Charging interface detection circuit

Abstract

A charging interface detection circuit belongs to the technical field of chargers. Comprising an external resistance detection circuit connected with a loop to be detected, a given input loop simulating the resistance value of the charging gun, and a measurement comparison circuit used for determining whether a gun head resistor and a gun base resistor in the loop to be detected are connected in parallel or not. And the phenomenon that charging cannot be conducted or short circuit accidents occur due to poor connection is avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of chargers, and particularly relates to a charging interface detection circuit. Background Art

[0002] According to the charger standard, the charger only needs to connect the charging gun when charging. If the charger gun is not in good contact, the charger will be unable to charge or a circuit breaker will occur. Therefore, the operator's operating level is required to be high during the charging process. Utility Model Content

[0003] The utility model aims to provide a charging interface detection circuit, which solves the problem of detecting whether the charging gun and the vehicle interface are fully connected, and avoids charging failure or short circuit accidents caused by improper connection.

[0004] The technical solution adopted by the utility model is: a charging interface detection circuit, the technical points of which are:

[0005] A wide voltage input circuit for providing input voltage;

[0006] An external resistance detection circuit is connected to the circuit to be tested and is used to divide the input voltage of the circuit to be tested and then output it after the charging gun is fully connected to the vehicle;

[0007] Given an input circuit, it is used to adjust the resistance of the access resistor to make it close to the resistance of the charging gun;

[0008] The measuring comparison circuit has one input end connected to the external resistance detection circuit for receiving the detection input voltage after voltage division provided by the external resistance detection circuit; the other input end is connected to the output end of the given input circuit for receiving the given input voltage after voltage division. If the two input signals are compared and a low-level signal is output, the gun tip resistance and the gun base resistance in the circuit to be measured are connected in parallel;

[0009] The output control circuit is connected to the measurement comparison circuit and is used to control the on and off of the relay according to the output signal of the measurement comparison circuit. The control indicator light is on when the gun head is fully connected to the gun seat, and the protection is triggered when the gun head is not fully connected to the gun seat.

[0010] In the above scheme, the external resistance detection circuit is connected to the circuit to be tested through the second terminal, an output end of the second terminal and one end of the second resistor are connected to the detection input point A, and the other end of the second resistor is connected to the power supply.

[0011] In the above scheme, the given input circuit includes a dip switch, the fifth port of the dip switch is connected to one end of the third resistor, the sixth port is connected to one end of the fourth resistor, the seventh port is connected to one end of the fifth resistor, and the eighth port is connected to one end of the sixth resistor. The other end of the third resistor, the other end of the fourth resistor, the other end of the fifth resistor and the other end of the sixth resistor are connected and grounded. The first port, the second port, the third port and the fourth port of the dip switch are connected in parallel with the ninth resistor and voltage is divided.

[0012] In the above scheme, the measurement comparison circuit includes a first comparator, the voltage of the monitoring input point A of the external resistance detection circuit is connected to the reverse input terminal of the first comparator, the output terminal of the given input loop is connected to the positive input terminal of the second comparator, the output terminal of the first comparator is connected to the positive input terminal of the second comparator and is pulled up to a high level through a pull-up resistor, the reverse input terminal of the second comparator is connected to the given input voltage of the given input loop, and the output terminal of the second comparator is connected to a relay.

[0013] The beneficial effects of the utility model are as follows: the charging interface detection circuit includes an external resistance detection circuit connected to the circuit to be tested, a given input circuit for simulating the resistance value of the charging gun, and a measurement comparison circuit for determining whether the gun head resistance and the gun seat resistance in the circuit to be tested are connected in parallel. The circuit can ensure the complete connection between the charging gun and the vehicle interface, avoiding charging failure or short circuit accidents due to improper connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 This is a circuit usage state diagram of the electrical interface detection circuit of the embodiment of the utility model;

[0016] Figure 2 This is a circuit schematic diagram of the electrical interface detection circuit of an embodiment of the utility model. DETAILED DESCRIPTION

[0017] To make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the following is a brief description of the present invention in conjunction with the attached Figure 1 , Figure 2 The utility model is further described in detail with specific implementation methods.

