CN204103467U - A kind of protective circuit of automobile instrument circuit - Google Patents
A kind of protective circuit of automobile instrument circuit Download PDFInfo
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- CN204103467U CN204103467U CN201420612463.9U CN201420612463U CN204103467U CN 204103467 U CN204103467 U CN 204103467U CN 201420612463 U CN201420612463 U CN 201420612463U CN 204103467 U CN204103467 U CN 204103467U
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Abstract
The utility model provides a kind of protective circuit of automobile instrument circuit, comprises low voltage protection circuit, comparator, electronic switch and single-chip microcomputer; Low voltage protection circuit comprises the first filter capacitor C1, the first pull-up resistor R1, the second pull-up resistor R2, the first voltage-stabiliser tube Q1, the second voltage-stabiliser tube Q2, triode Q3, the first divider resistance R3, the second divider resistance R4, protective resistance R5 and the second filter capacitor C3; Low voltage protection circuit is connected with electronic switch with comparator respectively; Single-chip microcomputer is connected with the output of comparator and the control end of electronic switch respectively; The output of electronic switch is used for being connected to appliance circuit.This protective circuit not only has high voltage protective function, also has low-voltage variation function.
Description
Technical field
The utility model relates to a kind of protective circuit, especially a kind of protective circuit for automobile instrument circuit.
Background technology
When powering to automobile instrument circuit; owing to producing high high voltage when storage battery power supply termination contact is bad and powerful inductive load works; during in order to solve the high voltage interference of power end; damage problem is caused to the circuit module connecting power supply; need to adopt protective circuit at power input, the amplitude that power supply is exported controls in certain scope.
At present; existing technical scheme increases TVS device at power input; to absorb higher than TVS limit value voltage; protection rear end power circuit; but the shortcoming of this technical scheme is when high pressure amplitude is too high and width is longer; TVS shielding failure, causes interior power supply circuit to damage, system failure.The power of TVS domestic is at present less, can not meet design requirement, and import TVS price is more expensive, requiring the occasion that voltage disturbance amplitude is higher, can not meet design requirement.
And the protective circuit of existing automobile instrument circuit only possesses high voltage protective function, does not also possess under-voltage protection function, effective low-voltage variation can not be carried out to the power supply unit of automobile.
Summary of the invention
The technical problems to be solved in the utility model is that the protective circuit of existing automobile instrument circuit easily lost efficacy when high pressure amplitude is too high and width is longer and do not possess under-voltage protection.
In order to solve the problems of the technologies described above, the utility model provides a kind of protective circuit of automobile instrument circuit, comprises low voltage protection circuit, comparator, electronic switch and single-chip microcomputer; Low voltage protection circuit comprises the first filter capacitor C1, the first pull-up resistor R1, the second pull-up resistor R2, the first voltage-stabiliser tube Q1, the second voltage-stabiliser tube Q2, triode Q3, the first divider resistance R3, the second divider resistance R4, protective resistance R5 and the second filter capacitor C3; The emitter of triode Q3 is used for being connected to input power; The positive pole of the second voltage-stabiliser tube Q2 is connected with the base stage of triode Q3, and the negative pole of the second voltage-stabiliser tube Q2 is connected with the emitter of triode Q3; One end of first pull-up resistor R1 is connected with the negative pole of the second voltage-stabiliser tube Q2, and the other end is connected with the negative pole of the first voltage-stabiliser tube Q1; The positive pole of the first voltage-stabiliser tube Q1 is connected to the ground; One end of second pull-up resistor R2 is connected with the negative pole of the first voltage-stabiliser tube Q1, and the other end is connected with the positive pole of the second voltage-stabiliser tube Q2; Between the emitter that the two ends of the first filter capacitor C1 are connected to triode Q3 and ground; Between the collector electrode that first divider resistance R3 and the second divider resistance R4 is connected to triode Q3 after connecting and ground; One end of protective resistance R5 is connected to the junction of the first divider resistance R3 and the second divider resistance R4, and the other end is connected with the comparison input of comparator; Between the collector electrode that the two ends of the second filter capacitor C3 are connected to triode Q3 and ground; The collector electrode of triode Q3 is connected with the input of electronic switch again; Single-chip microcomputer is connected with the output of comparator and the control end of electronic switch respectively; The output of electronic switch is used for being connected to appliance circuit; Triode Q3 is PNP type triode.
