CN108923631B - A kind of switch power supply system and control circuit and device for switch power supply system - Google Patents
A kind of switch power supply system and control circuit and device for switch power supply system Download PDFInfo
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- CN108923631B CN108923631B CN201810820230.0A CN201810820230A CN108923631B CN 108923631 B CN108923631 B CN 108923631B CN 201810820230 A CN201810820230 A CN 201810820230A CN 108923631 B CN108923631 B CN 108923631B
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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Abstract
The invention belongs to electronic technology fields, it mainly provides in a kind of control circuit for switch power supply system, it is handled to obtain corresponding pulse-width signal by second overvoltage protection signal of the logic module to the first overvoltage protection signal and the output of the second overvoltage protective module that the first overvoltage protective module exports, and corresponding driving signal is exported by pulse-width signal control drive module, the turn-on and turn-off of switch module are controlled, when the input voltage of switch power supply system is high voltage, improve the consistency of Switching Power Supply output overloading protection point, it solves in existing AC-DC Switching Power Supply, inductive current enters continuous conduction mode as output loading increases, when the inputting line voltage of AC-DC switch power supply system also increases, meeting is so that the consistency of the output overloading protection point of inductive current reduces , the problem of increasing the error of inductive current, bring great security risk to AC-DC Switching Power Supply and back-end circuit.
Description
Technical field
The invention belongs to electronic technology field more particularly to a kind of switch power supply system and for the control of switch power supply system
Circuit and device processed.
Background technique
Switching Power Supply is as a kind of D.C. regulated power supply controlled using on-off mode, with small in size, light-weight, efficiency
High, the advantages that voltage stabilized range is wide, safe and reliable, is widely used in the neck such as computer, network communication equipment and consumer electronics product
In domain, with the development of electronic technology, the type of electronic product is enriched constantly, constantly proposes to the design of existing Switching Power Supply
New requirement.
In existing AC-DC Switching Power Supply, inductive current enters continuous conduction mode as output loading increases, in AC-
When the inputting line voltage of DC switch power supply system also increases, the output overloading of inductive current can be made to protect the consistency drop of point
It is low, the error of inductive current is increased, brings great security risk to AC-DC Switching Power Supply and back-end circuit.
Summary of the invention
Of the invention provides a kind of switch power supply system and control circuit and device for switch power supply system, solves
In existing AC-DC Switching Power Supply, inductive current enters continuous conduction mode as output loading increases, and switchs electricity in AC-DC
When the inputting line voltage of source system also increases, the consistency that the output overloading of inductive current can be made to protect point is reduced, and is increased
The error of inductive current, the problem of bringing great security risk to AC-DC Switching Power Supply and back-end circuit.
The present invention provides a kind of control circuits for switch power supply system, comprising:
For controlling the conducting and shutdown of the First Line voltage signal of the switch power supply system input, and exports first and adopt
The switch module of sample voltage signal；
It is connect with the switch module, for exporting the first overvoltage protection signal according to the first sampled voltage signal
First overvoltage protective module；
It is connect with the switch module, for exporting the second overvoltage protection signal according to the first sampled voltage signal
Second overvoltage protective module；
It is connect with first overvoltage protective module and second overvoltage protective module, for according to first mistake
The logic module of pressure protection signal and the second overvoltage protection signal output pulse width modulated signal；It is described
It is connect with the logic module, for the drive module according to the pulse-width signal output drive signal.
Optionally, first overvoltage protective module includes: the first comparing unit and first and door；
The first end of first comparing unit is connect with the first reference voltage source, the second end of first comparing unit
It is connect with the first sampled voltage signal output end of the switch module, the output end of first comparing unit and described first
Connect with the first end of door, described first connect with the second end of door with shielded signal source, described first with the output end of door with
The first input end of the logic module connects.
Optionally, first comparing unit is voltage comparator, and the inverting input terminal of the voltage comparator is as institute
State the first end of the first comparing unit, the normal phase input end of the voltage comparator as first comparing unit second
End, output end of the output end of the voltage comparator as first comparing unit.
Optionally, second overvoltage protective module includes: the second comparing unit, reverse phase delay unit, the first triggering list
Member and the first nor gate；
The first end of second comparing unit is connect with the second reference voltage source, the second end of second comparing unit
It is connect with the first sampled voltage signal output end of the switch module, the input terminal of the reverse phase delay unit and described
The first input end of one nor gate is connect with signal source of clock, and the output end of the reverse phase delay unit and first triggering are single
Second input terminal of the first input end connection of member, the output end of second comparing unit and first trigger unit connects
It connects, the output end of first trigger unit is connect with the second input terminal of first nor gate, first nor gate
Output end is connect with the second input terminal of the logic module.
