CN207719806U - A kind of protection circuit of car-mounted terminal - Google Patents
A kind of protection circuit of car-mounted terminal Download PDFInfo
- Publication number
- CN207719806U CN207719806U CN201721721752.2U CN201721721752U CN207719806U CN 207719806 U CN207719806 U CN 207719806U CN 201721721752 U CN201721721752 U CN 201721721752U CN 207719806 U CN207719806 U CN 207719806U
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- China
- Prior art keywords
- resistance
- operational amplifier
- mcu
- protection circuit
- car
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Abstract
The utility model provides a kind of protection circuit of car-mounted terminal, and the car-mounted terminal includes vehicle-mounted interface and MCU, and the protection circuit includes resistance R1, resistance R2 and an operational amplifier；The one end the resistance R1 is connected to the vehicle-mounted interface, and the resistance R1 other ends are connected to the anode of the operational amplifier, the MCU is connected to after the cathode and output end short circuit of the operational amplifier；One end of the resistance R2 is connected between the resistance R1 and the cathode of the operational amplifier, the other end ground connection of the resistance R2, and the power end of the operational amplifier is connected to the power end of the MCU, the ground terminal ground connection of the operational amplifier.Partial pressure current limliting is carried out by resistance and operational amplifier, and then protects the MCU of car-mounted terminal.
Description
Technical field
The utility model is related to a kind of circuit, the protection circuit of especially a kind of car-mounted terminal.
Background technology
Car-mounted terminal need to be adapted to various sensors, and MCU is reached through vehicle-mounted interface, by the AD thief hatch gathered datas of MCU.
But vehicle-mounted internal environment is severe, high pressure or electrostatic are inputted from AD thief hatch, and MCU AD samplings input port unprotect itself is arranged
It applies so that MCU is easily broken, and maintenance cost is increased.
Utility model content
The technical problems to be solved in the utility model is to provide a kind of protection circuit of car-mounted terminal, in car-mounted terminal
Interface and MCU between increase by a protection circuit, can effectively prevent the destruction of high pressure and electrostatic to car-mounted terminal, reduce dimension
Protect cost.
The utility model is realized in this way：A kind of protection circuit of car-mounted terminal, the car-mounted terminal include vehicle-mounted connect
Mouth and MCU, the protection circuit include resistance R1, resistance R2 and an operational amplifier；The one end the resistance R1 is connected to institute
State vehicle-mounted interface, the resistance R1 other ends are connected to the anode of the operational amplifier, the cathode of the operational amplifier and
The MCU is connected to after output end short circuit；One end of the resistance R2 is connected to the resistance R1 and the operational amplifier
Between cathode, the other end of the resistance R2 is grounded, and the power end of the operational amplifier is connected to the power end of the MCU,
The ground terminal of the operational amplifier is grounded.
Further, the protection circuit further includes a cache switching diodes, the anode of the cache switching diodes
It is connected between the resistance R1 and the cathode of the operational amplifier, the cathodes of the cache switching diodes is connected to described
The power end of MCU.
Further, the protection circuit further includes capacitance C1, and the capacitance C1 and the resistance R2 are in parallel.
Further, the protection circuit further includes capacitance C2 and capacitance C3, and the capacitance C2 and capacitance C3 are in parallel,
And one end is connected between the power end of the operational amplifier and the power end of the MCU, other end ground connection.
The utility model has the following advantages that：The utility model provides a kind of protection circuit of car-mounted terminal, described vehicle-mounted
Terminal includes vehicle-mounted interface and MCU, and the protection circuit includes resistance R1, resistance R2 and an operational amplifier；The resistance
The one end R1 is connected to the vehicle-mounted interface, and the resistance R1 other ends are connected to the anode of the operational amplifier, the operation
It is connected to the MCU after the cathode and output end short circuit of amplifier；One end of the resistance R2 is connected to the resistance R1 and institute
Between the cathode for stating operational amplifier, the other end of the resistance R2 is grounded, and the power end of the operational amplifier is connected to institute
State the power end of MCU, the ground terminal ground connection of the operational amplifier.Partial pressure current limliting is carried out by resistance and operational amplifier, into
And protect the MCU of car-mounted terminal.
Description of the drawings
The utility model is further described in conjunction with the embodiments with reference to the accompanying drawings.
Fig. 1 is a kind of protection circuit of car-mounted terminal of the utility model.
Specific implementation mode
Refering to Figure 1, a kind of protection circuit of car-mounted terminal of the utility model, the car-mounted terminal includes vehicle-mounted connects
Mouth and MCU, the protection circuit include resistance R1, resistance R2 and an operational amplifier；The one end the resistance R1 is connected to institute
State vehicle-mounted interface, the resistance R1 other ends are connected to the anode of the operational amplifier, the cathode of the operational amplifier and
The MCU is connected to after output end short circuit；One end of the resistance R2 is connected to the resistance R1 and the operational amplifier
Between cathode, the other end of the resistance R2 is grounded, and the power end of the operational amplifier is connected to the power end of the MCU,
The ground terminal of the operational amplifier is grounded.Partial pressure current limliting is carried out by resistance and operational amplifier, and then protects car-mounted terminal
MCU.
