Anti-static switching power supply circuit

Abstract

The utility model discloses a switch power supply circuit of preventing static, including input module, power control module, transformer T1 and output module, the output of input module is divided into two ways, one way is connected with the input of power control module, and the other way is connected with the primary side winding of transformer T1, and the output of power control module is connected with the primary side winding of transformer T1, and the secondary side winding of transformer T1 is connected with output module, and the discharge needle X3 is connected between output module and input module, when static electricity occurs, static electricity pulse enters from the output of output module, then flows into input module through discharge needle X3, makes static electricity pulse to have clear, low impedance's discharge path, avoids static electricity to accumulate in the power supply inside, effectively reduces the impact risk of static electricity to control chip, and promotes circuit anti static interference ability.

Description

Technical Field

[0001] This utility model relates to a protection circuit device, and more particularly to an anti-static circuit. Background Technology

[0002] A switching power supply mainly consists of an input rectifier and filter circuit, a power conversion circuit, a PWM controller circuit, and an output rectifier and filter circuit. To improve circuit safety, multiple protection circuits are typically included, such as input over / under voltage protection, output over / under voltage protection, output overcurrent protection, and output short-circuit protection. However, its electrostatic discharge (ESD) protection is relatively weak. Without ESD protection, electrostatic pulses can easily penetrate the internal circuitry through the power output, potentially damaging the control chip and MOSFETs in the power conversion circuit, resulting in overall circuit failure and poor ESD immunity. Utility Model Content

[0003] In order to overcome the shortcomings of the prior art, this utility model provides an anti-static switching power supply circuit.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] An anti-static switching power supply circuit includes an input module, a power control module, a transformer T1, and an output module. The output terminal of the input module is divided into two paths: one path is connected to the input terminal of the power control module, and the other path is connected to the primary winding of the transformer T1. The output terminal of the power control module is connected to the primary winding of the transformer T1, and the secondary winding of the transformer T1 is connected to the output module. A discharge needle X3 is connected between the output module and the input module.

[0006] The input module includes a rectifier bridge BD1 and a discharge controller U1. The input terminal of the rectifier bridge BD1 is connected to the live wire L and the neutral wire N of the mains power. A varistor MOV1 is connected between the live wire L and the neutral wire N. A fuse F1 is connected in series with the live wire L. A capacitor CX1 is connected in parallel with the input terminal of the rectifier bridge BD1. The discharge pin of the discharge controller U1 is connected in parallel across the two ends of the capacitor CX1.

[0007] Pin 2 of the rectifier bridge BD1 is connected to pin 4 of the common-mode inductor LF1, pin 3 of the rectifier bridge BD1 is connected to pin 2 of the common-mode inductor LF1, a capacitor CX1 is connected between pin 1 and pin 3 of the common-mode inductor LF1, and a thermistor RT1 is connected in series with pin 1 of the common-mode inductor LF1; pins 1-4 of the discharge controller U1 are connected to one side of the capacitor CX1 through resistors RX1 and RX3 in parallel, and pins 5-8 of the discharge controller U1 are connected to the other side of the capacitor CX1 through resistors RX2 and RX4 in parallel.

[0008] The power control module includes a control chip U2. Pin 5 of the control chip U2 is split into two paths: one path connects to the output of the rectifier bridge BD1 via resistor R4, and the other path connects to pin 5 of the transformer T1 via switching diode D3, resistor R6, and switching diode D2. Pin 3 of the control chip U2 is also split into two paths: one path connects to pin 5 of the transformer T1 via resistor R13, and the other path connects to ground via resistor R14. Pin 2 of the control chip U2 is connected to the optocoupler U2A via resistor R12, and pin 1 of the control chip U2 is grounded. A capacitor C3 is connected between pin 1 and pin 2 of the control chip U2; pin 6 of the control chip U2 is connected to pin 1 of transistor Q1 through resistor R8; pin 2 of transistor Q1 is connected to pin 3 of transformer T1; pin 3 of transistor Q1 is divided into two paths, one path is connected to pin 1 of transistor Q1 through resistor R10, and the other path is grounded through resistor RS1; pin 4 of the control chip U2 is divided into two paths, one path is connected to pin 3 of transistor Q1 through resistor R11, and the other path is grounded through capacitor C4.

[0009] A filter circuit is connected between the output terminal of the input module and the primary winding of the transformer T1. The filter circuit includes a capacitor C1, resistors R1, R1A, R1B, R2, R2A, R2B, and a fast recovery diode D1.

