CN205453099U - Sampling circuit and mistake, undervoltage protection control circuit - Google Patents
Sampling circuit and mistake, undervoltage protection control circuit Download PDFInfo
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Abstract
The utility model provides a mistake, undervoltage protection control circuit, includes sampling circuit, under -voltage control circuit, excessive pressure control circuit and control signal output circuit, sampling circuit, including resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5, wherein, positive input voltage vin is not through resistance R5, resistance R4, resistance R3, resistance R2 and the resistance R1 who establishes ties the in proper order ground that flows back, resistance R5 draws forth as first sampling point with resistance R4's public node for offer under -voltage control circuit, resistance R4 draws forth as the second sampling point with resistance R3's public node for offer excessive pressure control circuit. Compared with the prior art, the utility model discloses a sampling and mistake, under -voltage return difference control circuit design in a flexible way, and mistake, under -voltage trigger point, recovery point easily design, are convenient for to debug.
Description
Technical field
This utility model relates to circuit field, concrete, relates to a kind of in switch power supply system, improves sample circuit and overvoltage based on this sample circuit, the under-voltage protection control circuit of transducer reliability.
Background technology
In recent years, energy problem is increasingly serious, and the new forms of energy such as photovoltaic solar, wind-power electricity generation obtain national policy and support energetically, and the sector quickly grows.Photovoltaic auxiliary power supply is a kind of switch converters, for providing stable, reliable DC voltage for photovoltaic solar, wind-power electricity generation, SVG dispatch control system.
Affected by application scenario, photo-voltaic power supply operating voltage range is the widest, as a example by photovoltaic solar electric station, by illumination intensity effect, the output voltage of photovoltaic solar electric station tens volts on kilovolt, corresponding auxiliary electric power supply operating voltage range also tens volts on kilovolt.The widest input voltage range, it is desirable to switch converters must possess overvoltage, under-voltage protection function, when preventing input voltage too low, power device crosses cause thermal damage, switching device excessive pressure damages when input voltage is too high.
Over voltage function is integrated into inside controller by part semiconductor manufacturer, easy to use.But for not having controller or the particular application then necessary individually designed over voltage protection circuit of this function integrated, existing scheme there is problems in that
Patent publication No. is that CN104283193A discloses a kind of over voltage protection circuit; trigger point and recovery point are same electrical voltage point; the risk faced is: if this trigger point is too close to changer normal working voltage scope; easily cause false triggering; therefore, need between trigger point changer normal range of operation to retain certain allowance.
Patent publication No. is that CN101752829A discloses a kind of under-voltage protecting circuit; this circuit possesses sluggish protective loop; use TL431 as error amplification, comparator; existing problems are: can produce repeated switching phenomenon near the critical voltage points such as over voltage trigger point, recovery point; easily cause logic control chaotic; there is relatively large deviation, occur that critical voltage point drifts around exception in return difference recovery point in kind and Design Theory, reduces the reliability of loop of power circuit.
Patent publication No. is that CN103683206A discloses a kind of over voltage protection circuit, and this circuit start-up circuit under overvoltage protection state is constantly on, powers for operational amplifier, and power consumption is big, reduces the reliability of start-up circuit.
Existing some other protection circuit; the state of having the hiccups is worked at overvoltage protection state downconverter; in the case of input voltage exceeds well over pressure protection point; switching device in inverter power loop still suffers from over-voltage breakdown risk; therefore, existing over voltage protection circuit performance needs improvement further badly.
The distinct disadvantage existed for foregoing circuit, this patent utility model people analyse in depth isolated drive circuit, and this case thus produces.
Utility model content
Having in view of that, in order to tackle above-mentioned challenge, this utility model purpose is to provide a kind of sampling and the sample circuit of over voltage return difference control circuit flexible design.
Corresponding to this, another purpose of the present utility model is to provide a kind of over voltage trigger point, recovery point is easily designed, be easy to the over voltage protection circuit of debugging.
In order to realize above-mentioned utility model purpose; this utility model provides a kind of sample circuit; it is applicable to the overvoltage of changer, under-voltage protection control circuit; in order to the situation of change according to changer positive pole input voltage vin; sampled signal is provided to overvoltage, the under-voltage control circuit of under-voltage protection control circuit and overvoltage control circuit; described sample circuit; including resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5; wherein, positive pole input voltage vin is back to ground by resistance R5, resistance R4, resistance R3, resistance R2 and the resistance R1 being sequentially connected in series；The common node of resistance R5 and resistance R4 is drawn as the first sampled point, is used for being supplied to under-voltage control circuit；The common node of resistance R4 and resistance R3 is drawn as the second sampled point, is used for being supplied to overvoltage control circuit.
