Vehicle-mounted electronic expansion valve driving circuit with protection function

Abstract

This utility model discloses a protective electronic expansion valve drive circuit for vehicle air conditioning, relating to the field of electronic expansion valve drive circuits. It aims to solve the problem of existing technologies lacking the ability to detect overcurrent, overtemperature, overpressure, short circuit, and open circuit faults. The technical solution involves driving the electronic expansion valve with a driver chip. The main control chip is connected to a voltage divider circuit and a signal conditioning circuit, and then connected to the driver chip. By using a driver chip to drive the electronic expansion valve, it is possible to determine whether overcurrent, overtemperature, overpressure, short circuit, or open circuit faults exist during or before the electronic expansion valve operates. When a fault occurs, the entire air conditioning system stops operating, thus effectively solving the problem of excessively high system operating pressure or a large amount of liquid refrigerant flowing back to the compressor when the electronic expansion valve malfunctions.

Description

Technical Field

[0001] This utility model relates to the field of electronic expansion valve drive circuit technology, specifically to an electronic expansion valve drive circuit for vehicle air conditioning with protection function. Background Technology

[0002] Currently, in the application of electronic expansion valve drive circuits in automotive air conditioning systems, MCUs typically directly drive MOSFETs or transistors to control the opening and closing of the electronic expansion valve. However, such drive circuits lack the ability to detect overcurrent, overtemperature, overvoltage, short circuit, and open circuit faults. This makes it highly susceptible to malfunctions in the electronic expansion valve or drive circuit, which can lead to excessively high system operating pressure or a large amount of liquid refrigerant flowing back into the compressor. This can result in damage to the air conditioning system and the vehicle, causing property loss and even endangering lives. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the existing defects and provide an electronic expansion valve drive circuit for vehicle air conditioning with protective function, which can effectively solve the problems in the background art.

[0004] To achieve the above objectives, this utility model discloses a drive circuit for an electronic expansion valve in a vehicle air conditioner with protective functions. The technical solution includes an MCU and a driver chip. The driver chip is connected to a power supply, a power decoupling network, an electronic expansion valve, a voltage divider circuit, and a signal conditioning circuit. Both the voltage divider circuit and the signal conditioning circuit are connected to the MCU. The electronic expansion valve includes... port, port, ports and The four ports are connected to the four output ports of the driver chip; the power supply is connected to the VBB pin of the driver chip after the power decoupling network; the voltage divider circuit is connected to the input port of the driver chip and the I / O port of the MCU; the signal conditioning circuit is connected to the status indicator pin of the driver chip and the I / O port of the MCU; the ground pin of the driver chip is grounded after being connected to a resistor. The voltage divider circuit provides a safe and suitable level signal for the driver chip; the signal conditioning circuit provides additional power supply and current limiting protection; the power decoupling network performs power filtering and voltage regulation; and the ground pin, after being grounded after being connected to a resistor, limits the current and protects the electronic expansion valve coil and the driver circuit.

[0005] In a preferred embodiment of this invention, the power decoupling network includes capacitors C1 and C2. One end of capacitors C1 and C2 is connected to the DC12V power supply and the VBB pin of the driver chip, while the other end is grounded. The power decoupling network is used to filter out ripple, noise, and high-frequency interference in the power supply, providing a stable DC voltage for the subsequent driver chip. Furthermore, the capacitors can provide stored energy during instantaneous high current demands.

[0006] In a preferred embodiment of this invention, the voltage divider circuit includes a first resistor and a second resistor. One end of the first resistor is connected to the MCU, and the other end is connected to the driver chip. One end of the second resistor is connected between the first resistor and the driver chip, and the other end of the second resistor is grounded. This circuit proportionally divides the input voltage to provide a suitable low-voltage signal to the pins of the driver chip, thus providing both level conversion and protection functions.

[0007] As a preferred embodiment of this utility model, the voltage divider circuit has four groups, which are respectively connected between the PD pins of the four I / O ports of the MCU and the four input ports of the driver chip.

[0008] In a preferred embodiment of this invention, the signal conditioning circuit includes a third resistor and a fourth resistor. One end of the third resistor is connected to the MCU, and the other end is connected to the driver chip. One end of the fourth resistor is connected between the third resistor and the driver chip, and the other end of the fourth resistor is connected to a DC 5V power supply. The signal conditioning circuit is mainly used to provide additional power to the driver chip and for current protection.

[0009] As a preferred embodiment of this utility model, the signal conditioning circuit has two sets, which are respectively connected between the PH pin of the two I / O ports of the MCU and the two status indicator pins (ST1 / 2 pins) of the driver chip.

[0010] As a preferred technical solution of this utility model, the MCU is a KF32A146IQT chip.

[0011] As a preferred technical solution of this utility model, the driver chip is a BTS724G chip.

[0012] Compared with the prior art, the beneficial effects of this utility model are: by using a driver chip to drive the electronic expansion valve, this utility model can determine whether there are overcurrent, overtemperature, overpressure, short circuit, or open circuit faults in the electronic expansion valve during or before it starts working. When a fault occurs, the entire air conditioning system stops working, thereby effectively solving the problem of excessively high system working pressure or a large amount of liquid refrigerant flowing back to the compressor when the electronic expansion valve fails. Attached Figure Description

[0013] Figure 1This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] Example 1

[0016] like Figure 1 As shown, this utility model discloses a drive circuit for an electronic expansion valve with protection function for a vehicle air conditioner. The technical solution adopted includes a main control chip U2 and a drive chip U1. The main control chip U2 is an MCU, which adopts a KF32A146IQT processor. Its I / O ports include ports 1-4 of the PD pin and ports 5 and 6 of the PH pin. The drive chip U1 adopts a BTS724G drive chip.

[0017] Pins 1, 10, 11, 12, 15, 16, 19, and 20 of the driver chip U1 are all VBB pins. The VBB pins are connected in series to the power decoupling network, which in turn connects to a 12V DC power supply. The power decoupling network consists of capacitors C1 and C2 connected in parallel, with the ends of both capacitors grounded. This filters out ripple, noise, and high-frequency interference in the power supply, providing a stable DC voltage for the subsequent driver chip U1. The capacitors can also store energy to supply the driver chip U1 when there is a sudden surge in current.

[0018] To enable control signal transmission between the main control chip U2 and the driver chip U1, the I / O interface of the main control chip U2 is connected to the input pins and status indicator pins of the driver chip U1. Furthermore, for level conversion and circuit protection, a voltage divider circuit and a signal conditioning circuit are connected between the main control chip U2 and the driver chip U1. Specifically, the PD4 (1#) pin of the main control chip U2 is connected to one end of resistor R1, the other end of resistor R1 is connected to one end of resistor R2 and the IN1 (3#) pin of the driver chip U1, and the other end of resistor R2 is grounded. Resistors R1 and R2 together form a voltage divider circuit, which proportionally divides the input voltage to provide a suitable low-voltage signal to the input pins of the driver chip U1. The signal input from the main control chip U2 to the driver chip U1 is converted into a standard logic level that the driver chip U1 can recognize and used as a pull-up resistor to ensure that the input pin remains at a high level when no external signal is connected. The signal conditioning circuit can also provide current limiting protection to prevent excessive current from flowing into the input pin of the driver chip U1 and has a certain signal filtering effect. Similarly, voltage divider circuits with the same principle are connected between the PD5 (2#) pin of the main control chip U2 and the IN2 (5#) pin of the driver chip U1, between the PD6 (3#) pin of the main control chip U2 and the IN3 (7#) pin of the driver chip U1, and between the PD7 (4#) pin of the main control chip U2 and the IN4 (9#) pin of the driver chip U1. The PH8 (5#) pin of the main control chip U2 is connected to one end of the resistor R9. The other end of the resistor R9 is connected to the resistor R10 and the ST1 / 2 (4#) pin of the driver chip U1. The other end of the resistor R10 is connected to the 5V DC power supply. The resistor R9, the resistor R10 and the 5V DC power supply together constitute a signal conditioning circuit, which sends control signals and additional power to the ST1 / 2 (4#) pin of the driver chip U1. Similarly, there is a signal conditioning circuit with the same principle between the PH9 (6#) pin of the main control chip U2 and the ST1 / 2 (8#) pin of the driver chip U1.

