Bidirectional switching circuit

Abstract

The utility model discloses a bidirectional switching circuit, which relates to the field of charging and comprises a power supply port, a VCC pin of the power supply port is connected with a drain electrode of an MOS tube Q1, a source electrode of the MOS tube Q1 is connected with a drain electrode of an MOS tube Q2, a first end of a capacitor C1 and a first end of a resistor R3, a grid electrode of the MOS tube Q1, a second end of the capacitor C1, a second end of the resistor R3 and a grid electrode of the MOS tube Q2 are connected with a first end of a resistor R4, and the resistor R4 is connected with a second end of the capacitor C1. The second end of the resistor R4 is connected with the drain electrode of the MOS tube Q3, the grid electrode of the MOS tube Q3 is connected with the first end of the resistor R1 and the first end of the resistor R2, the second end of the resistor R1 serves as a control signal input end, and the second end of the resistor R2 is connected with the source electrode of the MOS tube Q3 and is grounded; the source electrode of the MOS tube Q2 is connected with the positive electrode of the battery BAT1, and the negative electrode of the battery BAT1 is grounded. According to the utility model, the bidirectional flow of current is realized mainly through the two back-to-back P-type MOS tubes, the circuit structure is simple, and the reliability is high.

Description

Technical Field

[0001] The utility model relates to the technical field of charging, in particular to the technical field of electric vehicle charging, and specifically to a bidirectional switch circuit. Background Art

[0002] Universal Serial Bus (USB) is a serial bus standard and a technical specification for input and output interfaces. It is widely used in civil, industrial and automotive products.

[0003] Designing a circuit that can charge a car battery when using a USB input port (for power) and power external devices when using a USB output port is crucial in real life. Existing technologies use different switches to charge and discharge a car battery. This utility model provides a novel bidirectional switching circuit. Utility Model Content

[0004] The purpose of the utility model is to provide a bidirectional switch circuit, which can realize charging of the car battery when the USB is used as an input interface (power supply), and rely on the car battery to provide power to external devices when the USB is used as an output interface.

[0005] The utility model solves the above problems through the following technical solutions:

[0006] A bidirectional switch circuit includes a power port, wherein a VCC pin of the power port is connected to the drain of a MOS transistor Q1, the source of the MOS transistor Q1 is connected to the drain of a MOS transistor Q2, the first end of a capacitor C1, and the first end of a resistor R3, the gate of the MOS transistor Q1, the second end of the capacitor C1, the second end of the resistor R3, and the gate of the MOS transistor Q2 are connected to the first end of a resistor R4, the second end of the resistor R4 is connected to the drain of the MOS transistor Q3, the gate of the MOS transistor Q3 is connected to the first end of the resistor R1 and the first end of the resistor R2, the second end of the resistor R1 serves as a control signal input terminal, and the second end of the resistor R2 is connected to the source of the MOS transistor Q3 and to ground; the source of the MOS transistor Q2 is connected to the positive electrode of a battery BAT1, and the negative electrode of the battery BAT1 is grounded.

[0007] Working principle:

[0008] When the power interface is used as an input, the function to be implemented is to charge the battery BAT1. The control signal input terminal input is high, driving the MOS transistor Q3 to turn on. The VCC pin of the power interface forms a path through the body diode of the MOS transistor Q1, the resistor R3, the resistor R4, and the MOS transistor Q3. The S-pole voltage of the MOS transistors Q1 and MOS transistors Q2 is equal to the output voltage of the VCC pin of the power port. The values ​​of the resistors R3 and R4 ensure that the voltage difference between the divided voltage of the resistor R4 and the output voltage of the VCC pin is less than the turn-on voltage of the MOS transistors Q1 and MOS transistors Q2. The MOS transistors Q1 and MOS transistors Q2 are turned on, and the power supply charges the battery BAT1 through the power port.

[0009] Furthermore, when battery BAT1 is used as the input, the function to be implemented is to power the load connected to the power port. The control signal input terminal is input at a high level, driving MOS transistor Q3 to turn on. The positive electrode of battery BAT1 forms a path through the body diode of MOS transistor Q2, resistors R3 and R4, and MOS transistor Q3. The S-pole voltage of MOS transistors Q1 and MOS transistor Q2 is equal to the voltage of battery BAT1. The values ​​of resistors R3 and R4 ensure that the voltage difference between the divided voltage of resistor R4 and the voltage of battery BAT1 is less than the turn-on voltage of MOS transistors Q1 and MOS transistor Q2. As a result, MOS transistors Q1 and MOS transistor Q2 are turned on, and battery BAT1 is used to power the power port circuit.

[0010] Furthermore, the MOS transistor Q1 is a P-type MOS transistor.

[0011] Furthermore, the MOS transistor Q2 is a P-type MOS transistor.

[0012] Furthermore, the MOS transistor Q3 is an N-type MOS transistor.

[0013] Furthermore, the power port is a USB interface.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0015] (1) The present invention mainly relies on two back-to-back P-type MOS tubes to achieve bidirectional current flow.

[0016] (2) The circuit architecture provided by the present invention is simple, highly reliable, and has high practicality and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the circuit principle diagram of the utility model

[0018] Among them, USB1-USB interface. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto.