Optionally, first trigger unit is reset-set flip-flop, the first input of the reset-set flip-flop
The first input end as first trigger unit is held, the second input terminal of the reset-set flip-flop is as described first
Second input terminal of trigger unit, output end of the output end of the reset-set flip-flop as first trigger unit.
Optionally, the switch module includes: first switch tube and sampling resistor unit；
The control terminal of the first switch tube is connect with the output end of the drive module, the electric current of the first switch tube
Current input terminal of the input terminal as the control circuit, the current output terminal of the first switch tube and the sampling resistor list
The first end of member connects the first sampled voltage signal output end as the switch module altogether, and the second of the sampling resistor unit
Hold the current output terminal as the control circuit.
Optionally, the sampling resistor unit is the first sampling resistor, and the first end of first sampling resistor is as institute
State the first end of sampling resistor unit, second end of the second end of first sampling resistor as the sampling resistor unit.
Optionally, the first switch tube is N-type metal-oxide-semiconductor, and the grid of the N-type metal-oxide-semiconductor is the first switch tube
Control terminal, the drain electrode of the N-type metal-oxide-semiconductor are the current input terminal of the first switch tube, and the source electrode of the N-type metal-oxide-semiconductor is institute
State the current output terminal of first switch tube.
In order to solve the above-mentioned technical problem, the embodiment of the present invention also proposed a kind of control dress for switch power supply system
It sets, the control device includes: the first reference voltage source, the second reference voltage source, signal source of clock and shielded signal source, institute
Stating control device further includes control circuit described in any of the above embodiments, and the current input terminal of the control circuit is as the control
The current output terminal of first current input terminal of device, the control circuit is exported as the first electric current of the control device
End.
The embodiment of the present invention also proposed a kind of switch power supply system, and the switch power supply system includes: first capacitor,
Two capacitors, the first inductance, first diode, the second diode, third capacitor and load；The switch power supply system further includes
Control device as described in any of the above-described embodiment；First electric current of the first end of the first capacitor, the control device
The electrode input end of input terminal and the switch power supply system connects altogether, the first current output terminal of the control device, described
The first end of the first end of second capacitor, the cathode of second diode and first inductance connects altogether, the control dress
Power end, the second end of second capacitor and the cathode of the first diode set connect altogether, the first diode
The first end of anode, the second end of first inductance and the load connects altogether, the second end of the first capacitor, described
The second end of the anode of two diodes, the second end of the third capacitor and the load is connected to ground altogether.
In a kind of control circuit for switch power supply system provided in an embodiment of the present invention, by logic module to
First overvoltage protection signal of one overvoltage protective module output and the second overvoltage protection letter of the second overvoltage protective module output
It number is handled to obtain corresponding pulse-width signal, and passes through pulse-width signal and control drive module and export corresponding driving
Signal controls the turn-on and turn-off of switch module, when the input voltage of switch power supply system is high voltage, improves
The consistency of Switching Power Supply output overloading protection point, solves in existing AC-DC Switching Power Supply, inductive current is negative with output
It carries to increase into continuous conduction mode and can make inductive current when the inputting line voltage of AC-DC switch power supply system also increases
Output overloading protection point consistency reduce, increase the error of inductive current, give AC-DC Switching Power Supply and back-end circuit
The problem of bringing great security risk.
Detailed description of the invention
Fig. 1 is a kind of modular structure signal of control circuit for switch power supply system provided in an embodiment of the present invention
Figure；
Fig. 2 is a kind of circuit structure signal of control circuit for switch power supply system provided in an embodiment of the present invention
Figure；
Fig. 3 is a kind of electrical block diagram of switch power supply system provided in an embodiment of the present invention；
Fig. 4 is the waveform of inductive current of the AC-DC switch power supply system shown in Fig. 3 under ideal working condition；
When Fig. 5 is that the inputting line voltage of AC-DC switch power supply system in actual operation is respectively high voltage and low-voltage
Inductive current waveform diagram when work；
Fig. 6 is the waveform and IOCP threshold value of inductive current of the AC-DC switch power supply system under different inputting line voltages
Comparison figure；
Fig. 7 is output voltage wave and the relational graph of corresponding overload point of AC-DC switch power supply system.
