CN206992680U - A kind of under-voltage protecting circuit - Google Patents

A kind of under-voltage protecting circuit Download PDF

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Publication number
CN206992680U
CN206992680U CN201720910160.9U CN201720910160U CN206992680U CN 206992680 U CN206992680 U CN 206992680U CN 201720910160 U CN201720910160 U CN 201720910160U CN 206992680 U CN206992680 U CN 206992680U
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voltage
module
input
output end
comparison
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邓国健
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Guangzhou Shiyuan Electronics Thecnology Co Ltd
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Guangzhou Shiyuan Electronics Thecnology Co Ltd
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Abstract

Switch power technology field is the utility model is related to, discloses a kind of under-voltage protecting circuit, including circuit input end, sampling module, comparison module, locking module and enabled output end;Wherein, circuit input end is used for the power supply for connecting BOOST circuits, and enabled output end is used to control BOOST power on circuitry or power-off;The input of sampling module is connected with circuit input end;The output end of sampling module and the first input end of comparison module are connected, and the second input of comparison module is connected to ground, and the comparison output end of comparison module is connected with enabled output end;The control terminal of locking module is connected with enabled output end, and the output end of locking module is connected to ground, and the input of locking module and the first input end of comparison module connect, and locking module is used for the incoming level for keeping the first input end of comparison module.The utility model improves the stability of BOOST circuits and extends the service life of BOOST circuits.

Description

A kind of under-voltage protecting circuit
Technical field
Switch power technology field is the utility model is related to, more particularly to a kind of under-voltage protecting circuit.
Background technology
BOOST circuits are a kind of common switch DC booster circuits, in BOOST circuits, when input voltage is too low (i.e. It is under-voltage) when so that the step-up ratio increase of BOOST circuits, so as to cause the power semiconductor and magnetic device hair in circuit It is hot serious, cause circuit unstable or even burn circuit, therefore, typically realized by setting under-voltage protection point to BOOST electricity The under-voltage protection on road.But in the under-voltage protection of existing BOOST circuits, when input voltage is less than under-voltage protection point, BOOST down circuitries are to realize under-voltage protection, and when input voltage is slightly increased to be higher than under-voltage protection point, BOOST circuits lead to Electricity;When input voltage somewhat decreases below under-voltage protection point, BOOST circuits power off again, it follows that working as input voltage During positioned at under-voltage protection point, because the fluctuation of input voltage make it that repeatedly switching is powered or powered off BOOST circuits in a short time State, so as to cause circuit unstable and be easily damaged circuit.
Utility model content
The utility model provides a kind of under-voltage protecting circuit, and it can improve the stability of BOOST circuits and extension The service life of BOOST circuits.
The utility model provides a kind of under-voltage protecting circuit, including circuit input end, sampling module, comparison module, locking Module and enabled output end;Wherein, the circuit input end is used for the power supply for connecting BOOST circuits, described enabled defeated Go out end to be used to control the BOOST power on circuitry or power-off;
The input of the sampling module is connected with the circuit input end;The output end of the sampling module and the ratio First input end compared with module connects, and the second input of the comparison module is connected to ground, the comparison module it is more defeated Go out end to be connected with the enabled output end;
The control terminal of the locking module is connected with the enabled output end, and output end and the ground of the locking module connect Connect, the input of the locking module is connected with the first input end of the comparison module, and the locking module is used to keep institute State the incoming level of the first input end of comparison module.
Above-mentioned under-voltage protecting circuit by the locking module by being connected to the enabled output end and the relatively mould Between block, when the BOOST circuits are under-voltage, by controlling the locking module to turn on, so that the comparison module The incoming level of first input end keeps stable, to ensure that the output of the comparison output end of the comparison module is stable, so that The stable enable signal of the enabled output end output, to control the BOOST down circuitries, avoids the BOOST circuits The state that repeatedly switching is powered and powered off in a short time, and then improve the stability of BOOST circuits and extend BOOST circuits Service life.