[0019] To control the ETS 5T electronic expansion valve, output ports 1-4 (18#, 17#, 14#, 13#) of the driver chip U1 are connected to the electronic expansion valve respectively. port, port, ports and The port, the COM pin of the electronic expansion valve, is grounded.

[0020] To provide current limiting protection for the driver chip U1, the GND1 / 2 (2#) pin and GND3 / 4 (6#) pin of the driver chip U1 are connected to resistors R14 and R13 respectively and then grounded.

[0021] The working principle of this utility model:

[0022] A 12V DC power supply is filtered by capacitors C1 and C2 before powering the driver chip U1. When control of the electronic expansion valve is required, the main control chip U2 sends an electrical signal to the driver chip U1. The electrical signal from the PD4-7 interface is converted by a voltage divider circuit and transmitted to the input ports (3#, 5#, 7#, 9#) of the driver chip U1 with circuit protection. The electrical signal from the PH8-9 interface of the main control chip U2 is divided and transmitted to the ST1 / 2 pin of the driver chip U1. The ST1 / 2 pin has an additional 5V DC power supply. After receiving the electrical signal, the driver chip U1 processes the signal and sends an electrical signal to the electronic expansion valve through the output ports (13#, 14#, 17#, 18#) to drive the electronic expansion valve. Resistors R13 and R14 provide current protection for the driver chip U1.

[0023] The circuit connection involved in this utility model is a common method used by those skilled in the art, and technical inspiration can be obtained through a limited number of experiments. It belongs to common knowledge.

[0024] Components not described in detail in this article are existing technologies.

[0025] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A protective electronic expansion valve drive circuit for vehicle air conditioning, comprising an MCU, characterized in that: It also includes a driver chip, which is connected to a power supply, a power decoupling network, an electronic expansion valve, a voltage divider circuit, and a signal conditioning circuit; both the voltage divider circuit and the signal conditioning circuit are connected to the MCU; the electronic expansion valve includes... port, port, ports and The four ports are connected to the four output ports of the driver chip; the power supply is connected to the VBB pin of the driver chip after the power decoupling network; the voltage divider circuit is connected to the input port of the driver chip and the I / O port of the MCU; the signal conditioning circuit is connected to the status indicator pin of the driver chip and the I / O port of the MCU; the ground pin of the driver chip is grounded after being connected to a resistor.

2. The electronic expansion valve drive circuit for vehicle air conditioning with protection function according to claim 1, characterized in that: The power decoupling network includes capacitors C1 and C2. One end of capacitors C1 and C2 is connected to the DC12V power supply and the VBB pin of the driver chip, and the other end is grounded.

3. The electronic expansion valve drive circuit for vehicle air conditioning with protection function according to claim 1, characterized in that: The voltage divider circuit includes a first resistor and a second resistor. One end of the first resistor is connected to the MCU and the other end is connected to the driver chip. One end of the second resistor is connected between the first resistor and the driver chip, and the other end of the second resistor is grounded.

4. The electronic expansion valve drive circuit for vehicle air conditioning with protection function according to claim 3, characterized in that: The voltage divider circuit consists of four groups, which are respectively connected between the PD pins of the four I / O ports of the MCU and the four input ports of the driver chip.

5. The electronic expansion valve drive circuit for vehicle air conditioning with protection function according to claim 1, characterized in that: The signal conditioning circuit includes a third resistor and a fourth resistor. One end of the third resistor is connected to the MCU and the other end is connected to the driver chip. One end of the fourth resistor is connected between the third resistor and the driver chip, and the other end of the fourth resistor is connected to the DC5V power supply.

6. The electronic expansion valve drive circuit for vehicle air conditioning with protection function according to claim 5, characterized in that: The signal conditioning circuit consists of two sets, which are respectively connected between the PH pin of the two I / O ports of the MCU and the two status indicator pins of the driver chip.

7. The electronic expansion valve drive circuit for vehicle air conditioning with protection function according to any one of claims 1-6, characterized in that: The MCU is a KF32A146IQT chip.

8. The electronic expansion valve drive circuit for vehicle air conditioning with protection function according to any one of claims 1-6, characterized in that: The driver chip is a BTS724G type chip.

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