Fig. 8 be in control circuit in the embodiment of the present invention in AC-DC switch power supply system the output signal of each unit with
The relational graph of inductive current.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.Meanwhile in the description of the present invention, term " first ", " second " etc. are only used for distinguishing description, without
It can be interpreted as indication or suggestion relative importance.
It should be appreciated that ought use in this specification and in the appended claims, term " includes " instruction is described special
Sign, entirety, step, operation, the presence of element and/or component, but be not precluded one or more of the other feature, entirety, step,
Operation, the presence or addition of element, component and/or its set.
It is also understood that mesh of the term used in this present specification merely for the sake of description specific embodiment
And be not intended to limit the application.As present specification and it is used in the attached claims, unless on
Other situations are hereafter clearly indicated, otherwise " one " of singular, "one" and "the" are intended to include plural form.
It will be further appreciated that the term "and/or" used in present specification and the appended claims is
Refer to any combination and all possible combinations of one or more of associated item listed, and including these combinations.
In order to illustrate the above-mentioned technical solution of the application, the following is a description of specific embodiments.
Fig. 1 is a kind of modular structure signal of control circuit for switch power supply system provided in an embodiment of the present invention
Figure, as shown in Figure 1, the control circuit in the present embodiment includes: the first line voltage letter for the input of control switch power-supply system
Number conducting and shutdown, and export the first sampled voltage signal switch module 50；It is connect with switch module 50, for according to the
One sampled voltage signal exports the first overvoltage protective module 10 of the first overvoltage protection signal；It connect, is used for switch module 50
The second overvoltage protective module 20 of the second overvoltage protection signal is exported according to the first sampled voltage signal；With the first overvoltage protection mould
Block 10 and the connection of the second overvoltage protective module 20, for defeated according to the first overvoltage protection signal and the second overvoltage protection signal
The logic module 30 of pulse-width signal out；It is connect with logic module 30, for according to pulse-width signal output drive signal
Drive module 40.
As an embodiment of the present invention, in the present embodiment, when the First Line voltage signal inputted in switch power supply system
When higher, switch power supply system output inductive current continuous conduction mode (Continuous Conduction Mode,
CCM occurs continuous raising under), at this point, the first sampled voltage signal that switch module 50 exports also can periodically increase.When first
When sampled voltage signal reaches the first reference voltage signal vref being arranged in the first overvoltage protective module 10, so that the first over-voltage
The pulse-width signal of the first overvoltage protection signal control logic module 30 output exported in protective module 10 is low level letter
Number.When the first sampled voltage signal reaches the second reference voltage signal vref2 being arranged in the second overvoltage protective module 20, the
The pulse-width signal that second overvoltage protection signal of two overvoltage protective modules 20 output will make logic module 30 export exists
Low level state is always remained as in next cycle.At this point, switch module 50 is in an off state, in switch power supply system
First inductance L1 is in the freewheeling state of the second diode D2, and the first sampled voltage signal remains low level signal, to mention
Rise the consistency of the peak value of the inductive current of switch power supply system output.
As an embodiment of the present invention, the ratio of the second reference voltage signal vref2 and the first reference voltage signal vref
It is 1.15.
As an embodiment of the present invention, Fig. 2 is a kind of control for switch power supply system provided in an embodiment of the present invention
The electrical block diagram of circuit, as shown in Fig. 2, the first overvoltage protective module 10 in the present embodiment includes: first relatively more single
Member 101 and first with door 102；The first end of first comparing unit 101 is connect with the first reference voltage source, the first comparing unit
101 second end is connect with the first sampled voltage signal output end of switch module 50, the output end of the first comparing unit 101 with
First connect with the first end of door 102, and first connect with the second end of door 102 with shielded signal source, first with the output of door 102
End is connect with the first input end of logic module 30.
In the present embodiment, the first reference voltage that the first comparing unit 101 is used to export the first reference voltage source is believed
Number vref is compared with the first sampled voltage signal VRcs that switch module 50 exports, when the second of the first comparing unit 101
First sampled voltage signal VRcs of end input is greater than the first reference voltage signal that the first end of the first comparing unit 101 inputs
When vref, the first comparing unit 101 exports high level signal, when the first sampling that the second end of the first comparing unit 101 inputs
When voltage signal VRcs is less than the first reference voltage signal vref that the first end of the first comparing unit 101 inputs, first compares
Unit 101 exports low level signal.