Preferably, the locking module includes first switch pipe and first resistor, and the first switch pipe passes through The first resistor is connected with the control terminal of the locking module, input and the locking module of the first switch pipe Input is connected, and the output end of the first switch pipe is connected with the output end of the locking module.When the BOOST circuits are owed During pressure, by controlling the first switch pipe to turn on, to drag down the current potential of the first input end of the comparison module, so as to keep The incoming level of the first input end of the comparison module is low level, to ensure that the comparison output end of the comparison module exports High level, so that the enabled output end output high level, to control the BOOST down circuitries, is avoided described The BOOST circuits state that repeatedly switching is powered and powered off in a short time, and then improve the stability of BOOST circuits and extension The service life of BOOST circuits;In addition, the first resistor plays metering function, to protect the first switch pipe, so as to improve The stability of the first switch pipe, and then improve the stability of the under-voltage protecting circuit.
Preferably, the first switch pipe is NPN type triode, and the control terminal of the first switch pipe is NPN The control pole of type triode, the input of the first switch pipe are the colelctor electrode of NPN type triode, the first switch pipe Output end is the emitter stage of NPN type triode.Because NPN type triode has Current amplifier effect, therefore the first switch Pipe can strengthen the driving force of the first switch pipe using NPN type triode, to ensure that the locking module turns on, so as to Ensure the under-voltage protecting circuit normal work.
Preferably, the first switch pipe is N-channel MOS pipe, and the control terminal of the first switch pipe is N-channel The grid of metal-oxide-semiconductor, the input of the first switch pipe are the drain electrode of N-channel MOS pipe, and the output end of the first switch pipe is The source electrode of N-channel MOS pipe.Because N-channel MOS pipe also has Current amplifier effect, therefore the first switch pipe uses N-channel Metal-oxide-semiconductor can strengthen the driving force of the first switch pipe, to ensure that the locking module turns on, so that it is guaranteed that described under-voltage Protection circuit normal work.
Preferably, the comparison module includes TL431 chips and second resistance, the reference of the TL431 chips Pole is connected with the first input end of the comparison module, the anode of the TL431 chips and the second input of the comparison module End connection, the negative electrode of the TL431 chips are connected with the comparison output end of the comparison module, the negative electrode of the TL431 chips Also it is connected by the second resistance with the circuit input end.Because reference voltage source is contained in the inside of the TL431 chips, Therefore without providing extra reference circuit for comparison module, and without additionally powering, so that using the TL431 chips energy Enough simplify the structure of the under-voltage protecting circuit and reduce cost.
Preferably, the comparison module includes voltage comparator, the first voltage-stabiliser tube and 3rd resistor;
The output end of the voltage comparator is connected with the comparison output end of the comparison module, the voltage comparator End of oppisite phase is connected with the first input end of the comparison module, the in-phase end of the voltage comparator by the 3rd resistor with The circuit input end connection, the in-phase end of the voltage comparator also pass through first voltage-stabiliser tube and the comparison module Second input connects, wherein, the anode of first voltage-stabiliser tube is connected with the second input of the comparison module, and described the The negative electrode of one voltage-stabiliser tube is connected with the in-phase end of the voltage comparator.It is the voltage comparator by first voltage-stabiliser tube Reference voltage is provided, and the output end of the sampling module is connected to by the end of oppisite phase of the voltage comparator, so as to by institute The voltage of the end of oppisite phase of voltage comparator is stated compared with the reference voltage, then passes through the relatively output end output voltage To the enabled output end, to control the BOOST power on circuitry or power-off;In addition, the 3rd resistor plays metering function, with First voltage-stabiliser tube is protected, so as to improve the stability of first voltage-stabiliser tube, and then improves the under-voltage protecting circuit Stability.
Preferably, the comparison module also includes electric capacity;
The first end of the electric capacity is connected with the in-phase end of the voltage comparator, the second end of the electric capacity and the ratio The second input compared with module connects.Because the electric capacity can filter, hence in so that the comparison module is more stable, so as to So that the under-voltage protecting circuit is more stable.
Preferably, the sampling module includes the 4th resistance and the 5th resistance, the first end of the 4th resistance It is connected with the input of the sampling module, the second end of the 4th resistance is connected with the output end of the sampling module, institute The first end for stating the 5th resistance is connected with the second end of the 4th resistance, and the second end of the 5th resistance is connected to ground.It is logical Cross the 4th resistance and the 5th resistant series so that the 5th electric resistance partial pressure, so as to by the circuit input end Voltage Feedback controls the output of the comparison module to the comparison module.