[0010] The output module includes a resistor R15, a capacitor C5, a Schottky diode D5, an electrolytic capacitor EC4, an electrolytic capacitor EC5, and a common-mode inductor LF2. The 8th pin of the transformer T1 is connected to the 4th pin of the common-mode inductor LF2 through the Schottky diode D5. A resistor R15 and a capacitor C5 for filtering are connected in parallel across the two ends of the Schottky diode D5. The 7th pin of the transformer T1 is divided into two paths, one grounded and the other connected to the 3rd pin of the common-mode inductor LF2. The 7th and 8th pins of the transformer T1 form the secondary winding. An electrolytic capacitor EC4 is connected in parallel between the 3rd and 4th pins of the common-mode inductor LF2.

[0011] The first and second pins of the common mode inductor LF2 are connected to one side of the discharge pin X3, and the other side of the discharge pin X3 is connected to the third pin of the rectifier bridge BD1.

[0012] The beneficial effects of this utility model are as follows: This utility model includes an input module, a power control module, a transformer T1, and an output module. The output terminal of the input module is divided into two paths: one path is connected to the input terminal of the power control module, and the other path is connected to the primary winding of the transformer T1. The output terminal of the power control module is connected to the primary winding of the transformer T1, and the secondary winding of the transformer T1 is connected to the output module. A discharge needle X3 is connected between the output module and the input module. When static electricity occurs, the static pulse enters from the output terminal of the output module and then flows into the input module through the discharge needle X3, providing a clear and low-impedance discharge path for the static pulse. This avoids the accumulation of static electricity inside the power supply, effectively reducing the risk of static electricity impacting the control chip and improving the circuit's anti-static interference capability. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0014] Figure 1 This is the circuit schematic diagram of this utility model. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features of the present utility model can be combined with each other.

[0016] It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this invention.

[0017] The following describes some embodiments of the present invention with reference to the accompanying drawings.

[0018] Reference Figure 1An anti-static switching power supply circuit includes an input module, a power control module, a transformer T1, and an output module. The output terminal of the input module is divided into two paths: one path is connected to the input terminal of the power control module, and the other path is connected to the primary winding of the transformer T1. The output terminal of the power control module is connected to the primary winding of the transformer T1, and the secondary winding of the transformer T1 is connected to the output module. A discharge needle X3 is connected between the output module and the input module. When static electricity occurs, the static pulse enters from the output terminal of the output module and then flows into the input module through the discharge needle X3, providing a clear, low-impedance discharge path for the static pulse. This prevents static electricity from accumulating inside the power supply, effectively reducing the risk of static electricity impacting the control chip and improving the circuit's anti-static interference capability.

[0019] The transformer T1 has its primary winding consisting of pins 1 and 3, its auxiliary winding consisting of pins 2 and 5, and its secondary winding consisting of pins 7 and 8.

[0020] The input module includes a rectifier bridge BD1 and a discharge controller U1. The input terminals of the rectifier bridge BD1 are connected to the live wire L and the neutral wire N of the mains power supply. A varistor MOV1 is connected between the live wire L and the neutral wire N. A fuse F1 is connected in series with the live wire L. A capacitor CX1 is connected in parallel with the input terminals of the rectifier bridge BD1. The discharge pin of the discharge controller U1 is connected in parallel across the two ends of the capacitor CX1. When the device is in standby mode, the discharge controller U1 discharges the capacitor CX1, quickly releasing the residual charge on the capacitor CX1, thereby avoiding residual charge on the live wire and neutral wire terminals, reducing the risk of electric shock, and improving electrical safety.

[0021] In this embodiment, the discharge controller U1 is model LN9901, which is an automatic discharge control chip specifically designed for X-capacitor systems. This chip has a highly reliable AC power calibration system, which can automatically discharge the X capacitor after the system is powered off to meet safety requirements, discharging the voltage below the allowable voltage. Furthermore, it automatically remains in a non-operating state during normal operation, maintaining power consumption at no more than 5mW, thus achieving a zero-power X-capacitor system.