[0018] This embodiment provides a charging interface detection circuit, which specifically includes: a wide voltage input circuit 1, an external resistance measurement circuit 2, a given input loop 3, a measurement comparison circuit 4 and an output control circuit 5. In this embodiment, the charging gun has an equivalent resistance R2 of the vehicle plug (nominal value 1KΩ), and the battery management has an equivalent resistance R4 of the vehicle socket (nominal 1KΩ). The use state of the charging interface detection circuit is as follows: Figure 1 shown.

[0019] The wide voltage input circuit 1 of this embodiment has a circuit structure as follows: a +12V power supply is connected to the positive electrode of a diode D3, and the negative electrode of the diode D3 is respectively connected in parallel with an indication circuit formed by a resistor R1 and an LED1 lamp connected in series, a circuit where resistor R9 is located, and a circuit where resistor R2 is located. The system power supply 12VDC is connected to the wide voltage input circuit via the CN1 terminal and passes through the anti-reverse connection diode D3. When the power is turned on, the current passes through the current limiting resistor R1 to light up LED1 (power indicator light).

[0020] The external resistance measurement circuit 2 of this embodiment includes a terminal CN2 for connecting the circuit to be measured, an output end of the terminal CN2 is connected to one end of the capacitor C2 and one end of the resistor R2 and connected together to the detection input point A, the other end of the capacitor C2 is grounded GND, and the other end of the resistor R2 is connected to the cathode of the diode D3 of the wide voltage input circuit 1. Two diodes are also connected in series between the cathode of the diode D3 and the ground, wherein the anode of the diode D2 is connected to the cathode of the other diode. The clamping diode D2 can limit the input signal between 12V and 0V. C2 is a buffer capacitor that can filter the detection signal, R2 is a voltage divider resistor, and the voltage of the detection input point A is calculated as (CN2-1 / 2 foot input resistance) / (CN2-1 / 2 foot input resistance+R2)*12V.

[0021] The given input circuit 3 of this embodiment includes a dial switch SW1, pin 5 of the dial switch SW1 is connected to one end of the resistor R3, pin 6 is connected to one end of the resistor R4, pin 7 is connected to one end of the resistor R5, pin 8 is connected to one end of the resistor R6, and the other end of the resistor R3, the other end of the resistor R4, the other end of the resistor R5 and the other end of the resistor R6 are grounded GND. Pins 1, 2, 3, and 4 of the dial switch SW1 are connected to one end of the capacitor C4 and one end of the resistor R9, and the other end of the capacitor C4 is connected to GND. The resistor R9 is connected in parallel with the circuit where the dial switch SW1 is located and divides the voltage. The divided voltage is connected to the first comparator U3.1 of the given input voltage measurement comparison circuit. The resistance values ​​of the resistors R3, R4, R5, and R6 are adjusted to adapt to the internal resistance of the charger through the SW1 dial switch, C4 is a signal filter, and the voltage at the given input is calculated as: given resistance / (given resistance+R9)*12V.

[0022] The measurement comparison circuit of this embodiment includes a first comparator U3.1, pin 2 of the first comparator U3.1 is connected to pin 1 of the dip switch SW1, pin 3 of the first comparator U3.1 is connected to one end of the resistor R2, pin 1 of the first comparator U3.1 is connected to pin 5 of the second comparator U3.2 via resistor R6, pin 1 of the dip switch SW1 is connected to pin 6 of the second comparator U3.2 via resistor R8, and output pin 7 of the second comparator U3.2 is connected to the output control circuit. Capacitor C3 is used as a power supply decoupling capacitor of LM393, one end of which is connected to the +12V power supply and the other end is connected to GND, which is used to eliminate parasitic coupling between circuits. When the voltage at the detection input terminal is greater than the given input terminal, the output of pin 1 of the first comparator U3.1 is pulled up to a high level by R10 and 12V, and the output voltage is obtained by voltage division with resistor R8 and the previous resistor R9: R8 / (R8+R9)*12V=8V, and the high level 12V output by pin 5 of the second comparator U3.2 is greater than the 8V output by pin 6 of the second comparator U3.2, and pin 7 outputs a high level. When the voltage at the detection input terminal is less than the given voltage, pin 1 of the first comparator U3.1 outputs a low level to pin 5 of the second comparator U3.2. When the output voltage of pin 5 of the second comparator U3.2 is less than the output voltage of pin 6 of the second comparator U3.2, pin 7 of the second comparator U3.2 outputs a low level.