Adopt low voltage protection circuit can stop power supply lower than during set point at voltage, available protecting can be carried out to input power, also can prevent spread of voltage from causing damage to automobile instrument simultaneously; Adopt comparator can the input voltage of real-time detector watch circuit, when input voltage exceedes the reference voltage level of comparator, disconnected by Single-chip Controlling electronic switch, realize the real-time high voltage protective to appliance circuit; Adopt the second voltage-stabiliser tube Q2 can protect triode Q3, prevent overtension from causing damage to triode Q3; Adopt the first filter capacitor C1 and the second filter capacitor C3 can carry out filtering to circuit, further appliance circuit is protected; Adopt protective resistance R5 can protect the comparison input of comparator, prevent comparator from damaging.
Electronic switch is PMOS, and the S pole of PMOS is connected with the collector electrode of triode Q3, and the D pole of PMOS is used for being connected to appliance circuit, and the G pole of PMOS is connected with single-chip microcomputer.Adopt PMOS as electronic switch, switching speed is fast, can guarantee the fail safe of automobile instrument circuit further.
The beneficial effects of the utility model are: (1) adopts low voltage protection circuit can stop power supply lower than during set point at voltage, can carry out available protecting to input power, also can prevent spread of voltage from causing damage to automobile instrument simultaneously; (2) adopt comparator can the input voltage of real-time detector watch circuit, when input voltage exceedes the reference voltage level of comparator, disconnected by Single-chip Controlling electronic switch, realize the real-time high voltage protective to appliance circuit; (3) adopt the second voltage-stabiliser tube Q2 can protect triode Q3, prevent overtension from causing damage to triode Q3; (4) adopt the first filter capacitor C1 and the second filter capacitor C3 can carry out filtering to circuit, further appliance circuit is protected; (5) adopt protective resistance R5 can protect the comparison input of comparator, prevent comparator from damaging.
Accompanying drawing explanation
Fig. 1 is structural representation of the present utility model;
Fig. 2 is low voltage protection circuit structural representation of the present utility model.
Embodiment
As illustrated in fig. 1 and 2, the protective circuit of automobile instrument circuit of the present utility model, comprises low voltage protection circuit, comparator, electronic switch and single-chip microcomputer; Low voltage protection circuit comprises the first filter capacitor C1, the first pull-up resistor R1, the second pull-up resistor R2, the first voltage-stabiliser tube Q1, the second voltage-stabiliser tube Q2, triode Q3, the first divider resistance R3, the second divider resistance R4, protective resistance R5 and the second filter capacitor C3; The emitter of triode Q3 is used for being connected to input power; The positive pole of the second voltage-stabiliser tube Q2 is connected with the base stage of triode Q3, and the negative pole of the second voltage-stabiliser tube Q2 is connected with the emitter of triode Q3; One end of first pull-up resistor R1 is connected with the negative pole of the second voltage-stabiliser tube Q2, and the other end is connected with the negative pole of the first voltage-stabiliser tube Q1; The positive pole of the first voltage-stabiliser tube Q1 is connected to the ground; One end of second pull-up resistor R2 is connected with the negative pole of the first voltage-stabiliser tube Q1, and the other end is connected with the positive pole of the second voltage-stabiliser tube Q2; Between the emitter that the two ends of the first filter capacitor C1 are connected to triode Q3 and ground; Between the collector electrode that first divider resistance R3 and the second divider resistance R4 is connected to triode Q3 after connecting and ground; One end of protective resistance R5 is connected to the junction of the first divider resistance R3 and the second divider resistance R4, and the other end is connected with the comparison input of comparator; Between the collector electrode that the two ends of the second filter capacitor C3 are connected to triode Q3 and ground; The collector electrode of triode Q3 is connected with the input of electronic switch again; Single-chip microcomputer is connected with the output of comparator and the control end of electronic switch respectively; The output of electronic switch is used for being connected to appliance circuit; Wherein, triode Q3 is PNP type triode, and electronic switch is PMOS, and the S pole of PMOS is connected with the collector electrode of triode Q3, and the D pole of PMOS is used for being connected to appliance circuit, and the G pole of PMOS is connected with single-chip microcomputer.
