CN202840946U - Switch voltage stabilizing circuit and voltage feedback circuit thereof - Google Patents
Switch voltage stabilizing circuit and voltage feedback circuit thereof Download PDFInfo
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- CN202840946U CN202840946U CN 201220467913 CN201220467913U CN202840946U CN 202840946 U CN202840946 U CN 202840946U CN 201220467913 CN201220467913 CN 201220467913 CN 201220467913 U CN201220467913 U CN 201220467913U CN 202840946 U CN202840946 U CN 202840946U
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Abstract
The utility model discloses a switch voltage stabilizing circuit and voltage feedback circuit thereof. The switching voltage stabilizing circuit comprises a switching circuit for converting an input voltage into an output voltage and an output current, and the voltage feedback circuit comprises: a resistance voltage divider circuit sampling an output voltage; a line loss detection circuit providing a compensation control signal at an output thereof, the compensation control signal being proportional to the output current; the controlled current source circuit is provided with a control end, a grounding end and an output end, wherein the control end is coupled to the output end of the line loss detection circuit to receive the compensation control signal, the grounding end is grounded, and the output end provides the compensation current; and wherein the output of the resistive divider circuit is coupled to the output of the controlled current source circuit to provide a feedback voltage representative of the post-line output voltage.
Description
Technical field
The utility model relates generally to Switching Power Supply, more specifically, relates to switch voltage-stabilizing circuit and voltage feedback circuit thereof with line loss compensation function.
Background technology
Nowadays, most of electronic equipments need Switching Power Supply to provide direct voltage to power.When Switching Power Supply is powered to load, the feedback voltage of the sampling of output voltage as control circuit, and this feedback voltage carried out after error amplifies, the conducting of adjusting switching tube and turn-off time are constant with the realization output voltage.Yet when long or wire diameter was thinner when output line, there was larger line resistance (for example in the charger plan) in the output line between Switching Power Supply and the load, and output current can produce larger line loss pressure drop when flowing through output line.And in the situation that output current changes greatly, output voltage also has larger variation behind the line of output line, affects the normal operation of load.Under the constant voltage output mode, this variation is can not be received in some occasion.
The utility model content
For one or more problems of the prior art, a purpose of the present utility model provides a kind of switch voltage-stabilizing circuit and voltage feedback circuit thereof with line loss compensation function, the line loss pressure drop that causes when flowing through output line by the compensation output current, keep Switching Power Supply and reach setting voltage to the voltage that load provides, work with proof load.
Aspect one of the utility model, a kind of voltage feedback circuit for switch voltage-stabilizing circuit is proposed, this switch voltage-stabilizing circuit comprises the switching circuit that input voltage is converted to output voltage and output current, and this voltage feedback circuit comprises: resistor voltage divider circuit, sampling and outputting voltage; The line loss testing circuit, in its output control signal that affords redress, this compensating control signal is directly proportional with output current; The controlled current flow source circuit has control end, earth terminal and output, and wherein the control end output that is coupled to the line loss testing circuit to be receiving compensating control signal, earth terminal ground connection, the output electric current that affords redress; And wherein the output of the output of resistor voltage divider circuit and controlled current flow source circuit links together to provide the feedback voltage that represents output voltage behind the line.
In one embodiment, voltage feedback circuit further comprises the startup blanking circuit, and this startup blanking circuit comprises: enable comparator, have in-phase input end, inverting input and output, wherein in-phase input end is coupled to feedback voltage, and inverting input is coupled to and enables reference voltage; Single-shot trigger circuit has input and output, and wherein input is coupled to the machine that the opens signal of switch voltage-stabilizing circuit; The first trigger has set end, reset terminal and output, and wherein the set end is coupled to the output of single-shot trigger circuit, and reset terminal is coupled to the output that enables comparator; And the discharge switch pipe, have first end, the second end and control end, wherein first end is coupled to the control end of controlled current flow source circuit, and the second end is coupled to ground, and control end is coupled to the output of the first trigger.
In one embodiment, the controlled current flow source circuit comprises: operational amplifier, have in-phase input end, inverting input and output, and wherein in-phase input end is coupled to the output of line loss testing circuit as the control end of controlled current flow source circuit; The first switching tube has first end, the second end and control end, and wherein the second end is coupled to the inverting input of operational amplifier, and control end is coupled to the output of operational amplifier; Compensating resistor has first end and the second end, and wherein first end is coupled to the second end of the first switching tube, the second end ground connection; And current mirroring circuit, have input and output, wherein input is coupled to the first end of the first switching tube, and output is as the output of the controlled current flow source circuit electric current that affords redress.
Aspect another, propose a kind of switch voltage-stabilizing circuit with line loss compensation function of the present utility model, comprising: switching circuit, comprise main switch, the conducting by main switch is converted to output voltage and output current with input voltage with turn-offing; Aforesaid voltage feedback circuit, the output voltage of sampling switch circuit produces the feedback voltage represent output voltage behind the line; Control circuit based on feedback voltage and reference voltage, produces the control signal of control main switch conducting and shutoff, so that output voltage reaches set point behind the line of switch voltage-stabilizing circuit.
