CN206992680U - Undervoltage protection circuit - Google Patents
Undervoltage protection circuit Download PDFInfo
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- 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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Abstract
The utility model relates to the technical field of switching power supplies, and discloses an under-voltage protection circuit, which comprises a circuit input end, a sampling module, a comparison module, a locking module and an enabling output end; the input end of the circuit is connected with a power supply of the BOOST circuit, and the enabling output end of the circuit is used for controlling the power-on or power-off of the BOOST circuit; the input end of the sampling module is connected with the input end of the circuit; the output end of the sampling module is connected with the first input end of the comparison module, the second input end of the comparison module is connected with the ground, and the comparison output end of the comparison module is connected with the enable output end; the control end of the locking module is connected with the enabling output end, the output end of the locking module is connected with the ground, the input end of the locking module is connected with the first input end of the comparing module, and the locking module is used for keeping the input level of the first input end of the comparing module. The utility model provides the high stability of BOOST circuit and the life of extension BOOST circuit.
Description
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)
- 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. 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. 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. 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. 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. 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. 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. 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. 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. 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.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720910160.9U CN206992680U (en) | 2017-07-25 | 2017-07-25 | Undervoltage protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720910160.9U CN206992680U (en) | 2017-07-25 | 2017-07-25 | Undervoltage protection circuit |
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| CN206992680U true CN206992680U (en) | 2018-02-09 |
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Cited By (2)
| 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 |
| CN111800008B (en) * | 2019-04-01 | 2024-07-16 | Ls电气株式会社 | Output voltage stabilizing device |
-
2017
- 2017-07-25 CN CN201720910160.9U patent/CN206992680U/en active Active
Cited By (2)
| 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 |
| CN111800008B (en) * | 2019-04-01 | 2024-07-16 | Ls电气株式会社 | Output voltage stabilizing device |
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