CN212304842U - Battery under-voltage protection circuit and power module - Google Patents
Battery under-voltage protection circuit and power module Download PDFInfo
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- CN212304842U CN212304842U CN202021820201.3U CN202021820201U CN212304842U CN 212304842 U CN212304842 U CN 212304842U CN 202021820201 U CN202021820201 U CN 202021820201U CN 212304842 U CN212304842 U CN 212304842U
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Abstract
The utility model discloses a battery under-voltage protection circuit and power module can be applied in the electronic circuit technology, wherein, the battery under-voltage protection circuit comprises a first input end, a second input end, a first output end, a second output end, a first resistor, a second resistor, a third resistor, a PMOS tube, an NMOS tube, an NPN triode, a PNP triode, a first voltage regulator tube, a second voltage regulator tube and a third voltage regulator tube; the utility model discloses can realize undervoltage protection and hysteresis function, can avoid battery voltage to cause the output unstability when the critical point is undulant.
Description
Technical Field
The utility model relates to an electronic circuit technique, especially a battery under-voltage protection circuit and power module.
Background
Rechargeable batteries, such as lithium batteries, are commonly used in various electronic devices, and most of the rechargeable batteries are damaged by over-discharge. In order to prevent an over-discharge state of the rechargeable battery, some protective measures, for example, an over-discharge protection IC, are generally employed. If the battery is connected with a load, when the voltage of the battery is lower than the over-discharge voltage detection point, the over-discharge protection IC triggers protection, so that the power MOSFET of the output end is switched from on to off to cut off the discharge, the over-discharge phenomenon of the battery is avoided, and the battery is kept in a standby mode with low quiescent current. But the form of the IC has a limited operating voltage and is relatively costly. At present, a battery voltage protection circuit built by adopting discrete devices is also available, but the battery voltage protection circuit is realized by adopting a simple comparison circuit, and when the battery voltage fluctuates near a trigger point, the unstable output condition can be generated.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the utility model aims to provide a: the battery under-voltage protection circuit and the power module are low in cost and have a hysteresis function.
In one aspect, the utility model discloses the technical scheme who takes is:
a battery under-voltage protection circuit comprises a first input end, a second input end, a first output end, a second output end, a first resistor, a second resistor, a third resistor, a PMOS (P-channel metal oxide semiconductor) tube, an NMOS (N-channel metal oxide semiconductor) tube, an NPN (negative-positive-negative) triode, a PNP (plug-and-play) triode, a first voltage-regulator tube, a second voltage-regulator tube and a third voltage-regulator tube;
the first input end is connected with a source electrode of the PMOS tube, the first output end is connected with a drain electrode of the PMOS tube, the second input end is connected with the second output end, a negative electrode of the first voltage-stabilizing tube is connected with the first input end through the first resistor, a positive electrode of the first voltage-stabilizing tube is connected with a negative electrode of the second voltage-stabilizing tube, and a positive electrode of the second voltage-stabilizing tube is connected with the second input end through the second resistor;
the third resistor is connected between the first input end and the grid electrode of the PMOS tube, the grid electrode of the PMOS tube is connected with the base electrode of the PNP triode, the emitting electrode of the PNP triode is connected with the first input end, and the collecting electrode of the PNP triode is connected with the negative electrode of the second voltage-stabilizing tube;
the source electrode of the NMOS tube is connected with the positive electrode of the second voltage-regulator tube, the drain electrode of the NMOS tube is connected with the negative electrode of the third voltage-regulator tube, the grid electrode of the NMOS tube is connected with the first input end, the positive electrode of the third voltage-regulator tube is connected with the base electrode of the NPN triode, the emitting electrode of the NPN triode is connected with the second input end, and the collector electrode of the NPN triode is connected with the grid electrode of the PMOS tube.
In some embodiments, the circuit further comprises a fourth resistor, and the gate of the PMOS transistor is connected to the base of the PNP triode through the fourth resistor.
In some embodiments, at least one of the first, second, or third regulators is a tunable regulator.
In some embodiments, at least one of the first resistance or the second resistance is an adjustable resistance.
On the other hand, the utility model adopts the technical scheme that:
a power module comprises a battery and a battery under-voltage protection circuit, wherein the positive pole of the battery is connected with a first input end, and the negative pole of the battery is connected with a second input end.
