CN215222152U - Circuit with reverse connection prevention and current detection functions - Google Patents
Circuit with reverse connection prevention and current detection functions Download PDFInfo
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- CN215222152U CN215222152U CN202121258341.0U CN202121258341U CN215222152U CN 215222152 U CN215222152 U CN 215222152U CN 202121258341 U CN202121258341 U CN 202121258341U CN 215222152 U CN215222152 U CN 215222152U
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Abstract
The utility model discloses a circuit with prevent joining in reverse and current detection function belongs to car fuel supply system technical field, including concatenating the N type MOSFET switch element in controller power supply loop, MOSFET switch element's source electrode be connected with the load, the drain electrode is connected with ground, grid series resistor connects the power supply anodally, the zener diode who is used for the protective grid is gone into to source electrode and grid indirectly, MOSFET switch element's source electrode and drain electrode go into operational amplifier indirectly and constitute differential amplifier circuit, differential amplifier circuit's output be current detection's signal output part, MOSFET switch element's source electrode and drain electrode go into filter capacitor indirectly. The circuit has the advantages of simple circuit, reliable performance, less element number, small circuit voltage drop, low cost and the like, and is not easy to break down. The method is suitable for various control unit applications needing reverse connection prevention protection and current measurement.
Description
Technical Field
The utility model discloses a circuit with prevent reverse connection and current detection function belongs to car fuel supply system technical field.
Background
The fuel pump controller of the automobile is an important component in an electronic control system of an engine, generally 12V or 24V power is supplied, and a single power supply is used for supplying power to the system. The existing fuel pump controller is provided with an anti-reverse connection circuit and a current detection circuit, and is used for power protection and current magnitude in the detection circuit.
The existing anti-reverse connection circuit and the current detection circuit are mutually independent, an independent current detection element is needed, the current detection element brings extra voltage drop, the number of elements is large, the occupied area of a circuit board is large, and the cost is high.
Disclosure of Invention
The utility model provides a circuit with prevent reverse connection and current detection function.
The technical scheme of the utility model is that: the N-type MOSFET is used as a switching element, the source electrode of the MOSFET is connected with a load, the drain electrode of the MOSFET is connected with the ground, the grid electrode of the MOSFET is connected with a resistor in series, the source electrode and the grid electrode of the MOSFET are indirectly connected with a voltage stabilizing diode for protecting the grid electrode, the MOSFET can be conducted only when the power supply is correctly connected, and the reverse connection of the power supply can not switch on a circuit and can not cause damage to the circuit; since the on-resistance of the MOSFET is substantially constant after the MOSFET is turned on, a differential amplifier circuit is formed by using an operational amplifier to measure and amplify the voltage between the source and the drain of the MOSFET, so that the current flowing through the MOSFET can be measured. Thus, a circuit with reverse connection prevention and current detection functions is formed.
A circuit with functions of preventing reverse connection and detecting current comprises an N-type MOSFET switch element connected in a power supply loop of a controller in series, wherein a source electrode of the MOSFET switch element is connected with a load, a drain electrode of the MOSFET switch element is connected with the ground, a grid electrode series resistor is connected with the positive electrode of a power supply, a voltage stabilizing diode used for protecting the grid electrode is connected between the source electrode and the grid electrode, the source electrode and the drain electrode of the MOSFET switch element are connected into an operational amplifier indirectly to form a differential amplification circuit, the output end of the differential amplification circuit is a signal output end for detecting current, and the source electrode and the drain electrode of the MOSFET switch element are connected into a filter capacitor indirectly.
Installed the utility model discloses a fuel pump controller can effectually prevent that the power joins conversely from causing the damage of controller, and the electric current measurement function can the effectual electric current that flows through MOSFET of measurement provide the current reference for the controller, at the reliable and stable operation of practical application circuit, the effectual device quantity that has reduced saves circuit board space, saves the cost and has reached anticipated effect.
