CN107046368B - Power supply change-over device - Google Patents
Power supply change-over device Download PDFInfo
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- CN107046368B CN107046368B CN201610081449.4A CN201610081449A CN107046368B CN 107046368 B CN107046368 B CN 107046368B CN 201610081449 A CN201610081449 A CN 201610081449A CN 107046368 B CN107046368 B CN 107046368B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
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- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The present invention provides a kind of power supply change-over device comprising power-switching circuit, synchronous rectification transistor, synchronous commutating control circuit, feedback circuit and line loss compensation circuit.Power-switching circuit carries out power supply conversion to input voltage, uses generation output voltage, and output voltage is supplied to load.Synchronous rectification transistor is serially connected on the secondary side current path of power-switching circuit, and be controlled by synchronous rectification control signal and switched conductive state.Synchronous commutating control circuit generates synchronous rectification control signal to control the switching of synchronous rectification transistor.Feedback circuit generates the output indicator current for being associated with output voltage.Line loss compensation circuit draws compensation electric current according to synchronous rectification control signal from feedback circuit, uses the summation based on compensation electric current and output indicator current and compensates output voltage.
Description
Technical field
The present invention relates to a kind of power supply change-over device more particularly to a kind of power supply change-over devices that can compensate for line loss.
Background technique
Power supply change-over device (power conversion apparatus) main purposes is to be provided Utilities Electric Co.
High pressure and the input voltage (input voltage) of low stability be converted into being suitble to various electronic device (electronic
Device the preferable DC output voltage of low pressure and stability (DC output voltage)) used.Therefore, power supply is converted
Device is widely used in the electronic devices such as computer, office automation devices, industrial control equipment and communication apparatus.
When the required power supply of load end is larger, power supply change-over device needs to provide biggish output electric current for load
It uses, the operating state of power supply change-over device is referred to as heavy duty running at this time.Under heavy duty running, due to biggish output electric current
Pressure drop would generally be caused online in output, may so make the voltage for being provided to load end beyond specification.Such phenomenon is general
Referred to as line loss (cable loss).
Some line loss compensation mechanism would generally be used in existing power supply change-over device with compensate heavy duty running when because
Output voltage pressure drop caused by line loss.In general common line loss compensation mode, one of which is by detection function
Rate switch cut-off during length come judge export size of current, then accordingly determine output voltage compensation rate；It is wherein another
For by setting output current detection circuit directly detect output size of current, then accordingly decision output voltage compensation rate.
However, due to when power supply change-over device running continuous conduction mode (continuous conduction mode,
It is to fix and output size of current cannot be reacted, therefore carried out according to during the cut-off of power switch during cut-off when CCM)
The mode of line loss compensation is only capable of applying the electricity in discontinuous conduction mode (discontinuous conduction mode, DCM)
Supply changeover device.
On the other hand, since the current detection mechanism of general current detection circuit usually exports electric current by sampling, then
So that sampling current is flowed through a specific electrical resistance, uses by measuring the ohmically cross-pressure and judge to flow through the sampling current of the resistance
Size pushes back further according to sampling current and calculates output size of current.Therefore, under general output electric current measure mode,
Additional power consumption certainly will be will cause.
Summary of the invention
In view of this, the present invention provides a kind of power supply change-over device, uses and solve the problems, such as that prior art is addressed.
Power supply change-over device of the invention include power-switching circuit, synchronous rectification transistor, synchronous commutating control circuit,
Feedback circuit and line loss compensation circuit.Power-switching circuit uses generation output to carry out power supply conversion to input voltage
Voltage, and output voltage is supplied to load.Synchronous rectification transistor is serially connected with the secondary side current road of power-switching circuit
On diameter, and be controlled by synchronous rectification control signal and switched conductive state.It is brilliant that synchronous commutating control circuit couples synchronous rectification
Body pipe, to generate synchronous rectification control signal to control the switching of synchronous rectification transistor.Feedback circuit couples power supply conversion
Circuit, to generate the output indicator current for being associated with output voltage.Line loss compensation circuit couple synchronous commutating control circuit with
Feedback circuit, to according to synchronous rectification control signal compensation electric current is drawn from feedback circuit, use based on compensation electric current with
The summation for exporting indicator current compensates output voltage.
