Protection circuit for high-voltage input linear voltage stabilizing circuit

Abstract

The utility model relates to the technical field of circuit protection, in particular to a protection circuit for a high-voltage input linear voltage stabilizing circuit, which comprises a linear voltage stabilizing circuit, a rectifying circuit and a protection circuit, and is characterized in that the rectifying circuit is connected with an auxiliary winding T1-C of a transformer; the linear voltage stabilizing circuit comprises a resistor R4, an MOS tube Q1 and a voltage stabilizing diode Z1. A D end of the MOS tube Q1 inputs a voltage VIN end, a G end of the MOS tube Q1 is connected with one end of the resistor R4, the other end of the resistor R4 is connected with the input voltage VIN end, one end of the voltage stabilizing diode Z1 is connected with the G end of the MOS tube Q1, and the other end of the voltage stabilizing diode Z1 is grounded. According to the utility model, the operational amplifier is adopted, the charging and discharging characteristics of the capacitor through the resistor are utilized, the linear voltage-stabilizing field-effect tube is protected, the design is simple, the application range is wide, the circuit is suitable for protection of a high-voltage input linear voltage-stabilizing starting circuit, and the size of the linear voltage-stabilizing field-effect tube can be effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of circuit protection technology, specifically a high-voltage input linear voltage regulator circuit protection circuit. Background Technology

[0002] High-voltage input power supplies typically employ linear voltage regulator circuits to power the chips during startup. After the control chip starts up, power is supplied to the chip and other control circuits via the auxiliary winding of a transformer. When the control chip is externally disabled or the power module output is short-circuited, the auxiliary winding has no voltage output. The linear voltage regulator circuit, supplying power to the system continuously, consumes a large amount of power and faces a significant risk of burnout.

[0003] To address the aforementioned problems, we propose a high-voltage input linear regulator circuit protection circuit. Utility Model Content

[0004] The purpose of this invention is to provide a protection circuit for a high-voltage input linear regulator circuit to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A protection circuit for a high-voltage input linear regulator circuit, comprising:

[0007] A linear voltage regulator circuit, a rectifier circuit, and a protection circuit, wherein the rectifier circuit is connected to the auxiliary winding T1-C of the transformer;

[0008] The linear voltage regulator circuit includes:

[0009] Resistor R4, MOSFET Q1, Zener diode Z1;

[0010] The drain terminal of the MOSFET Q1 is connected to the input voltage VIN terminal. The gate terminal of the MOSFET Q1 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the input voltage VIN terminal. One end of the Zener diode Z1 is connected to the gate terminal of the MOSFET Q1, and the other end is grounded.

[0011] Preferably, the rectifier circuit includes:

[0012] Rectifier diodes D2 and D3, and capacitor C5;

[0013] One end of the rectifier diode D2 is connected to the source terminal of the MOSFET Q1, and the other end is connected to the rectifier diode D3. One end of the capacitor C5 is connected between the rectifier diodes D2 and D3, and the other end is grounded.

[0014] Preferably, one end of the auxiliary winding T1-C of the transformer is connected to the rectifier diode D3, and the other end is grounded.

[0015] Preferably, the protection circuit includes an operational amplifier U1, a MOSFET Q2, a rectifier diode D1, resistors R1, R2, R3, R5, and R6, and capacitors C1, C2, C3, and C4.

[0016] Preferably, the non-inverting input terminal of the operational amplifier U1 is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to the VCC voltage terminal.

[0017] Preferably, the inverting input terminal of the operational amplifier U1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the voltage reference source VREF terminal.

[0018] Preferably, one end of the resistor R3 and one end of the capacitor C1 are connected between the resistor R1 and the non-inverting input terminal of the operational amplifier U1, and the other end of the resistor R3 and the capacitor C1 are grounded.

[0019] One end of the capacitor C2 is connected between the resistor R2 and the inverting input of the operational amplifier U1, and the other end of the capacitor C2 is grounded.

[0020] Preferably, the output terminal of the operational amplifier U1 is connected to one end of the rectifier diode D1, the other end of the rectifier diode D1 is connected to the resistor R5, and one end of the resistor R5 is connected to the source of the MOS transistor Q2.

[0021] Preferably, one end of the capacitor C4 and the resistor R6 are both connected between the resistor R5 and the source of the MOS transistor Q2, and the other end is grounded.

[0022] Preferably, the source of the MOS transistor Q2 is grounded, and the drain of the MOS transistor Q2 is connected between the resistor R4 and the G terminal of the MOS transistor Q1.

[0023] Compared with the prior art, the beneficial effects of this utility model are:

[0024] This invention addresses the problem of high losses and easy damage in linear voltage regulator circuits during control chip protection by proposing a high-voltage input linear voltage regulator circuit protection circuit.

[0025] This invention employs an operational amplifier and utilizes the charging and discharging characteristics of a capacitor through a resistor to protect a linear Zener MOSFET.

[0026] This invention features a simple design and wide range of applications. It is suitable for use in high-voltage input linear regulator start-up circuit protection and can effectively reduce the size of the linear regulator MOSFET. Attached Figure Description

[0027] Figure 1This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0028] 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.

[0029] Example 1:

[0030] Please see Figure 1 A high-voltage input linear regulator circuit protection circuit includes:

[0031] The circuit includes a linear voltage regulator circuit, a rectifier circuit, and a protection circuit, wherein the rectifier circuit is connected to the auxiliary winding T1-C of the transformer.

[0032] VREF is the voltage reference source, VIN is the input voltage, VCC is the supply voltage after linear regulation and bucking, D1, D2, and D3 are rectifier diodes, Q1 and Q2 are N-channel MOSFETs, U1 is the operational amplifier, Z1 is the Zener diode, and T1-C are the auxiliary windings of the transformer. VREF establishes a stable 2.5V through VCC. When the voltage at the non-inverting input of the operational amplifier is greater than the voltage at the inverting input, the operational amplifier outputs a high level; when the voltage at the non-inverting input is less than the voltage at the inverting input, the operational amplifier outputs a low level.

[0033] Example 2:

[0034] Based on Embodiment 1, a linear voltage regulator circuit is further disclosed.

[0035] like Figure 1 As shown, the linear voltage regulator circuit includes:

[0036] Resistor R4, MOSFET Q1, Zener diode Z1;

[0037] The drain terminal of the MOSFET Q1 is connected to the input voltage VIN terminal. The gate terminal of the MOSFET Q1 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the input voltage VIN terminal. One end of the Zener diode Z1 is connected to the gate terminal of the MOSFET Q1, and the other end is grounded.

[0038] In the above embodiments, further:

[0039] A linear voltage regulator circuit is formed by resistor R4, MOSFET Q1, and Zener diode Z1, which serves to protect against overvoltage and reverse connection.

[0040] Example 3:

[0041] Based on Embodiment 1, a rectifier circuit is further disclosed.

[0042] like Figure 1 As shown, the rectifier circuit includes:

[0043] Rectifier diodes D2 and D3, and capacitor C5;

[0044] One end of the rectifier diode D2 is connected to the S terminal of the MOSFET Q1, and the other end is connected to the rectifier diode D3. One end of the capacitor C5 is connected between the rectifier diodes D2 and D3, and the other end is grounded. One end of the auxiliary winding T1-C of the transformer is connected to the rectifier diode D3, and the other end is grounded.

[0045] In the above embodiments, further:

[0046] When the VIN input voltage is established, R4, Q1, and Z1 form a linear voltage regulator circuit. When the VCC voltage is established, the PWM control chip works, outputting a drive signal to the main circuit. The auxiliary winding T1-C outputs voltage through D3, raising the VCC voltage so that the VGS of Q1 is less than the turn-on threshold. The current flowing through Q1 is cut off. When external interference or output short circuit occurs, and there is no voltage on the winding of T1-C, the chip is powered by the linear voltage regulator circuit.

[0047] Example 4:

[0048] Based on Embodiment 1, a protection circuit is further disclosed.

[0049] like Figure 1As shown, the protection circuit includes an operational amplifier U1, a MOSFET Q2, a rectifier diode D1, resistors R1, R2, R3, R5, and R6, and capacitors C1, C2, C3, and C4. The non-inverting input of the operational amplifier U1 is connected to one end of resistor R1, and the other end of resistor R1 is connected to the VCC voltage terminal. The inverting input of the operational amplifier U1 is connected to one end of resistor R2, and the other end of resistor R2 is connected to the voltage reference source VREF terminal. One end of resistor R3 and one end of capacitor C1 are both connected between resistor R1 and the non-inverting input of the operational amplifier U1. The other end is grounded; one end of capacitor C2 is connected between resistor R2 and the inverting input terminal of operational amplifier U1, and the other end of capacitor C2 is grounded. The output terminal of operational amplifier U1 is connected to one end of rectifier diode D1, and the other end of rectifier diode D1 is connected to resistor R5. One end of resistor R5 is connected to the source of MOSFET Q2. One end of capacitor C4 and resistor R6 are both connected between resistor R5 and the source of MOSFET Q2, and the other end is grounded. The source of MOSFET Q2 is grounded, and the drain of MOSFET Q2 is connected between resistor R4 and the gate terminal (G) of MOSFET Q1.

[0050] In the above embodiments, further:

[0051] When the VCC voltage exceeds the set value, it is divided by resistors R1 and R3 and supplied to the non-inverting input of the operational amplifier. When it exceeds the VREF voltage of the inverting input, the operational amplifier outputs a high level, charging capacitor C4 through resistor R5. After exceeding the threshold voltage of MOSFET Q2, Q2 turns on, pulling down the gate of Q1 and turning it off, thus interrupting the power supply and reducing the power loss of Q1 to 0W. As the voltage of C4 discharges through resistor R6, when the gate voltage of Q2 falls below the turn-on threshold, Q2 turns off, and Q1 continues to supply power to VCC. As described above, when there is no power supply to the auxiliary winding, the linear regulator operates intermittently. By adjusting the parameters of R5, C4, and R6, the duty cycle of MOSFET Q1 can be adjusted, thereby controlling the circuit power consumption. After the main control chip resumes driving, the circuit can resume normal operation.

[0052] 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 protection circuit for a high-voltage input linear voltage regulator circuit, characterized in that, The application relates to a linear voltage stabilizing circuit, a rectifying circuit and a protection circuit. The linear voltage stabilizing circuit comprises: a resistance R4, a MOS transistor Q1 and a voltage stabilizing diode Z1; the D end of the MOS transistor Q1 is connected with a voltage input end VIN, the G end of the MOS transistor Q1 is connected with one end of the resistance R4, the other end of the resistance R4 is connected with the voltage input end VIN, one end of the voltage stabilizing diode Z1 is connected with the G end of the MOS transistor Q1, and the other end is grounded; the protection circuit comprises an operational amplifier U1, a MOS transistor Q2, a rectifying diode D1, resistances R1, R2, R3, R5 and R6, and capacitors C1, C2, C3 and C4; one end of the resistance R1 is connected with the same-phase input end of the operational amplifier U1, and the other end of the resistance R1 is connected with a VCC voltage end; one end of the resistance R2 is connected with the reverse input end of the operational amplifier U1, and the other end of the resistance R2 is connected with a voltage reference source VREF end; one end of the resistance R3 and one end of the capacitor C1 are both connected between the resistance R1 and the same-phase input end of the operational amplifier U1, and the other ends of the resistance R3 and the capacitor C1 are grounded; one end of the capacitor C2 is connected between the resistance R2 and the reverse input end of the operational amplifier U1, and the other end of the capacitor C2 is grounded; the output end of the operational amplifier U1 is connected with one end of the rectifying diode D1, the other end of the rectifying diode D1 is connected with the resistance R5, and one end of the resistance R5 is connected with the source electrode of the MOS transistor Q2; one end of the capacitor C4 and one end of the resistance R6 are both connected between the resistance R5 and the source electrode of the MOS transistor Q2, and the other ends are grounded; the source electrode of the MOS transistor Q2 is grounded, and the drain electrode of the MOS transistor Q2 is connected between the resistance R4 and the G end of the MOS transistor Q1. The rectifying circuit comprises:

2. The protection circuit for a high-voltage input linear regulator circuit according to claim 1, wherein rectifying diodes D2 and D3 and a capacitor C5; one end of the rectifying diode D2 is connected with the S end of the MOS transistor Q1, the other end of the rectifying diode D2 is connected with the rectifying diode D3, one end of the capacitor C5 is connected between the rectifying diode D2 and the rectifying diode D3, and the other end is grounded. one end of the auxiliary winding T1-C of the transformer is connected with the rectifying diode D3, and the other end is grounded.

3. The protection circuit for a high-voltage input linear voltage regulator circuit according to claim 2, wherein ​

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