CN105576617A - Speed frequency output protection circuit of automobile instrument - Google Patents
Speed frequency output protection circuit of automobile instrument Download PDFInfo
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- CN105576617A CN105576617A CN201410524570.0A CN201410524570A CN105576617A CN 105576617 A CN105576617 A CN 105576617A CN 201410524570 A CN201410524570 A CN 201410524570A CN 105576617 A CN105576617 A CN 105576617A
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- triode
- protective resistance
- controller
- collector electrode
- comparator
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Abstract
The invention provides a speed frequency output protection circuit of an automobile instrument. The circuit comprises a speed sensor, a controller, a signal conversion circuit and a comparator, wherein the signal conversion circuit comprises a first protective resistor R1, a second protective resistor R2, a third protective resistor R3, a fourth protective resistor R4, a pull-up resistor R5, a fifth protective resistor R6, a first triode T1, a second triode T2 and a filtering capacitor C1. The output protection circuit can effectively prevent the second triode T2 of the signal conversion circuit from damage.
Description
Technical field
The present invention relates to a kind of protective circuit, especially a kind of output protection circuit of automobile speed in automobile instrument frequency, belongs to vehicle electric field.
Background technology
Current automobile speed in automobile instrument frequency output circuitry functional module has two kinds of modes, a kind of mode is the frequency signal gathering vehicle speed sensor input, and by hardware circuit be directly converted to frequency signal export to miscellaneous equipment use, another kind of mode is the frequency signal of Gather and input transducer, again by after microprocessor processes, be converted into rate-adaptive pacemaker, the mode of these two kinds of frequency output circuitry, after frequency signal carries out level conversion by triode, exports to instrument terminal.The shortcoming of these two kinds of circuit arrangements is: when the base stage input high level of triode, collector electrode is by after outside pull-up, output low level, when the collector electrode of triode and instrument terminal input current larger time, because the impedance of collector electrode during triode switch is very little, the electric current passed through is too large, causes triode to damage, speed of a motor vehicle frequency signal output function lost efficacy, and also can not be just the speed of a motor vehicle frequency signal of the relevant device stable output of automobile.
Summary of the invention
The technical problem to be solved in the present invention is in existing speed of a motor vehicle frequency output circuitry, when the electric current of the collector electrode of triode is excessive, triode will be caused to burn.
In order to solve the problems of the technologies described above, the invention provides a kind of output protection circuit of automobile speed in automobile instrument frequency, comprise vehicle speed sensor, controller, signaling conversion circuit and comparator, signaling conversion circuit comprises the first protective resistance R1, second protective resistance R2, 3rd protective resistance R3, 4th protective resistance R4, pull-up resistor R5, 5th protective resistance R6, first triode T1, second triode T2 and filter capacitor C1, the signal output part of vehicle speed sensor is connected with the vehicle speed signal input of controller, one end of first protective resistance R1 is connected with the vehicle speed signal output of controller, the other end of the first protective resistance R1 is connected with one end of the second protective resistance R2 and the collector electrode of the first triode T1 respectively, the other end of the second protective resistance R2 is connected with the base stage of the second triode T2, the base stage of the first triode T1 is connected with one end of the 3rd protective resistance R3, the transmitting collection ground connection of the first triode T1, the collector electrode of the second triode T2 is connected with voltage source by after pull-up resistor R5, automobile instrument is exported to after the collector electrode of the second triode T2 is also extremely connected with one of filter capacitor C1, another pole ground connection of filter capacitor C1, the transmitting collection of the second triode T2 respectively with the other end of the 3rd protective resistance R3, one end of 4th protective resistance R4 and one end of the 5th protective resistance R6 are connected, the other end of the 4th protective resistance R4 is connected with the comparison signal input of comparator, the output of comparator is connected with the guard signal input of controller, the other end ground connection of the 5th protective resistance R6.