Based on above-mentioned, the present invention proposes a kind of power supply change-over device comprising one makees using synchronous rectification control signal
For the line loss compensation circuit of the foundation of line loss compensation.Wherein, the line loss compensation circuit can be produced based on synchronous rectification control signal
The raw compensation electric current for corresponding to output size of current, and output voltage is compensated accordingly in line loss when overloaded.Due to nothing
By at DCM or CCM, the waveform of synchronous rectification control signal can all indicate output size of current, therefore the embodiment of the present invention
Power supply change-over device is either operated at DCM or CCM, and line loss compensation can all be effectively performed, and is turned without being limited to power supply
The operating mode of changing device.Further, since the power supply change-over device of the embodiment of the present invention and being not required to using additional current detecting
Circuit directly detects output electric current, therefore the overall power dissipation of power supply change-over device is minimized.
To make the foregoing features and advantages of the present invention clearer and more comprehensible, special embodiment below, and it is detailed to cooperate attached drawing to make
Carefully it is described as follows.
Detailed description of the invention
Fig. 1 is the function box schematic diagram of the power supply change-over device of one embodiment of the invention；
Fig. 2 is the circuit diagram of the power supply change-over device of one embodiment of the invention；
Fig. 3 is the signal sequence schematic diagram of the power supply change-over device of one embodiment of the invention；
Fig. 4 is the signal sequence schematic diagram of the power supply change-over device of another embodiment of the present invention.
Appended drawing reference:
100,200: power supply change-over device
110,210: power-switching circuit
120,220: synchronous rectification transistor
130,230: synchronous commutating control circuit
140,240: feedback circuit
150,250: line loss compensation circuit
Ib: base current
Iout: output electric current
Iic: output indicator current
Icomp: compensation electric current
C1, C2: capacitor
Cin: input capacitance
Cout: output capacitance
CTP: control chip
GND1, GND2: ground terminal
NB, NC: node
NP: first side winding
NS: secondary side winding
PC: photo-coupler
PSW: power switch
LD: load
Rb, Ri, R1, R2, R3, R4, R5: resistance
Spwm: pulse-width modulation signal
Ssr: synchronous rectification controls signal
T: transformer
T1, T2, T3: period
V1, V2, V3, Vb, Vnb: voltage
Vin: input voltage
Vout: output voltage
Vth: barrier voltages
Vfb: feedback voltage
U1: voltage-stablizer
Vu: voltage of voltage regulation
Q1: transistor
DCM: discontinuous conduction mode
CCM: continuous conduction mode
Specific embodiment
In order to be illustrated that the contents of the present invention more easily, spy can actually evidence as the present invention for embodiment below
With the example of implementation.In addition, all possible places, use component/component/step of identical label in the drawings and embodiments,
Represent same or like component.
Fig. 1 is the schematic diagram of the power supply change-over device of one embodiment of the invention.Fig. 1 is please referred to, the power supply of the present embodiment turns
Changing device 100 includes power-switching circuit 110, synchronous rectification transistor 120, synchronous commutating control circuit 130, feedback circuit
140 and detection auxiliary circuit 130.
Power-switching circuit 110 can be for example with synchronous rectification (synchronous rectification
Function flyback power converter (flyback converter)).In the present embodiment, power-switching circuit 110 is used
To receive input voltage vin, and power supply conversion is carried out to input voltage vin, uses the output voltage Vout for generating direct current,
Middle output voltage Vout can be provided to load LD, wherein load LD may be, for example, any kind of electronic device, the present invention is not
This is limited.
Synchronous rectification transistor 120 is serially connected on the secondary side current path of power-switching circuit 110 (subsequent embodiment
Circuit framework can be particularly shown), and it is controlled by the control of synchronous rectification caused by synchronous commutating control circuit 130 signal Ssr
And switched conductive state.