[0020] Example 1:

[0021] Combined with attachment Figure 1 As shown, a bidirectional switch circuit includes a power port, a VCC pin of the power port connected to the drain of a MOS transistor Q1, a source of the MOS transistor Q1 connected to the drain of a MOS transistor Q2, a first end of a capacitor C1, and a first end of a resistor R3, a gate of the MOS transistor Q1, a second end of the capacitor C1, a second end of the resistor R3, and a gate of the MOS transistor Q2 connected to the first end of a resistor R4, a second end of the resistor R4 connected to the drain of the MOS transistor Q3, a gate of the MOS transistor Q3 connected to the first end of the resistor R1 and a first end of the resistor R2, a second end of the resistor R1 serving as a control signal input terminal, a second end of the resistor R2 connected to the source of the MOS transistor Q3 and to ground; a source of the MOS transistor Q2 connected to the positive electrode of a battery BAT1, and a negative electrode of the battery BAT1 connected to ground.

[0022] Working principle:

[0023] In this embodiment, the power port uses a standard 4-pin USB 2.0 port, USB1. The VCC pin is connected to the drain D of the P-type MOS transistor Q1. The D+ and D- pins are used for data transmission (not involved in the circuit of this utility model). The GND pin is grounded. The battery BAT1 is an electric vehicle battery. Both ports can be used as inputs or outputs. In the circuit, resistor R2 acts as a pull-down resistor, resistor R1 acts as a current-limiting resistor, capacitor C1 acts as a filter, and resistors R3 and R4 act as voltage divider resistors.

[0024] When USB interface USB1 is used as an input, the function to be implemented is to charge the car battery BAT1. The control signal input terminal input Q3_EN is high, driving the N-type MOS transistor Q3 to turn on. The VCC pin of USB interface USB1 forms a path through the body diode of P-type MOS transistor Q1, resistors R3 and R4, and MOS transistor Q3. The S-pole (source) voltage of MOS transistor Q1 and P-type MOS transistor Q2 is equal to the output voltage of the VCC pin of USB interface USB1. The values ​​of resistors R3 and R4 ensure that the voltage difference between the divided voltage of resistor R4 and the output voltage of the VCC pin is less than the turn-on voltage of MOS transistors Q1 and MOS transistors Q2. MOS transistors Q1 and MOS transistors Q2 are turned on, and the power supply can charge battery BAT1 through USB interface USB1.

[0025] Furthermore, when the battery BAT1 is used as the input, the function to be implemented is to power the load external to the USB interface USB1. The control signal input terminal input Q3_EN is at a high level, driving the MOS transistor Q3 to turn on. The positive electrode of the battery BAT1 forms a path through the body diode of the MOS transistor Q2 through the resistors R3 and R4, and the MOS transistor Q3. The S-pole (source) voltage of the MOS transistors Q1 and MOS transistors Q2 is equal to the voltage of the battery BAT1. The values ​​of the resistors R3 and R4 ensure that the voltage difference between the divided voltage of the resistor R4 and the battery BAT1 voltage is less than the turn-on voltage of the MOS transistors Q1 and MOS transistors Q2. As a result, the MOS transistors Q1 and MOS transistors Q2 are turned on, and the battery BAT1 supplies power to the power port circuit.

[0026] This utility model provides a bidirectional switch circuit. This circuit primarily utilizes two back-to-back P-type MOS transistors to achieve bidirectional current flow. When USB port USB1 is used as an input (power supply), it can charge the vehicle battery BAT1. When USB port USB1 is used as an output, it relies on the vehicle battery BAT1 to provide power to external devices. This utility model has a simple circuit architecture and high reliability.

[0027] Although the present invention is described herein with reference to the illustrative embodiments of the present invention, the above embodiments are merely preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A bidirectional switch circuit, characterized in that: The device includes a power port, wherein a VCC pin of the power port is connected to the drain of a MOS transistor Q1, a source of the MOS transistor Q1 is connected to the drain of a MOS transistor Q2, a first end of a capacitor C1, and a first end of a resistor R3, a gate of the MOS transistor Q1, a second end of the capacitor C1, a second end of the resistor R3, and a gate of the MOS transistor Q2 are connected to the first end of a resistor R4, a second end of the resistor R4 is connected to the drain of the MOS transistor Q3, a gate of the MOS transistor Q3 is connected to the first end of the resistor R1 and the first end of the resistor R2, a second end of the resistor R1 serves as a control signal input end, and a second end of the resistor R2 is connected to the source of the MOS transistor Q3 and to ground; the source of the MOS transistor Q2 is connected to the positive electrode of a battery BAT1, and the negative electrode of the battery BAT1 is grounded.

2. A bidirectional switch circuit according to claim 1, characterized in that: The MOS transistor Q1 is a P-type MOS transistor.

3. The bidirectional switch circuit according to claim 1, wherein: The MOS transistor Q2 is a P-type MOS transistor.

4. The bidirectional switch circuit according to claim 1, wherein: The MOS transistor Q3 is an N-type MOS transistor.

5. The bidirectional switch circuit according to claim 1, characterized in that: The power port is a USB interface.

Images