Preferably, the under-voltage protecting circuit also includes Voltage stabilizing module, the comparison output end of the comparison module It is connected by the Voltage stabilizing module with the enabled output end;Wherein, the input of the Voltage stabilizing module and the comparison module The connection of comparison output end, the output end of the Voltage stabilizing module is connected with the enabled output end.By by the Voltage stabilizing module It is connected between the comparison module and the enabled output end so that the output of the enabled output end is more stable, so as to So that the under-voltage protecting circuit is more stable.
Preferably, the Voltage stabilizing module includes the second voltage-stabiliser tube, the positive pole of second voltage-stabiliser tube with it is described steady The input connection of die block, the negative pole of second voltage-stabiliser tube are connected with the output end of the Voltage stabilizing module.By by described in Second voltage-stabiliser tube is connected between the comparison module and the enabled output end so that the output of the enabled output end is more It is stable, so that the under-voltage protecting circuit is more stable.
Brief description of the drawings
Fig. 1 is the circuit block diagram of the under-voltage protecting circuit in the utility model embodiment;
Fig. 2 is the circuit theory diagrams of the under-voltage protecting circuit in the utility model embodiment;
Fig. 3 is the circuit theory diagrams of another embodiment of the under-voltage protecting circuit in the utility model embodiment.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the embodiment of the utility model is carried out Clearly and completely describing, it is clear that described embodiment is only the utility model part of the embodiment, rather than whole Embodiment.Based on the embodiment in the utility model, those of ordinary skill in the art are not under the premise of creative work is made The every other embodiment obtained, belong to the scope of the utility model protection.
It is shown in Figure 1, a kind of under-voltage protecting circuit of the utility model preferred embodiment, including circuit input end Vin, Sampling module 201, comparison module 202, locking module 203 and enabled output end vo ut;Wherein, the circuit input end Vin For connecting the power supply of BOOST circuits, the enabled output end vo ut is used to control the BOOST power on circuitry or disconnected Electricity;
The input of the sampling module 201 is connected with the circuit input end Vin;The output of the sampling module 201 End is connected with the first input end of the comparison module 202, and the second input of the comparison module 202 is connected to ground, described The comparison output end of comparison module 202 is connected with the enabled output end vo ut;
The control terminal of the locking module 203 is connected with the enabled output end vo ut, the output of the locking module 203 End is connected to ground, and the input of the locking module 203 is connected with the first input end of the comparison module 202, the locking Module 203 is used for the incoming level for keeping the first input end of the comparison module 202.
The specific work process of the under-voltage protecting circuit provided below the utility model embodiment is described in detail:
The circuit input end Vin accesses the power supply of the BOOST circuits, when the electricity of the circuit input end Vin When pressure is higher than under-voltage protection point, the sampling module 201 for being connected to the circuit input end Vin exports a control signal to institute State the first input end of comparison module 202 so that the output end of the comparison module 202 exports another control signal to be made to described Energy output end vo ut, so that the enabled output end vo ut outputs enable signal, to control the BOOST power on circuitry; Now, cut-in voltage, therefore the locking are not up to due to being connected to the locking module 203 of the enabled output end vo ut Module 203 is ended, so that the incoming level of the first input end of the comparison module 202 keeps stable, and then causes institute BOOST circuits are stated to remain powered on.
When the voltage of the circuit input end Vin is less than under-voltage protection point, the institute of the circuit input end Vin is connected to State sampling module 201 and export a control signal to the first input end of the comparison module 202 so that the comparison module 202 Output end export another control signal to the enabled output end vo ut so that the enabled output end vo ut outputs make Energy signal, to control the BOOST down circuitries;Now, due to being connected to the locking mould of the enabled output end vo ut Block 203 reaches cut-in voltage, therefore the locking module 203 turns on, so that the first input end of the comparison module 202 Incoming level keep stable, and then the BOOST circuits are remained powered off.
, it is necessary to which explanation, the under-voltage protection point are needed according to actual operation requirements in the utility model embodiment And set by the comparison module 202, in addition, the enable signal passes through triode or metal-oxide-semiconductor or micro-control unit Etc. (MCU) element controls the BOOST power on circuitry or power-off.
Above-mentioned under-voltage protecting circuit by the locking module 203 by being connected to the enabled output end vo ut and described Between comparison module 202, when the BOOST circuits are under-voltage, by controlling the locking module 203 to turn on, so that institute The incoming level for stating the first input end of comparison module 202 keeps stable, to ensure the comparison output end of the comparison module 202 Output is stable, so that the enable signal that the enabled output end vo ut outputs are stable, to control the BOOST circuits to break Electricity, the BOOST circuits state that repeatedly switching is powered and powered off in a short time is avoided, and then improve BOOST circuits Stability and the service life for extending BOOST circuits.