[0022] Pin 2 of the rectifier bridge BD1 is connected to pin 4 of the common-mode inductor LF1, and pin 3 of the rectifier bridge BD1 is connected to pin 2 of the common-mode inductor LF1. A capacitor CX1 is connected between pins 1 and 3 of the common-mode inductor LF1, and a thermistor RT1 is connected in series with pin 1 of the common-mode inductor LF1. Pins 1-4 of the discharge controller U1 are connected to one side of capacitor CX1 through parallel resistors RX1 and RX3, and pins 5-8 of the discharge controller U1 are connected through parallel resistors RX2 and RX3. Resistor RX4 is connected to the other side of capacitor CX1. When the equipment is working, if the discharge controller U1 detects that the voltage on the live wire L and the neutral wire N is normal, the discharge controller U1 will automatically remain in a non-working state, that is, the discharge pin will be in an open circuit state, which will not affect the circuit. However, when the discharge controller U1 detects a drop in the voltage on the live wire L and the neutral wire N or a power outage, the discharge controller U1 will automatically start and discharge capacitor CX1 through a circuit formed by resistors RX1, RX3, RX2, and RX4, thereby avoiding charge residue on the live wire terminal and the neutral wire terminal and reducing the risk of electric shock.

[0023] The power control module includes a control chip U2. Pin 5 of the control chip U2 is divided into two paths: one path connects to the output of rectifier bridge BD1 via resistor R4, providing the DC power for the control chip U2's startup; the other path connects to pin 5 of transformer T1 via switching diode D3, resistor R6, and switching diode D2. Transformer T1's pin 5 steps down the high-voltage DC power to provide operating power for the control chip U2. Pin 3 of the control chip U2 is also divided into two paths: one path connects to pin 5 of transformer T1 via resistor R13, used to acquire feedback signals from transformer T1. These feedback signals reflect the transformer's operating status and output voltage and current information; the other path connects to ground via resistor R14. Pin 2 of the control chip U2 is connected to optocoupler U2A via resistor R12, primarily for transmitting feedback signals. Specifically, the optocoupler... Optocoupler U2A and optocoupler U2B are combined into a single optocoupler. The feedback acquisition terminal of optocoupler U2B is connected to the output module. When the output voltage changes, it is transmitted back to control chip U2 through the optocoupler. Control chip U2 makes appropriate adjustments based on the output voltage. Pin 1 of control chip U2 is grounded, and capacitor C3 is connected between pin 1 and pin 2 of control chip U2. Pin 6 of control chip U2 is connected to pin 1 of transistor Q1 through resistor R8. Pin 2 of transistor Q1 is connected to pin 3 of transformer T1. Pin 3 of transistor Q1 is split into two paths: one path is connected to pin 1 of transistor Q1 through resistor R10, and the other path is grounded through resistor RS1. Pin 4 of control chip U2 is split into two paths: one path is connected to pin 3 of transistor Q1 through resistor R11, and the other path is grounded through capacitor C4. In this embodiment, pin 5 of the control chip U2 is the chip power supply pin. In this embodiment, pin 6 of the control chip U2 is used to output a drive signal to control the conduction and cutoff of transistor Q1. When the drive signal is high, transistor Q1 is turned on, and current flows through the primary winding of transformer T1. When the drive signal is low, transistor Q1 is cut off, cutting off the current in the primary winding.

[0024] A filter circuit is connected between the output terminal of the input module and the primary winding of the transformer T1. The filter circuit includes a capacitor C1, a resistor R1, a resistor R1A, a resistor R1B, a resistor R2, a resistor R2A, a resistor R2B, and a fast recovery diode D1. The filter circuit filters the voltage of the primary winding of the transformer T1 to remove high-frequency noise and ensure that the voltage input to the transformer T1 is relatively smooth.

[0025] The output module includes a resistor R15, a capacitor C5, a Schottky diode D5, an electrolytic capacitor EC4, an electrolytic capacitor EC5, and a common-mode inductor LF2. Pin 8 of the transformer T1 is connected to pin 4 of the common-mode inductor LF2 via the Schottky diode D5. A resistor R15 and a capacitor C5 for filtering are connected in parallel across the Schottky diode D5. Pin 7 of the transformer T1 is split into two paths: one grounded, and the other connected to pin 3 of the common-mode inductor LF2. Pins 7 and 8 of the transformer T1 form the secondary winding. An electrolytic capacitor EC4 is connected in parallel between pins 3 and 4 of the common-mode inductor LF2. Pins 1 and 2 of the common-mode inductor LF2 are connected to one side of a discharge pin X3, and the other side of the discharge pin X3 is connected to pin 3 of the rectifier bridge BD1. When an electrostatic pulse enters from the output terminal of the output module, it can be discharged to the input module through the discharge pin X3, preventing damage to the output load and circuitry caused by static electricity.