Synchronous commutating control circuit 130 couples synchronous rectification transistor 120, and in conjunction with power-switching circuit 110
Power switch (not shown) switching sequence and provide corresponding synchronous rectification control signal Ssr to control synchronous rectification transistor
120 switching, so that secondary side power supply may be provided to the load end LD.
Feedback circuit 140 couples power-switching circuit 110, can be used to sample the output voltage on the output end of secondary side
Vout, and the output indicator current Iic for being associated with output voltage Vout is generated accordingly.In addition, feedback circuit 140 can will also take
Sample to information of voltage as feedback voltage Vfb be coupled back into primary side using be supplied to power-switching circuit 110 as control according to
According to.
Line loss compensation circuit 150 couples synchronous commutating control circuit 130 and feedback circuit 140, can be used to according to synchronous
Synchronous rectification caused by rectifier control circuit 130 controls signal Ssr and draws corresponding compensation electric current from feedback circuit 140
Icomp.Whereby, other than the voltage originally established based on output indicator current Iic in feedback circuit 140, line loss compensation
Circuit 150 can establish additional voltage based on the compensation electric current Icomp drawn to compensate output electricity in feedback circuit 140
Press Vout.In other words, line loss compensation circuit 150 can be compensated based on the summation of compensation electric current Icomp language output indicator current Iic
Output voltage Vout.
Specifically, in the synchronous commutating control circuit 130 applied by the present embodiment, generated synchronous rectification control
No matter signal Ssr processed operates in continuous conduction mode (continuous conduction mode, CCM) or discontinuous conducting
Under mode (discontinuous conduction mode, DCM), all have waveform can be with output electric current Iout size/load
The characteristic of weight variation.The line loss compensation circuit 150 of the present embodiment is mainly using the characteristic as judging that power supply conversion is electric
The foundation of the operating state on road 110 is associated with output size of current based on synchronous rectification control signal Ssr generation and load LD is light
The compensation electric current Icomp changed again compensates the pressure drop in the output voltage Vout of high current/when overloaded.
More specifically, for compared to the mode for carrying out line loss compensation during the cut-off according to power switch, this implementation
The line loss compensation mode of example can be applied simultaneously at DCM and CCM, and is not only restricted to the operating mode of power-switching circuit 110.Separately
On the one hand, for compared to side output electric current Iout and the accordingly mode of progress line loss compensation is directly detectd, the line loss of the present embodiment
Compensation way directly detects output electric current Iout due to being not required to, and can reduce power loss.
Illustrate the line loss compensation mechanism of the present embodiment with physical circuit shown by Fig. 2 below.Wherein, Fig. 2 is this hair
The circuit diagram of the power supply change-over device of a bright embodiment.
Referring to figure 2., the power supply change-over device 200 of the present embodiment includes power-switching circuit 210, synchronous rectification transistor
220, synchronous commutating control circuit 230, feedback circuit 240 and line loss compensation circuit 250.Wherein, power-switching circuit 210 wraps
Include transformer T, input capacitance Cin, power switch PSW, control chip CTP and output capacitance Cout.Line loss compensation circuit 250
Including resistance R1, resistance R2 and Rb, capacitor C1 and transistor Q1.Feedback circuit 240 includes resistance R3, resistance R4 and resistance
R5, capacitor C2, voltage-stablizer U1 and photo-coupler PC.
In power-switching circuit 210, transformer T has first side winding (primary winding) Np and secondary side
Wind (secondary winding) Ns.Wherein, a lateral circuit (side of first side winding Np) is with ground terminal GND1 work
For voltage reference points, and secondary side circuit (side of secondary side winding Ns) is then using ground terminal GND2 as Voltage Reference
Point.Wherein, ground terminal GND1 and GND2 can be identical or different ground plane, and the present invention limits not to this.