With reference to shown in Fig. 1 to Fig. 3, the locking module 203 in the present embodiment includes the electricity of first switch pipe Q1 and first R1 is hindered, the first switch pipe Q1 is connected by the first resistor R1 with the control terminal of the locking module 203, and described first Switching tube Q1 input is connected with the input of the locking module 203, the output end of the first switch pipe Q1 with it is described The output end connection of locking module 203.When the BOOST circuits are under-voltage, by controlling the first switch pipe Q1 to turn on, with The current potential of the first input end of the comparison module 202 is dragged down, so as to keep the defeated of the first input end of the comparison module 202 It is low level to enter level, to ensure that the comparison output end of the comparison module 202 exports high level, so that described enabled defeated Go out to hold Vout to export high level, to control the BOOST down circuitries, it is multiple in a short time to avoid the BOOST circuits Switching is powered and the state of power-off, and then improves the stability of BOOST circuits and extend the service life of BOOST circuits;In addition, The first resistor R1 plays metering function, to protect the first switch pipe Q1, so as to improve the steady of the first switch pipe Q1 It is qualitative, and then improve the stability of the under-voltage protecting circuit.
With reference to shown in Fig. 1 to Fig. 3, the first switch pipe Q1 in the present embodiment is NPN type triode, and described first opens The control terminal for closing pipe Q1 is the control pole of NPN type triode, and the input of the first switch pipe Q1 is the collection of NPN type triode Electrode, the output end of the first switch pipe Q1 are the emitter stage of NPN type triode.Because there is NPN type triode electric current to put Big effect, therefore the first switch pipe Q1 can strengthen the driving force of the first switch pipe Q1 using NPN type triode, To ensure that the locking module 203 turns on, so that it is guaranteed that the under-voltage protecting circuit normal work.
Obviously, in order to realize the conducting of the locking module 203 and cutoff function, the first switch in the present embodiment Pipe Q1 can also be the element that N-channel MOS pipe etc. has conducting and cut-off state, the first switch pipe Q1 in the present embodiment Control terminal be N-channel MOS pipe grid, the input of the first switch pipe Q1 is the drain electrode of N-channel MOS pipe, described the One switching tube Q1 output end is the source electrode of N-channel MOS pipe.Because N-channel MOS pipe also has Current amplifier effect, therefore institute The driving force of the first switch pipe Q1 can be strengthened using N-channel MOS pipe by stating first switch pipe Q1, to ensure the locking Module 203 turns on, so that it is guaranteed that the under-voltage protecting circuit normal work.
With reference to shown in Fig. 1 to Fig. 3, the sampling module 201 includes the 4th resistance R4 and the 5th resistance R5, the 4th electricity Resistance R4 first end is connected with the input of the sampling module 201, the second end and the sampling mould of the 4th resistance R4 The output end connection of block 201, the first end of the 5th resistance R5 are connected with the second end of the 4th resistance R4, and the described 5th Resistance R5 the second end is connected to ground.Connected by the 4th resistance R4 and the 5th resistance R5 so that the 5th electricity R5 partial pressures are hindered, so that by the Voltage Feedback of the circuit input end Vin to the comparison module 202, and then control the comparison The output of module 202.
With reference to shown in Fig. 1 to Fig. 3, the under-voltage protecting circuit also includes Voltage stabilizing module, the comparison of the comparison module 202 Output end is connected by the Voltage stabilizing module with the enabled output end vo ut;Wherein, the input of the Voltage stabilizing module and institute The comparison output end connection of comparison module 202 is stated, the output end of the Voltage stabilizing module is connected with the enabled output end vo ut.It is logical Cross and the Voltage stabilizing module is connected between the comparison module 202 and the enabled output end vo ut so that be described enabled defeated Go out to hold Vout output more stable, so that the under-voltage protecting circuit is more stable.
With reference to shown in Fig. 1 to Fig. 3, the Voltage stabilizing module includes the second voltage-stabiliser tube Z2, the positive pole of the second voltage-stabiliser tube Z2 It is connected with the input of the Voltage stabilizing module, the negative pole of the second voltage-stabiliser tube Z2 is connected with the output end of the Voltage stabilizing module. By the way that the second voltage-stabiliser tube Z2 is connected between the comparison module 202 and the enabled output end vo ut so that described Enabled output end vo ut output is more stable, so that the under-voltage protecting circuit is more stable.