[0023] The output control circuit of this embodiment includes a resistor R12 connected to a +12 volt power supply at one end, the other end of the resistor R12 connected to the positive electrode of the LED lamp and the pin 8 of the relay K1, the negative electrode of the LED lamp connected to the positive electrode of the diode D6 and the pin 1 of the relay K1, the negative electrode of the diode D6 connected to the +12 volt power supply, R12 is the current limiting resistor of LED2 (operation indicator light), and D6 is the freewheeling diode of the relay K1, which can eliminate the reverse current generated by the coil when the relay is restored. Pins 2, 3, and 4 of the relay K1 are respectively connected to pins 1, 2, and 3 of the terminal CN3, and pins 5, 6, and 7 of the relay K1 are respectively connected to pins 1, 2, and 3 of the terminal CN4. When pin 7 is at a high level, the voltages at both ends of LED2 and relay K1 are equal, and the system does not operate. When the output of pin 7 is low level, relay K1 is energized, LED2 lights up, CN3 / 4 terminals 23 / 67 are disconnected and 34 / 56 are closed, and can be connected to the digital input terminal of PLC or microcontroller for feedback.

[0024] The working principle of the charging interface detection circuit in this embodiment is:

[0025] The working principle of this embodiment is:

[0026] A measurement comparison circuit is used to detect whether the gun tip resistor (1k) and the gun base resistor (1k) in the circuit to be tested are connected in parallel to determine whether the charging gun is fully connected. The detected resistance value is compared with the voltage divider value V1 generated by the voltage divider resistor R2, and the voltage divider value V2 generated by the voltage divider resistors R10 and R5 in the DIP switch circuit in parallel with R9, and then output through the relay. When it is detected that the two resistors are connected in parallel, the gun tip and the gun base are fully connected, LED2 lights up, and the output relay coil is energized. When it is detected that the two resistors are disconnected from parallel, the protection is triggered, LED2 goes out, and the output relay coil is reset.

[0027] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A charging interface detection circuit, comprising: A wide voltage input circuit for powering a charging interface detection circuit, characterized in that it also includes: An external resistance detection circuit is connected to the circuit to be tested and is used to divide the input voltage of the circuit to be tested and then output it after the charging gun is fully connected to the vehicle; Given an input circuit, it is used to adjust the resistance of the access resistor so that its resistance is close to that of the charging gun; The measuring comparison circuit has one input end connected to the external resistance detection circuit for receiving the detection input voltage after voltage division provided by the external resistance detection circuit; the other input end is connected to the output end of the given input circuit for receiving the given input voltage after voltage division. If the two input signals are compared and a low-level signal is output, the gun tip resistance and the gun base resistance in the circuit to be measured are connected in parallel; The output control circuit is connected to the measurement comparison circuit and is used to control the on and off of the relay according to the output signal of the measurement comparison circuit. The control indicator light is on when the gun head is fully connected to the gun seat, and the protection is triggered when the gun head is not fully connected to the gun seat.

2. A charging port detection circuit as claimed in claim 1, characterized in that The external resistance detection circuit is connected to the circuit to be tested through the second terminal, an output end of the second terminal and one end of the second resistor are connected to the detection input point A, and the other end of the second resistor is connected to the power supply.

3. A charging port detection circuit as claimed in claim 1, characterized in that The given input circuit includes a dip switch, the fifth port of the dip switch is connected to one end of the third resistor, the sixth port is connected to one end of the fourth resistor, the seventh port is connected to one end of the fifth resistor, and the eighth port is connected to one end of the sixth resistor. The other end of the third resistor, the other end of the fourth resistor, and the other end of the fifth resistor are connected to the other end of the sixth resistor and grounded. The first port, the second port, the third port and the fourth port of the dip switch are connected in parallel with the ninth resistor and voltage is divided.

4. A charging port detection circuit as claimed in claim 1, characterized in that The measurement comparison circuit includes a first comparator, the voltage of the monitoring input point A of the external resistance detection circuit is connected to the reverse input terminal of the first comparator, the output terminal of the given input loop is connected to the positive input terminal of the second comparator, the output terminal of the first comparator is connected to the positive input terminal of the second comparator and is pulled up to a high level through a pull-up resistor, the reverse input terminal of the second comparator is connected to the given input voltage of the given input loop, and the output terminal of the second comparator is connected to a relay.

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