The protection circuit further includes a cache switching diodes, and the anodes of the cache switching diodes is connected to described
Between resistance R1 and the cathode of the operational amplifier, the cathode of the cache switching diodes is connected to the power supply of the MCU
End.Clamper is carried out to power supply by the cache switching diodes, and then protects operational amplifier and MCU.
The protection circuit further includes capacitance C1, and the capacitance C1 and the resistance R2 are in parallel.External signal is through capacitance
C1 is filtered, filtering clutter, the effective stabilization for ensureing input signal.
The protection circuit further includes capacitance C2 and capacitance C3, and the capacitance C2 and capacitance C3 are in parallel, and one end connects
Between the power end and the power end of the MCU of the operational amplifier, other end ground connection.Input signal is filtered,
Further strengthen the stabilization of input signal.
A specific embodiment：Resistance R1=2200 Ω ± 5%, resistance R2=110000 Ω ± 5%, capacitance C1=104/
50V, the cache switching diodes are 1N4148, and the operational amplifier is LM358, capacitance C2=104/50V, capacitance C3=
10μF/10V；
External interference signals enter through the vehicle-mounted interface, first pass through the resistance R1, resistance R2 carries out partial pressure current limliting, into
And the MCU is protected, it is connected to the MCU after the cathode and output end short circuit of the LM358, follows mode to design using amplifier
Make input voltage and the same phase of output voltage, play impedance variations, the influence of front stage can be isolated, is also used as described
The protection prime of MCU reduces maintenance cost；The 1N4148 carries out clamper to the voltage of input signal, and voltage is made to be limited in
Within 3.3V, the further protection operational amplifier LM358 and MCU passes through the capacitance C1, capacitance C2 and capacitance
C3 is filtered, filtering clutter, is effectively protected the stability of input signal.
The utility model protects circuit by increasing by one between vehicle-mounted interface and MCU, is effectively protected car-mounted terminal,
It prevents from being destroyed by external interference signals, while improving the stability of input signal.
Although the foregoing describe specific embodiment of the present utility model, those familiar with the art answers
Working as understanding, we are merely exemplary described specific embodiment, rather than for the limit to the scope of the utility model
Fixed, those skilled in the art modification and variation equivalent made by the spirit according to the utility model all should
Cover in the scope of the claimed protection of the utility model.
Claims (4)
1. a kind of protection circuit of car-mounted terminal, the car-mounted terminal includes vehicle-mounted interface and MCU, it is characterised in that：The guarantor
Protection circuit includes resistance R1, resistance R2 and an operational amplifier；The one end the resistance R1 is connected to the vehicle-mounted interface, described
The resistance R1 other ends are connected to the anode of the operational amplifier, are connected after the cathode and output end short circuit of the operational amplifier
In the MCU；One end of the resistance R2 is connected between the resistance R1 and the cathode of the operational amplifier, the resistance
The other end of R2 is grounded, and the power end of the operational amplifier is connected to the power end of the MCU, and the operational amplifier connects
Ground terminal is grounded.
2. a kind of protection circuit of car-mounted terminal according to claim 1, it is characterised in that：The protection circuit further includes
One cache switching diodes, the anode of the cache switching diodes are connected to the moon of the resistance R1 and the operational amplifier
Between pole, the cathode of the cache switching diodes is connected to the power end of the MCU.
3. according to a kind of protection circuit of car-mounted terminal of claims 1 or 2 any one of them, it is characterised in that：The protection
Circuit further includes capacitance C1, and the capacitance C1 and the resistance R2 are in parallel.
4. according to a kind of protection circuit of car-mounted terminal of claims 1 or 2 any one of them, it is characterised in that：The protection
Circuit further includes capacitance C2 and capacitance C3, and the capacitance C2 and capacitance C3 are in parallel, and one end is connected to the operational amplifier
Power end and the power end of the MCU between, the other end ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721721752.2U CN207719806U (en) | 2017-12-12 | 2017-12-12 | A kind of protection circuit of car-mounted terminal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721721752.2U CN207719806U (en) | 2017-12-12 | 2017-12-12 | A kind of protection circuit of car-mounted terminal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207719806U true CN207719806U (en) | 2018-08-10 |
Family
ID=63060472
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721721752.2U Active CN207719806U (en) | 2017-12-12 | 2017-12-12 | A kind of protection circuit of car-mounted terminal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207719806U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107809108A (en) * | 2017-12-12 | 2018-03-16 | 福建星海通信科技有限公司 | A kind of protection circuit of car-mounted terminal |
-
2017
- 2017-12-12 CN CN201721721752.2U patent/CN207719806U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107809108A (en) * | 2017-12-12 | 2018-03-16 | 福建星海通信科技有限公司 | A kind of protection circuit of car-mounted terminal |
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