CN204118730U - The protective circuit that a kind of automobile instrument is powered - Google Patents

Abstract

The utility model provides the protective circuit that a kind of automobile instrument is powered, and comprises input power protective circuit, input power Acquisition Circuit, electronic switch and single-chip microcomputer; Input power protective circuit comprises the first filter capacitor C6, the second filter capacitor C9, the first diode Z3, suppresses electric capacity C2, pull-up resistor R4, the first ground capacity C10, the first triode T1, the second triode T2, the first voltage-stabiliser tube Z4, the second voltage-stabiliser tube Z5 and the second ground capacity C7; Input power Acquisition Circuit comprises the second diode Z2, the 3rd filter capacitor C3, the first divider resistance R1, the second divider resistance R3, protective resistance R2 and the 4th filter capacitor C4; The other end of protective resistance R2 is connected to single-chip microcomputer; The input of electronic switch is connected with the emitter of the second triode T2, and the output of electronic switch is used for being connected with automobile instrument circuit, and the control end of electronic switch is connected with single-chip microcomputer.This protective circuit can realize when high pressure amplitude is too high and width is longer protecting automobile instrument circuit, and cost is lower.

Description

The protective circuit that a kind of automobile instrument is powered

Technical field

The utility model relates to a kind of protective circuit, and especially a kind of protective circuit for automobile instrument circuit supply, belongs to vehicle electric field.

Background technology

When powering to automobile instrument power source; 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.

Summary of the invention

The technical problems to be solved in the utility model is that the protection when high pressure amplitude is too high and width is longer of existing protection device can be lost efficacy, and causes appliance circuit to damage.

In order to solve the problem, the utility model provides the protective circuit that a kind of automobile instrument is powered, and comprises input power protective circuit, input power Acquisition Circuit, electronic switch and single-chip microcomputer; Input power protective circuit comprises the first filter capacitor C6, the second filter capacitor C9, the first diode Z3, suppresses electric capacity C2, pull-up resistor R4, the first ground capacity C10, the first triode T1, the second triode T2, the first voltage-stabiliser tube Z4, the second voltage-stabiliser tube Z5 and the second ground capacity C7; The positive pole of the first diode Z3 is used for being connected with input power, and the negative pole of the first diode Z3 is connected with the emitter of the first triode T1; Between the positive pole that first filter capacitor C6 and the second filter capacitor C9 is connected to the first diode Z3 after connecting and ground; Electric capacity C2 and the first diode Z3 is suppressed to be in parallel; The collector electrode of the second triode T2 is connected with the base stage of the first triode T1, and the emitter of the second triode T2 is connected with the collector electrode of the first triode T1; Pull-up resistor R4 is connected between the emitter of the first triode T1 and the base stage of the second triode T2; The negative pole of the first voltage-stabiliser tube Z4 is connected to the base stage of the second triode T2, and the positive pole of the first voltage-stabiliser tube Z4 is connected to the negative pole of the second voltage-stabiliser tube Z5, the plus earth of the second voltage-stabiliser tube Z5; Between the positive pole that first ground capacity C10 is connected to the first voltage-stabiliser tube Z4 and ground; Between the emitter that second ground capacity C7 is connected to the second triode T2 and ground; First triode T1 is PNP type triode, and the second triode T2 is NPN type triode; Input power Acquisition Circuit comprises the second diode Z2, the 3rd filter capacitor C3, the first divider resistance R1, the second divider resistance R3, protective resistance R2 and the 4th filter capacitor C4; The positive pole of the second diode Z2 is connected to the emitter of the second triode T2; Between the negative pole that first divider resistance R1 and the second divider resistance R3 is connected to the second diode Z2 after connecting and ground; Between the negative pole that 3rd filter capacitor C3 is connected to the second diode Z2 and ground; One end of protective resistance R2 is connected to the junction of the first divider resistance R1 and the second divider resistance R3, and the other end of protective resistance R2 is connected to single-chip microcomputer; 4th filter capacitor C4 is connected between the other end of protective resistance R2 and ground; The input of electronic switch is connected with the emitter of the second triode T2, and the output of electronic switch is used for being connected with automobile instrument circuit, and the control end of electronic switch is connected with single-chip microcomputer.