With reference to shown in Fig. 1 and Fig. 2, the comparison module 202 includes TL431 chips U1 and second resistance R2, the TL431 Chip U1 reference pole is connected with the first input end of the comparison module 202, anode and the ratio of the TL431 chips U1 The second input compared with module 202 connects, the negative electrode of the TL431 chips U1 and the comparison output end of the comparison module 202 Connection, the negative electrode of the TL431 chips U1 are also connected by the second resistance R2 with the circuit input end Vin.By institute Reference voltage source is contained in the inside for stating TL431 chips U1, therefore need not provide extra reference circuit, and nothing for comparison module 202 Need to additionally power so that using the TL431 chips U1 can simplify the under-voltage protecting circuit structure and reduce into This.
The specific work process of the under-voltage protecting circuit provided below the utility model embodiment is described in detail:
The circuit input end Vin accesses the power supply of the BOOST circuits, when the electricity of the circuit input end Vin When pressure is higher than under-voltage protection point, pass through the 4th resistance R4 for being connected to the circuit input end Vin and the 5th resistance R5 partial pressures, the high level of the circuit input end Vin is fed back to the reference pole of the TL431 chips U1, then by by institute The voltage of TL431 chips U1 reference pole is stated compared with the reference voltage source of TL431 chips U1 inside so that described TL431 chips U1 negative electrode exports low level to the enabled output end vo ut, so that the enabled output end vo ut is defeated Go out low level as enable signal, to control the BOOST power on circuitry;Now, because the first switch pipe Q1 is not up to Cut-in voltage, therefore the first switch pipe Q1 ends, so that the reference pole of the TL431 chips U1 keeps high level, And then the BOOST circuits are remained powered on.
When the voltage of the circuit input end Vin is less than under-voltage protection point, by being connected to the circuit input end Vin The 4th resistance R4 and the 5th resistance R5 partial pressures, the low level of the circuit input end Vin is fed back to described TL431 chips U1 reference pole, then by by the voltage of the reference pole of the TL431 chips U1 and TL431 chips U1 The reference voltage source in portion is compared so that the negative electrode of the TL431 chips U1 exports high level to the enabled output end Vout, so that the enabled output end vo ut exports high level as enable signal, to control the BOOST circuits to break Electricity;Now, because the first switch pipe Q1 reaches cut-in voltage, therefore the first switch pipe Q1 is turned on, while is dragged down The current potential of the reference pole of the TL431 chips U1, so that the reference pole of the TL431 chips U1 keeps low level, and then So that the BOOST circuits remain powered off.
Above-mentioned under-voltage protecting circuit by the first switch pipe Q1 by being connected to the enabled output end vo ut and institute Between stating TL431 chips U1, when the BOOST circuits are under-voltage, by controlling the first switch pipe Q1 to turn on, to drag down The current potential of TL431 chips U1 reference pole is stated, so that the incoming level of the reference pole of the TL431 chips U1 keeps low electricity It is flat, to ensure that the negative electrode of the TL431 chips U1 exports high level, so that the enabled output end vo ut outputs high level As enable signal, to control the BOOST down circuitries, avoiding the BOOST circuits, repeatedly switching is logical in a short time Electricity and the state of power-off, and then improve the stability of BOOST circuits and extend the service life of BOOST circuits.
With reference to shown in Fig. 1 and Fig. 3, the comparison module 202 includes voltage comparator U2, the first voltage-stabiliser tube Z1 and the 3rd electricity Hinder R3;
The output end of the voltage comparator U2 is connected with the comparison output end of the comparison module 202, the voltage ratio End of oppisite phase compared with device U2 is connected with the first input end of the comparison module 202, and the in-phase end of the voltage comparator U2 passes through The 3rd resistor R3 is connected with the circuit input end Vin, and the in-phase end of the voltage comparator U2 also passes through described first Voltage-stabiliser tube Z1 is connected with the second input of the comparison module 202, wherein, anode and the ratio of the first voltage-stabiliser tube Z1 The second input compared with module 202 connects, and the negative electrode of the first voltage-stabiliser tube Z1 connects with the in-phase end of the voltage comparator U2 Connect.Reference voltage is provided for the voltage comparator U2 by the first voltage-stabiliser tube Z1, and passes through the voltage comparator U2 End of oppisite phase be connected to the output end of the sampling module 201, so as to by the voltage of the end of oppisite phase of the voltage comparator U2 with The reference voltage is compared, then by the relatively output end output voltage to the enabled output end vo ut, with control The BOOST power on circuitry or power-off;In addition, the 3rd resistor R3 plays metering function, to protect the first voltage-stabiliser tube Z1, So as to improve the stability of the first voltage-stabiliser tube Z1, and then improve the stability of the under-voltage protecting circuit.