In one embodiment, resistor voltage divider circuit is coupled between the output and ground of switching circuit, directly output voltage is carried out dividing potential drop.
In one embodiment, the line loss testing circuit comprises output current detection circuit.
In one embodiment, the line loss testing circuit comprises the switching frequency testing circuit, produces the compensating control signal that is directly proportional with switching frequency at its output.
In one embodiment, switching circuit comprises flyback transformer, the auxiliary winding identical with the secondary winding polarity that has former limit winding, secondary winding and be positioned at former limit, resistor voltage divider circuit are coupled in the two ends of the auxiliary winding of flyback transformer, the voltage at the auxiliary winding two ends of sampling.In a further embodiment, the line loss testing circuit comprises: the first not gate, have input and output, and wherein input is coupled to control signal; The first rising edge testing circuit has input and output, and wherein input is coupled to the output of the first not gate; The first comparator has in-phase input end, inverting input and output, and wherein in-phase input end is coupled to the output of resistor voltage divider circuit, and inverting input is coupled to comparison reference signal; The second not gate has input and output, and wherein input is coupled to the output of the first comparator; The second rising edge testing circuit has input and output, and wherein input is coupled to the output of the second not gate; The second trigger has set end, reset terminal and output, and wherein the set end is coupled to the output of the first rising edge testing circuit, and reset terminal is coupled to the output of the second rising edge testing circuit; Buffer circuit has input and output, and wherein input is coupled to the output of the second trigger; The first resistor has first end and the second end, and wherein first end is coupled to the output of buffer circuit; The second end is coupled to the control end of controlled current flow source circuit; The first capacitor has first end and the second end, and wherein first end is coupled to the second end of the first resistor, the second end ground connection as the output of line loss testing circuit.
According to embodiment of the present utility model, apply a negative offset current by the output at resistor voltage divider circuit, the compensation output current changes the line loss pressure drop that brings with the output line line resistance, thus output voltage is constant behind the line of maintained switch voltage stabilizing circuit.
Description of drawings
In order better to understand the utility model, will be described in detail the utility model according to the following drawings:
Fig. 1 is the block diagram according to the switch voltage-stabilizing circuit 100 of the utility model one embodiment;
Fig. 2 is the circuit diagram that is used for explanation line loss compensation function according to the utility model one embodiment;
Fig. 3 is the circuit theory diagrams according to the voltage feedback circuit of the utility model one embodiment;
Fig. 4 is the application schematic diagram according to the switch voltage-stabilizing circuit of the utility model one embodiment;
Fig. 5 is the circuit theory diagrams according to management chip 220 among Fig. 4 of the utility model one embodiment;
Fig. 6 is the circuit theory diagrams according to line loss testing circuit 203 among Fig. 5 of the utility model one embodiment;
Fig. 7 is the basic waveform according to testing circuit 310 among Fig. 6 of the utility model one embodiment.
Embodiment
The below will describe specific embodiment of the utility model in detail, should be noted that the embodiments described herein only is used for illustrating, and be not limited to the utility model.In the following description, in order to provide thorough understanding of the present utility model, a large amount of specific detail have been set forth.Yet, it is evident that for those of ordinary skills: needn't adopt these specific detail to carry out the utility model.In other examples, for fear of obscuring the utility model, do not specifically describe known circuit, material or method.
In whole specification, " embodiment ", " embodiment ", " example " or mentioning of " example " are meaned: special characteristic, structure or characteristic in conjunction with this embodiment or example description are comprised among at least one embodiment of the utility model.Therefore, phrase " in one embodiment ", " in an embodiment ", " example " or " example " that occurs in each place of whole specification differs to establish a capital and refers to same embodiment or example.In addition, can with any suitable combination and or sub-portfolio with specific feature, structure or property combination in one or more embodiment or example.In addition, it should be understood by one skilled in the art that at this diagram that provides all be for illustrative purposes, and diagram is drawn in proportion not necessarily.Should be appreciated that when claiming " element " " to be connected to " or " coupling " during to another element, it can be directly to connect or be couple to another element or can have intermediary element.On the contrary, when claiming element " to be directly connected to " or during " being directly coupled to " another element, not having intermediary element.
Fig. 1 is the block diagram according to the switch voltage-stabilizing circuit 100 of the utility model one embodiment.As shown in Figure 1, switch voltage-stabilizing circuit 100 comprises switching circuit 101, voltage feedback circuit and control circuit 105.Voltage feedback circuit comprises resistor voltage divider circuit 102, line loss testing circuit 103, controlled current flow source circuit 104.Wherein switching circuit 101 comprises main switch, by conducting and the shutoff of controlling main switch input voltage vin is converted to output voltage V out and output current Iout.Switching circuit 101 can adopt any ac/dc or DC/DC conversion topological structure, for example synchronous or asynchronously boost, buck converter, and normal shock, anti exciting converter etc.Switching circuit 101 is operated in constant voltage mode, and the voltage that provides for load 106 should equal setting voltage Vo.