[0026] Although embodiments of the present invention have been shown and described, those skilled in the art will understand 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 claims and their equivalents.

Claims

1. An anti-static switching power supply circuit, characterized in that... It includes an input module, a power control module, a transformer T1, and an output module. The output terminal of the input module is divided into two paths: one path is connected to the input terminal of the power control module, and the other path is connected to the primary winding of the transformer T1. The output terminal of the power control module is connected to the primary winding of the transformer T1, and the secondary winding of the transformer T1 is connected to the output module. A discharge needle X3 is connected between the output module and the input module.

2. The anti-static switching power supply circuit according to claim 1, characterized in that... The input module includes a rectifier bridge BD1 and a discharge controller U1. The input terminal of the rectifier bridge BD1 is connected to the live wire L and the neutral wire N of the mains power. A varistor MOV1 is connected between the live wire L and the neutral wire N. A fuse F1 is connected in series with the live wire L. A capacitor CX1 is connected in parallel with the input terminal of the rectifier bridge BD1. The discharge pin of the discharge controller U1 is connected in parallel across the two ends of the capacitor CX1.

3. The anti-static switching power supply circuit according to claim 2, characterized in that... Pin 2 of the rectifier bridge BD1 is connected to pin 4 of the common-mode inductor LF1, pin 3 of the rectifier bridge BD1 is connected to pin 2 of the common-mode inductor LF1, a capacitor CX1 is connected between pin 1 and pin 3 of the common-mode inductor LF1, and a thermistor RT1 is connected in series with pin 1 of the common-mode inductor LF1; pins 1-4 of the discharge controller U1 are connected to one side of the capacitor CX1 through resistors RX1 and RX3 in parallel, and pins 5-8 of the discharge controller U1 are connected to the other side of the capacitor CX1 through resistors RX2 and RX4 in parallel.

4. The anti-static switching power supply circuit according to claim 1, characterized in that... The power control module includes a control chip U2. Pin 5 of the control chip U2 is split into two paths: one path connects to the output of the rectifier bridge BD1 via resistor R4, and the other path connects to pin 5 of the transformer T1 via switching diode D3, resistor R6, and switching diode D2. Pin 3 of the control chip U2 is also split into two paths: one path connects to pin 5 of the transformer T1 via resistor R13, and the other path connects to ground via resistor R14. Pin 2 of the control chip U2 is connected to the optocoupler U2A via resistor R12, and pin 1 of the control chip U2 is grounded. A capacitor C3 is connected between pin 1 and pin 2 of the control chip U2; pin 6 of the control chip U2 is connected to pin 1 of transistor Q1 through resistor R8; pin 2 of transistor Q1 is connected to pin 3 of transformer T1; pin 3 of transistor Q1 is divided into two paths, one path is connected to pin 1 of transistor Q1 through resistor R10, and the other path is grounded through resistor RS1; pin 4 of the control chip U2 is divided into two paths, one path is connected to pin 3 of transistor Q1 through resistor R11, and the other path is grounded through capacitor C4.

5. The anti-static switching power supply circuit according to claim 1, characterized in that... A filter circuit is connected between the output terminal of the input module and the primary winding of the transformer T1. The filter circuit includes a capacitor C1, resistors R1, R1A, R1B, R2, R2A, R2B, and a fast recovery diode D1.

6. The anti-static switching power supply circuit according to claim 1, characterized in that... The output module includes a resistor R15, a capacitor C5, a Schottky diode D5, an electrolytic capacitor EC4, an electrolytic capacitor EC5, and a common-mode inductor LF2. The 8th pin of the transformer T1 is connected to the 4th pin of the common-mode inductor LF2 through the Schottky diode D5. A resistor R15 and a capacitor C5 for filtering are connected in parallel across the two ends of the Schottky diode D5. The 7th pin of the transformer T1 is divided into two paths, one grounded and the other connected to the 3rd pin of the common-mode inductor LF2. The 7th and 8th pins of the transformer T1 form the secondary winding. An electrolytic capacitor EC4 is connected in parallel between the 3rd and 4th pins of the common-mode inductor LF2.

7. The anti-static switching power supply circuit according to claim 6, characterized in that... The first and second pins of the common mode inductor LF2 are connected to one side of the discharge pin X3, and the other side of the discharge pin X3 is connected to the third pin of the rectifier bridge BD1.

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