In order that structure rationalization, the comparison module 202 in the present embodiment also includes electric capacity C1;
The first end of the electric capacity C1 is connected with the in-phase end of the voltage comparator U2, the second end of the electric capacity C1 with The second input connection of the comparison module 202.Because the electric capacity C1 can be filtered, hence in so that the comparison module 202 is more stable, so that the under-voltage protecting circuit is more stable.
The specific work process of the under-voltage protecting circuit provided below the utility model embodiment is described in detail:
The circuit input end Vin accesses the power supply of the BOOST circuits, when the electricity of the circuit input end Vin When pressure is higher than under-voltage protection point, pass through the 4th resistance R4 for being connected to the circuit input end Vin and the 5th resistance R5 partial pressures, the high level of the circuit input end Vin is fed back to the end of oppisite phase of the voltage comparator U2, in addition, described One voltage-stabiliser tube Z1 control source to the voltage comparator U2 in-phase end, by by the end of oppisite phase of the voltage comparator U2 Voltage compared with the voltage of the in-phase end of the voltage comparator U2 so that the output end of the voltage comparator U2 is defeated Go out low level to the enabled output end vo ut, so that the enabled output end vo ut output low levels are as enabled letter Number, to control the BOOST power on circuitry;Now, because the first switch pipe Q1 is not up to cut-in voltage, therefore described One switching tube Q1 ends, so that the end of oppisite phase of the voltage comparator U2 keeps high level, and then causes the BOOST electricity Road remains powered on.
When the voltage of the circuit input end Vin is less than under-voltage protection point, by being connected to the circuit input end Vin The 4th resistance R4 and the 5th resistance R5 partial pressures, the low level of the circuit input end Vin is fed back into the electricity Comparator U2 end of oppisite phase is pressed, in addition, in-phase end of the control source of the first voltage-stabiliser tube Z1 to the voltage comparator U2, By by the voltage of the end of oppisite phase of the voltage comparator U2 compared with the voltage of voltage comparator U2 in-phase end so that The output end of the voltage comparator U2 exports high level to the enabled output end vo ut, so that the enabled output end Vout exports high level as enable signal, to control the BOOST down circuitries;Now, due to the first switch pipe Q1 Reach cut-in voltage, therefore the first switch pipe Q1 is turned on, while dragged down the electricity of the end of oppisite phase of the voltage comparator U2 Position, so that the end of oppisite phase of the voltage comparator U2 keeps low level, and then the BOOST circuits are remained powered off.
Above-mentioned under-voltage protecting circuit by the first switch pipe Q1 by being connected to the enabled output end vo ut and institute Between stating voltage comparator U2, when the BOOST circuits are under-voltage, by controlling the first switch pipe Q1 to turn on, to drag down The current potential of the end of oppisite phase of the voltage comparator U2, so that the incoming level of the end of oppisite phase of the voltage comparator U2 is kept Low level, to ensure that the output end of the voltage comparator U2 exports high level, so that the enabled output end vo ut is defeated Go out high level as enable signal, to control the BOOST down circuitries, it is more in a short time to avoid the BOOST circuits Secondary switching is powered and the state of power-off, and then improves the stability of BOOST circuits and extend the service life of BOOST circuits.
Described above is only preferred embodiment of the present utility model, it is noted that for the common skill of the art For art personnel, on the premise of the utility model technical principle is not departed from, some improvement and replacement can also be made, these change Enter and replace and also should be regarded as the scope of protection of the utility model.