Resistor voltage divider circuit 102 is used for sampling and outputting voltage Vout.In the embodiment shown in fig. 1, resistor voltage divider circuit 102 is coupled to the output of switching circuit 101, directly output voltage V out is carried out the dividing potential drop sampling.In another embodiment, resistor voltage divider circuit 102 is coupled to the auxiliary winding two ends of transformer in the switching circuit 101, and the voltage of assisting the winding two ends is carried out the dividing potential drop sampling.In one embodiment, resistor voltage divider circuit 102 comprises the first voltage grading resistor R that is connected in series
1With the second voltage grading resistor R
2, the first voltage grading resistor R
1With the second voltage grading resistor R
2Tie point be the output of resistor voltage divider circuit 102.
Line loss testing circuit 103 is used for providing the compensating control signal that is directly proportional with output current Iout CC.In one embodiment, line loss testing circuit 103 comprises the testing circuit of output current Iout, produces the compensating control signal CC that is directly proportional with output current Iout based on output current Iout.Compensating control signal CC can be voltage signal, also can be current signal.In another embodiment, the line loss testing circuit produces the compensating control signal CC that is directly proportional with output current Iout according to other signals, and for example among the embodiment of back, the line loss testing circuit is according to feedback voltage V
FBProduce the compensating control signal CC that is directly proportional with output current Iout with the control signal CTRL of main switch.
Controlled current flow source circuit 104 has control end, earth terminal and output, wherein control end is coupled to the output of line loss testing circuit 103, to receive compensating control signal CC, earth terminal ground connection, the offset current I that controlled current flow source circuit 104 is directly proportional with output current Iout in its output generation
CPThe output of the output of controlled current flow source circuit 104 and resistor voltage divider circuit 102 links together, and the feedback voltage V that represents output voltage V out1 behind the line is provided
FBCC is corresponding with compensating control signal, and controlled current flow source circuit 104 can be voltage-controlled current source, also can be the current source of Current Control.
Fig. 2 is the circuit diagram that is used for explanation line loss compensation function according to the utility model one embodiment.When not accessing the controlled current flow source circuit, 102 couples of output voltage V out of resistor voltage divider circuit carry out dividing potential drop, obtain representing the first sampled voltage V of output voltage V out at its output (node S)
Sl:
Wherein, R
1And R
2Be respectively the resistance value of the first and second voltage grading resistors.In fact, reach setting voltage Vo for guaranteeing the voltage that switch voltage-stabilizing circuit offers load, we wish the second sampled voltage of output voltage V out1 after the output of resistor voltage divider circuit 102 (node S) obtains representing line
Wherein, Iout is the output current of Switching Power Supply, R
LineResistance value for output line between switching circuit and the load.
For obtaining the second sampled voltage V in the formula (2)
S2, as shown in Figure 2, apply a negative offset current I at the output of resistor voltage divider circuit 102
CP, offset current I
CPFlow through the first voltage grading resistor R
1, with the first sampled voltage V
S1Be down to the second sampled voltage V
S2, as shown in Figure 2, the second sampled voltage V that obtains thus
S2With the pass of output voltage V out be:
With formula (3) substitution formula (2), be compensated electric current I
CPFor:
Can be found out required offset current I by formula (4)
CPValue and the resistance value R of output current Iout, output line
LineAnd the resistance value R of the first voltage grading resistor
1Relevant.For the switch voltage-stabilizing circuit of specific circuit architecture, the resistance value R of its output line
LineResistance value R with the first voltage grading resistor
1It is constant.Therefore, offset current I
CPValue change with output current Iout, Iout is directly proportional with output current.
Like this, switch voltage-stabilizing circuit adopts the offset current I of suitable size
CPTo the first sampled voltage V
S1Compensate, will meet the second sampled voltage V of sampling expectation
S2As feedback voltage V
FBProvide to the control circuit of switch voltage-stabilizing voltage, by adjusting the turn-on and turn-off time of main switch in the switching circuit, keep switching circuit and provide that output voltage V out1 reaches setting voltage Vo to the line of load.
Fig. 3 is the circuit theory diagrams according to the voltage feedback circuit of the utility model one embodiment.Voltage feedback circuit comprises resistor voltage divider circuit 102, line loss testing circuit 103 and controlled current flow source circuit 104.Wherein, resistor voltage divider circuit 102 is used for sampling and outputting voltage Vout.Line loss testing circuit 103 provides a compensating control signal CC who is directly proportional with output current Iout at its output.Controlled current flow source circuit 104 has control end, earth terminal and output, and wherein the control end output that is coupled to line loss testing circuit 103 receives compensating control signal CC, earth terminal ground connection, the output electric current I that affords redress
CPThe output of the output of resistor voltage divider circuit 102 and controlled current flow source circuit 104 links together to provide the feedback voltage V that represents output voltage V out1 behind the line
FB
In the embodiment shown in fig. 3, controlled current flow source circuit 104 is voltage-controlled current source circuit, comprise operational amplifier 141, switching tube 142 and compensating resistor 143 and current mirror circuit, wherein the in-phase input end of operational amplifier 141 is coupled to the output of line loss testing circuit 103 to receive compensating control signal CC as the control end of controlled current flow source circuit 104.The inverting input of operational amplifier 141 is coupled to the source electrode of switching tube 132, and output is coupled to the grid of switching tube 132.The drain electrode of switching tube 132 is coupled to the input of current mirror circuit, and source electrode is through compensating resistor 133 ground connection.Current mirror circuit provides required offset current I at its output
CPIn one embodiment, current mirror circuit comprises current mirror 1 (144) and the current mirror 2 (145) that cascade connects.In the embodiment shown in fig. 3, controlled current flow source circuit 104 can be regulated offset current I by the resistance value that changes compensating resistor 143
CPSize.