In a similar way, the utility model discloses can be applied to in the electric mechanism adjustment control ware of car.
The utility model has the advantages that: the reverse connection preventing circuit is combined with the current detection circuit, and the MOSFET is used as a sensor element of the current detection circuit, so that the number of elements is reduced; the current detection element in the circuit is omitted, and the voltage drop caused by the current detection element is avoided. The circuit has the advantages of simple circuit, reliable performance, less element number, small circuit voltage drop, low cost and the like, and is not easy to break down. The method is suitable for various control unit applications needing reverse connection prevention protection and current measurement.
Drawings
Fig. 1 is a circuit diagram of the present invention.
Detailed Description
The following further description is made in conjunction with the accompanying drawings and specific embodiments.
A circuit with reverse connection prevention and current detection functions comprises an N-type MOSFET Q1 switching element connected in series in a power supply loop of a controller, wherein a source electrode of the MOSFET switching element is connected with a load, a drain electrode of the MOSFET switching element is connected with the ground, a grid electrode series resistor R2 is connected with the positive electrode of a power supply, a voltage stabilizing diode D1 used for protecting a grid electrode is connected between the source electrode and the grid electrode, an operational amplifier is connected between the source electrode and the drain electrode of the MOSFET switching element to form a differential amplification circuit, and the output end of the differential amplification circuit is a signal output end for current detection.
The source and drain of the MOSFET switch element are connected to the filter capacitor C1 to filter out the high frequency interference waves of the load.
Referring to fig. 1, in the circuit, an N-type MOSFET Q1 is used as a switching element, a source of the MOSFET is connected to a load, a drain of the MOSFET is connected to ground, a gate series resistor R2 is connected to a power supply, and a source and gate indirect voltage stabilizing diode D1 is used for protecting a gate, so that the MOSFET cannot be damaged even if the voltage between the gate and the source is too high, the MOSFET can be turned on only when the power supply is correctly connected, and the reverse connection of the power supply cannot turn on the circuit and cannot damage the circuit; since the on-resistance of the MOSFET is basically constant after the MOSFET is turned on, the operational amplifier and the R1, R3, R4 and R5 are used to form a differential amplification circuit to measure and amplify the voltage between the source and the drain of the MOSFET, the amplification factor can be adjusted according to the resistance values of R1, R3, R4 and R5, the current flowing through the MOSFET can be measured, and the current is output in the form of voltage. Thus, a circuit with reverse connection prevention and current detection functions is formed. The circuit has simple structure, few devices, small circuit voltage drop, stability and reliability.
Claims (1)
1. A circuit with functions of reverse connection prevention and current detection is characterized by comprising an N-type MOSFET switching element which is connected in a power supply loop of a controller in series, wherein a source electrode of the MOSFET switching element is connected with a load, a drain electrode of the MOSFET switching element is connected with the ground, a grid electrode series resistor is connected with the positive electrode of a power supply, a voltage stabilizing diode used for protecting the grid electrode is connected between the source electrode and the grid electrode, the source electrode and the drain electrode of the MOSFET switching element are connected into an operational amplifier indirectly to form a differential amplification circuit, an output end of the differential amplification circuit is a signal output end for current detection, and the source electrode and the drain electrode of the MOSFET switching element are connected into a filter capacitor indirectly.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121258341.0U CN215222152U (en) | 2021-06-07 | 2021-06-07 | Circuit with reverse connection prevention and current detection functions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121258341.0U CN215222152U (en) | 2021-06-07 | 2021-06-07 | Circuit with reverse connection prevention and current detection functions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215222152U true CN215222152U (en) | 2021-12-17 |
Family
ID=79424068
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121258341.0U Active CN215222152U (en) | 2021-06-07 | 2021-06-07 | Circuit with reverse connection prevention and current detection functions |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215222152U (en) |
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2021
- 2021-06-07 CN CN202121258341.0U patent/CN215222152U/en active Active
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