The Same Name of Ends (common-polarity terminal gets place ready) of the first side winding Np of transformer T couples
Power switch PSW, and the first side winding Np of transformer T different name end (opposite-polarity terminal, i.e., not
The place of getting ready) to receive input voltage vin.The of the Same Name of Ends coupling output capacitance Cout of the secondary side winding Ns of transformer T
One end, and the different name end of the secondary side winding Ns of transformer T is coupled to output capacitance Cout via synchronous rectification transistor 220
Second end and secondary side ground terminal GND2.
The control terminal for controlling chip CTP coupling power switch PSW is used and provides pulse-width modulation signal Spwm to control power
The switching of switch PSW.Power switch PSW is, for example, by taking NMOS as an example in this.Power switch PSW first end (in this for drain electrode,
But be not limited only to this, can be depending on the type of power switch PSW) Same Name of Ends of the first side winding Np of coupling transformer T, power
Switch PSW second end (in this be source electrode) coupling ground terminal GND1, and power switch PSW control terminal (in this be grid)
Then to receive the pulse-width modulation signal Spwm from control chip 120.
The different name end of the first end coupling first side winding Np of input capacitance Cin, and the second end coupling of input capacitance Cin
Meet ground terminal GND1.The Same Name of Ends of the first end coupling secondary side winding Ns of output capacitance Cout, and output capacitance Cout
Second end couples ground terminal GND2.
Synchronous rectification transistor 220 is, for example, by taking NMOS as an example in this.The first end of synchronous rectification transistor 220 is (in this
For drain electrode, but be not limited only to this, can be depending on the type of synchronous rectification transistor 220) second end of coupling output capacitance Cout,
Synchronous rectification transistor 220 second end (in this be source electrode) the different name end of the secondary side winding Ns of coupling transformer T, and it is same
Walk rectifying transistor 220 control terminal (in this be grid) to receive the synchronous rectification control from synchronous commutating control circuit 23
Signal Ssr processed.In other words, the first end Yu second end of synchronous rectification transistor 220 are the electric currents for being serially connected in secondary side winding Ns
On path, therefore the on state of synchronous rectification transistor 220 can determine whether secondary side current path is interrupted.
In feedback circuit 240, the first end of the first end coupling output capacitance Cout of resistance R3.The first end of resistance R4
The second end of coupling resistance R3, and the second end of resistance R4 couples ground terminal GND2.The first end coupling resistance R3 of resistance R5
Second end and resistance R4 first end.The second end of the first end coupling resistance R5 of capacitor C2.
The first end of the first end coupling resistance R3 of the input side of photo-coupler PC, and the input side of photo-coupler PC
The second end of second end coupling capacitance C2.The first end reset voltage Vfb of the outlet side of photo-coupler PC, and optical coupling
The second end of the outlet side of device PC couples ground terminal GND1.
The second end of the input side of the second end and photo-coupler PC of the first end coupling capacitance C2 of voltage-stablizer U1, voltage-stablizer
The second end of U1 couples ground terminal GND2, and the first of the second end of the pressure stabilizing end coupling resistance R3 of voltage-stablizer U1 and resistance R4
It holds (that is, node NC), and pressure stabilizing operation is carried out to the voltage on node NC.
Wherein, photo-coupler PC can in conjunction with voltage-stablizer U1 running and according to DC output voltage Vout in its outlet side
It generates and is associated with the feedback voltage Vfb of output voltage Vout size and gives control chip CTP, to enable control chip CTP can be according to returning
Award foundation of the voltage Vfb as control power switch PSW.
In line loss compensation circuit 250, the signal output of the first end coupling synchronous commutating control circuit 230 of resistance R1
End uses and receives synchronous rectification control signal Ssr.The first end of resistance R2 is coupled to node NC (that is, in feedback circuit 240
The first end of resistance R4).The second end of the first end coupling resistance R1 of capacitor C1, and the second end of capacitor C1 couples ground terminal
GND2.Transistor Q1 is, for example, by taking BJT as an example in this.Transistor Q1 first end (in this be collector) coupling resistance R2 second
End, transistor Q1 second end (in this be emitter-base bandgap grading) coupling ground terminal GND2, and the base stage coupling resistance R1 of transistor Q1
The first end of second end and capacitor C1.