Adopt the combinational circuit of two triodes and two voltage-stabiliser tubes, voltage higher than voltage stabilizing can be absorbed by launching base and collector electrode, prevent high pressure from causing damage to automobile instrument circuit, and all adopt simple electrical equipment original paper, compare existing circuit and effectively provide cost savings; Adopt the first triode T1 and the second triode T2 to form multiple tube, better Current amplifier effect can be obtained, improve circuit performance; Adopt and suppress electric capacity C2 and the first diode Z3 to be in parallel formation surge restraint circuit, can effectively prevent peak-inverse voltage from impacting circuit, the reliability of raising circuit; Adopt input power Acquisition Circuit that the voltage of input is carried out dividing potential drop, the A/D in single-chip microcomputer is facilitated to gather, by single-chip microcomputer real-time judge whether superpressure, and by Single-chip Controlling electronic switch, realize instant disconnection automobile instrument circuit, prevent automobile instrument from damaging.

As further restriction scheme of the present utility model, electronic switch is PMOS, and the S pole of PMOS is connected with the emitter of the second triode T2, and the D pole of PMOS is used for being connected with automobile instrument circuit, and the G pole of PMOS is connected with single-chip microcomputer.Adopt PMOS as electronic switch, switching speed is fast, guarantees the fail safe of automobile instrument circuit further.

The beneficial effects of the utility model are: (1) adopts the combinational circuit of two triodes and two voltage-stabiliser tubes, voltage higher than voltage stabilizing can be absorbed by launching base and collector electrode, prevent high pressure from causing damage to automobile instrument circuit, and all adopt simple electrical equipment original paper, compare existing circuit and effectively provide cost savings; (2) adopt the first triode T1 and the second triode T2 to form multiple tube, better Current amplifier effect can be obtained, improve circuit performance; (3) adopt and suppress electric capacity C2 and the first diode Z3 to be in parallel formation surge restraint circuit, can effectively prevent peak-inverse voltage from impacting circuit, the reliability of raising circuit; (4) adopt input power Acquisition Circuit that the voltage of input is carried out dividing potential drop, the A/D in single-chip microcomputer is facilitated to gather, by single-chip microcomputer real-time judge whether superpressure, and by Single-chip Controlling electronic switch, realize instant disconnection automobile instrument circuit, prevent automobile instrument from damaging.

Accompanying drawing explanation

Fig. 1 is electrical block diagram of the present utility model;

Fig. 2 is input power protective circuit structural representation of the present utility model;

Fig. 3 is input power Acquisition Circuit structural representation of the present utility model.

Embodiment

As Figure 1-3, the protective circuit that the automobile instrument that the utility model provides is powered, comprises input power protective circuit, input power Acquisition Circuit, electronic switch and single-chip microcomputer; Input power protective circuit comprises the first filter capacitor C6, the second filter capacitor C9, the first diode Z3, suppresses electric capacity C2, pull-up resistor R4, the first ground capacity C10, the first triode T1, the second triode T2, the first voltage-stabiliser tube Z4, the second voltage-stabiliser tube Z5 and the second ground capacity C7; The positive pole of the first diode Z3 is used for being connected with input power, and the negative pole of the first diode Z3 is connected with the emitter of the first triode T1; Between the positive pole that first filter capacitor C6 and the second filter capacitor C9 is connected to the first diode Z3 after connecting and ground; Electric capacity C2 and the first diode Z3 is suppressed to be in parallel; The collector electrode of the second triode T2 is connected with the base stage of the first triode T1, and the emitter of the second triode T2 is connected with the collector electrode of the first triode T1; Pull-up resistor R4 is connected between the emitter of the first triode T1 and the base stage of the second triode T2; The negative pole of the first voltage-stabiliser tube Z4 is connected to the base stage of the second triode T2, and the positive pole of the first voltage-stabiliser tube Z4 is connected to the negative pole of the second voltage-stabiliser tube Z5, the plus earth of the second voltage-stabiliser tube Z5; Between the positive pole that first ground capacity C10 is connected to the first voltage-stabiliser tube Z4 and ground; Between the emitter that second ground capacity C7 is connected to the second triode T2 and ground; First triode T1 is PNP type triode, and the second triode T2 is NPN type triode; Input power Acquisition Circuit comprises the second diode Z2, the 3rd filter capacitor C3, the first divider resistance R1, the second divider resistance R3, protective resistance R2 and the 4th filter capacitor C4; The positive pole of the second diode Z2 is connected to the emitter of the second triode T2; Between the negative pole that first divider resistance R1 and the second divider resistance R3 is connected to the second diode Z2 after connecting and ground; Between the negative pole that 3rd filter capacitor C3 is connected to the second diode Z2 and ground; One end of protective resistance R2 is connected to the junction of the first divider resistance R1 and the second divider resistance R3, and the other end of protective resistance R2 is connected to single-chip microcomputer; 4th filter capacitor C4 is connected between the other end of protective resistance R2 and ground; The input of electronic switch is connected with the emitter of the second triode T2, and the output of electronic switch is used for being connected with automobile instrument circuit, and the control end of electronic switch is connected with single-chip microcomputer; In the specific implementation, single-chip microcomputer possesses A/D and adopts function, and electronic switch can select PMOS, and the S pole of PMOS is connected with the emitter of the second triode T2, and the D pole of PMOS is used for being connected with automobile instrument circuit, and the G pole of PMOS is connected with single-chip microcomputer.

