Auxiliary power supply protection circuit

Abstract

The utility model relates to the technical field of power supply protection, in particular to an auxiliary power supply protection circuit, which comprises a voltage output circuit, a differential amplification circuit and a voltage division circuit, and is characterized in that the voltage output circuit comprises a main control chip U1, resistors R1 to R10, capacitors C1 to C4, an anti-reverse connection diode D1 and a protection diode T1; the differential amplification circuit comprises a dual-channel operational amplifier U2A, a comparator U2B, resistors R11 to R14, R17, R18 and R20, capacitors C5 to C10, and input protection diodes D2 and D3; high-frequency signals output by the double-channel operational amplifier are filtered out through the double low-pass filters, it is guaranteed that signals entering a comparator are smoother, the resistors are used for configuring a hysteresis comparator, the ringing effect is prevented, when the output current of a power source is smaller than a set upper limit value VREF, enable signals are pulled up, and the output current of the power source is not larger than the set upper limit value VREF. And when the voltage is higher than the set upper limit value VREF, the enable signal is pulled down, and the output of the chip is cut off, so that the protection of the power supply is realized.

Description

Technical Field

[0001] This utility model relates to the field of power protection technology, and in particular to an auxiliary power protection circuit. Background Technology

[0002] Electrical equipment typically uses a main control chip to intelligently and automatically control the input power voltage. This prevents the equipment from malfunctioning due to insufficient power input or from burning out internal components due to excessive power input, thus providing protection. However, the main control circuits in general electrical equipment often lack signal filtering, leading to unstable signals received by the comparators and inconsistent detection results. Furthermore, existing main control circuits often fail to effectively prevent ringing. Therefore, we propose an auxiliary power protection circuit. Utility Model Content

[0003] The main objective of this invention is to provide an auxiliary power supply protection circuit, comprising a voltage output circuit, a differential amplifier circuit, and a voltage divider circuit. The voltage output circuit includes a main control chip U1, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, capacitors C1, C2, C3, C4, a reverse polarity protection diode D1, and a protection diode T1. The differential amplifier circuit includes a dual-channel operational amplifier U2A, a comparator U2B, resistors R11, R12, R13, R14, R17, R18, R20, capacitors C5, C6, C7, C8, C9, C10, and input protection diodes D2 and D3. The voltage divider circuit includes resistors R15, R16, and R19.

[0004] As a preferred embodiment of this invention, pin 17 of the main control chip U1 is connected to the reverse polarity protection diode D1, the other end of the reverse polarity protection diode D1 is connected to the power supply, pin 1 of the main control chip U1 is connected to the resistor R5, the other end of the resistor R5 is grounded, and capacitors C1, C2, and C3 are connected in parallel between pin 1 and pin 17 of the main control chip U1.

[0005] As a preferred embodiment of this invention, pins 6, 7, and 8 of the main control chip U1 are voltage output pins. Pin 16 of the main control chip U1 is connected to resistor R1, pin 14 of the main control chip U1 is connected to resistor R2, and the other end of resistor R2 is grounded. Pin 4 of the main control chip U1 is connected to resistors R3 and R4, pin 3 of the main control chip U1 is connected to resistor R6, pin 5 of the main control chip U1 is connected to resistor R7, resistors R9 and R10 are connected in series and then in parallel with resistor R8, capacitor C4 and protection diode T1 are connected in parallel and then connected between resistors R8, R9, and R10, and the other end of resistor R9 is grounded.

[0006] As a preferred embodiment of this invention, resistors R12 and R14 are connected in parallel to pin 3 of the dual-channel operational amplifier U2A; input protection diode D2 is connected between resistor R14 and pin 3 of the dual-channel operational amplifier U2A; resistor R20 is connected to pin 2 of the dual-channel operational amplifier U2A; input protection diode D3 is connected between resistor R20 and pin 2 of the dual-channel operational amplifier U2A; resistor R21 is connected between pin 1 and pin 2 of the dual-channel operational amplifier U2A; capacitors C5 and C6 are connected in parallel to pin 8 of the dual-channel operational amplifier U2A; and capacitors C9 and C10 are connected in parallel to pin 4 of the dual-channel operational amplifier U2A.

[0007] As a preferred embodiment of this invention, resistors R17 and R18 are connected between pin 1 of the dual-channel operational amplifier U2A and pin 6 of the comparator U2B. Capacitor C7 is connected between resistors R17 and R18, with its other end grounded. Capacitor C8 is connected between resistor R18 and pin 6 of the comparator U2B. Pin 5 of the comparator U2B is connected to resistor R13, and resistor R11 is connected between pins 5 and 7 of the comparator U2B.

[0008] As a preferred embodiment of this invention, resistors R15, R16, and R19 are connected in series to pin 7 of comparator U2B, with the other end grounded. Pin 4 of the main control chip U1 is connected to comparator U2B, and pin 2 of the main control chip U1 is connected to dual-channel operational amplifier U2A.

[0009] Compared with the prior art, the present invention has the following beneficial effects:

[0010] This invention uses a dual low-pass filter to filter out high-frequency signals from the dual-channel operational amplifier output, ensuring a smoother signal entering the comparator. A resistor is used to configure the hysteresis comparator to prevent ringing. When the power supply output current is less than the set upper limit value VREF, the enable signal is pulled high, and the chip outputs normally. When it is higher than the set upper limit value VREF, the enable signal is pulled low, and the chip output is turned off, thus protecting the power supply. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall circuit of this utility model. Detailed Implementation

[0012] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0013] Please see Figure 1This embodiment provides an auxiliary power supply protection circuit, including a voltage output circuit, a differential amplifier circuit, and a voltage divider circuit. The voltage output circuit includes a main control chip U1, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, capacitors C1, C2, C3, C4, a reverse connection protection diode D1, and a protection diode T1. The differential amplifier circuit includes a dual-channel operational amplifier U2A, a comparator U2B, resistors R11, R12, R13, R14, R17, R18, R20, capacitors C5, C6, C7, C8, C9, C10, and input protection diodes D2 and D3. The voltage divider circuit includes resistors R15, R16, and R19.

[0014] As a preferred embodiment of this invention, pin 17 of the main control chip U1 is connected to the reverse polarity protection diode D1, the other end of the reverse polarity protection diode D1 is connected to the power supply, pin 1 of the main control chip U1 is connected to the resistor R5, the other end of the resistor R5 is grounded, and capacitors C1, C2, and C3 are connected in parallel between pin 1 and pin 17 of the main control chip U1.

[0015] As a preferred embodiment of this invention, pins 6, 7, and 8 of the main control chip U1 are voltage output pins. Pin 16 of the main control chip U1 is connected to resistor R1, pin 14 of the main control chip U1 is connected to resistor R2, and the other end of resistor R2 is grounded. Pin 4 of the main control chip U1 is connected to resistors R3 and R4, pin 3 of the main control chip U1 is connected to resistor R6, pin 5 of the main control chip U1 is connected to resistor R7, resistors R9 and R10 are connected in series and then in parallel with resistor R8, capacitor C4 and protection diode T1 are connected in parallel and then connected between resistors R8, R9, and R10, and the other end of resistor R9 is grounded.

[0016] As a preferred embodiment of this invention, resistors R12 and R14 are connected in parallel to pin 3 of the dual-channel operational amplifier U2A; input protection diode D2 is connected between resistor R14 and pin 3 of the dual-channel operational amplifier U2A; resistor R20 is connected to pin 2 of the dual-channel operational amplifier U2A; input protection diode D3 is connected between resistor R20 and pin 2 of the dual-channel operational amplifier U2A; resistor R21 is connected between pin 1 and pin 2 of the dual-channel operational amplifier U2A; capacitors C5 and C6 are connected in parallel to pin 8 of the dual-channel operational amplifier U2A; and capacitors C9 and C10 are connected in parallel to pin 4 of the dual-channel operational amplifier U2A.

[0017] As a preferred embodiment of this invention, resistors R17 and R18 are connected between pin 1 of the dual-channel operational amplifier U2A and pin 6 of the comparator U2B. Capacitor C7 is connected between resistors R17 and R18, with its other end grounded. Capacitor C8 is connected between resistor R18 and pin 6 of the comparator U2B. Pin 5 of the comparator U2B is connected to resistor R13, and resistor R11 is connected between pins 5 and 7 of the comparator U2B.

[0018] As a preferred embodiment of this invention, resistors R15, R16, and R19 are connected in series to pin 7 of comparator U2B, with the other end grounded. Pin 4 of the main control chip U1 is connected to comparator U2B, and pin 2 of the main control chip U1 is connected to dual-channel operational amplifier U2A.

[0019] The main control chip U1 in the voltage output circuit is model TPS1HB35AQPWPRQ1. This chip is used for power management and can achieve a wide input voltage range of 6~18V. Pin 17 is the voltage input signal, and pin 1 is the voltage input reference ground. Capacitor C1 is used as an input energy storage and filtering capacitor, D1 is used as a reverse connection protection diode, resistor R5 is used for common ground, and capacitors C2 and C3 are used as input filtering capacitors. Pins 6, 7, and 8 are used as voltage output pins; pins 3, 14, and 16 are used to configure the chip to operate normally. Resistors R6, R1, and R2 are used for current limiting; pin 4 enables the chip output; pin 5 sets the maximum output current of the chip, IMAX = 50 / R7; pin 2 detects the chip output current, with a ratio of 1:2000 to the actual output current. A 2K resistor is used to convert the current signal into a voltage signal, so that the ISNS output voltage and the chip output current have a 1:1 relationship, which is convenient for detection; R8, R9, and C4 are used to match the output frequency, and T1 is used to protect the output and prevent the output voltage from being too high and burning out the subsequent circuitry.

[0020] A differential amplifier circuit is used to sample the ISNS pin. U2A is a dual-channel operational amplifier, and the amplification factor of this differential amplifier circuit is R12 / R14=2. D2 and D3 are used for input protection to prevent the dual-channel operational amplifier U2A from burning out due to excessive voltage. R17 and C7 form a low-pass filter to filter out the high-frequency signal output by the dual-channel operational amplifier U2A. R18 and C8 form a low-pass filter for further filtering to ensure that the signal entering comparator U2B is smoother. U2B is used as a comparator here. R13 is used as a current-limiting resistor. R11 is used to configure the hysteresis comparator U2B to prevent ringing. R15, R16, and R19 form a voltage divider circuit. When the input of pin 6 of comparator U2B is less than the VREF setting value, the output voltage of comparator U2B is 15V. Through the voltage divider circuit, the chip enable signal level is reduced to 3.3V to prevent the chip from burning out due to excessive enable signal voltage.

[0021] Overall system functionality description:

[0022] When the power supply output current is less than the set upper limit value VREF, the enable signal goes high and the chip outputs normally. When it exceeds the set upper limit value VREF, the enable signal goes low and the chip output is turned off, thus protecting the power supply.

[0023] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. An auxiliary power supply protection circuit, characterized by, It includes a voltage output circuit, a differential amplifier circuit, and a voltage divider circuit. The voltage output circuit includes a main control chip U1, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, capacitors C1, C2, C3, C4, a reverse polarity protection diode D1, and a protection diode T1. The differential amplifier circuit includes a dual-channel operational amplifier U2A, a comparator U2B, resistors R11, R12, R13, R14, R17, R18, R20, capacitors C5, C6, C7, C8, C9, C10, and input protection diodes D2 and D3. The voltage divider circuit includes resistors R15, R16, and R19. The main control chip U1 is model TPS1HB35AQPWPRQ1. Pin 17 of the main control chip U1 is connected to the reverse protection diode D1. The other end of the reverse protection diode D1 is connected to the power supply. Pin 1 of the main control chip U1 is connected to the resistor R5. The other end of the resistor R5 is grounded. Capacitors C1, C2, and C3 are connected in parallel between pin 1 and pin 17 of the main control chip U1. Pins 6, 7, and 8 of the main control chip U1 are voltage output pins. Pin 16 of the main control chip U1 is connected to resistor R1. Pin 14 of the main control chip U1 is connected to resistor R2. The other end of resistor R2 is grounded. Pin 4 of the main control chip U1 is connected to resistors R3 and R4. Pin 3 of the main control chip U1 is connected to resistor R6. Pin 5 of the main control chip U1 is connected to resistor R7. Resistors R9 and R10 are connected in series and then in parallel with resistor R8. Capacitor C4 and protection diode T1 are connected in parallel and then connected between resistors R8, R9, and R10. The other end of resistor R9 is grounded. Resistors R12 and R14 are connected in parallel to pin 3 of the dual-channel operational amplifier U2A. Input protection diode D2 is connected between resistor R14 and pin 3 of the dual-channel operational amplifier U2A. Resistor R20 is connected to pin 2 of the dual-channel operational amplifier U2A. Input protection diode D3 is connected between resistor R20 and pin 2 of the dual-channel operational amplifier U2A. Resistor R21 is connected between pin 1 and pin 2 of the dual-channel operational amplifier U2A. Capacitors C5 and C6 are connected in parallel to pin 8 of the dual-channel operational amplifier U2A. Capacitors C9 and C10 are connected in parallel to pin 4 of the dual-channel operational amplifier U2A. Resistors R17 and R18 are connected between pin 1 of the dual-channel operational amplifier U2A and pin 6 of the comparator U2B. Capacitor C7 is connected between resistors R17 and R18, with the other end grounded. Capacitor C8 is connected between resistor R18 and pin 6 of the comparator U2B. Pin 5 of the comparator U2B is connected to resistor R13. Resistor R11 is connected between pins 5 and 7 of the comparator U2B. Resistors R15, R16, and R19 are connected in series to pin 7 of comparator U2B, with the other end grounded. Pin 4 of the main control chip U1 is connected to comparator U2B, and pin 2 of the main control chip U1 is connected to dual-channel operational amplifier U2A.

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