As an embodiment of the present invention, the first comparing unit 101 is voltage comparator, the inverting input terminal of voltage comparator
As the first end of the first comparing unit, second end of the normal phase input end of voltage comparator as the first comparing unit, voltage
Output end of the output end of comparator as the first comparing unit.
In the present embodiment, voltage comparator is used to compare the voltage signal of normal phase input end and reverse input end input
Size, when the voltage signal of normal phase input end input is higher than the voltage signal of inverting input terminal input, voltage comparator output
For high level, when voltage signal of the voltage signal of normal phase input end input lower than inverting input terminal input, voltage comparator
Output is low level.
As an embodiment of the present invention, as shown in Fig. 2, the second overvoltage protective module 20 include: the second comparing unit 202,
Reverse phase delay unit 201, the first trigger unit 203 and the first nor gate 204.Specifically, the first of the second comparing unit 202
End is connect with the second reference voltage source, the second end of the second comparing unit 202 and the first sampled voltage signal of switch module 50
Output end connection, the first input end and signal source of clock of the input terminal of reverse phase delay unit 201 and the first nor gate 204 connect
It connects, the output end of reverse phase delay unit 201 is connect with the first input end of the first trigger unit 203, the second comparing unit 202
Output end is connect with the second input terminal of the first trigger unit 203, the output end and the first nor gate of the first trigger unit 203
204 the second input terminal connection, the output end of the first nor gate 204 are connect with the second input terminal of logic module 30.
Specifically, the oscillator signal osc of signal source of clock output obtains delay vibration after the processing of reverse phase delay unit 201
Signal osc_del is swung, the second overvoltage protection signal for postponing oscillator signal osc_del and the output of the second comparing unit 202 is passed through
The processing of first trigger unit 203 obtains trigger signal pwm_mask.
As an embodiment of the present invention, the first trigger unit 203 is reset-set flip-flop, the of reset-set flip-flop
First input end of one input terminal as the first trigger unit 203, the second input terminal of reset-set flip-flop is as the first touching
Second input terminal of bill member 203, output end of the output end of reset-set flip-flop as the first trigger unit 203.
In the present embodiment, the reset-set flip-flop in the present embodiment is rest-set flip-flop, the of reset-set flip-flop
One input terminal is the end S, and the second input terminal of reset-set flip-flop is the end R, and the output end of reset-set flip-flop is the end QN, when
When the input of the end R is high level, the output of the end QN is high level, and rest-set flip-flop is in 0 state, i.e. referred to as reset state.
As an embodiment of the present invention, as shown in Fig. 2, switch module 50 includes: first switch tube M1 and sampling resistor
Unit 501.Specifically, the control terminal of first switch tube M1 is connect with the output end of drive module 40, the electricity of first switch tube M1
Flow current input terminal of the input terminal as control circuit, current output terminal and the sampling resistor unit 501 of first switch tube M1
First end connects the first sampled voltage signal output end as switch module 50, the second end conduct of sampling resistor unit 501 altogether
The current output terminal of control circuit.
In the present embodiment, sampling resistor unit 501 can be the resistance list of the formation in series or in parallel of multiple resistance
Member.
As an embodiment of the present invention, as shown in Fig. 2, sampling resistor unit 501 is the first sampling resistor Rcs, first is adopted
First end of the first end of sample resistance Rcs as sampling resistor unit 501, the second end of the first sampling resistor Rcs is as sampling
The second end of resistance unit 501.
In the present embodiment, the resistance value size of the first sampling resistor Rcs needs to be arranged according to user.
As an embodiment of the present invention, as indicated with 2, first switch tube M1 is N-type metal-oxide-semiconductor, and the grid of N-type metal-oxide-semiconductor is the
The control terminal of one switching tube M1, the drain electrode of N-type metal-oxide-semiconductor are the current input terminal of first switch tube M1, and the source electrode of N-type metal-oxide-semiconductor is
The current output terminal of first switch tube M1.
As an embodiment of the present invention, a kind of control device 110 for switch power supply system is present embodiments provided, is controlled
Device 110 processed includes: the first reference voltage source, the second reference voltage source, signal source of clock and shielded signal source, control device
100 further include the control circuit of any of the above-described embodiment.Specifically, the current input terminal of control circuit is as control device
110 the first current input terminal VIN, first current output terminal of the current output terminal of control circuit as control device 110
GND。
As an embodiment of the present invention, Fig. 3 is a kind of circuit structure of switch power supply system provided in an embodiment of the present invention
Schematic diagram, the switch power supply system in the present embodiment are AC-DC switch power supply system, which includes: the
One capacitor C1, the second capacitor C2, the first inductance L1, first diode D1, the second diode D2, third capacitor C3, load R1 with
And the control device 110 in above-described embodiment, specifically, the first electric current of the first end of first capacitor C1, control device 110 is defeated
Enter to hold the electrode input end of VIN and AC-DC switch power supply system to connect altogether, the first current output terminal of control device 110, second
The first end of the first end of capacitor C2, the cathode of the second diode D2 and the first inductance L1 connects altogether, the power supply of control device 110
End VCC, the second end of the second capacitor C2 and the cathode of first diode D1 connect altogether, the anode of first diode D1, the first electricity
The second end for feeling L1 and the first end for loading R1 connect altogether, the second end of first capacitor C1, the anode of the second diode D2, third
The second end of capacitor C3 and the second end for loading R1 are connected to ground altogether.
In AC-DC switch power supply system as shown in Figure 3, first capacitor C1 is used to be used as AC-DC switch power supply system
In input capacitance, the second capacitor C2 is used for for power supply capacitor as control device 110, the first inductance L1 as AC-DC
Energy storage inductor in switch power supply system, first diode D1 are used to input AC-DC switch power supply system to control device 110
Output voltage feedback signal, the second diode D2 are used to carry out afterflow to inductive current.
AC-DC switch power supply system as shown in Figure 3 is under ideal working condition, the inductance electricity of switch power supply system output
The waveform of stream is as shown in figure 4, it is high voltage and low-voltage that wherein I1 and I2, which is respectively the inputting line voltage of switch power supply system,
When switch power supply system output the corresponding rate of rise of inductive current and corresponding current waveform, from Fig. 4 it can be found that its peak
It is completely the same to be worth the electric current I_OCP threshold value being arranged with switch power supply system inside, and the inductive current of switch power supply system output
ILIt can be expressed as:
IL=(V/L) * T,
Wherein, V is the inputting line voltage of switch power supply system, and L is the sensibility reciprocal of the first inductance L1, and T is a switch week
It is required when inductive current rises to overcurrent protection (Over Current Protection, OCP) threshold value from initial point in phase
Time.
For AC-DC switch power supply system shown in Fig. 3 in actual work, peak value would generally be beyond the OCP of internal setting
Threshold value.Inductive current I at this timeLIt can be expressed as:
IL=(V/L) * T=V/L* (T+Td)=V/L*T+V/L*Td,
Wherein, V is the inputting line voltage of switch power supply system, and L is the sensibility reciprocal of the first inductance L1, and time T is opened at one
Required time when inductive current rises to OCP threshold value from initial point in the period is closed, Td is from inductive current ILReach OCP threshold
The delay time between switch unit shutdown when value and in control circuit.Delay time Td can be expressed as, Td=Tcomp+
Tds, wherein Tcomp is the response time of the comparing unit in control circuit, and Tds indicates relatively more single from shown in Fig. 2 first
Required for the grid signal VG of the cut-off signals Vcomp to first switch tube M1 shown in Fig. 2 of 101 output of member is lower by height
Time.As it can be seen that, due to the presence of Td, inductive current can generate Δ I=for actual AC-DC switch power supply system
LVTdError, and with inputting line voltage and delay Td direct proportionality, and AC-DC system known for one is said
The delay Td stated be it is fixed, the sensibility reciprocal of the inductance L1 in system is
Δ I=TdV=k*V
Fixed, then current error can further be expressed as L, i.e. inputting line voltage is bigger, and inductive current error is got over
Greatly, the smaller inductive current error of inputting line voltage is smaller, as shown in the waveform in Fig. 5, the wherein corresponding input line of I1 waveform
Voltage is height, and the corresponding inputting line voltage of I2 waveform is low.
