dividing potential drop to PWM (width modulation) waveform adjustment resistance R 23 and resistance R 24.When the change in duty cycle of PWM, the corresponding change of voltage of adjustable reference voltage source V ERF, dutycycle is big more, and then the voltage of adjustable reference voltage source V ERF is big more, by regulating the dutycycle of PWM within the specific limits, can realize the voltage of the adjustable reference voltage source V ERF in the certain limit.RP2 be used for when the PWM waveform during at a certain fixed duty cycle and output electric current semi-load with the output voltage inching to rated output voltage, when not having the PWM waveform, the dark saturation conduction of VT1, the CE junction voltage is near zero.Voltage VREF1 is high-precision reference voltage, and resistance R 15, resistance R 16, resistance R 18, resistance R 23 and resistance R 24 are all got precision resister as 1%, thereby adjustable reference voltage VREF also is high-precision fixed voltage source.

The correlated expression formula is as follows:

$\mathrm{VREF}1=\mathrm{VREF}2\&times;\frac{R20+R21}{R21}$

Order $R100=\frac{R24\&times;(R15+R16+R18)}{R24+R15+R16+18}$

Then $\mathrm{VREF}=\mathrm{VREF}1\&times;\frac{R100+R23}{R100}$

The high precision of this voltage source has guaranteed when not having the PWM waveform, can output voltage be adjusted highly consistent by regulating adjustable potentiometer RP1, as in order to guarantee the current-sharing better each other of each monomer of the power supply system for communications, general the output voltage of monomer is adjusted be no more than in error ± 0.2% scope in.

When not having the PWM waveform, behind the output voltage of having adjusted adjustable potentiometer RP1 is fixed.When PWM waveform during at a certain fixed duty cycle and output electric current semi-load, by regulating adjustable potentiometer RP2 output voltage is finely tuned the rated output voltage of adjusting, thereby guarantee the high precision of output voltage, guarantee that communication power supply is being no more than in ± 0.2% the scope at output voltage error under the same PWM pressure regulation.

Fig. 4 is the circuit theory diagrams that are used to improve the device of power supply load regulation rate, and the corresponding relation of the functional circuit among wherein each element and Fig. 3 is as follows: output current sampling compensating circuit is by shunt R5, resistance R 7, constitute with resistance R 8; Output compensating signal filtering circuit is made of resistance R 9 and capacitor C 2; Output voltage sampling feedback circuit is made of resistance R 2, resistance R 1, adjustable potentiometer RP1 and R9; Resistance on the outlet line is total equivalent resistance of resistance R 3 and resistance R 4; Adjustable reference voltage source V REF is the reference voltage source circuit of regulating with PWM.

Wherein, the negative electrode of output commutation diode VD1, the negative electrode of output commutation diode VD2 links to each other with the end of output inductor L1 and (exports the anode of commutation diode VD1, the anode of output commutation diode VD2 links to each other with the secondary winding of transformer respectively), the other end of output inductor L1, one end of capacitor C 1, one end of resistance R 3 and an end of resistance R 2 are connected in Vout+, one end of the other end of resistance R 3 and capacitor C 4 is connected in Vbus+, the other end of resistance R 2, one end of resistance R 1 links to each other with an end of resistance R 11, the other end of resistance R 11 links to each other with reverse input end the 2nd pin of voltage error amplifier D1A, the 8th pin of voltage error amplifier D1A meets VCC, the 4th pin of voltage error amplifier D1A meets GND, the other end of resistance R 1 links to each other with an end and the adjustable end of adjustable potentiometer RP1, the other end of adjustable potentiometer RP1, one end of capacitor C 2 links to each other with an end of resistance R 9, the other end of resistance R 9, one end of resistance R 7 links to each other with an end of resistance R 8, the other end of resistance R 7, the end of shunt R5 is connected in Vout-(end of transformer secondary winding), the other end of capacitor C 1, the other end of capacitor C 2, one end of capacitor C 3, the other end of resistance R 8, the other end of resistance R 4 and the other end of shunt are connected in power supply ground GND, the other end of the other end of resistance R 4 and capacitor C 4 is connected in Vbus-, one end of resistance R 10 links to each other the other end of resistance R 10 with adjustable reference voltage source V RF, the other end of capacitor C 3 links to each other with the 3rd pin of input end in the same way of voltage error amplifier D1A.