Beneficial effect of the present invention is: the base voltage dragging down the second triode T2 when (1) adopts the first triode T1 to occur big current on the collector electrode of the second triode T2, makes the second triode T2 turn off, thus protect the second triode T2 in time; (2) voltage on comparator collection the 5th protective resistance R6 is adopted, when its magnitude of voltage is greater than reference voltage, guard signal is sent to controller, thus make controller no longer send speed of a motor vehicle frequency signal to signaling conversion circuit, again open the second triode T2 when also would not there is big current on the collector electrode of the second triode T2, prevent the continuous switch of the second triode T2; (3) by setting the reference voltage level of comparator, the sensitivity of protective circuit is regulated.
Accompanying drawing explanation
Fig. 1 is structural representation of the present invention;
Fig. 2 is signaling conversion circuit schematic diagram of the present invention.
Embodiment
As illustrated in fig. 1 and 2, the output protection circuit of automobile speed in automobile instrument frequency provided by the invention comprises: vehicle speed sensor, controller, signaling conversion circuit and comparator, signaling conversion circuit comprises the first protective resistance R1, second protective resistance R2, 3rd protective resistance R3, 4th protective resistance R4, pull-up resistor R5, 5th protective resistance R6, first triode T1, second triode T2 and filter capacitor C1, the signal output part of vehicle speed sensor is connected with the vehicle speed signal input of controller, one end of first protective resistance R1 is connected with the vehicle speed signal output of controller, the other end of the first protective resistance R1 is connected with one end of the second protective resistance R2 and the collector electrode of the first triode T1 respectively, the other end of the second protective resistance R2 is connected with the base stage of the second triode T2, the base stage of the first triode T1 is connected with one end of the 3rd protective resistance R3, the transmitting collection ground connection of the first triode T1, the collector electrode of the second triode T2 is connected with 12V voltage source by after pull-up resistor R5, automobile instrument is exported to after the collector electrode of the second triode T2 is also extremely connected with one of filter capacitor C1, another pole ground connection of filter capacitor C1, the transmitting collection of the second triode T2 respectively with the other end of the 3rd protective resistance R3, one end of 4th protective resistance R4 and one end of the 5th protective resistance R6 are connected, the other end of the 4th protective resistance R4 is connected with the comparison signal input of comparator, the output of comparator is connected with the guard signal input of controller, the other end ground connection of the 5th protective resistance R6.
Protective circuit of the present invention in the specific implementation, first according to protection sensitivity needs, regulates the reference voltage of comparator, makes the voltage of the 5th protective resistance R6 trigger protection when set point.When vehicle speed sensor sends speed of a motor vehicle frequency signal to controller, vehicle speed signal is sent to signaling conversion circuit by controller simultaneously, when the impedance of automobile instrument is larger, namely when input load electric current is less, the conducting when base level of the second triode T2 is high, the collector electrode of the second triode T2 diminishes to the impedance of emitter, so the collector electrode level of the second triode T2 is low, exporting automobile instrument to is low level signal, otherwise, the ON-OFF when the base level of the second triode T2 is low, the collector electrode of the second triode T2 is large to the impedance change of emitter, the collector electrode level of the second triode T2 is pulled up resistance R5 and is pulled upward to 12V, when the impedance of automobile instrument is less, namely when input load electric current is larger, as conducting voltage 0.7V more than the first triode T1 of the voltage of the 5th protective resistance R6, first triode T1 conducting, the collector electrode of the first triode T1 is to emitter Low ESR, the now current collection very low level of the first triode T1, namely ON-OFF when the base level of the second triode T2 is low, in high-impedance state between the collector electrode of the second triode T2 and emitter, achieve the object of closedown second triode T2, thus the second triode T2 is protected.
In order to solve the problem of the continuous switch of the second triode T2, as long as because the speed of a motor vehicle frequency signal being subject at the second triode T2 inputting after protection is closed occurs high level again, second triode T2 will conducting again, and then owing to protecting closedown to be absorbed in continuous circulation on off state, in order to avoid the appearance of this state, when the voltage of the 5th protective resistance R6 exceedes the reference voltage of comparator, just guard signal is sent by comparator to controller, this Time Controller just stops sending speed of a motor vehicle frequency signal to signaling conversion circuit, make the second triode T2 again can conducting, effectively prevent the continuous switch damage of the second triode T2.
Wherein, the first triode T1 and the second triode T2 is NPN type.
Claims (1)
1. the output protection circuit of an automobile speed in automobile instrument frequency, it is characterized in that: comprise vehicle speed sensor, controller, signaling conversion circuit and comparator, described signaling conversion circuit comprises the first protective resistance R1, second protective resistance R2, 3rd protective resistance R3, 4th protective resistance R4, pull-up resistor R5, 5th protective resistance R6, first triode T1, second triode T2 and filter capacitor C1, the signal output part of described vehicle speed sensor is connected with the vehicle speed signal input of controller, one end of described first protective resistance R1 is connected with the vehicle speed signal output of controller, the other end of described first protective resistance R1 is connected with one end of the second protective resistance R2 and the collector electrode of the first triode T1 respectively, the other end of described second protective resistance R2 is connected with the base stage of the second triode T2, the base stage of described first triode T1 is connected with one end of the 3rd protective resistance R3, the transmitting collection ground connection of described first triode T1, the collector electrode of described second triode T2 is connected with voltage source by after pull-up resistor R5, automobile instrument is exported to after the collector electrode of described second triode T2 is also extremely connected with one of filter capacitor C1, another pole ground connection of described filter capacitor C1, the transmitting collection of described second triode T2 respectively with the other end of the 3rd protective resistance R3, one end of 4th protective resistance R4 and one end of the 5th protective resistance R6 are connected, the described other end of the 4th protective resistance R4 is connected with the comparison signal input of comparator, the output of described comparator is connected with the guard signal input of controller, the other end ground connection of described 5th protective resistance R6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410524570.0A CN105576617A (en) | 2014-10-09 | 2014-10-09 | Speed frequency output protection circuit of automobile instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410524570.0A CN105576617A (en) | 2014-10-09 | 2014-10-09 | Speed frequency output protection circuit of automobile instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN105576617A true CN105576617A (en) | 2016-05-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410524570.0A Pending CN105576617A (en) | 2014-10-09 | 2014-10-09 | Speed frequency output protection circuit of automobile instrument |
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| CN (1) | CN105576617A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108749579A (en) * | 2018-06-04 | 2018-11-06 | 北京新能源汽车股份有限公司 | A kind of ground self-checking method, apparatus, high-pressure system and the automobile of high-pressure system |
| CN109975582A (en) * | 2019-02-28 | 2019-07-05 | 西安法士特汽车传动有限公司 | A kind of PWM wave output detection circuit of automobile |
| CN113741239A (en) * | 2021-08-02 | 2021-12-03 | 惠州市德赛西威汽车电子股份有限公司 | Vehicle speed input and output signal control circuit and method |
-
2014
- 2014-10-09 CN CN201410524570.0A patent/CN105576617A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108749579A (en) * | 2018-06-04 | 2018-11-06 | 北京新能源汽车股份有限公司 | A kind of ground self-checking method, apparatus, high-pressure system and the automobile of high-pressure system |
| CN108749579B (en) * | 2018-06-04 | 2020-07-24 | 北京新能源汽车股份有限公司 | Grounding self-inspection method and device for high-voltage system, high-voltage system and automobile |
| CN109975582A (en) * | 2019-02-28 | 2019-07-05 | 西安法士特汽车传动有限公司 | A kind of PWM wave output detection circuit of automobile |
| CN113741239A (en) * | 2021-08-02 | 2021-12-03 | 惠州市德赛西威汽车电子股份有限公司 | Vehicle speed input and output signal control circuit and method |
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Legal Events
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| C06 | Publication | ||
| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20160511 |