The utility model has the advantages that: the scheme is provided with a first resistor, a second resistor, a third resistor, a PMOS tube, an NMOS tube, an NPN triode, a PNP triode, a first voltage regulator tube, a second voltage regulator tube and a third voltage regulator tube, when the voltage difference between a first input end and a second input end is smaller than a first threshold value, the PMOS tube can be turned off, so that undervoltage protection is realized, and under the action of the first resistor, the second resistor, the third resistor, the NMOS tube, the NPN triode, the PNP triode, the first voltage regulator tube, the second voltage regulator tube and the third voltage regulator tube, the PMOS tube can be turned on again only when the voltage is recovered to a second threshold value larger than the first threshold value, so that the hysteresis function is realized.
Drawings
Fig. 1 is a circuit for protecting a battery from a low voltage according to an embodiment of the present invention;
fig. 2 is a power module according to an embodiment of the present invention.
Detailed Description
The invention is further described with reference to the drawings and the specific embodiments.
Referring to fig. 1, the undervoltage protection circuit for the battery comprises a first input end VIN +, a second input end VIN-, a first output end VO +, a second output end VO-, a first resistor R1, a second resistor R2, a third resistor R3, a PMOS transistor Q1, an NMOS transistor Q2, an NPN triode Q3, a PNP triode Q4, a first voltage regulator D1, a second voltage regulator D2 and a third voltage regulator D3;
the first input end VIN + is connected with the source electrode of the PMOS tube Q1, the first output end VO + is connected with the drain electrode of the PMOS tube Q1, the second input end VIN-is connected with the second output end VO-, the negative electrode of the first voltage-stabilizing tube D1 is connected with the first input end VIN + through the first resistor R1, the positive electrode of the first voltage-stabilizing tube D1 is connected with the negative electrode of the second voltage-stabilizing tube D2, and the positive electrode of the second voltage-stabilizing tube D2 is connected with the second input end VIN-through the second resistor R2;
the third resistor R3 is connected between the first input terminal VIN + and the gate of the PMOS transistor Q1, the gate of the PMOS transistor Q1 is connected with the base of the PNP triode Q4, the emitter of the PNP triode Q4 is connected with the first input terminal VIN +, and the collector of the PNP triode Q4 is connected with the negative electrode of the second voltage regulator D2;
the source electrode of the NMOS tube Q2 is connected with the positive electrode of the second voltage-regulator tube D2, the drain electrode of the NMOS tube Q2 is connected with the negative electrode of the third voltage-regulator tube D3, the grid electrode of the NMOS tube Q2 is connected with the first input end, the positive electrode of the third voltage-regulator tube D3 is connected with the base electrode of the NPN triode Q3, the emitting electrode of the NPN triode Q3 is connected with the second input end, and the collector electrode of the NPN triode Q3 is connected with the grid electrode of the PMOS tube Q1.
The working principle of the utility model comprises:
firstly, when the circuit is used, a battery is connected between a first input end VIN + and a second input end VIN-, and a first output end VO + and a second output end VO-are taken as load ends.
When the power is normally supplied, the PNP triode Q4 is in a saturation amplification state, at the moment, the first resistor R1 and the first voltage regulator tube D1 are in short circuit connection with the PNP triode Q4, and the grid and drain voltage of the NMOS tube Q2 are higher than the conduction threshold value of the NMOS tube Q2 and are conducted; the collector of the PNP triode Q4 forms a path through the base and the emitter of the second, third and NPN triodes D2, D3, Q3, so the path resistance is low, the PNP triode Q4 can be saturated and amplified, meanwhile, the base current of the NPN triode Q3 can be high, the NPN triode Q3 is deeply saturated and conducted, the collector voltage of the NPN triode Q3 can be pulled to be close to the ground potential, the voltage difference between the gate and the source of the PMOS transistor Q1 is smaller than the turn-on voltage, then the source and drain are normally conducted, and the battery can normally supply power to the output terminal.
In the using process, the battery voltage continuously decreases, the collector voltage of the PNP triode Q4 also decreases, and when the battery voltage decreases to the first threshold value, the voltage stabilizing path is broken, that is, the balance among the second voltage regulator D2, the third voltage regulator D3, the NPN triode Q3, and the NMOS Q2 causes the base current of the NPN triode Q3 to decrease, so that the collector voltage of the NPN triode Q3 increases, thereby aggravating the reduction of the on-state current of the PNP triode Q4, and consequently causing the collector voltage of the PNP triode Q4 to be lower, the reduction of the difference between the gate voltage and the source voltage of the NMOS Q2 accelerates the positive feedback effect, and finally causes the source drain of the NMOS Q2 to be cut off, and the NPN triode Q3 to be cut off. The gate voltage of the PMOS transistor Q1 is approximately equal to the source voltage, and the PMOS transistor Q1 is turned off. Therefore, the battery can not output externally any more, and is in a protected state.
When the battery voltage is recovered after triggering protection, only when the battery voltage rises to a certain value (the value can be configured to be larger than a first threshold value by adjusting device parameters), the voltage difference between the gate voltage and the source voltage of the NMOS transistor Q2 is higher than a starting threshold value, the NPN triode Q3 and the PNP triode Q4 enter a saturation amplification state again, the PMOS transistor Q1 can be started, and the battery supplies power normally.
In some embodiments, the circuit further includes a fourth resistor R4, and the gate of the PMOS transistor Q1 is connected to the base of the PNP transistor Q4 through the fourth resistor R4. The fourth resistor R4 is provided primarily for current limiting.
In some embodiments, at least one of the first resistor R1 or the second resistor R2 is an adjustable resistor. In this embodiment, the first resistor R1 or the second resistor R2 is configured as an adjustable resistor, which can adjust the source voltage of the NMOS transistor Q2 when triggering protection, so that a user can configure the protection voltage and the hysteresis voltage according to actual needs.
In some embodiments, at least one of the first, second, or third regulators D1, D2, or D3 is a tunable regulator. The present embodiment can be applied to users to adjust the parameters of the circuit according to actual needs, such as adjusting the protection voltage and the hysteresis voltage.
Referring to fig. 2, a power module includes a battery BAT and the under-voltage battery protection circuit, wherein a positive electrode of the battery BAT is connected to the first input terminal VIN +, and a negative electrode of the battery BAT is connected to the second input terminal VIN-.
While the preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and such equivalent modifications or substitutions are intended to be included within the scope of the present invention as defined by the appended claims.
Claims (5)
1. A battery under-voltage protection circuit is characterized by comprising a first input end, a second input end, a first output end, a second output end, a first resistor, a second resistor, a third resistor, a PMOS (P-channel metal oxide semiconductor) tube, an NMOS (N-channel metal oxide semiconductor) tube, an NPN (negative-positive-negative) triode, a PNP (plug-and-play) triode, a first voltage regulator tube, a second voltage regulator tube and a third voltage regulator tube;
the first input end is connected with a source electrode of the PMOS tube, the first output end is connected with a drain electrode of the PMOS tube, the second input end is connected with the second output end, a negative electrode of the first voltage-stabilizing tube is connected with the first input end through the first resistor, a positive electrode of the first voltage-stabilizing tube is connected with a negative electrode of the second voltage-stabilizing tube, and a positive electrode of the second voltage-stabilizing tube is connected with the second input end through the second resistor;
the third resistor is connected between the first input end and the grid electrode of the PMOS tube, the grid electrode of the PMOS tube is connected with the base electrode of the PNP triode, the emitting electrode of the PNP triode is connected with the first input end, and the collecting electrode of the PNP triode is connected with the negative electrode of the second voltage-stabilizing tube;
the source electrode of the NMOS tube is connected with the positive electrode of the second voltage-regulator tube, the drain electrode of the NMOS tube is connected with the negative electrode of the third voltage-regulator tube, the grid electrode of the NMOS tube is connected with the first input end, the positive electrode of the third voltage-regulator tube is connected with the base electrode of the NPN triode, the emitting electrode of the NPN triode is connected with the second input end, and the collector electrode of the NPN triode is connected with the grid electrode of the PMOS tube.
2. The under-voltage battery protection circuit of claim 1, further comprising a fourth resistor, wherein the gate of the PMOS transistor is connected to the base of the PNP transistor through the fourth resistor.
3. The under-voltage battery protection circuit of claim 1, wherein at least one of the first resistor or the second resistor is an adjustable resistor.
4. The under-voltage battery protection circuit of claim 1, wherein at least one of the first, second, or third regulator tubes is a tunable regulator tube.
5. A power supply module comprising a battery and the undervoltage battery protection circuit of any of claims 1-4, wherein the positive pole of the battery is connected to the first input terminal and the negative pole of the battery is connected to the second input terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021820201.3U CN212304842U (en) | 2020-08-26 | 2020-08-26 | Battery under-voltage protection circuit and power module |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021820201.3U CN212304842U (en) | 2020-08-26 | 2020-08-26 | Battery under-voltage protection circuit and power module |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212304842U true CN212304842U (en) | 2021-01-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021820201.3U Active CN212304842U (en) | 2020-08-26 | 2020-08-26 | Battery under-voltage protection circuit and power module |
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| Country | Link |
|---|---|
| CN (1) | CN212304842U (en) |
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2020
- 2020-08-26 CN CN202021820201.3U patent/CN212304842U/en active Active
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