In another embodiment, controlled current flow source circuit 104 comprises the current source circuit of Current Control, and for example the proportional current mirror circuit receives the compensating control signal CC that is directly proportional with output current Iott, and is converted into the offset current I that meets formula (4)
CP
In one embodiment, voltage feedback circuit also comprises startup blanking circuit 130.Switch voltage-stabilizing circuit the startup stage, output voltage is less, output voltage increases to setting voltage Vo needs the regular hour.Generally, the startup stage switch voltage-stabilizing circuit can be operated in constant current mode, namely output current is constant.The offset current that provides of controlled current flow source circuit 104 can cause the output voltage overshoot like this, prolongs output voltage and enters the time of stable state, affects the service behaviour of switch voltage-stabilizing circuit.For this reason, voltage feedback circuit comprises the startup blanking circuit 130 with blanking function, opening machine (power on) signal at switch voltage-stabilizing circuit comes interim, start blanking circuit 130 and trigger the controlled current flow source circuit, the compensating control signal CC of blanking controlled current flow source circuit 104 control ends makes offset current I
CPBe zero, and when output voltage V out increased near setting voltage Vo, restoration and compensation control signal CC made offset current I to the normal control of controlled current flow source circuit 103
CPChange with compensating control signal CC.
In the embodiment shown in fig. 3, start that blanking circuit 130 comprises single-shot trigger circuit 131, enables comparator 132, trigger 133 and discharge switch pipe 134.The machine that the opens signal Pwr_on of single-shot trigger circuit 131 receiving key voltage stabilizing circuits, the output of single-shot trigger circuit 131 is coupled to the set end S of trigger 133.The output that the in-phase input end that enables comparator 132 is coupled to resistor voltage divider circuit 102 is to receive the feedback voltage V that represents output voltage behind the line
FB, inverting input receives and enables reference voltage V
EN, output is coupled to the reset terminal R of trigger 133.Discharge switch pipe 134 has first end, the second end and control end, and wherein first end is coupled to the control end of controlled current flow source circuit 104, and the second end is coupled to ground, and control end is coupled to the output of trigger 133.When switch voltage-stabilizing circuit starts, single-shot trigger circuit 131 produces single pulse signal to the set end S of trigger 133, set flip-flop 133,134 conductings of controlled discharge switching tube, with the compensating control signal CC zero setting of controlled current flow source circuit 104 control ends, realize the blanking to compensating control signal.So startup stage output voltage foundation, offset current I
CPBe 0, the feedback voltage V that resistor voltage divider circuit 102 provides at its output
FBEqual the first sampled voltage V
S1 Enable comparator 132 with feedback voltage V
FBWith enable reference voltage V
ENCompare, work as feedback voltage V
FBIncrease to and enable reference voltage V
ENThe time, reset flip-flop 133, discharge switch pipe 134 turn-offs, and restoration and compensation control signal CC makes offset current I to the normal control of controlled current flow source circuit 104
CPChange with compensating control signal CC.In one embodiment, enable reference voltage V
EN=0.9*Vo, wherein Vo is the setting voltage that switch voltage-stabilizing circuit offers load.
When switch voltage-stabilizing circuit is operated in the discontinuous current pattern, power output P
OutBe expressed as:
Wherein, L is the inductance value (for anti exciting converter, L is transformer primary side magnetizing inductance value) of energy-storage travelling wave tube, and Ipeak is the peak value that flows through the electric current of energy-storage travelling wave tube, and f is the switching frequency of switching circuit.Switch voltage-stabilizing circuit requires output voltage V out to keep constant, when peak current Ipeak is constant, controls power output by the switching frequency of control switch circuit.By formula (5) as can be known, the switching frequency f of switching circuit is directly proportional with output current Iout in the above-mentioned situation.Again convolution (4) as can be known, the peak current one that switch voltage-stabilizing circuit is operated in the discontinuous current pattern and flows through energy-storage travelling wave tube regularly, offset current I
CPBe directly proportional with the switching frequency f of switching circuit.Therefore, in one embodiment, line loss testing circuit 103 comprises the switching frequency testing circuit, and line loss testing circuit 103 produces the offset current I that is directly proportional with output current Iout according to the switching frequency f of switching circuit at its output
CPIn other embodiments, controlled current flow source circuit 104 can receive other signals that is directly proportional with output current Iout, produces required offset current I
CP
Fig. 4 is the application schematic diagram according to the switch voltage-stabilizing circuit of the utility model one embodiment.This switch voltage-stabilizing circuit has the line loss compensation function, comprises switching circuit, resistor voltage divider circuit, line loss testing circuit, controlled current flow source circuit and control circuit.Switch voltage-stabilizing circuit adopts the inverse-excitation converting topology, receives AC-input voltage Vin, through not control rectifying circuit 211 and input capacitor C
INDC input voitage is provided behind the rectifying and wave-filtering.Switching circuit comprises main switch M, flyback transformer T, secondary diode D and output capacitor C
OUT, its circuit connection structure as shown in Figure 4.Wherein flyback transformer T comprises former limit winding Np, secondary winding Ns and the auxiliary winding Na identical with the secondary winding polarity that is positioned at former limit.