Claims (10)

  1. A kind of 1. under-voltage protecting circuit, it is characterised in that including circuit input end, sampling module, comparison module, locking module with And enabled output end;Wherein, the circuit input end is used for the power supply for connecting BOOST circuits, and the enabled output end is used In the control BOOST power on circuitry or power-off;
    The input of the sampling module is connected with the circuit input end;The output end of sampling module mould compared with described The first input end connection of block, the second input of the comparison module are connected to ground, the comparison output end of the comparison module It is connected with the enabled output end;
    The control terminal of the locking module is connected with the enabled output end, and the output end of the locking module is connected to ground, institute The input for stating locking module is connected with the first input end of the comparison module, and the locking module is used to keep the comparison The incoming level of the first input end of module.
  2. 2. under-voltage protecting circuit as claimed in claim 1, it is characterised in that the locking module includes first switch pipe and the One resistance, the first switch pipe are connected by the first resistor with the control terminal of the locking module, the first switch The input of pipe is connected with the input of the locking module, and the output end of the first switch pipe is defeated with the locking module Go out end connection.
  3. 3. under-voltage protecting circuit as claimed in claim 2, it is characterised in that the first switch pipe is NPN type triode, institute The control terminal for stating first switch pipe is the control pole of NPN type triode, and the input of the first switch pipe is NPN type triode Colelctor electrode, the output end of the first switch pipe is the emitter stage of NPN type triode.
  4. 4. under-voltage protecting circuit as claimed in claim 2, it is characterised in that the first switch pipe is N-channel MOS pipe, institute The control terminal for stating first switch pipe is the grid of N-channel MOS pipe, and the input of the first switch pipe is the leakage of N-channel MOS pipe Pole, the output end of the first switch pipe are the source electrode of N-channel MOS pipe.
  5. 5. under-voltage protecting circuit as claimed in claim 1, it is characterised in that the comparison module includes TL431 chips and the Two resistance, the reference pole of the TL431 chips are connected with the first input end of the comparison module, the sun of the TL431 chips Pole is connected with the second input of the comparison module, and the negative electrode of the TL431 chips exports with the comparison of the comparison module End connection, the negative electrode of the TL431 chips are also connected by the second resistance with the circuit input end.
  6. 6. under-voltage protecting circuit as claimed in claim 1, it is characterised in that the comparison module includes voltage comparator, the One voltage-stabiliser tube and 3rd resistor;
    The output end of the voltage comparator is connected with the comparison output end of the comparison module, the voltage comparator it is anti-phase End is connected with the first input end of the comparison module, the in-phase end of the voltage comparator by the 3rd resistor with it is described Circuit input end connects, and the in-phase end of the voltage comparator also passes through the second of first voltage-stabiliser tube and the comparison module Input connects, wherein, the anode of first voltage-stabiliser tube is connected with the second input of the comparison module, and described first is steady The negative electrode of pressure pipe is connected with the in-phase end of the voltage comparator.
  7. 7. under-voltage protecting circuit as claimed in claim 6, it is characterised in that the comparison module also includes electric capacity;
    The first end of the electric capacity is connected with the in-phase end of the voltage comparator, the second end of electric capacity mould compared with described The second input connection of block.
  8. 8. under-voltage protecting circuit as claimed in claim 1, it is characterised in that the sampling module includes the 4th resistance and the 5th Resistance, the first end of the 4th resistance are connected with the input of the sampling module, the second end of the 4th resistance and institute The output end connection of sampling module is stated, the first end of the 5th resistance is connected with the second end of the 4th resistance, and described the Second end of five resistance is connected to ground.
  9. 9. the under-voltage protecting circuit as described in claim any one of 1-8, it is characterised in that the under-voltage protecting circuit also includes Voltage stabilizing module, the comparison output end of the comparison module are connected by the Voltage stabilizing module with the enabled output end;Wherein, institute State the input of Voltage stabilizing module to be connected with the comparison output end of the comparison module, the output end of the Voltage stabilizing module makes with described Can output end connection.
  10. 10. under-voltage protecting circuit as claimed in claim 9, it is characterised in that the Voltage stabilizing module includes the second voltage-stabiliser tube, institute The positive pole for stating the second voltage-stabiliser tube is connected with the input of the Voltage stabilizing module, the negative pole of second voltage-stabiliser tube and the voltage stabilizing mould The output end connection of block.
CN201720910160.9U 2017-07-25 2017-07-25 A kind of under-voltage protecting circuit Active CN206992680U (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111800008A (en) * 2019-04-01 2020-10-20 Ls电气株式会社 Output voltage stabilizing device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111800008A (en) * 2019-04-01 2020-10-20 Ls电气株式会社 Output voltage stabilizing device

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