Specifically, in the case where power supply change-over device 200 is in normal operation, control chip CTP can react on the electricity of load
Source supply requirement and generate pulse-width modulation signal Spwm accordingly to control the running of power-switching circuit 210.With this condition,
It is defeated when power switch PSW, which is reacted on, to be controlled pulse-width modulation signal Spwm caused by chip CTP and (turned on) is connected
Enter the first side winding Np that voltage Vin can be connected across transformer T, so that the inductive current of the first side winding Np of transformer T
Meeting is linearly increasing and carries out energy storage.At the same time, synchronous commutating control circuit 230 can generate forbidden energy in the secondary side winding side Ns
Synchronous rectification controls signal Ssr to end (turned off) synchronous rectification transistor 220.Due to the synchronous rectification crystal of cut-off
The barrier of pipe 220, so the secondary side winding Ns of transformer T passes through no current.
When power switch PSW, which is reacted on, to be controlled pulse-width modulation signal Spwm caused by chip CTP and end, based on stupefied
Secondary law (Lenz's law), the energy stored by the first side winding Np of transformer T can be transferred to the secondary side of transformer T around
Hinder Ns.At the same time, synchronous commutating control circuit 230 controls signal in the synchronous rectification that the secondary side winding side Ns can generate enable
Ssr is to be connected synchronous rectification transistor 220.Since synchronous rectification transistor 220 is switched on, so being transferred to the two of transformer T
The energy of secondary side winding Ns will charge to output capacitance Cout, and supply output voltage Vout and give load (electronics dress
It sets).
It follows that being alternately conducted and cut-off function based on pulse-width modulation signal Spwm caused by control chip CTP
The function mode of rate switch PSW, power supply change-over device 200 sustainably supply output voltage Vout.
On the other hand, from the point of view of with regard to the running of line loss compensation circuit 250, in the feelings that synchronous rectification control signal Ssr is enable
Under condition, capacitor C1 can react on the voltage quasi position of synchronous rectification control signal Ssr and charge, so that the voltage on node NB
Vnb can gradually rise during synchronous rectification controls the enable of signal Ssr, and in synchronous rectification control signal Ssr switching
To be maintained on specific voltage value when forbidden energy by capacitor C1.
When the cross-pressure between the base stage of transistor Q1 and emitter-base bandgap grading is more than barrier voltages, transistor Q1 can be generated and base current
Emitter current with multiple proportion flows through the compensation electric current Icomp of resistance R2.It is uncreated in compensation electric current Icomp
Under situation, the resistance value (that is, cross-pressure of resistance R3) that output voltage Vout can be multiplied by resistance R3 equal to output indicator current Iic adds
Upper voltage of voltage regulation Vu (being indicated with formula, as Vout=Iic*R3+Vu).When compensating electric current Icomp generation, due to transistor
Q1 is that electric current all the way is additionally drawn from node Nc, and the electric current for passing through resistance R3 becomes to export indicator current Iic plus benefit
Repay electric current Icomp.In other words, in the case where compensating electric current Icomp generation, output voltage Vout can be equal to output indicator current
The resistance value that the current value summation of Iic and compensation electric current Icomp is multiplied by resistance R3 (is indicated, i.e., plus voltage of voltage regulation Vu with formula
For Vout=(Iic+Icomp) * R3+Vu).
As shown from the above formula, compensation electricity is generated when line loss compensation circuit 250 reacts on synchronous rectification control signal Ssr
When flowing Icomp, i.e., output voltage Vout can be drawn high, to reach the effect of compensation output voltage Vout.In addition to this, by
In compensation electric current Icomp size be is determined by the voltage Vnb on node NB, and the level of voltage Vnb just can with it is synchronous whole
The voltage quasi position of flow control signals Ssr and the product of enable time are positively correlated, wherein the voltage of synchronous rectification control signal Ssr
Level and the product of enable time can indicate output electric current Iout size.Therefore, the line loss compensation circuit 250 of the present embodiment can
It realizes with output electric current Iout size/load weight and provides corresponding offset to compensate the effect of output voltage Vout.