The protective circuit of automobile instrument circuit of the present utility model operationally, when the voltage stabilizing value of input supply voltage lower than the first voltage-stabiliser tube Q1, the base stage of triode Q3 is identical with the emitter voltage of triode Q3 under the pull-up effect of the first pull-up resistor R1 with the second pull-up resistor R2, triode Q3 ends, and will disconnect the connection between input power and appliance circuit; When the voltage stabilizing value of input supply voltage higher than the first voltage-stabiliser tube Q1; the voltage exceeded will make triode Q3 conducting; thus appliance circuit obtains electric work; simultaneously the input of comparator introduces the voltage after the first divider resistance R3 and the second divider resistance R4 dividing potential drop; when the comparison input terminal voltage of comparator is greater than reference voltage; then send high level by comparator to single-chip microcomputer; shutdown signal is sent to electronic switch again by single-chip microcomputer; the power supply of appliance circuit is disconnected by electronic switch; thus high voltage protective is timely carried out to appliance circuit, prevent appliance circuit from damaging.
Claims (2)
1. a protective circuit for automobile instrument circuit, is characterized in that: comprise low voltage protection circuit, comparator, electronic switch and single-chip microcomputer; Described low voltage protection circuit comprises the first filter capacitor C1, the first pull-up resistor R1, the second pull-up resistor R2, the first voltage-stabiliser tube Q1, the second voltage-stabiliser tube Q2, triode Q3, the first divider resistance R3, the second divider resistance R4, protective resistance R5 and the second filter capacitor C3; The emitter of described triode Q3 is used for being connected to input power; The positive pole of described second voltage-stabiliser tube Q2 is connected with the base stage of triode Q3, and the negative pole of the second voltage-stabiliser tube Q2 is connected with the emitter of triode Q3; One end of described first pull-up resistor R1 is connected with the negative pole of the second voltage-stabiliser tube Q2, and the other end is connected with the negative pole of the first voltage-stabiliser tube Q1; The positive pole of described first voltage-stabiliser tube Q1 is connected to the ground; One end of described second pull-up resistor R2 is connected with the negative pole of the first voltage-stabiliser tube Q1, and the other end is connected with the positive pole of the second voltage-stabiliser tube Q2; Between the emitter that the two ends of described first filter capacitor C1 are connected to triode Q3 and ground; Between the collector electrode that described first divider resistance R3 and the second divider resistance R4 is connected to triode Q3 after connecting and ground; One end of described protective resistance R5 is connected to the junction of the first divider resistance R3 and the second divider resistance R4, and the other end is connected with the comparison input of comparator; Between the collector electrode that the two ends of described second filter capacitor C3 are connected to triode Q3 and ground; The collector electrode of described triode Q3 is connected with the input of electronic switch again; Described single-chip microcomputer is connected with the output of comparator and the control end of electronic switch respectively; The output of described electronic switch is used for being connected to appliance circuit; Described triode Q3 is PNP type triode.
2. the protective circuit of automobile instrument circuit according to claim 1; it is characterized in that: described electronic switch is PMOS; the S pole of described PMOS is connected with the collector electrode of triode Q3, and the D pole of described PMOS is used for being connected to appliance circuit, and the G pole of described PMOS is connected with single-chip microcomputer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420612463.9U CN204103467U (en) | 2014-10-22 | 2014-10-22 | A kind of protective circuit of automobile instrument circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420612463.9U CN204103467U (en) | 2014-10-22 | 2014-10-22 | A kind of protective circuit of automobile instrument circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204103467U true CN204103467U (en) | 2015-01-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420612463.9U Active CN204103467U (en) | 2014-10-22 | 2014-10-22 | A kind of protective circuit of automobile instrument circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204103467U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104821543A (en) * | 2015-05-19 | 2015-08-05 | 中国兵器工业集团第二一四研究所苏州研发中心 | Device with function of isolation DC/DC power supply input under-voltage or power-off protection |
| CN112803515A (en) * | 2020-12-28 | 2021-05-14 | 中天储能科技有限公司 | Protection circuit and battery management system with same |
-
2014
- 2014-10-22 CN CN201420612463.9U patent/CN204103467U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104821543A (en) * | 2015-05-19 | 2015-08-05 | 中国兵器工业集团第二一四研究所苏州研发中心 | Device with function of isolation DC/DC power supply input under-voltage or power-off protection |
| CN112803515A (en) * | 2020-12-28 | 2021-05-14 | 中天储能科技有限公司 | Protection circuit and battery management system with same |
| CN112803515B (en) * | 2020-12-28 | 2024-03-26 | 中天储能科技有限公司 | Protection circuit and battery management system with same |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |