PFC detection circuit

By designing a PFC detection circuit that includes voltage detection, comparison and isolation circuits, and using optocoupler U2 to achieve high-voltage and low-voltage isolation, the problem of low-voltage circuit components being broken down is solved, and high-voltage protection is achieved.

CN223436040UActive Publication Date: 2025-10-14HENGTAI HARDWARE ELECTRIC FUYANG CITY
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Patent Information

Application Number
CN202422644222.9
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-10-31
Publication Date
2025-10-14
Estimated Expiration
2034-10-31

AI Technical Summary

Technical Problem

In existing PFC detection circuits, low-voltage circuit components are easily broken down when connected to high voltage, and the lack of an isolation circuit leads to insufficient protection.

Method used

A PFC detection circuit including a voltage detection circuit, a comparison circuit and an isolation circuit is designed. The high voltage and low voltage are isolated by the optocoupler U2, and the positive and negative input terminals of the operational amplifier U1 are used to compare the voltages to protect the low voltage part from being broken down by the high voltage.

Benefits of technology

It achieves effective isolation between high voltage and low voltage, protects low voltage electronic devices, reduces damage, and has the characteristics of high voltage resistance.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model discloses a PFC (Power Factor Correction) detection circuit, which is characterized by further comprising an isolation circuit connected with a comparison circuit, the isolation circuit comprises a pin 1 of an optocoupler U2 connected with the comparison circuit, a resistor R4 connected with a pin 3 of the optocoupler U2, a capacitor C1 and a PFC MCU (Microprogrammed Control Unit) signal, a power supply end 3.3 V connected with the other end of the resistor R4, and a capacitor C1 connected with a pin 4 of the optocoupler U2, a pin 2 and a pin 4 of the optocoupler U2 and the capacitor C1 are grounded; according to the PFC detection circuit, through the arrangement of the isolation circuit, when the comparison circuit sends out a low signal, the optical coupler U2 is not started, the optical coupler U2 is not lowered and the output is high, and when the comparison circuit sends out a high signal, the optical coupler U2 is started, the optical coupler U2 is lowered after being started and the output is low, so that the purpose of high-voltage and low-voltage isolation is achieved, and a low-voltage part is protected from being broken down by high voltage; therefore, the electronic device is protected and has the characteristics of high voltage resistance, small damage to the electronic device and the like.
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Description

Technical Field

[0001] The utility model relates to the technical field of new energy vehicles, in particular to a PFC detection circuit. Background Art

[0002] At present, in the field of new energy vehicles, in order to comply with safety regulations and strengthen the protection of electronic equipment, more and more electronic equipment need to add FPC detection circuits; in the existing PFC detection circuit, there is no isolation circuit, and low-voltage circuit components are easily broken down when connected to high voltage. Therefore, a PFC detection circuit is proposed. Utility Model Content

[0003] The main purpose of the present invention is to provide a method for effectively solving the problems in the background technology.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a PFC detection circuit, including a voltage detection circuit connected to the PFC voltage, and a comparison circuit connected to the voltage detection circuit, characterized in that: it also includes an isolation circuit connected to the comparison circuit, the isolation circuit including pin 1 of an optocoupler U2 connected to the comparison circuit, a resistor R4, a capacitor C1, and a PFC MCU signal connected to pin 3 of the optocoupler U2, a power supply terminal 3.3V connected to the other end of the resistor R4, a capacitor C1 connected to pin 4 of the optocoupler U2, and pins 2, 4, and capacitor C1 of the optocoupler U2 are grounded.

[0005] Preferably, the voltage detection circuit includes a resistor R1 connected to the PFC voltage, a resistor R2, a resistor R3, and a resistor R5 connected in series with the resistor R1 in sequence, a resistor R9, a resistor R10, a capacitor C3, and a comparison circuit connected to the other end of the resistor R5, the other end of the resistor R10 and the other end of the capacitor C3 connected to the other end of the resistor R9, and the other end of the resistor R9, the other end of the resistor R10, and the other end of the capacitor C3 are grounded.

[0006] Preferably, the comparison circuit includes pin 4 of the operational amplifier U1 connected to the voltage detection circuit, resistors R7, R8 and R11 connected to pin 3 of the operational amplifier U1, a power supply terminal 5V connected to the other end of the resistor R7, and the other end of the resistor R8 is grounded, resistors R11 and R6 connected to pin 1 of the operational amplifier U1, an isolation circuit connected to the other end of the resistor R6, a power supply terminal 5V and a capacitor C2 connected to pin 5 of the operational amplifier U1, and the other end of the capacitor C2 and pin 2 of the operational amplifier U1 are grounded, pin 3 of the operational amplifier U1 is the positive input terminal, pin 4 of the operational amplifier U1 is the negative input terminal, and pin 1 of the operational amplifier U1 is the output terminal.

[0007] The utility model has the following beneficial effects: the circuit is a PFC detection circuit. Through the setting of the isolation circuit, when the comparison circuit sends a low signal, the optocoupler U2 is enabled and not turned on, the optocoupler U2 does not pull down, and the output is high. When the comparison circuit sends a high signal, the optocoupler U2 is enabled and pulled down after being turned on, and the output is low, so as to achieve the purpose of isolating high voltage and low voltage, protect the low voltage part from being broken down by the high voltage, thereby protecting the electronic devices, and having the characteristics of high voltage resistance and little damage to electronic devices.

[0008] The input PFC voltage is detected by setting the voltage detection circuit, and the high voltage is reduced to a safe low voltage through resistor voltage division and transmitted to the comparison circuit;

[0009] By setting up the comparison circuit, a preset voltage is connected to the positive input terminal of the operational amplifier U1, and the voltage divided by the voltage detection circuit is connected to the negative input terminal of the operational amplifier U1. When the voltage at the negative input terminal of the operational amplifier U1 is less than the voltage at the positive input terminal of the operational amplifier U1, it indicates undervoltage. When the voltage at the negative input terminal of the operational amplifier U1 is greater than the voltage at the positive input terminal of the operational amplifier U1, it indicates normal. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic diagram of the PFC detection circuit structure of the utility model;

[0011] Figure 2 This is a connection diagram of the voltage detection circuit of the utility model;

[0012] Figure 3 It is a connection diagram of the comparison circuit of the utility model;

[0013] Figure 4 It is a connection diagram of the isolation circuit of the utility model.

[0014] Legend: 1. Voltage detection circuit; 2. Comparison circuit; 3. Isolation circuit. DETAILED DESCRIPTION

[0015] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0016] like Figure 1-4As shown, a PFC detection circuit includes a voltage detection circuit 1 connected to the PFC voltage, a comparison circuit 2 connected to the voltage detection circuit 1, and is characterized in that it also includes an isolation circuit 3 connected to the comparison circuit 2, the isolation circuit 3 including pin 1 of an optocoupler U2 connected to the comparison circuit 2, a resistor R4, a capacitor C1, and a PFC MCU signal connected to pin 3 of the optocoupler U2, a power supply terminal 3.3V connected to the other end of the resistor R4, and a capacitor C1 connected to pin 4 of the optocoupler U2, and pins 2 and 4 of the optocoupler U2 and capacitor C1 are grounded. This circuit is a PFC detection circuit. Through the setting of the isolation circuit 3, when the comparison circuit 2 sends a low signal, the optocoupler U2 is enabled to be turned off, the optocoupler U2 does not pull down, and the output is high. When the comparison circuit 2 sends a high signal, the optocoupler U2 is enabled to be turned on, and the optocoupler U2 is pulled down after turning on, and the output is low, thereby achieving the purpose of isolating high voltage from low voltage, protecting the low voltage part from being broken down by the high voltage, thereby protecting electronic devices, and having the characteristics of high voltage resistance and minimal damage to electronic devices.

[0017] In one embodiment, the voltage detection circuit 1 includes a resistor R1 connected to the PFC voltage, resistors R2, R3, and R5 connected in series with the resistor R1, a resistor R9, a resistor R10, a capacitor C3 connected to the other end of the resistor R5, and a comparison circuit 2. The other end of the resistor R10 and the other end of the capacitor C3 are connected to the other end of the resistor R9, and the other ends of the resistor R9, R10, and C3 are grounded. The voltage detection circuit 1 detects the input PFC voltage and reduces the high voltage to a safe low voltage through resistor voltage division and transmits it to the comparison circuit.