It is beneath that letter of the running of power supply change-over device 200 of the present embodiment at DCM and CCM is illustrated respectively with Fig. 3 and Fig. 4
Number timing.
The running of power supply change-over device 200 is as shown in Figure 3 in the signal sequence of DCM.Please first referring concurrently to Fig. 2 and Fig. 3, due to
It is not fixed at DCM, during the cut-off of power switch PSW, therefore can be with during the enable of synchronous rectification control signal Ssr
Change during the cut-off of power switch PSW.In addition, there is meeting in the signal waveform of synchronous rectification control signal Ssr
The characteristic to decay after specific period.In other words, at DCM, synchronous rectification controls enable waveform area and the output of signal Ssr
Electric current Iout size is positively correlated.
The present embodiment is to illustrate the fortune of power supply change-over device 200 under different loads to load the situation gradually increased
Make.In cycle T 1, light load, shorter during the enable of synchronous rectification control signal Ssr at this time, so that the base of transistor Q1
Pole tension Vb has not exceeded barrier voltages Vth in cycle T 1, therefore line loss compensation circuit 250 will not also be to electricity in cycle T 1
Power-switching circuit 210 makees output voltage Vout compensation, therefore the voltage value of output voltage Vout can be maintained substantially in cycle T 1
On V1.
When load improve when, such as the function situation of cycle T 2, during the enable that synchronous rectification controls signal Ssr can with increasing
Add.Since capacitor C1 can be persistently electrically charged during synchronous rectification controls the enable of signal Ssr, so that the base stage of transistor Q1
Voltage Vb can be more than barrier voltages Vth.In the case, the pressure difference of voltage Vnb and base voltage Vb can be established on resistance Rb
Base current Ib, so that compensation electric current Icomp can be generated therewith and (be had β multiple proportion with base current Ib).Wherein, output voltage
Vout is pulled to voltage value V2 because of the effect of compensation electric current Icomp, uses generated pressure drop when compensation load improves.
Similarly, in successively cycle T 3, as output loading continues to increase, base current Ib also can be with synchronous rectification
Area increases and improves during controlling the enable of signal Ssr, so that compensation electric current Icomp also increases, to make output voltage
Vout is pulled to voltage value V3 from voltage value V2 again, generated pressure drop when being improved with compensation load.
The running of power supply change-over device 200 is as shown in Figure 4 in the signal sequence of CCM.Referring to Fig. 2 and Fig. 4, due to
It is fixed under CCM, during the cut-off of power switch PSW, so that being also solid during the enable of synchronous rectification control signal Ssr
It is fixed.But when output electric current Iout is larger, synchronous rectification control signal Ssr relatively can just decay slowly；On the contrary, when output electricity
When stream Iout is smaller, synchronous rectification control signal Ssr then can more early decay.In other words, at CCM, synchronous rectification controls signal
Electric current Iout size is same is positively correlated with output for the enable waveform area of Ssr.
The present embodiment is equally to illustrate power supply change-over device 200 under different loads to load the situation gradually increased
Running.In cycle T 1, since light load, the voltage quasi position of synchronous rectification control signal Ssr can more early decay at this time, so that
Voltage quasi position of the voltage Vnb in cycle T 1 on node NB is lower, therefore in cycle T 1 produced by line loss compensation circuit 250
Compensation electric current Icomp it is smaller, therefore the voltage value of output voltage Vout can be maintained substantially on V1 in cycle T 1.
When loading raising, as the voltage quasi position of the function situation of cycle T 2, synchronous rectification control signal Ssr can be delayed
It is later just to decay, so that capacitor C1 is longer with the time that high voltage level charges, therefore enable the voltage of the voltage Vnb on node NB
Level rises.In the case, since base current Ib can rise with it with the rising of voltage Vnb, and electric current is compensated
The size of Icomp has multiple proportion with base current Ib again, therefore output voltage Vout can be because of the work of compensation electric current Icomp
It is pulled to voltage value V2 with and from voltage value V1, uses generated pressure drop when compensation load improves.
Similarly, in successively cycle T 3, as output loading continues to increase, base current Ib also can be with synchronous rectification
Area increases and improves during controlling the enable of signal Ssr, so that compensation electric current Icomp also increases, to make output voltage
Vout is pulled to voltage value V3 from voltage value V2 again, generated pressure drop when being improved with compensation load.
In conclusion the present invention proposes a kind of power supply change-over device comprising one makees using synchronous rectification control signal
For the line loss compensation circuit of the foundation of line loss compensation.Wherein, the line loss compensation circuit can be produced based on synchronous rectification control signal
The raw compensation electric current for corresponding to output size of current, and output voltage is compensated accordingly in line loss when overloaded.Due to nothing
By at DCM or CCM, the waveform of synchronous rectification control signal can all indicate output size of current, therefore the embodiment of the present invention
Power supply change-over device is either operated at DCM or CCM, and line loss compensation can all be effectively performed, and is turned without being limited to power supply
The operating mode of changing device.Further, since the power supply change-over device of the embodiment of the present invention and being not required to using additional current detecting
Circuit directly detects output electric current, therefore the overall power dissipation of power supply change-over device is minimized.
Although the present invention is disclosed as above with embodiment, however, it is not to limit the invention, any technical field
Middle those of ordinary skill, it is without departing from the spirit and scope of the present invention, therefore of the invention when can make a little change and retouching
Protection scope is subject to view appended claims confining spectrum.
Claims (9)
1. a kind of power supply change-over device characterized by comprising
One power-switching circuit is used to carry out power supply conversion to an input voltage and generates an output voltage, and will be described
Output voltage is supplied to a load；
One synchronous rectification transistor is serially connected on a secondary side current path of the power-switching circuit, and is controlled by one
Synchronous rectification controls signal and switched conductive state；
One synchronous commutating control circuit couples the synchronous rectification transistor, to generate synchronous rectification control signal with
Control the switching of the synchronous rectification transistor；
One feedback circuit couples the power-switching circuit, to generate the output instruction electricity for being associated with the output voltage
Stream；And
One line loss compensation circuit couples the synchronous commutating control circuit and the feedback circuit, to according to it is described synchronize it is whole
Flow control signals draw a compensation electric current from the feedback circuit, use based on the compensation electric current and output instruction electricity
The summation of stream compensates the output voltage,
Wherein the feedback circuit includes:
One 3rd resistor, first end couples the output end of the power-switching circuit, and its second end couples the line loss and mends
Repay the output end of circuit；
One the 4th resistance, first end couple the line loss compensation circuit the output end and the 3rd resistor described the
Two ends, and its second end couples a secondary side ground terminal；
One the 5th resistance, first end couple the second end and described the first of the 4th resistance of the 3rd resistor
End；
One second capacitor, first end couple the second end of the 5th resistance；And
One voltage-stablizer, first end couple the second end of second capacitor, and second end couples the secondary side ground terminal, and
Its pressure stabilizing end couples the second end of the 3rd resistor and the first end of the 4th resistance.
2. power supply change-over device according to claim 1, which is characterized in that the waveform of synchronous rectification control signal with
An output size of current variation caused by the power-switching circuit.
3. power supply change-over device according to claim 1, which is characterized in that it is described compensation electric current size with it is described synchronous
One enable time of whole flow control signals and the product of a voltage quasi position are positively correlated.
4. power supply change-over device according to claim 1, which is characterized in that the line loss compensation circuit includes:
One first resistor, first end couple the synchronous commutating control circuit, use and receive the synchronous rectification control signal；
One second resistance, first end couple the feedback circuit；
One first capacitor, first end couples the second end of the first resistor, and its second end couples the secondary side ground connection
End；
One the first transistor, first end couple the second end of the second resistance, and second end couples the secondary side ground connection
End, and its control terminal couples the second end of the first resistor and the first end of the first capacitor；And
One resistance, first end couple the second end of the first resistor and the first end of the first capacitor,
Second end couples the control terminal of the first transistor.
5. power supply change-over device according to claim 4, which is characterized in that it is described for flowing through the electric current of the second resistance
Compensate electric current.
6. power supply change-over device according to claim 4, which is characterized in that the power-switching circuit includes:
One transformer has a first side winding and a secondary side winding, wherein the different name end of the first side winding receives institute
State input voltage；
One input capacitance, first end couples the different name end of the first side winding, and its second end coupling one once flanks ground
End；
One power switch, first end couple the Same Name of Ends of the first side winding, and the coupling of its second end is described once flanks
Ground terminal；
One control chip, couples the control terminal of the power switch, uses and provides a pulse-width modulation signal to control the power
The switching of switch；And
One output capacitance, first end couple the Same Name of Ends of secondary side winding, and the coupling of its second end is described secondary flanks
Ground terminal.
7. power supply change-over device according to claim 6, which is characterized in that the first end coupling of the synchronous rectification transistor
The second end of the output capacitance is connect, the second end of the synchronous rectification transistor couples the different name of the secondary side winding
End, and the control terminal of the synchronous rectification transistor couples the synchronous commutating control circuit.
8. power supply change-over device according to claim 6, which is characterized in that the output end of the power-switching circuit
For the first end of the output capacitance, the output end of the line loss compensation circuit is described the of the second resistance
One end.
9. power supply change-over device according to claim 1, which is characterized in that it is described for flowing through the electric current of the 4th resistance
Indicator current is exported, and flows through the electric current of the 3rd resistor and compensates the total of electric current with described for the output indicator current
With.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610081449.4A CN107046368B (en) | 2016-02-05 | 2016-02-05 | Power supply change-over device |
| US15/161,300 US9729073B1 (en) | 2016-02-05 | 2016-05-23 | Power conversion apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610081449.4A CN107046368B (en) | 2016-02-05 | 2016-02-05 | Power supply change-over device |
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| CN107046368A CN107046368A (en) | 2017-08-15 |
| CN107046368B true CN107046368B (en) | 2019-03-08 |
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| CN201610081449.4A Active CN107046368B (en) | 2016-02-05 | 2016-02-05 | Power supply change-over device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111596115B (en) * | 2019-02-01 | 2022-09-13 | 群光电能科技股份有限公司 | Method for measuring output current by resistance compensation and conversion circuit thereof |
| CN111698812B (en) * | 2019-02-27 | 2022-10-21 | 宏碁股份有限公司 | Voltage compensation driving circuit |
| WO2021088273A1 (en) | 2019-11-04 | 2021-05-14 | 海信视像科技股份有限公司 | Display device and compensation circuit |
| CN115565472A (en) * | 2019-11-04 | 2023-01-03 | 海信视像科技股份有限公司 | Display device and compensation circuit |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102904449A (en) * | 2011-07-26 | 2013-01-30 | 崇贸科技股份有限公司 | Regulation circuit providing cable compensation for power converter |
| JP2013118780A (en) * | 2011-12-05 | 2013-06-13 | Sanken Electric Co Ltd | Switching power supply device |
| CN105094189A (en) * | 2014-05-14 | 2015-11-25 | 登丰微电子股份有限公司 | Cable loss compensation circuit and power supply circuit having cable loss compensation |
-
2016
- 2016-02-05 CN CN201610081449.4A patent/CN107046368B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102904449A (en) * | 2011-07-26 | 2013-01-30 | 崇贸科技股份有限公司 | Regulation circuit providing cable compensation for power converter |
| JP2013118780A (en) * | 2011-12-05 | 2013-06-13 | Sanken Electric Co Ltd | Switching power supply device |
| CN105094189A (en) * | 2014-05-14 | 2015-11-25 | 登丰微电子股份有限公司 | Cable loss compensation circuit and power supply circuit having cable loss compensation |
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| CN107046368A (en) | 2017-08-15 |
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