For general AC-DC system, when output loading changes from small to large, inductive current will be led from discontinuous
Logical mode (Discontinuous Condition Mode, DCM) gradually enters continuous conduction mode (Conti nuous
Condition Mode, CCM).When inputting line voltage is smaller, the inductive current error due to caused by above-mentioned Td is smaller, inductance
Current waveform is as shown in IL1 in Fig. 6, and in CCM, the consistency of its peak point current is preferable, and IPEAK1 and IOCP threshold value are close.When
When inputting line voltage is larger, the inductive current error due to caused by above-mentioned Td is larger, as shown in inductive current waveform IL2 in Fig. 6,
In CCM, the consistency of peak point current is very poor, and at the last one period of CCM, the peak I PEAK2 of inductive current is much larger than electricity
The shutdown threshold value IOCP of inducing current, when this means that inputting line voltage is higher, energy that each switch periods are stored to inductance L1
Amount be greater than inputting line voltage it is lower when stored ability, so as to cause system output load capacity in low inputting line voltage
When it is smaller, when high inputting line voltage, is larger, as the corresponding overload point of output voltage Vo1 and Vo2 shown in Fig. 7 is
Iload1 and Iload2, therefore, the load overload protection point for the AC-DC system that general control method is realized is in different line voltages
Under consistency it is poor.
In the present embodiment, when AC-DC switch power supply system is in CCM operating mode, inductive current peak is high and low
Still it can achieve good consistency under different input voltages, the overload protection point of system can be made to reach good one
Cause property, while it is possible to prevente effectively from First Line voltage signal be high voltage signal when inductive current enter saturation state, for example,
High voltage signal in the present embodiment can be 380V.
In the present embodiment, the CCM mode under high inputting line voltage is effectively inhibited by the second overvoltage protective module 20
When, it the phenomenon that peak point current continuously increases, avoids inductive current and enters saturation.To ensure that no matter inductive current peak is defeated
Line voltage it is high and low, good consistency can be kept, further ensure the output of AC-DC switch power supply system
It carries protection point and reaches good consistency, as output voltage the wave Vo1 and Vo3 of AC-DC switch power supply system in Fig. 7 are right respectively
The overload point Iload1 answered is as Iload3.
Specifically, signal source of clock in the first overvoltage protective module 10 will be by the first nor gate 204 by logic module
The pulse-width signal pwm of 30 outputs is set as high level signal, and then pulse-width signal pwm passes through control drive module 30
First switch tube M1 is connected, when first switch tube M1 conducting, the inputting line voltage VIN in AC-DC switch power supply system is
First inductance L1 charging, inductive current starts linear rise, until the first sampled voltage signal VRcs reaches the first overvoltage protection
The first comparing unit 101 output high level letter when the first reference voltage vref of module 10, in the first overvoltage protective module 10
Number, the pulse-width signal pwm that logic module 30 exports is reset to low level signal, at this point, first switch tube M1 is turned off, the
One inductance L1 carries out afterflow by the second diode D2.When the first sampled voltage signal VRcs reaches the second overvoltage protective module 20
The second reference voltage vref2 when, second comparing unit 202 exports high level signal, and the high level signal is by the first touching
Bill member 203 resets, and the first trigger unit 203 is made to export high level signal, at this point, the height electricity of the first trigger unit 203 output
Ordinary mail number will shield the pulse-width signal next week that the oscillator signal osc of signal source of clock output exports logic module 30
The unlatching of phase, so that the pulse-width signal that logic module 30 exports is always maintained at low level state in next cycle, as
When the 6th oscillator signal osc period shown in Fig. 8, PWM_MASK signal is got higher by low, then the 7th OSC period corresponding pulsewidth
Modulated signal pwm is not set to high level, also means that first switch tube M1 is kept within the 7th oscillator signal osc period
Shutdown.First inductance L1 is in the freewheeling state of the second diode D2, so that the first sampled voltage signal VRcs remains low electricity
Flat, the second reference voltage signal vref of the first input end input of the second comparing unit 202 is higher than the input of the second input terminal
First sampled voltage signal VRcs, the output of the second comparing unit 202 is low level signal, and the first trigger unit 203 is no longer answered
Position, the 8th oscillator signal osc period can be by 203 set of the first trigger unit, so that trigger signal pwm_mask shown in Fig. 8
Low level is become from high level, while logic module 30 can be normally arranged in oscillator signal osc, so that the 8th oscillator signal osc
When the period, pulse-width signal pwm is got higher by low, so that the power tube M1 can be by just the 8th oscillator signal osc period
It is normally open.As described above, if the first sampled voltage signal VRcs reaches vref2, the 9th oscillation letter as shown in Figure 8 again
When number osc period, trigger signal pwm_mask is high level signal again, then first switch tube M1 can be in the 10th oscillator signal
The osc period is opened primary by shielding again.