The protective circuit that automobile instrument of the present utility model is powered operationally, first the voltage of input power input carry out filtering through the first filter capacitor C6 and the second filter capacitor C9, again through suppressing electric capacity C2 and the first diode Z3 to be in parallel formation surge restraint circuit, prevent peak-inverse voltage from impacting circuit; When the voltage of input power is less than two series voltage stabilizing pipe voltage stabilizing values, input supply voltage equals output voltage, and single-chip microcomputer sends high level to electronic switch, electronic switch conducting, and input power is that automobile instrument is powered; When the voltage of input power be greater than output voltage and voltage higher than two voltage-stabiliser tubes time, the voltage segment exceeded changes launching base and the collector voltage of the first triode T1 into; When overtension; by the first divider resistance R1 of input power Acquisition Circuit and the second divider resistance R3, dividing potential drop is carried out to the supply voltage exported; sampled by the A/D mouth of single-chip microcomputer again; judge whether the threshold value exceeding setting; if exceed threshold value; then disconnected by Single-chip Controlling electronic switch, automobile instrument circuit and high pressure are separated, protective resistance R2 can protect the A/D mouth of single-chip microcomputer simultaneously.

Claims (2)

1. an automobile instrument protective circuit of powering, is characterized in that: comprise input power protective circuit, input power Acquisition Circuit, electronic switch and single-chip microcomputer; Described input power protective circuit comprises the first filter capacitor C6, the second filter capacitor C9, the first diode Z3, suppresses electric capacity C2, pull-up resistor R4, the first ground capacity C10, the first triode T1, the second triode T2, the first voltage-stabiliser tube Z4, the second voltage-stabiliser tube Z5 and the second ground capacity C7; The positive pole of described first diode Z3 is used for being connected with input power, and the negative pole of described first diode Z3 is connected with the emitter of the first triode T1; Between the positive pole that described first filter capacitor C6 and the second filter capacitor C9 is connected to the first diode Z3 after connecting and ground; Described suppression electric capacity C2 and the first diode Z3 is in parallel; The collector electrode of described second triode T2 is connected with the base stage of the first triode T1, and the emitter of described second triode T2 is connected with the collector electrode of the first triode T1; Described pull-up resistor R4 is connected between the emitter of the first triode T1 and the base stage of the second triode T2; The negative pole of described first voltage-stabiliser tube Z4 is connected to the base stage of the second triode T2, and the positive pole of described first voltage-stabiliser tube Z4 is connected to the negative pole of the second voltage-stabiliser tube Z5, the plus earth of described second voltage-stabiliser tube Z5; Between the positive pole that described first ground capacity C10 is connected to the first voltage-stabiliser tube Z4 and ground; Between the emitter that described second ground capacity C7 is connected to the second triode T2 and ground; Described first triode T1 is PNP type triode, and described second triode T2 is NPN type triode; Described input power Acquisition Circuit comprises the second diode Z2, the 3rd filter capacitor C3, the first divider resistance R1, the second divider resistance R3, protective resistance R2 and the 4th filter capacitor C4; The positive pole of described second diode Z2 is connected to the emitter of the second triode T2; Between the negative pole that described first divider resistance R1 and the second divider resistance R3 is connected to the second diode Z2 after connecting and ground; Between the negative pole that described 3rd filter capacitor C3 is connected to the second diode Z2 and ground; One end of described protective resistance R2 is connected to the junction of the first divider resistance R1 and the second divider resistance R3, and the other end of described protective resistance R2 is connected to single-chip microcomputer; Described 4th filter capacitor C4 is connected between the other end of protective resistance R2 and ground; The input of described electronic switch is connected with the emitter of the second triode T2, and the output of described electronic switch is used for being connected with automobile instrument circuit, and the control end of described electronic switch is connected with single-chip microcomputer.

2. the automobile instrument according to claim 1 protective circuit of powering; it is characterized in that: described electronic switch is PMOS; the S pole of described PMOS is connected with the emitter of the second triode T2; the D pole of described PMOS is used for being connected with automobile instrument circuit, and the G pole of described PMOS is connected with single-chip microcomputer.