Shown in Figure 4 220 is management chip, comprises control unit 205 and compensating unit 204.In other embodiments, management chip 220 also comprises main switch M.Wherein compensating unit 204 comprises the controlled current flow source circuit.As shown in Figure 4, management chip 220 has control pin CTRL, current detecting pin CS, power supply input pin VCC, feedback pin FB, compensation pin CP and grounding pin GND.Wherein control the control end that pin CTRL is coupled to main switch M, provide control signal CTRL to adjust opening and the turn-off time of main switch M.Current detecting pin CS is for detection of the electric current that flows through main switch M.Feedback pin FB is coupled to the output of resistor voltage divider circuit and the output of compensating unit 204, for control unit provides feedback voltage.Compensation condenser Cp is external between compensation pin CP and the ground, for the controlled current flow source circuit in the compensating unit 204 provides suitable compensating control signal CC.
Switch voltage-stabilizing circuit shown in Figure 4 also comprises start-up circuit and auxiliary power supply circuit.Start-up circuit receives DC input voitage, produces and opens machine signal Pwr_on, and will open the power supply input pin VCC that machine signal Pwr_on is input to management chip 220, for 220 electronic circuit in the management chip provides starting resistor.In the embodiment shown in fig. 4, start-up circuit comprises resistor R0 and the capacitor C0 that is connected in series, and produces at the tie point A of resistor R0 and capacitor C0 and opens machine signal Pwr_on.Start-up circuit be management chip 220 set up starting resistor and produce open machine signal Pwr_on after, the auxiliary power supply circuit replaces start-up circuit that management chip 220 is powered, and to reduce power loss, improves the efficient of switch voltage-stabilizing circuit.In the embodiment shown in fig. 4, the auxiliary power supply circuit is from the auxiliary winding Na up-sampling voltage of flyback transformer T, and D1 powers to management chip by diode.In other embodiments, switch voltage-stabilizing circuit comprises the power supply circuits that are coupled to power supply input pin VCC, and when the normal working voltage of power supply circuits access power managing chip and generation, power supply input pin VCC provides and opens machine signal Pwr_on.
Similar with line loss compensation principle shown in Figure 2, resistor voltage divider circuit (comprises the resistor R that is connected in series
1And R
2) being coupled to the two ends of auxiliary winding Na, the voltage Vaux by the auxiliary winding two ends of sampling realizes the sampling to output voltage V out.The voltage Vaux at auxiliary winding Na two ends is:
Wherein, Naux and Ns are respectively the number of turn of auxiliary winding Na and secondary winding Ns, and Vout is the output voltage of switching circuit, V
DConduction voltage drop for secondary diode D.
Resistor voltage divider circuit carries out dividing potential drop to the voltage Vaux at auxiliary winding two ends, obtains representing the first sampled voltage V of output voltage V out
S11:
Wherein, R
1And R
2Be respectively the resistance value of the first and second voltage grading resistors.We wish the second sampled voltage V of output voltage V out1 after the output of resistor voltage divider circuit obtains representing line
S22:
Wherein, Iout is the output current of Switching Power Supply, and Rline is the resistance value of the output line between switch voltage-stabilizing circuit and the load.Offset current I
CPFlow through the first voltage grading resistor R
1, with the first sampled voltage V
S11Be down to the second sampled voltage V
S22, as shown in Figure 2, the second sampled voltage V that obtains thus
S22With the pass of the voltage Vaux at auxiliary winding Na two ends be:
With formula (9) and formula (6) substitution formula (8), be compensated electric current I
CPFor:
Can be found out required offset current I by formula (10)
CPValue and the resistance value R of output current Iout, output line
Line, the first voltage grading resistor resistance value R
1, the number of turn Naux of auxiliary winding Na and secondary winding number of turn Ns relevant.For the switch voltage-stabilizing circuit of specific circuit architecture, the resistance value R of its output line
Line, the first voltage grading resistor resistance value R
1, the number of turn Naux of auxiliary winding Na and the number of turn Ns of secondary winding fix.Therefore, offset current I
CPValue change with output current Iout, Iout is directly proportional with output current.