[0018] In one embodiment, the comparison circuit 2 includes pin 4 of the operational amplifier U1 connected to the voltage detection circuit 1, resistors R7, R8, and R11 connected to pin 3 of the operational amplifier U1, a power supply terminal 5V connected to the other end of the resistor R7, and the other end of the resistor R8 is grounded, resistors R11 and R6 connected to pin 1 of the operational amplifier U1, an isolation circuit 3 connected to the other end of the resistor R6, a power supply terminal 5V and a capacitor C2 connected to pin 5 of the operational amplifier U1, and the other end of the capacitor C2 and pin 2 of the operational amplifier U1 are grounded. Pin 3 of the amplifier U1 is the positive input terminal, pin 4 of the operational amplifier U1 is the negative input terminal, and pin 1 of the operational amplifier U1 is the output terminal; through the setting of the comparison circuit 2, a preset voltage is connected to the positive input terminal of the operational amplifier U1, and the voltage after voltage division by the voltage detection circuit 1 is connected to the negative input terminal of the operational amplifier U1. When the voltage at the negative input terminal of the operational amplifier U1 is less than the voltage at the positive input terminal of the operational amplifier U1, it indicates undervoltage. When the voltage at the negative input terminal of the operational amplifier U1 is greater than the voltage at the positive input terminal of the operational amplifier U1, it indicates normal.

[0019] The working principle of the present utility model is as follows: the PFC voltage is divided by the resistors in the voltage detection circuit 1, and the high voltage is converted into a safe low voltage. The divided voltage is connected to the negative input terminal of the operational amplifier U1 in the comparison circuit 2, and a voltage of 5V at the power supply end is preset to be connected to the positive input terminal of the operational amplifier U1. When the voltage at the positive input terminal is higher than that at the negative input terminal, the output is high, and the enabling optocoupler U2 of the isolation circuit 3 is turned on. Through the isolation of the optocoupler U2, the output of the optocoupler U2 is low. When the voltage at the positive input terminal is lower than the voltage at the negative input terminal, the output is low, and the enabling optocoupler U2 of the isolation circuit 3 is not turned on. The output of the optocoupler U2 is high, thereby achieving the purpose of isolating high voltage and low voltage.

[0020] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements are intended to fall within the scope of the present invention. The scope of protection claimed in this invention is defined by the appended claims and their equivalents.

Claims

1. A PFC detection circuit, comprising a voltage detection circuit (1) connected to a PFC voltage, a comparison circuit (2) connected to the voltage detection circuit (1), and characterized in that: it also comprises an isolation circuit (3) connected to the comparison circuit (2), the isolation circuit (3) comprising pin 1 of an optocoupler U2 connected to the comparison circuit (2), a resistor R4, a capacitor C1 and a PFC MCU signal connected to pin 3 of the optocoupler U2, a power supply terminal 3.3V connected to the other end of the resistor R4, a capacitor C1 connected to pin 4 of the optocoupler U2, and pins 2 and 4 of the optocoupler U2 and the capacitor C1 are grounded.

2. The PFC detection circuit according to claim 1, wherein: The voltage detection circuit (1) includes a resistor R1 connected to the PFC voltage, a resistor R2, a resistor R3 and a resistor R5 connected in series with the resistor R1, a resistor R9, a resistor R10, a capacitor C3 connected to the other end of the resistor R5, and a comparison circuit (2), the other end of the resistor R10 and the other end of the capacitor C3 connected to the other end of the resistor R9, and the other end of the resistor R9, the other end of the resistor R10 and the other end of the capacitor C3 are grounded.

3. The PFC detection circuit according to claim 1, wherein: The comparison circuit (2) includes pin 4 of the operational amplifier U1 connected to the voltage detection circuit (1), resistors R7, R8 and R11 connected to pin 3 of the operational amplifier U1, a power supply terminal 5V connected to the other end of the resistor R7, and the other end of the resistor R8 is grounded, resistors R11 and R6 connected to pin 1 of the operational amplifier U1, an isolation circuit (3) connected to the other end of the resistor R6, a power supply terminal 5V and a capacitor C2 connected to pin 5 of the operational amplifier U1, and the other end of the capacitor C2 and pin 2 of the operational amplifier U1 are grounded, pin 3 of the operational amplifier U1 is a positive input terminal, pin 4 of the operational amplifier U1 is a negative input terminal, and pin 1 of the operational amplifier U1 is an output terminal.