In order to enable the peak value of inductive current reaches good consistency, the value ratio of vref and vref2 in the present invention
For vref2/vref=1.15.
In a kind of control circuit for switch power supply system provided in an embodiment of the present invention, by logic module to
First overvoltage protection signal of one overvoltage protective module output and the second overvoltage protection letter of the second overvoltage protective module output
It number is handled to obtain corresponding pulse-width signal, and passes through pulse-width signal and control drive module and export corresponding driving
Signal controls the turn-on and turn-off of switch module, when the input voltage of switch power supply system is high voltage, improves
The consistency of Switching Power Supply output overloading protection point, solves in existing AC-DC Switching Power Supply, inductive current is negative with output
It carries to increase into continuous conduction mode and can make inductive current when the inputting line voltage of AC-DC switch power supply system also increases
Output overloading protection point consistency reduce, increase the error of inductive current, give AC-DC Switching Power Supply and back-end circuit
The problem of bringing great security risk.
The above, the only specific embodiment of the application, but the protection scope of the application is not limited thereto, it is any
Those familiar with the art within the technical scope of the present application, can easily think of the change or the replacement, and should all contain
Lid is within the scope of protection of this application.Therefore, the protection scope of the application shall be subject to the protection scope of the claim.
Claims (8)
1. a kind of control circuit for switch power supply system characterized by comprising
For controlling the conducting and shutdown of the First Line voltage signal of the switch power supply system input, and export the first sampling electricity
Press the switch module of signal；
It is connect with the switch module, for exporting the first of the first overvoltage protection signal according to the first sampled voltage signal
Overvoltage protective module；
It is connect with the switch module, for exporting the second of the second overvoltage protection signal according to the first sampled voltage signal
Overvoltage protective module；
It is connect with first overvoltage protective module and second overvoltage protective module, for being protected according to first over-voltage
Protect the logic module of signal and the second overvoltage protection signal output pulse width modulated signal；And
It is connect with the logic module, for the drive module according to the pulse-width signal output drive signal；
Second overvoltage protective module include: the second comparing unit, reverse phase delay unit, the first trigger unit and first or
NOT gate；
The first end of second comparing unit is connect with the second reference voltage source, the second end of second comparing unit and institute
State switch module the first sampled voltage signal output end connection, the input terminal of the reverse phase delay unit and described first or
The first input end of NOT gate is connect with signal source of clock, the output end of the reverse phase delay unit and first trigger unit
First input end connection, the output end of second comparing unit are connect with the second input terminal of first trigger unit, institute
The output end for stating the first trigger unit is connect with the second input terminal of first nor gate, the output end of first nor gate
It is connect with the second input terminal of the logic module；Wherein, second comparing unit is a voltage comparator, second ratio
First end compared with unit is the inverting input terminal of voltage comparator, and the second end of second comparing unit is voltage comparator
Normal phase input end, the output end of second comparing unit are the output end of voltage comparator；
First trigger unit is reset-set flip-flop, and the first input end of the reset-set flip-flop is as described the
The first input end of one trigger unit, the second input terminal of the reset-set flip-flop as first trigger unit
Two input terminals, output end of the output end of the reset-set flip-flop as first trigger unit；
Wherein, the first input end of the reset-set flip-flop is the end S, and the second input terminal of the reset-set flip-flop is
The end R, the output end of the reset-set flip-flop are the end QN.
2. control circuit as described in claim 1, which is characterized in that first overvoltage protective module includes: first to compare
Unit and first and door；
The first end of first comparing unit is connect with the first reference voltage source, the second end of first comparing unit and institute
State the first sampled voltage signal output end connection of switch module, the output end and described first and door of first comparing unit
First end connection, described first connect with the second end of door with shielded signal source, described first with the output end of door with it is described
The first input end of logic module connects.
3. control circuit as claimed in claim 2, which is characterized in that first comparing unit is voltage comparator, described
First end of the inverting input terminal of voltage comparator as first comparing unit, the normal phase input end of the voltage comparator
As the second end of first comparing unit, output of the output end of the voltage comparator as first comparing unit
End.
4. control circuit as described in claim 1, which is characterized in that the switch module includes: first switch tube and adopts
Sample resistance unit；
The control terminal of the first switch tube is connect with the output end of the drive module, the electric current input of the first switch tube
Hold the current input terminal as the control circuit, the current output terminal of the first switch tube and the sampling resistor unit
First end connects the first sampled voltage signal output end as the switch module altogether, and the second end of the sampling resistor unit is made
For the current output terminal of the control circuit.
5. control circuit as claimed in claim 4, which is characterized in that the sampling resistor unit is the first sampling resistor, institute
First end of the first end of the first sampling resistor as the sampling resistor unit is stated, the second end of first sampling resistor is made
For the second end of the sampling resistor unit.
6. control circuit as claimed in claim 4, which is characterized in that the first switch tube is N-type metal-oxide-semiconductor, the N-type
The grid of metal-oxide-semiconductor is the control terminal of the first switch tube, and the drain electrode of the N-type metal-oxide-semiconductor is the electric current of the first switch tube
Input terminal, the source electrode of the N-type metal-oxide-semiconductor are the current output terminal of the first switch tube.
7. a kind of control device for switch power supply system, which is characterized in that the control device includes: the first reference voltage
Source, the second reference voltage source, signal source of clock and shielded signal source, the control device further include that claim 1-6 such as appoints
Control circuit described in one, first current input terminal of the current input terminal of the control circuit as the control device,
First current output terminal of the current output terminal of the control circuit as the control device.
8. a kind of switch power supply system, which is characterized in that the switch power supply system includes: first capacitor, the second capacitor, first
Inductance, first diode, the second diode, third capacitor and load；
The switch power supply system further includes control device as claimed in claim 7；
The first end of the first capacitor, the first current input terminal of the control device and the switch power supply system are just
Pole input terminal connects altogether, the first current output terminal of the control device, the first end of second capacitor, second diode
Cathode and the first end of first inductance connect altogether, the second end of the power end of the control device, second capacitor
And the cathode of the first diode connects altogether, the anode of the first diode, the second end of first inductance and institute
The first end for stating load connects altogether, the second end of the first capacitor, the anode of second diode, the third capacitor
The second end of two ends and the load is connected to ground altogether.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810820230.0A CN108923631B (en) | 2018-07-24 | 2018-07-24 | A kind of switch power supply system and control circuit and device for switch power supply system |
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| CN201810820230.0A CN108923631B (en) | 2018-07-24 | 2018-07-24 | A kind of switch power supply system and control circuit and device for switch power supply system |
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| CN108923631B true CN108923631B (en) | 2019-11-26 |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109713637B (en) * | 2018-12-27 | 2020-09-15 | 惠科股份有限公司 | Overcurrent protection method, overcurrent protection circuit and display device |
| CN111555643B (en) * | 2020-06-05 | 2024-02-27 | 上海晶丰明源半导体股份有限公司 | Switching power supply controller, switching power supply system and switching power supply system power supply method |
| CN114614437B (en) * | 2022-03-30 | 2023-10-20 | 广州金升阳科技有限公司 | Undervoltage delay protection circuit and power supply system |
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| CN1964172A (en) * | 2005-11-09 | 2007-05-16 | 崇贸科技股份有限公司 | A switch-over type control device for output power compensation |
| CN101594064A (en) * | 2009-05-31 | 2009-12-02 | 成都芯源系统有限公司 | Switching power supply controller |
| CN202160100U (en) * | 2011-07-21 | 2012-03-07 | 中兴通讯股份有限公司 | Power supply module and power supply system |
| CN106487248A (en) * | 2016-10-10 | 2017-03-08 | 上海晶丰明源半导体有限公司 | Controller, Switching Power Supply and line voltage compensation method |
| CN107528450A (en) * | 2017-08-29 | 2017-12-29 | 深圳市稳先微电子有限公司 | Voltage comparator, control chip and Switching Power Supply |
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|---|---|---|---|---|
| CN1964172A (en) * | 2005-11-09 | 2007-05-16 | 崇贸科技股份有限公司 | A switch-over type control device for output power compensation |
| CN101594064A (en) * | 2009-05-31 | 2009-12-02 | 成都芯源系统有限公司 | Switching power supply controller |
| CN202160100U (en) * | 2011-07-21 | 2012-03-07 | 中兴通讯股份有限公司 | Power supply module and power supply system |
| CN106487248A (en) * | 2016-10-10 | 2017-03-08 | 上海晶丰明源半导体有限公司 | Controller, Switching Power Supply and line voltage compensation method |
| CN107528450A (en) * | 2017-08-29 | 2017-12-29 | 深圳市稳先微电子有限公司 | Voltage comparator, control chip and Switching Power Supply |
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| CN108923631A (en) | 2018-11-30 |
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