Wherein, R5 for the string output main circuit shunt since through the filtering circuit filtering flow through the sampling compensating circuit noise, so ignore the influence that noise current brings, steady-state analysis is as follows:

Order: R101=R3+R4,

R102＝R1+R9+RP1

$R103=R7//R102=\frac{R7\&times;(R1+R9+\mathrm{RP}1)}{R7+R1+R9+\mathrm{RP}1}$

$R104=R8//(R7+R5)=\frac{R8\&times;(R7+R5)}{R8+R7+R5}$

R105＝R8+R7//R102

R106＝R105//R5

$\mathrm{Vbus}=\mathrm{Vout}\_I\&times;R101=\mathrm{Vout}1+V1\_I\&times;R101$

$=\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2+R102}{R102}\&times;(\mathrm{VREF}-V1)+V1-I\&times;R101$

$=\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2+R102}{R102}\&times;\mathrm{VREF}-\frac{R2}{R102}\&times;V1-I\&times;R101$

$V1=\mathrm{IR}8\&times;R8$

$=(\frac{-I\&times;R5}{R105+R5}+\frac{\mathrm{VREF}}{R102+R104}\&times;\frac{R104}{R8})\&times;R8$

$\mathrm{Vbus}=\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2+R102}{R102}\&times;\mathrm{VREF}+(\frac{I\&times;R5}{R105+R5}-\frac{\mathrm{VREF}}{R102+R104}\&times;\frac{R104}{R8})\&times;R8\&times;\frac{R2}{R102}$

$-I\&times;R101$

Order $\mathrm{VOUT}$ $2=\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2+R102}{R102}\&times;\mathrm{VREF}-\frac{\mathrm{VREF}}{R102+R104}\&times;\frac{R104\&times;R2}{R102}$

Then $\mathrm{Vbus}=\mathrm{<figure-callout\; id="2"\; label="VOUT"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">VOUT</figure-callout>}2+(\frac{R5\&times;R8\&times;R2}{(R105+R5)\&times;R102}-R101)\&times;I---\left(1\right)$

From above Vbus expression formula (1) as can be known, as long as get $\frac{R5\&times;R8\&times;R2}{(R105+R5)\&times;R102}=R101,$ Then the output voltage V bus that draws suc as formula (2) keeps constant, and is irrelevant with output current, thereby load regulation is zero in theory; The value that only change VREF this moment can change output voltage V bus, can not influence load regulation.

Vbus＝VOUT2 (2)

As R5=0 or R8=0, promptly do not introduce the circuit of compensation, then (1) formula becomes,

Vbus＝VOUT2-I×R101， (3)

Be that output voltage will the linear decline with the increase of output current I.

When actual design, the resistance of shunt is the milliohm level, and the resistance of R7, R8 is about ohm level, and the resistance of R102 is a kilohm level, then because of R7, and R8＜＜R102; R5＜＜R7, R8, thus Vbus expression formula (1) can be similar to as follows:

$\mathrm{Vbus}=\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2+R102}{R102}\&times;\mathrm{VREF}+(\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2\&times;R8}{R102\&times;(R7+R8)}\&times;R5-R101)\&times;I---\left(4\right)$

From (4) as can be known, when $\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2\&times;R8}{R102\&times;(R7+R8)}\&times;R5=R101$ The time, the load regulation of the output voltage that draws suc as formula (5) is zero; The value that only change VREF this moment can change output voltage V bus, but can not influence load regulation, but change output voltage as regulating RP1 by the value that changes R102, then load regulation no longer is zero, heighten output voltage and cause output voltage linear increase with the increase of output current, turn down output voltage and can cause the load regulation variation, depart from ideal and be approximately zero effect.

$\mathrm{Vbus}=\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2+R102}{R102}\&times;\mathrm{VREF}---\left(5\right)$

When R8 is zero, then introduce compensation, (4) expression at this moment becomes as follows:

$\mathrm{Vbus}=\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2+R102}{R102}\&times;\mathrm{VREF}+-R101\&times;I---\left(6\right)$

Be that output voltage will the linear decline with the increase of output current I.

When R8 is infinitely great, be about to all usefulness by way of compensation of shunt R5, (4) are expressed and are become at this moment

$\mathrm{Vbus}=\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2+R102}{R102}\&times;\mathrm{VREF}+(\frac{R2}{R102}\&times;R5-R101)\&times;I---\left(7\right)$

As this moment $R5=\frac{R102}{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2}\&times;R101,$ Then the load regulation of power supply is zero.But, under actual conditions, for certain output voltage,

Determine, as $R5>\frac{R102}{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C2007100032010018H1.png,C2007100032010020H1.png"\; state="\{\{state\}\}">R</figure-callout>}2}\&times;R101$ The time, as R5 being done compensation fully with then causing over-compensation, promptly can cause output voltage will be with the increase of output current I linear the increase, therefore,, by the introducing of R7, R8, regulate parameter neatly, realize that load regulation is zero to this situation.

In addition, for filtering circuit R9 and C2, R9 is can not value excessive, as get R9＞＞(RP1+R1), can cause the output voltage dynamic response slack-off in the time of then can causing the output voltage sudden change, transient response performance index variation because of reasons such as the existence of capacitor C 2, load moment switchings.In order to guarantee good transient response, can resistance R 9 values are suitably little, but capacitor C 2 capacity are suitably got greatly, remove noise to guarantee energy rate.Wherein, capacitor C 4 is used for the high frequency noise of filtering output terminal.

When not having the PWM ripple, very little for output voltage being adjusted into error range, need utilize adjustable potentiometer RP1 to finely tune, even guarantee the high precision of communication power supply output voltage under the situation that does not have the PWM waveform, the resistance value of adjusting of adjustable potentiometer RP1 is that to satisfy the output load regulation in output this voltage following time of adjusting be zero, after output voltage is adjusted by pre-design, can not regulate change voltage by regulating this potentiometer again, can cause the load regulation deviation excessive like that.In order to guarantee to be approximately zero, behind the output voltage of having adjusted by RP1 and RP2, can only recently regulate output voltage by the duty of regulating PWM in output voltage gamut internal burden regulation.

As from the foregoing, the circuit of device that is used to improve power supply load regulation rate according to the embodiment of the invention has following characteristics: one, shunt is positioned at the normal steady operation that does not influence power supply before and after the output filtering; Two, easy to the type selecting of shunt, enlarged the Standard resistance range of shunt, also can directly use the existing shunt of making output current sampling usefulness and be used as compensating sampling resistance; Three, can be implemented in and accomplish effective compensation in the wide output voltage gamut, output voltage load regulation down all can be near zero arbitrarily in theory.

The present invention can compensate the load regulation of single output voltage power supply or wide region output voltage power supply flexibly and effectively by introducing sampling compensating circuit and adjustable reference circuit, thereby makes load regulation near zero.For having the circuit of output steering device as the output current sampling, then only need several miniwatt resistance of increase and electric capacity can realize very desirable approaching zero load regulation, increase cost less than 0.1 yuan, cost is very little; Circuit for there not being shunt as the current sample of output then increases a shunt again, and the cost of increase is also very low.

The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (8)

1. a device that is used to improve power supply load regulation rate is characterized in that, comprising:

The adjustable reference voltage source is connected to the input end in the same way of voltage error amplifier, and the reference voltage that is used for the input end in the same way by regulating described voltage error amplifier is regulated the output voltage V bus of power supply;

Output current sampling compensating module is used for output current I to power supply and samples and the signal of sampling is handled the formation compensating signal, and described compensating signal is transferred to output voltage sampling feedback module;

Output compensating signal filtration module be used for the compensating signal of described output current sampling compensating module output is filtered, and the compensating signal after will filtering exports described output voltage sampling feedback module to;

Described output voltage sampling feedback module is connected to the reverse input end of described voltage error amplifier, is used for the output voltage V out of the reverse input end of described voltage error amplifier is detected in real time;

Resistance is positioned on the outlet line.

2. the device that is used to improve power supply load regulation rate according to claim 1 is characterized in that, described device also comprises: filter capacitor, and one end ground connection, the other end is connected to described output voltage V out.

3. the device that is used to improve power supply load regulation rate according to claim 1 is characterized in that, described device also comprises: filter inductor, be connected to described output voltage V out, and be used for described output voltage V out is carried out filtering.

4. the device that is used to improve power supply load regulation rate according to claim 3 is characterized in that, described device also comprises: commutation diode, connect described filter inductor, and be used for the input alternating voltage before the filtering is carried out rectification.

5. the device that is used to improve power supply load regulation rate according to claim 1 is characterized in that, described adjustable reference voltage source is realized by following at least a mode: hardware adjustments mode and software adjustment method.

6. according to each described device that is used to improve power supply load regulation rate in the claim 1 to 5, it is characterized in that described output current sampling compensating module comprises:

Sampling module is used for output current I is sampled, and sampled signal is sent to signal processing module; And

Described signal processing module is used for described sampled signal is handled with the formation compensating signal, and described compensating signal is sent to described output voltage sampling feedback module.

7. the device that is used to improve power supply load regulation rate according to claim 6 is characterized in that, described sampling module is a shunt.

8. the device that is used to improve power supply load regulation rate according to claim 7 is characterized in that, described signal processing module is decayed described sampled signal pro rata to form compensating signal.

Images