This utility model also provides for a kind of mistake, under-voltage protection control circuit, for the positive pole input voltage vin with changer, direct voltage source VDD, after reference voltage signal Vref connects, situation of change according to changer positive pole input voltage vin, error comparator input to changer master control IC exported, under-voltage protection control signal, to control changer entrance guard mode, described mistake, under-voltage protection control circuit, including sample circuit, under-voltage control circuit, overvoltage control circuit and control signal output circuit, described sample circuit, including resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5, wherein, positive pole input voltage vin is by the resistance R5 being sequentially connected in series, resistance R4, resistance R3, resistance R2 and resistance R1 is back to ground；The common node of resistance R5 and resistance R4 is drawn as the first sampled point, is used for being supplied to under-voltage control circuit；The common node of resistance R4 and resistance R3 is drawn as the second sampled point, is used for being supplied to overvoltage control circuit；Described under-voltage control circuit, when the positive pole input voltage vin of changer gradually rises from under-voltage protection trigger point voltage, is determined to exit the recovery point voltage of under-voltage protection state by the resistance R2 connected, resistance R3, resistance R4 with total resistance of resistance R6 in parallel；Described overvoltage control circuit, when the positive pole input voltage vin of changer is gradually lowered from overvoltage protection trigger point voltage, is determined to exit the recovery point voltage of overvoltage protection state by total resistance of the resistance R1 connected, resistance R2, resistance R3.
Preferably, described under-voltage control circuit, including operational amplifier U1A, diode D1, N type switch tube Q2, resistance R6, resistance R9 and resistance R10, wherein, operational amplifier U1A in-phase input end connects reference voltage signal Vref, the inverting input of operational amplifier U1A is connected to electric capacity C1, resistance R4, the common node of resistance R5 three, and the inverting input of operational amplifier U1A is connected with the colelctor electrode of N type switch tube Q2 also by resistance R6, the grounded emitter of N type switch tube Q2；Operational amplifier U1A outfan is by the resistance R9 connected and resistance R10 ground connection；The base stage of N type switch tube Q2 is connected to the common node of resistance R9 and resistance R10；The outfan of operational amplifier U1A also anode with diode D1 is connected, and the negative electrode of diode D1 is as the output of under-voltage control circuit, for being connected with control signal output circuit.
Described overvoltage control circuit, including operational amplifier U1B, diode D2, direct voltage source VDD, N type switch tube Q4, N type switch tube Q5, resistance R11, resistance R12, resistance R13 and resistance R14, wherein, operational amplifier U1B inverting input is connected with reference voltage signal Vref, and operational amplifier U1B in-phase input end is connected to resistance R4, the common node of resistance R3；The outfan of operational amplifier U1B is connected with N type switch tube Q5 base stage by resistance R12, the grounded emitter of N type switch tube Q5；Resistance R11 be connected in parallel on N type switch tube Q5 base stage and emitter stage between；Direct voltage source VDD is by the resistance R13 connected and resistance R14 ground connection, and the common node of resistance R13 and resistance R14 is connected with the colelctor electrode of N type switch tube Q5 and the base stage of N type switch tube Q4 respectively, the grounded emitter of N type switch tube Q4；N type switch tube Q4 colelctor electrode be connected with the common node of resistance R1 and resistance R2；The outfan of operational amplifier U1B also anode with diode D2 is connected, and the negative electrode of diode D2 is as the output of overvoltage control circuit, for being connected with control signal output circuit.
Described control signal output circuit, including resistance R7, resistance R8 and N type switch tube Q1, wherein, one end of resistance R7 is connected with the outfan of under-voltage control circuit and overvoltage control circuit, the other end of resistance R7 is connected with the base stage of N type switch tube Q1, the grounded emitter of N type switch tube Q1；Resistance R8 is connected in parallel between the base stage of N type switch tube Q1 and emitter stage；The output as control signal output circuit drawn by the colelctor electrode of N type switch tube Q1, for being connected with the error comparator input of changer master control IC.
As the further improvement of above-mentioned utility model, described sample circuit, also including that electric capacity C1, electric capacity C1 are used for filtering the interference signal of switch converters input, one end of electric capacity C1 is connected to the common node of resistance R5 and resistance R4, the other end ground connection of electric capacity C1.
Improvement is further walked as above-mentioned utility model; described over voltage protection control circuit; also include over-voltage locking circuit; described over-voltage locking circuit includes that NPN type triode Q3 and start-up circuit control end; wherein; the colelctor electrode of NPN type triode Q3 controls end with start-up circuit and is connected, and the base stage of NPN type triode Q3 is connected with the common node of resistance R3 and resistance R2, the grounded emitter of NPN type triode Q3；When the positive pole input voltage vin of changer gradually rises to the over-voltage locking point voltage set from overvoltage protection trigger point voltage, NPN type triode Q3 turns on, and making start-up circuit control end is low level state, is used for controlling start-up circuit and quits work.
Preferably, above-mentioned N type switch tube Q1, N type switch tube Q2, N type switch tube Q4 and N type switch tube Q5 are NPN type triode or NPN type metal-oxide-semiconductor.
Compared with prior art, this utility model has the advantages that
1) this programme sampling and over voltage return difference control circuit flexible design, over voltage trigger point, recovery point is easily designed, be easy to debugging.
2) the critical voltage points such as over voltage trigger point, recovery point can be overcome to drift around exception, the drifting problem of critical voltage point can be avoided.
3) under guard mode, this programme capacity of resisting disturbance is strong, stand-by power consumption is low, and reliability is high.
4) this programme circuit structure is simple, and components and parts number is few, flexible design, and cost has superiority.
Accompanying drawing explanation
Fig. 1 is the circuit theory diagrams of this utility model first embodiment over voltage protection control circuit；
Fig. 2 is that this utility model first embodiment over voltage protects the circuit interdependent node voltage of control circuit, control signal waveform；
Fig. 3 is the circuit theory diagrams of this utility model the second embodiment over voltage protection control circuit；
Fig. 4 is the circuit theory diagrams of this utility model the 3rd embodiment over voltage protection control circuit；
Fig. 5 is that this utility model the 3rd embodiment over voltage protects the circuit interdependent node voltage of control circuit, control signal waveform；
Fig. 6 is the circuit theory diagrams of this utility model the 4th embodiment over voltage protection control circuit.
Detailed description of the invention
In order to be more fully understood that this utility model, relative to the improvement done by prior art, before being described in detail two kinds of detailed description of the invention of the present utility model, first combines the prior art that background section is previously mentioned, is illustrated improved though.
Thinking of the present utility model is: use operational amplifier (such as LM324) as sampled signal error computing comparator; avoid producing repeated switching near the critical voltage points such as over voltage trigger point, recovery point; by adjusting return difference control circuit; avoid the abnormal phenomena that repeated switching occurs near the critical voltage points such as over voltage trigger point, recovery point, improve protection circuit accuracy of action；Operational amplifier number is two, and wherein, the first operational amplifier controls under-voltage logic circuit, and the second operational amplifier controls overvoltage logic circuit；Under overvoltage condition, the overvoltage protection state of switch converters is set to two stages, pre-over pressure phase and over-voltage locking stage by overvoltage crowbar, reduces stand-by power consumption under overvoltage condition, improves model machine reliability.
Further, pre-overvoltage condition voltage triggered point is less than over-voltage locking state trigger point.
Under-voltage protection operation process is as follows: when input voltage triggers under-voltage protection point; first operational amplifier output high level signal; drive the first switch, second switch conducting; wherein; first switch in parallel at the error comparator input of PWM switch converters loop of power circuit controller (as a example by UC3842; this pin is comp pin); during the first switch conduction; dragging down and maintain this pin is low level state; PWM controller stops output pwm signal; changer is in under-voltage protection state, without output；
Further, being connected in parallel on under-voltage sampling resistor two ends after second switch and the first resistant series, after second switch conducting, the first resistance is in parallel with under-voltage sampling resistor, and the resistance after parallel connection determines under-voltage condition recovery point, forms the return difference of under-voltage protecting circuit.
Overvoltage protection operation process is as follows: when input voltage triggers pre-over-voltage protection point; second operational amplifier output high level signal; drive the first switch, the 4th switch conduction; first switch process is completely the same with the under-voltage stage herein; no longer describe in detail; after first switch conduction, changer is without output；
4th switch adjusts the high and low of input voltage overvoltage condition sampled signal amplitude, and after the 4th switch conduction, input voltage overvoltage condition sampled signal amplitude raises, and automatically sets pre-overvoltage condition recovery point, forms the return difference of the pre-overvoltage of overvoltage crowbar；
When input voltage is increased to trigger overvoltage condition keyed end, over-voltage locking circuit output control signal, control start-up circuit and work in off state, changer quits work, now, Overall Power Consumption only comprises sample circuit part, and stand-by power consumption is extremely low and avoids loop of power circuit switching tube excessive pressure damages, improves switch converters reliability.
Particularly, the sampling of this utility model scheme and the design of over voltage return difference control circuit are the most flexible, the two common input signal sample circuit, by exporting control signal after over voltage operational amplifier comparison operation, automatically over voltage recovery point is adjusted, hence it is evident that distinguish and be better than existing sampling and return difference control program.
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with drawings and Examples, this utility model is further elaborated.
First embodiment
Fig. 1 shows the schematic block circuit diagram of this utility model first embodiment over voltage protection control circuit, a kind of over voltage protection circuit: includes sample circuit, reference voltage signal Vref, direct voltage source VDD, under-voltage compare and return difference control circuit, overvoltage is compared and return difference control circuit, over voltage control signal output circuit.
Sample circuit is inputted Vin by switch converters positive pole, electric capacity C1, resistance R5, resistance R4, resistance R3, resistance R2, resistance R1 forms, wherein, one end of resistance R5 is connected with changer positive pole input Vin, the other end is connected with one end of resistance R4, the other end of resistance R4 is connected with resistance R3, the other end of resistance R3 is in series with resistance R1 after resistance R2, the other end of resistance R1 (is numbered GND) with being connected to input circuit in Fig. 1, one end of electric capacity C1 is connected to the common node of resistance R5 and resistance R4, the other end (is numbered GND) with being connected to input circuit in Fig. 1.
Particularly, the over voltage of this utility model scheme compares and return difference control circuit common input signal sample circuit, flexible design, hence it is evident that distinguishes and is better than existing sampling plan.
Further; electric capacity C1 can filter switch converters input-terminal disturbance signal; avoid interference effect of signals sampled result; thus eliminate the over voltage protection misoperation that interference signal is triggered; greatly strengthen the capacity of resisting disturbance of over voltage protection control circuit, improve the reliability of circuit protection.
nullUnder-voltage compare and return difference control circuit is by operational amplifier U1A、Diode D1、NPN type triode Q2、Resistance R6、Resistance R9、Resistance R10、Reference voltage signal Vref forms，Wherein，Reference voltage signal Vref concatenation operation amplifier U1A in-phase input end (in Fig. 1 U1A mark "+" one end)，The inverting input (one end of U1A mark " " in Fig. 1) of operational amplifier U1A is connected to electric capacity C1、Resistance R4、The common node of resistance R5 three，The outfan of operational amplifier U1A is connected with the anode of diode D1，This point is the common node of the two，Resistance R9 one end is connected to the common node of operational amplifier U1A outfan and diode D1 anode，The other end (is numbered GND) with being connected to input circuit through resistance R10 in Fig. 1，One end of resistance R6 connects electric capacity C1、Resistance R4、The common node of resistance R5 three，The other end is connected with the colelctor electrode of NPN type triode Q2，The base stage of NPN type triode Q2 is connected to the common node of resistance R9 and resistance R10，The emitter stage of NPN type triode Q2 (is numbered GND) with being connected to input circuit in Fig. 1.
nullOvervoltage is compared and return difference control circuit is by operational amplifier U1B、Diode D2、Direct voltage source VDD、NPN type triode Q4、Q5、Resistance R11、Resistance R12、Resistance R13、Resistance R14 and reference voltage signal Vref composition，Wherein，Reference voltage signal Vref concatenation operation amplifier U1B inverting input (one end of U1B mark " " in Fig. 1)，Operational amplifier U1B in-phase input end (in Fig. 1 U1B mark "+" one end) be connected to resistance R4、The common node of resistance R3，The outfan of operational amplifier U1B is connected with the anode of diode D2，This point is the common node of the two，One end of resistance R12 is connected to the common node of operational amplifier U1B outfan and diode D2 anode，The other end (is numbered GND) with being connected to input circuit through resistance R11 in Fig. 1，After resistance R14 and resistance R13 is in series，The other end of resistance R14 is connected to direct voltage source VDD，The other end of resistance R13 (is numbered GND) with being connected to input circuit in Fig. 1，NPN type triode Q5 base stage is connected to the common node of resistance R11 and resistance R12，The colelctor electrode of Q5 is connected to the common node of resistance R14 and resistance R13，The emitter stage of Q5 (is numbered GND) with being connected to input circuit in Fig. 1，The base stage of NPN type triode Q4 is connected to the common node of resistance R13 and resistance R14，The colelctor electrode of Q4 is connected to the common node of resistance R1 and resistance R2，The emitter stage of Q4 (is numbered GND) with being connected to input circuit in Fig. 1.
Particularly, over voltage compares and diode D1, D2 negative electrode in return difference control circuit is connected, and this point is the common node of the two.
Cross, under-voltage control signal output circuit is by resistance R7, resistance R8, NPN type triode Q1, the error comparator input of switch converters master control IC is (as a example by UC3842, this pin is comp pin) composition, wherein, after resistance R7 connects with resistance R8, the other end of resistance R7 is connected to diode D1, the common node of D2, the resistance R8 other end (is numbered GND) with being connected to input circuit in Fig. 1, the base stage of NPN type triode Q1 is connected to the common node of resistance R7 and resistance R8, the colelctor electrode of Q1 is connected to the error comparator input of switch converters master control IC, the emitter stage of Q1 (is numbered GND) with being connected to input circuit in Fig. 1.
Particularly, the over voltage return difference control circuit design of this utility model scheme is the most flexible, input sample signal exports control signal after over voltage operational amplifier comparison operation, automatically adjusts over voltage recovery point, hence it is evident that distinguish and be better than existing sampling and return difference control program.
The annexation of circuit shown in Figure 1, in conjunction with Fig. 2 circuit interdependent node voltage, control signal waveform, tells about the operation principle of this utility model circuit.
Fig. 2, in 5, Vin is switch converters input voltage, A, B, C, D, E, F, G represent different input voltage points respectively, wherein, C, D represent the input voltage lower bound of normal working voltage scope, ceiling value respectively, V1A, V1B represent the outputs level signals of operational amplifier U1A, U1B in Fig. 1 respectively, and Comp represents error comparator input (as a example by UC3842, this pin is comp pin) the level signal amplitude of Fig. 1 breaker in middle changer master control IC.
Particularly, numeral 1 represents high level signal, and numeral 0 represents low level signal.
Under-voltage protection operation process: before the T0 moment, switch converters input voltage is C, the T0 moment, input voltage is gradually lowered, to the T1 moment, input voltage drops to an A, operational amplifier U1A in-phase input end voltage magnitude is higher than reverse input end voltage magnitude, U1A exports high level signal, NPN type triode Q1 emitter junction, collector junction positively biased turns on, the error comparator input i.e. Comp pin level of switch converters master control IC is pulled to low level signal, circuit enters under-voltage protection state, voltage magnitude corresponding for some A is under-voltage protection state trigger point voltage.
In the same time; operational amplifier U1B in-phase input end voltage magnitude is less than reverse input end voltage magnitude; U1B output low level signal, the reverse-biased cut-off of NPN type triode Q5 emitter junction, collector junction, NPN type triode Q4 emitter junction, collector junction turn on; resistance R1 is shorted; because U1A exports high level signal, NPN type triode Q2 collector junction turns on, in the same time; being in parallel with resistance R6 after resistance R2, R3, R4 series connection, the resistance after parallel connection determines the recovery point under changer input undervoltage guard mode；Input voltage gradually rises; the T2 moment; input voltage rises to a B; operational amplifier U1A in-phase input end voltage magnitude is less than reverse input end voltage magnitude; U1A output low level signal, NPN type triode Q1, Q2 emitter junction, the reverse-biased cut-off of collector junction, the error comparator input i.e. Comp pin level of switch converters master control IC rises to high level signal; circuit enters normal operating conditions, and voltage magnitude corresponding for some B is under-voltage protection recovering state point.
Under-voltage trigger point voltage VAAmplitude calculate as shown in Equation 1:
Under-voltage recovery point voltage VBAmplitude calculate as shown in Equation 2:
Can Exact Design under-voltage protection trigger point, recovery point according to formula 1,2.
Overvoltage protection operation process: before the T3 moment, switch converters input voltage is D, the T3 moment, input voltage gradually rises, to the T4 moment, input voltage rises to a F, operational amplifier U1B in-phase input end voltage magnitude is higher than reverse input end voltage magnitude, U1B exports high level signal, NPN type triode Q1 emitter junction, collector junction turns on, the error comparator input i.e. Comp pin level of switch converters master control IC is pulled to low level signal, circuit enters overvoltage protection state, voltage magnitude corresponding for some F is overvoltage protection state trigger point voltage.
In the same time, the in-phase input end voltage magnitude of operational amplifier U1A is less than reverse input end voltage magnitude, U1A continues to keep output low level state, because of the high level signal of U1B output, being added in NPN type triode Q5 emitter junction two ends after resistance R12, R11 dividing potential drop, the emitter junction of Q5, collector junction turn on, NPN type triode Q4 emitter junction is shorted, the reverse-biased cut-off of Q4 collector junction, resistance R1, resistance R2, resistance R3 be in series, and the all-in resistance after series connection determines overvoltage recovery point；The T5 moment; input voltage starts to be gradually reduced; the T6 moment; input voltage drops to an E; operational amplifier U1B in-phase input end voltage magnitude is less than reverse input end voltage magnitude; U1B output low level signal; NPN type triode Q1, Q5 emitter junction, the reverse-biased cut-off of collector junction; NPN type triode Q4 emitter junction, collector junction positively biased turn on; the error comparator input i.e. Comp pin level of switch converters master control IC rises to high level signal; circuit enters normal operating conditions, and voltage magnitude corresponding for some E is overvoltage protection recovering state point.
Overvoltage trigger point voltage VFAmplitude calculate as shown in Equation 3:
Overvoltage recovery point voltage VEAmplitude calculate as shown in Equation 4:
Can Exact Design overvoltage protection trigger point, recovery point according to formula 3,4.
Second embodiment
It is illustrated in figure 3 the over voltage protection control circuit of this utility model the second embodiment; different from first embodiment are; NPN type triode Q1 shown in Fig. 1, Q2, Q4, Q5 can also be NPN type metal-oxide-semiconductors; as shown in Figure 3; or combine (listing particular combination the most one by one) for NPN type triode with metal-oxide-semiconductor; after adjustment, the operation principle of circuit is just the same with first embodiment, can realize equivalent efficacy.
3rd embodiment
Fig. 4 shows the schematic block circuit diagram of the over voltage protection control circuit of this utility model the 3rd embodiment; a kind of over voltage protection circuit, including: include sample circuit, reference voltage signal Vref, direct voltage source VDD, under-voltage compare and return difference control circuit, overvoltage is compared and return difference control circuit, over voltage control signal output circuit, over-voltage locking circuit.The present embodiment and first, second embodiment are compared, and difference is, increase over-voltage locking circuit, and other parts are completely the same.The concrete structure of the present embodiment over-voltage locking circuit is:
Over-voltage locking circuit includes NPN type triode Q3, start-up circuit control signal, and wherein, the colelctor electrode of NPN type triode Q3 connects start-up circuit control signal, and the base stage of Q3 is connected to the common node of resistance R2, R3, and the emitter stage of Q3 is connected to input ground.
Start-up circuit control signal operation principle is: when start-up circuit control signal is high level, the duty of start-up circuit itself is unaffected；When start-up circuit control signal is low level, start-up circuit quits work.
After adjustment, the present embodiment circuit work process and first embodiment differs only in the over-voltage locking stage; in conjunction with the coherent signal waveform shown in Fig. 4; tell about the operation principle in over-voltage locking stage: before the T6 moment, the duty of circuit is just the same with embodiment one; after the T6 moment; input voltage is gradually increasing; triggering over-voltage protection point to T7 moment input voltage, circuit enters overvoltage protection state, and defining this stage is the pre-overvoltage protection stage；After the T7 moment, before input voltage continues to rise to the T8 moment, operational amplifier U1B continues to put out high level, and NPN type triode Q5 collector junction positively biased turns on, the reverse-biased cut-off of Q4 collector junction, after resistance R1, R2 series connection samples input voltage；Input voltage continues to rise, and to the T8 moment, the equal positively biased of NPN type triode Q3 emitter junction, collector junction turns on, and start-up circuit control signal is low level state, and start-up circuit quits work, and changer overvoltage is locked, quits work；Meanwhile, operational amplifier U1A, U1B all quit work, and after the definition T8 moment, the duty of circuit is the overvoltage locked stage.
Particularly, before the T8 moment, start-up circuit control signal exports equal high level state, and the duty of start-up circuit itself is not affected；
Set NPN type triode Q3 emitter junction voltage as Vd, overvoltage locking state corresponding voltage VLockAmplitude calculate as shown in Equation 5:
Get final product Exact Design overvoltage locking state point according to formula 5, it is to avoid loop of power circuit switching tube is by excessive pressure damages, and meanwhile, start-up circuit quits work, reduce overvoltage condition stand-by power consumption and also improve switch converters reliability.
4th embodiment
In 3rd embodiment, NPN type triode Q1 shown in Fig. 4, Q2, Q4, Q5 can also be NPN type metal-oxide-semiconductors, as shown in Figure 6, or combine (listing particular combination the most one by one) for NPN type triode with metal-oxide-semiconductor, after adjustment, the operation principle of circuit is just the same with first embodiment, can realize equivalent efficacy.
Below it is only preferred implementation of the present utility model; it should be noted that; above-mentioned preferred implementation is not construed as restriction of the present utility model; for those skilled in the art; without departing from spirit and scope of the present utility model, it is also possible to making some improvements and modifications, these improvements and modifications also should be regarded as protection domain of the present utility model; the most no longer repeating by embodiment, protection domain of the present utility model should be as the criterion with claim limited range.
Claims (13)
1. an over voltage protection control circuit; after being connected with the positive pole input voltage vin of changer, direct voltage source VDD, reference voltage signal Vref; situation of change according to changer positive pole input voltage vin; over voltage protection control signal is exported to the error comparator input of changer master control IC; to control changer entrance guard mode; it is characterized in that: include sample circuit, under-voltage control circuit, overvoltage control circuit and control signal output circuit
Described sample circuit, including resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5, wherein, positive pole input voltage vin is back to ground by resistance R5, resistance R4, resistance R3, resistance R2 and the resistance R1 being sequentially connected in series；The common node of resistance R5 and resistance R4 is drawn as the first sampled point, is used for being supplied to under-voltage control circuit；The common node of resistance R4 and resistance R3 is drawn as the second sampled point, is used for being supplied to overvoltage control circuit；
Described under-voltage control circuit, when the positive pole input voltage vin of changer gradually rises from under-voltage protection trigger point voltage, is determined to exit the recovery point voltage of under-voltage protection state by the resistance R2 connected, resistance R3, resistance R4 with total resistance of resistance R6 in parallel；
Described overvoltage control circuit, when the positive pole input voltage vin of changer is gradually lowered from overvoltage protection trigger point voltage, is determined to exit the recovery point voltage of overvoltage protection state by total resistance of the resistance R1 connected, resistance R2, resistance R3.
Over voltage the most according to claim 1 protection control circuit; it is characterized in that: described under-voltage control circuit; including operational amplifier U1A, diode D1, N type switch tube Q2, resistance R6, resistance R9 and resistance R10; wherein; operational amplifier U1A in-phase input end connects reference voltage signal Vref; the inverting input of operational amplifier U1A is connected to electric capacity C1, resistance R4, the common node of resistance R5 three; the inverting input of operational amplifier U1A is connected with the colelctor electrode of N type switch tube Q2 also by resistance R6, the grounded emitter of N type switch tube Q2；Operational amplifier U1A outfan is by the resistance R9 connected and resistance R10 ground connection；The base stage of N type switch tube Q2 is connected to the common node of resistance R9 and resistance R10；The outfan of operational amplifier U1A also anode with diode D1 is connected, and the negative electrode of diode D1 is as the output of under-voltage control circuit, for being connected with control signal output circuit.
Over voltage the most according to claim 1 protection control circuit; it is characterized in that: described overvoltage control circuit; including operational amplifier U1B, diode D2, direct voltage source VDD, N type switch tube Q4, N type switch tube Q5, resistance R11, resistance R12, resistance R13 and resistance R14; wherein; operational amplifier U1B inverting input is connected with reference voltage signal Vref, and operational amplifier U1B in-phase input end is connected to resistance R4, the common node of resistance R3；The outfan of operational amplifier U1B is connected with N type switch tube Q5 base stage by resistance R12, the grounded emitter of N type switch tube Q5；Resistance R11 be connected in parallel on N type switch tube Q5 base stage and emitter stage between；Direct voltage source VDD is by the resistance R13 connected and resistance R14 ground connection, and the common node of resistance R13 and resistance R14 is connected with the colelctor electrode of N type switch tube Q5 and the base stage of N type switch tube Q4 respectively, the grounded emitter of N type switch tube Q4；N type switch tube Q4 colelctor electrode be connected with the common node of resistance R1 and resistance R2；The outfan of operational amplifier U1B also anode with diode D2 is connected, and the negative electrode of diode D2 is as the output of overvoltage control circuit, for being connected with control signal output circuit.
Over voltage the most according to claim 1 protection control circuit; it is characterized in that: described control signal output circuit; including resistance R7, resistance R8 and N type switch tube Q1; wherein; one end of resistance R7 is connected with the outfan of under-voltage control circuit and overvoltage control circuit; the other end of resistance R7 is connected with the base stage of N type switch tube Q1, the grounded emitter of N type switch tube Q1；Resistance R8 is connected in parallel between the base stage of N type switch tube Q1 and emitter stage；The output as control signal output circuit drawn by the colelctor electrode of N type switch tube Q1, for being connected with the error comparator input of changer master control IC.
Over voltage the most according to claim 1 protection control circuit; it is characterized in that: described sample circuit; also include electric capacity C1; electric capacity C1 is for filtering the interference signal of switch converters input; one end of electric capacity C1 is connected to the common node of resistance R5 and resistance R4, the other end ground connection of electric capacity C1.
Over voltage the most according to claim 5 protection control circuit; it is characterized in that: described under-voltage control circuit; including operational amplifier U1A, diode D1, N type switch tube Q2, resistance R6, resistance R9 and resistance R10; wherein; operational amplifier U1A in-phase input end connects reference voltage signal Vref; the inverting input of operational amplifier U1A is connected to electric capacity C1, resistance R4, the common node of resistance R5 three; the inverting input of operational amplifier U1A is connected with the colelctor electrode of N type switch tube Q2 also by resistance R6, the grounded emitter of N type switch tube Q2；Operational amplifier U1A outfan is by the resistance R9 connected and resistance R10 ground connection；The base stage of N type switch tube Q2 is connected to the common node of resistance R9 and resistance R10；The outfan of operational amplifier U1A also anode with diode D1 is connected, and the negative electrode of diode D1 is as the output of under-voltage control circuit, for being connected with control signal output circuit.
Over voltage the most according to claim 5 protection control circuit; it is characterized in that: described overvoltage control circuit; including operational amplifier U1B, diode D2, direct voltage source VDD, N type switch tube Q4, Q5, resistance R11, resistance R12, resistance R13 and resistance R14; wherein; operational amplifier U1B inverting input is connected with reference voltage signal Vref, and operational amplifier U1B in-phase input end is connected to resistance R4, the common node of resistance R3；The outfan of operational amplifier U1B is connected with N type switch tube Q5 base stage by resistance R12, the grounded emitter of N type switch tube Q5；Resistance R11 be connected in parallel on N type switch tube Q5 base stage and emitter stage between；Direct voltage source VDD is by the resistance R13 connected and resistance R14 ground connection, and the common node of resistance R13 and resistance R14 is connected with the colelctor electrode of N type switch tube Q5 and the base stage of N type switch tube Q4 respectively, the grounded emitter of N type switch tube Q4；N type switch tube Q4 colelctor electrode be connected with the common node of resistance R1 and resistance R2；The outfan of operational amplifier U1B also anode with diode D2 is connected, and the negative electrode of diode D2 is as the output of overvoltage control circuit, for being connected with control signal output circuit.
Over voltage the most according to claim 5 protection control circuit; it is characterized in that: described control signal output circuit; including resistance R7, resistance R8 and N type switch tube Q1; wherein; one end of resistance R7 is connected with the outfan of under-voltage control circuit and overvoltage control circuit; the other end of resistance R7 is connected with the base stage of N type switch tube Q1, the grounded emitter of N type switch tube Q1；Resistance R8 is connected in parallel between the base stage of N type switch tube Q1 and emitter stage；The output as control signal output circuit drawn by the colelctor electrode of N type switch tube Q1, for being connected with the error comparator input of changer master control IC.
Over voltage the most according to any one of claim 1 to 8 protection control circuit; it is characterized in that: described over voltage protection control circuit; also include over-voltage locking circuit; described over-voltage locking circuit includes that NPN type triode Q3 and start-up circuit control end; wherein; the colelctor electrode of NPN type triode Q3 controls end with start-up circuit and is connected, and the base stage of NPN type triode Q3 is connected with the common node of resistance R3 and resistance R2, the grounded emitter of NPN type triode Q3；When the positive pole input voltage vin of changer gradually rises to the over-voltage locking point voltage set from overvoltage protection trigger point voltage, NPN type triode Q3 turns on, and making start-up circuit control end is low level state, is used for controlling start-up circuit and quits work.
10. protect control circuit according to the over voltage described in claim 2 or 6, it is characterised in that: described N type switch tube Q2 is NPN type triode or NPN type metal-oxide-semiconductor.
11. protect control circuit according to the over voltage described in claim 3 or 7, it is characterised in that: described N type switch tube Q4 and N type switch tube Q5 are NPN type triode or NPN type metal-oxide-semiconductor.
12. protect control circuit according to the over voltage described in claim 4 or 8, it is characterised in that: described N type switch tube Q1 is NPN type triode or NPN type metal-oxide-semiconductor.
13. 1 kinds of sample circuits; it is applicable to the overvoltage of changer, under-voltage protection control circuit; in order to the situation of change according to changer positive pole input voltage vin; sampled signal is provided to overvoltage, the under-voltage control circuit of under-voltage protection control circuit and overvoltage control circuit; it is characterized in that: described sample circuit; including resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5; wherein, positive pole input voltage vin is back to ground by resistance R5, resistance R4, resistance R3, resistance R2 and the resistance R1 being sequentially connected in series；The common node of resistance R5 and resistance R4 is drawn as the first sampled point, is used for being supplied to under-voltage control circuit；The common node of resistance R4 and resistance R3 is drawn as the second sampled point, is used for being supplied to overvoltage control circuit.
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| CN201521112090.XU CN205453099U (en) | 2015-12-25 | 2015-12-25 | Sampling circuit and mistake, undervoltage protection control circuit |
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| CN201521112090.XU CN205453099U (en) | 2015-12-25 | 2015-12-25 | Sampling circuit and mistake, undervoltage protection control circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105610129A (en) * | 2015-12-25 | 2016-05-25 | 广州金升阳科技有限公司 | Sampling circuit and overvoltage and under-voltage protection control circuit |
| CN107482906A (en) * | 2017-07-24 | 2017-12-15 | 邹彦双 | Air purifier over-and under-voltage protection circuit |
| CN109245513A (en) * | 2018-11-09 | 2019-01-18 | 深圳南云微电子有限公司 | A kind of start-up circuit |
| CN111030045A (en) * | 2019-12-16 | 2020-04-17 | 珠海格力电器股份有限公司 | Voltage protection device and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105610129A (en) * | 2015-12-25 | 2016-05-25 | 广州金升阳科技有限公司 | Sampling circuit and overvoltage and under-voltage protection control circuit |
| CN105610129B (en) * | 2015-12-25 | 2018-11-09 | 广州金升阳科技有限公司 | Over voltage protects control circuit |
| CN107482906A (en) * | 2017-07-24 | 2017-12-15 | 邹彦双 | Air purifier over-and under-voltage protection circuit |
| CN107482906B (en) * | 2017-07-24 | 2018-12-28 | 宁夏锐盛明杰知识产权咨询有限公司 | Air purifier over-and under-voltage protects circuit |
| CN109245513A (en) * | 2018-11-09 | 2019-01-18 | 深圳南云微电子有限公司 | A kind of start-up circuit |
| CN109245513B (en) * | 2018-11-09 | 2024-04-09 | 深圳南云微电子有限公司 | Starting circuit |
| CN111030045A (en) * | 2019-12-16 | 2020-04-17 | 珠海格力电器股份有限公司 | Voltage protection device and method |
| CN117410934A (en) * | 2023-12-14 | 2024-01-16 | 广东东菱电源科技有限公司 | Bridgeless PFC input undervoltage protection circuit |
| CN117410934B (en) * | 2023-12-14 | 2024-04-12 | 广东东菱电源科技有限公司 | Bridgeless PFC input undervoltage protection circuit |
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