Fig. 5 is the circuit theory diagrams according to management chip 220 among Fig. 4 of the utility model one embodiment.Management chip 220 comprises compensating unit 204 and control unit 205.Wherein compensating unit 204 comprises line loss testing circuit 203, starts blanking circuit 130 and controlled current flow source circuit 204.Control unit 205 control switch circuit workings are in the discontinuous current pattern, and it is constant to flow through the peak current of main switch.In one embodiment, control unit 205 comprises error amplifier 252, comparator 253, rest-set flip-flop 254 and peak comparator 255.Among the embodiment shown in Figure 5, voltage feedback circuit comprises resistor voltage divider circuit 202, line loss testing circuit 203, startup blanking circuit 130, controlled current flow source circuit 204 and sampling hold circuit 140.Wherein sampling hold circuit 140 is coupled between feedback pin FB and the control unit 205, and the feedback voltage V of output voltage behind the representation switch circuit line is provided
FB
In one embodiment, error amplifier 252 has in-phase input end, inverting input and output, and wherein in-phase input end is coupled to the output of sampling hold circuit 140, receives the feedback voltage V represent output voltage behind the line
FB, inverting input is coupled to reference voltage Vref.Comparator 253 has in-phase input end, inverting input and output, and wherein in-phase input end is coupled to triangular modulation signal V
SAw, inverting input is coupled to the output of error amplifier 252, and output is coupled to the set end of rest-set flip-flop 254 so that the turn-off time control signal of main switch M to be provided.Peak comparator 255 has in-phase input end, inverting input and output, and wherein in-phase input end is coupled to current detecting pin CS flows through main switch M to receive representative current sampling signal, and inverting input receives constant peak current limit value V
TH, output is coupled to the reset terminal R of rest-set flip-flop 254, in the output generation ON time control signal of peak comparator 255, with the ON time of main switch M in the control switch circuit.Rest-set flip-flop 254 produces the control signal CTRL of main switch M based on ON time control signal and turn-off time control signal at the output Q of rest-set flip-flop 254.Those of ordinary skills should understand, and control signal CTRL can control the break-make of main switch M usually again after overdrive circuit is strengthened driving force.In one embodiment, control unit 205 further comprises drive circuit, and drive circuit comprises driver DRV.
Continue as shown in Figure 5, start that blanking circuit 130 comprises single-shot trigger circuit 131, enables comparator 132, trigger 133 and discharge switch pipe 134.Single-shot trigger circuit 131 is coupled to power supply input pin VCC, receives to open machine signal Pwr_on.Start blanking circuit 130 basic identical with startup blanking circuit shown in Figure 3, do not repeat them here.Controlled current flow source circuit 204 can adopt the circuit structure of controlled current flow source circuit 104 shown in Figure 3, also can adopt other circuit structure that can realize the Voltage-controlled Current Source function.
Fig. 6 is the circuit theory diagrams according to line loss testing circuit 203 among Fig. 5 of the utility model one embodiment.Line loss testing circuit 203 comprises testing circuit 310, buffer circuit 320 and resistor Rp and capacitor Cp.
The input of testing circuit 310 is coupled to feedback pin FB and control pin CTRL, for detection of the pulse signal Td of secondary ON time td with generation reflection secondary ON time td.Testing circuit 310 comprises the first not gate 311, the first rising edge testing circuit 312, trigger 313, comparator 314, the second not gate 315, the second rising edge testing circuit 316.Trigger 313 has set end S, reset terminal R and output Q.The first not gate 311 has input and output, and its input is coupled to control signal CTRL, the input of output termination the first rising edge testing circuit 312.The set end S of the output contact hair device 313 of the first rising edge testing circuit 312.Comparator 314 has in-phase input end, inverting input and output, and wherein inverting input is coupled to comparison reference signal V
REFX(for example 100mV), in-phase input end is coupled to feedback pin FB, and output is coupled to the input of the second not gate 315.The output of the second not gate 315 is coupled to the input of the second rising edge testing circuit 316.The output of the second rising edge testing circuit 316 is coupled to the reset terminal of trigger 313.Trigger 313 namely produces the pulse signal Td of reflection secondary ON time at its output at the output of testing circuit 310.
Fig. 7 is the oscillogram according to the testing circuit shown in Figure 6 310 of the utility model one embodiment.When the trailing edge arriving of control signal CTRL, when namely secondary diode D began conducting, pulse signal Td saltus step was high level (for example Vd); Work as feedback voltage V
FBTrailing edge arrive, i.e. when secondary diode D conducting finished, pulse signal Td saltus step was low level (for example 0).
Continue as shown in Figure 6, line loss testing circuit 203 at the compensating control signal CC that its output (CP pin) produces is:
CC＝T
d_av＝V
dt
df (10)
Wherein Td av be pulse signal Td through resistor Rp and the filtered direct voltage of capacitor Cp, Vd is the value of pulse signal Td when keeping high level, td is the ON time of secondary diode D, f is the switching frequency of switching circuit.Because control unit 204 is operated in the discontinuous current pattern, and the peak current that flows through main switch M is constant, convolution (5) and formula (10) are as can be known, the ON time td of secondary diode D is constant, compensating control signal CC is directly proportional with switching frequency f, Iout is directly proportional with output current, and controlled current flow source circuit 204 receives compensating control signal CC, the offset current I of generation
CPAlso be directly proportional with output current Iout.Because the capacitor Cp of line loss testing circuit 203 is external in the compensation pin CP of management chip 220, can save the size of management chip 220.
When switch voltage-stabilizing circuit restarted, the voltage of compensation pin CP floated, and may produce wrong offset current, affected the service behaviour of switch voltage-stabilizing circuit.Adopt the startup blanking circuit 130 of the utility model embodiment effectively to address this problem.When switch voltage-stabilizing circuit started, blanking compensating control signal CC was with offset current I
CPZero clearing is until feedback voltage V
FBDuring the setting voltage Vo of approach switch voltage stabilizing circuit, so that offset current I
CPVariation with compensating control signal CC changes, and has both eliminated wrong compensation, has shortened again output voltage and has entered the time of stable state, has kept the service behaviour of switch voltage-stabilizing circuit.
Some above-mentioned specific embodiments only describe the utility model in an exemplary fashion, and these embodiment are not fully detailed, and are not used in the scope of the present utility model that limits.It all is possible changing and revise for disclosed embodiment, the selectivity embodiment that other are feasible and can be understood by those skilled in the art the equivalent variations of element among the embodiment.Other variations of embodiment disclosed in the utility model and modification do not exceed spirit of the present utility model and protection range.
Claims (9)
1. a voltage feedback circuit is used for switch voltage-stabilizing circuit, it is characterized in that, this switch voltage-stabilizing circuit comprises the switching circuit that input voltage is converted to output voltage and output current, and this voltage feedback circuit comprises:
Resistor voltage divider circuit, sampling and outputting voltage;
The line loss testing circuit, in its output control signal that affords redress, this compensating control signal is directly proportional with output current;
The controlled current flow source circuit has control end, earth terminal and output, and wherein the control end output that is coupled to the line loss testing circuit to be receiving compensating control signal, earth terminal ground connection, the output electric current that affords redress; And
Wherein the output of the output of resistor voltage divider circuit and controlled current flow source circuit links together to provide the feedback voltage that represents output voltage behind the line.
2. voltage feedback circuit as claimed in claim 1 is characterized in that, further comprises the startup blanking circuit, and this startup blanking circuit comprises:
Enable comparator, have in-phase input end, inverting input and output, wherein in-phase input end is coupled to feedback voltage, and inverting input is coupled to and enables reference voltage;
Single-shot trigger circuit has input and output, and wherein input is coupled to the machine that the opens signal of switch voltage-stabilizing circuit;
The first trigger has set end, reset terminal and output, and wherein the set end is coupled to the output of single-shot trigger circuit, and reset terminal is coupled to the output that enables comparator; And
The discharge switch pipe has first end, the second end and control end, and wherein first end is coupled to the control end of controlled current flow source circuit, and the second end is coupled to ground, and control end is coupled to the output of the first trigger.
3. voltage feedback circuit as claimed in claim 2 is characterized in that, wherein the controlled current flow source circuit comprises:
Operational amplifier has in-phase input end, inverting input and output, and wherein in-phase input end is coupled to the output of line loss testing circuit as the control end of controlled current flow source circuit;
The first switching tube has first end, the second end and control end, and wherein the second end is coupled to the inverting input of operational amplifier, and control end is coupled to the output of operational amplifier;
Compensating resistor has first end and the second end, and wherein first end is coupled to the second end of the first switching tube, the second end ground connection; And
Current mirroring circuit has input and output, and wherein input is coupled to the first end of the first switching tube, and output is as the output of the controlled current flow source circuit electric current that affords redress.
4. the switch voltage-stabilizing circuit with line loss compensation function is characterized in that, comprising:
Switching circuit comprises main switch, and the conducting by main switch is converted to output voltage and output current with input voltage with turn-offing;
Such as each described voltage feedback circuit of claim 1～3, the output voltage of sampling switch circuit produces the feedback voltage represent output voltage behind the line;
Control circuit based on feedback voltage and reference voltage, produces the control signal of control main switch conducting and shutoff, so that output voltage reaches set point behind the line of switch voltage-stabilizing circuit.
5. switch voltage-stabilizing circuit as claimed in claim 4 is characterized in that, wherein resistor voltage divider circuit is coupled between the output and ground of switching circuit, directly output voltage is carried out dividing potential drop.
6. switch voltage-stabilizing circuit as claimed in claim 4 is characterized in that, wherein the line loss testing circuit comprises output current detection circuit.
7. switch voltage-stabilizing circuit as claimed in claim 4 is characterized in that, wherein the line loss testing circuit comprises the switching frequency testing circuit, produces the compensating control signal that is directly proportional with switching frequency at its output.
8. switch voltage-stabilizing circuit as claimed in claim 4 is characterized in that, wherein switching circuit comprises:
Flyback transformer, the auxiliary winding identical with the secondary winding polarity that has former limit winding, secondary winding and be positioned at former limit;
Resistor voltage divider circuit is coupled in the two ends of the auxiliary winding of flyback transformer, the voltage at the auxiliary winding two ends of sampling.
9. switch voltage-stabilizing circuit as claimed in claim 8 is characterized in that, wherein the line loss testing circuit comprises:
The first not gate has input and output, and wherein input is coupled to control signal;
The first rising edge testing circuit has input and output, and wherein input is coupled to the output of the first not gate;
The first comparator has in-phase input end, inverting input and output, and wherein in-phase input end is coupled to the output of resistor voltage divider circuit, and inverting input is coupled to comparison reference signal;
The second not gate has input and output, and wherein input is coupled to the output of the first comparator;
The second rising edge testing circuit has input and output, and wherein input is coupled to the output of the second not gate;
The second trigger has set end, reset terminal and output, and wherein the set end is coupled to the output of the first rising edge testing circuit, and reset terminal is coupled to the output of the second rising edge testing circuit;
Buffer circuit has input and output, and wherein input is coupled to the output of the second trigger;
The first resistor has first end and the second end, and wherein first end is coupled to the output of buffer circuit; The second end is coupled to the control end of controlled current flow source circuit;
The first capacitor has first end and the second end, and wherein first end is coupled to the second end of the first resistor, the second end ground connection as the output of line loss testing circuit.
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|---|---|---|---|
| CN 201220467913 CN202840946U (en) | 2012-09-14 | 2012-09-14 | Switch voltage stabilizing circuit and voltage feedback circuit thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220467913 CN202840946U (en) | 2012-09-14 | 2012-09-14 | Switch voltage stabilizing circuit and voltage feedback circuit thereof |
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| CN202840946U true CN202840946U (en) | 2013-03-27 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102832806A (en) * | 2012-09-14 | 2012-12-19 | 成都芯源系统有限公司 | Switch voltage stabilizing circuit and voltage feedback method thereof |
| CN104393759A (en) * | 2014-12-11 | 2015-03-04 | 无锡新硅微电子有限公司 | DC-DC (direct current-direct current) converter with line loss compensation function |
| CN104779792A (en) * | 2015-04-17 | 2015-07-15 | 无锡新硅微电子有限公司 | Control circuit and control method of vehicle-mounted charger DC-DC system |
| CN104836444A (en) * | 2015-04-24 | 2015-08-12 | 矽力杰半导体技术(杭州)有限公司 | Self-adaptive blanking time control method and circuit |
| CN107181252A (en) * | 2016-03-11 | 2017-09-19 | 华为技术有限公司 | Power supply control apparatus, electric power system, load and base station |
| CN112769331A (en) * | 2021-03-24 | 2021-05-07 | 苏州力生美半导体有限公司 | Output line compensation circuit without overcharging |
| CN114123778A (en) * | 2021-08-23 | 2022-03-01 | 珠海极海半导体有限公司 | Self-adaptive compensation circuit, protection circuit and integrated circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102832806A (en) * | 2012-09-14 | 2012-12-19 | 成都芯源系统有限公司 | Switch voltage stabilizing circuit and voltage feedback method thereof |
| CN102832806B (en) * | 2012-09-14 | 2015-02-25 | 成都芯源系统有限公司 | Switch voltage stabilizing circuit and voltage feedback method thereof |
| CN104393759A (en) * | 2014-12-11 | 2015-03-04 | 无锡新硅微电子有限公司 | DC-DC (direct current-direct current) converter with line loss compensation function |
| CN104779792A (en) * | 2015-04-17 | 2015-07-15 | 无锡新硅微电子有限公司 | Control circuit and control method of vehicle-mounted charger DC-DC system |
| CN104836444A (en) * | 2015-04-24 | 2015-08-12 | 矽力杰半导体技术(杭州)有限公司 | Self-adaptive blanking time control method and circuit |
| CN104836444B (en) * | 2015-04-24 | 2017-07-11 | 矽力杰半导体技术(杭州)有限公司 | The control method and circuit of a kind of self adaptation blanking time |
| CN107181252A (en) * | 2016-03-11 | 2017-09-19 | 华为技术有限公司 | Power supply control apparatus, electric power system, load and base station |
| CN112769331A (en) * | 2021-03-24 | 2021-05-07 | 苏州力生美半导体有限公司 | Output line compensation circuit without overcharging |
| CN112769331B (en) * | 2021-03-24 | 2021-08-27 | 苏州力生美半导体有限公司 | Output line compensation circuit without overcharging |
| CN114123778A (en) * | 2021-08-23 | 2022-03-01 | 珠海极海半导体有限公司 | Self-adaptive compensation circuit, protection circuit and integrated circuit |
| CN114123778B (en) * | 2021-08-23 | 2024-01-19 | 珠海极海半导体有限公司 | Self-adaptive compensation circuit, protection circuit and integrated circuit |
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