CN205248763U - Switch short -circuit protection circuit - Google Patents
Switch short -circuit protection circuit Download PDFInfo
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- CN205248763U CN205248763U CN201521062021.2U CN201521062021U CN205248763U CN 205248763 U CN205248763 U CN 205248763U CN 201521062021 U CN201521062021 U CN 201521062021U CN 205248763 U CN205248763 U CN 205248763U
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- triode
- switch
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- protection
- current
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Abstract
The utility model discloses a switch short -circuit protection circuit adopts discrete devices such as triode and resistance, and through the collection to the electric current and utilize the switching effect of triode, the realization is compared with the base driver chip who takes short -circuit protection the control of another triode switch, can effectual monitoring cost, improve the reliability simultaneously.
Description
Technical field
The utility model relates to the short-circuit protection technical field of circuit, is specifically related to a kind of switch short-circuit protection electricityRoad.
Background technology
Vehicle-mounted switch is the vitals in automotive trim, and the effect of vehicle-mounted switch is that power supply signal is passed toThe drive circuit of automobile-used load, thereby the duty of control load; In the time transmitting power supply signal by wire harness,Can be short-circuited, short circuit meeting causes producing excessive electric current on switch, causes switching component to damage.
Existing switch short-circuit protection circuit normally adopts with short-circuit protection function in switch output circuitLow limit drives chip, and this chip price is higher, and the cost of short-circuit protection circuit is larger.
But in the time of the car load layoutprocedure of low side vehicle, consider cost performance factor, conventionally can not adopt costHigher low limit drives chip, therefore at present in low side car field, be badly in need of a kind of switch short circuit of high performance-price ratioProtection scheme.
Summary of the invention
The application solves the higher problem of existing short-circuit protection circuit cost, and a kind of switch short circuit is providedHolding circuit, under the prerequisite of switch short-circuit protection function, effectively reduces cost, has improved short-circuit protectionThe cost performance of circuit.
The application's technical scheme is as follows:
A kind of switch short-circuit protection circuit, described circuit comprises switch, protection triode, drives triode,Current-limiting resistance, current sampling resistor;
The control end of described protection triode connect respectively described driving triode signal output part and described inThe first end of current sampling resistor, the signal input part of described protection triode connects respectively described driving three utmost pointsThe control end of pipe and the first end of described current-limiting resistance, the signal output part of described protection triode and described inThe equal ground connection of the second end of current acquisition resistance, the signal input part of described driving triode is connected with load,The second end of described current-limiting resistance is connected with the output of described switch, outside the input of described switch connectsPut power supply;
The triode that described protection triode and described driving triode are same model.
When original state, protection triode and driving triode are all in off state. After switch is pressed,Driving triode is opened, and current signal is by current sampling resistor, when electric current is during in normal range (NR), and electric currentThe undertension that sampling resistor two ends produce, to open protection triode, does not affect normal function. When circuit shortLu Shi, electric current becomes greatly very soon, and the voltage at current sampling resistor two ends raises very soon, makes to protect triode to be opened,Driving triode is closed, and cut-off loop is realized short-circuit protection.
Alternatively, described circuit also comprises divider resistance;
The first end of described divider resistance respectively with signal input part, the described driving three of described protection triodeThe control end of utmost point pipe, the first end of described current-limiting resistance are connected, the second end ground connection of described divider resistance.
Particularly:
Described protection triode and described driving triode are NPN type triode.
Described switch is limit switch or non-limit switch.
Described load is LED light emitting diode or LED light emitting diode matrix.
Compared with prior art, the utility model circuit only needs very simple device just can carry out short-circuit protection,Also normal output low level, drive chip with the base with short-circuit protection compared with, can effectively controlCost improves reliability simultaneously.
Brief description of the drawings
Fig. 1 is the structural representation of a kind of switch short-circuit protection circuit of embodiment 1 of the present utility model;
Fig. 2 is the structural representation of a kind of switch short-circuit protection circuit of embodiment 1 of the present utility model;
Drawing reference numeral explanation:
R1-current-limiting resistance; R2-current acquisition resistance; R3-divider resistance; Q1-protects triode;Q2-switch triode; SW-switch; VCC-external power supply;
Below in conjunction with the drawings and specific embodiments, the utility model is described in more detail, this practicality is newThe protection domain of type is not limited to following detailed description of the invention.
Detailed description of the invention
A kind of switch short-circuit protection circuit, described circuit comprises switch SW, protection triode Q1, drives three utmost pointsPipe Q2, current-limiting resistance R1, current sampling resistor R2;
The signal output part that the control end of described protection triode Q1 connects respectively described driving triode Q2 withAnd the first end of described current sampling resistor R2, the signal input part of described protection triode Q1 connects respectivelyThe control end of described driving triode Q2 and the first end of described current-limiting resistance R1, described protection triodeThe equal ground connection of the second end of the signal output part of Q2 and described current acquisition resistance R 2, described driving triode Q2Signal input part be connected with load, the second end of described current-limiting resistance R1 and the output of described switch SWEnd is connected, and the input of described switch SW connects external power supply VCC;
The triode that described protection triode Q1 and described driving triode Q2 are same model.
Embodiment 1
As shown in Figure 1, described protection triode Q1 and described driving triode Q2 are NPN type triode.
The base stage of described protection triode Q1 connect respectively described driving triode Q2 emitter stage and described inThe first end of current sampling resistor R2, the colelctor electrode of described protection triode Q1 connects respectively described driving threeThe base stage of utmost point pipe Q2 and the first end of described current-limiting resistance R1, the emitter stage of described protection triode Q1 andThe equal ground connection of the second end of described current acquisition resistance R 2, the colelctor electrode of described driving triode Q2 and load phaseConnect, the second end of described current-limiting resistance R1 is connected with the output of described switch SW, described switch SWInput connect external power supply VCC.
Described switch SW is limit switch, in the time that described switch SW is closed, and the high level of external power supply VCCSignal transfers to described driving triode Q2 through described current-limiting resistance R1, makes described driving triode Q2Base-emitter between level reach 0.7V, described driving triode Q2 opens, i.e. load is in justNormal duty; When output short-circuit is after power supply, the electric current of current flowing sampling resistor R2 becomes greatly very soon, makesThe voltage that obtains current sampling resistor R2 two ends reaches rapidly 0.7V, protects triode Q1 conducting, makes to driveThe base stage of moving triode Q2 is shorted to ground, drives triode Q2 to disconnect, without low level signal output, realNow protection.
Embodiment 2
As shown in Figure 2, described protection triode Q1 and described driving triode Q2 are NPN type triode.
The base stage of described protection triode Q1 connect respectively described driving triode Q2 emitter stage and described inThe first end of current sampling resistor R2, the colelctor electrode of described protection triode Q1 connects respectively described driving threeThe base stage of utmost point pipe Q2 and the first end of described current-limiting resistance R1, the emitter stage of described protection triode Q1 andThe equal ground connection of the second end of described current acquisition resistance R 2, the colelctor electrode of described driving triode Q2 and load phaseConnect, the second end of described current-limiting resistance R1 is connected with the output of described switch SW, described switch SWInput connect external power supply VCC.
Described circuit also comprises divider resistance R3;
The first end of described divider resistance R3 respectively with the colelctor electrode of described protection triode Q1, described drivingThe base stage of triode Q2, the first end of described current-limiting resistance R1 are connected, second of described divider resistance R3End ground connection.
Described switch SW is limit switch, in the time that described switch SW is closed, and the high level of external power supply VCCSignal transfers to described driving triode Q2 after described current-limiting resistance R1 and spacing resistance R 3 dividing potential drops, makesThe level between the base-emitter of described driving triode Q2 reaches 0.7V, i.e. described driving triode Q2Open, load is in normal operating conditions; When output short-circuit is after power supply, current flowing sampling resistor R2Electric current become very soon greatly, make the voltage at current sampling resistor R2 two ends reach rapidly 0.7V, protect three utmost pointsPipe Q1 conducting, makes to drive the base stage of triode Q2 to be shorted to ground, drives triode Q2 to disconnect, without lowLevel signal output, realizes protection.
Technique scheme is a kind of embodiment of the present utility model, for those skilled in the art, the utility model discloses on the basis of application process and principle, be easy to make various types ofImprove or distortion, and be not limited only to the described structure of the above-mentioned detailed description of the invention of the utility model, because of before thisThe mode that face is described is preferably, and does not have restrictive meaning.
Claims (5)
1. a switch short-circuit protection circuit, is characterized in that:
Described circuit comprises switch, protection triode, drives triode, current-limiting resistance, current sampling resistor;
The control end of described protection triode connect respectively described driving triode signal output part and described inThe first end of current sampling resistor, the signal input part of described protection triode connects respectively described driving three utmost pointsThe control end of pipe and the first end of described current-limiting resistance, the signal output part of described protection triode and described inThe equal ground connection of the second end of current acquisition resistance, the signal input part of described driving triode is connected with load,The second end of described current-limiting resistance is connected with the output of described switch, outside the input of described switch connectsPut power supply;
The triode that described protection triode and described driving triode are same model.
2. a kind of switch short-circuit protection circuit according to claim 1, is characterized in that:
Described circuit also comprises divider resistance;
The first end of described divider resistance respectively with signal input part, the described driving three of described protection triodeThe control end of utmost point pipe, the first end of described current-limiting resistance are connected, the second end ground connection of described divider resistance.
3. a kind of switch short-circuit protection circuit according to claim 2, is characterized in that:
Described protection triode and described driving triode are NPN type triode.
4. a kind of switch short-circuit protection circuit according to claim 1, is characterized in that:
Described switch is limit switch or non-limit switch.
5. a kind of switch short-circuit protection circuit according to claim 1, is characterized in that:
Described load is LED light emitting diode or LED light emitting diode matrix.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521062021.2U CN205248763U (en) | 2015-12-17 | 2015-12-17 | Switch short -circuit protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521062021.2U CN205248763U (en) | 2015-12-17 | 2015-12-17 | Switch short -circuit protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205248763U true CN205248763U (en) | 2016-05-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201521062021.2U Active CN205248763U (en) | 2015-12-17 | 2015-12-17 | Switch short -circuit protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205248763U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108988840A (en) * | 2018-06-12 | 2018-12-11 | 北京车和家信息技术有限公司 | Mongline bidirectional wake-up circuit and vehicle |
| CN112736859A (en) * | 2020-12-29 | 2021-04-30 | 联合汽车电子有限公司 | Overcurrent diagnosis processing circuit and low-side drive circuit |
| CN112736859B (en) * | 2020-12-29 | 2024-04-26 | 联合汽车电子有限公司 | Overcurrent diagnosis processing circuit and low-side driving circuit |
-
2015
- 2015-12-17 CN CN201521062021.2U patent/CN205248763U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108988840A (en) * | 2018-06-12 | 2018-12-11 | 北京车和家信息技术有限公司 | Mongline bidirectional wake-up circuit and vehicle |
| CN108988840B (en) * | 2018-06-12 | 2023-02-21 | 北京车和家信息技术有限公司 | Single-wire bidirectional wake-up circuit and vehicle |
| CN112736859A (en) * | 2020-12-29 | 2021-04-30 | 联合汽车电子有限公司 | Overcurrent diagnosis processing circuit and low-side drive circuit |
| CN112736859B (en) * | 2020-12-29 | 2024-04-26 | 联合汽车电子有限公司 | Overcurrent diagnosis processing circuit and low-side driving circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | "change of name, title or address" | ||
| CP03 | "change of name, title or address" |
Address after: 4 / F, building 1, No.14 Jiuxianqiao Road, Chaoyang District, Beijing 100020 Patentee after: Beijing Jingwei Hengrun Technology Co., Ltd Address before: 8 / F, block B, No. 11, Anxiang Beili, Chaoyang District, Beijing 100101 Patentee before: Beijing Jingwei HiRain Technologies Co.,Ltd. |