Direct-current power supply protection device capable of preventing reverse connection of positive and negative electrodes and preventing static electricity and surge

Abstract

A direct-current power supply protection device capable of preventing reverse connection of positive and negative electrodes and preventing static electricity and surge can be used for preventing reverse connection of positive and negative electrodes, static electricity and surge in a circuit for protecting an input direct-current power supply. The device comprises two positive temperature coefficient thermistors (PTC), a piezoresistor (MOV), a gas discharge tube (GDT), two Schottky diodes (SBD), a transient voltage suppression (TVS) tube and a high-performance TVS tube.

Description

Technical Field

[0001] The present invention is a direct current power supply protection device that can prevent reverse connection of positive and negative poles and take into account anti-static and surge. The device can be connected to the input end of various retail devices to protect the back-end circuit. This device can prevent users from connecting the positive and negative poles in reverse during installation, which may cause damage to the device and unnecessary losses. The device can prevent surges (lightning strikes). When surges (lightning) occur, the normal operation of the device is affected due to unstable power supply or a large amount of induced voltage generated on the power supply line. The device can also prevent static electricity. When the human body touches the electronic equipment, a large amount of static electricity will be generated. Sometimes the static electricity voltage can be as high as thousands of volts, which can easily break down the electronic components and cause the equipment to fail to work normally. Background Art

[0002] With the development of electronic products, some chips are becoming more and more integrated, and the price is getting more and more expensive. Reverse connection of the positive and negative poles of the power supply will cause irreversible permanent damage to the circuit or components. The harm of surge is also relatively large. It may burn the circuit in an instant, causing data loss and equipment damage. Electrostatic discharge can cause electronic components to fail or performance degradation. Power supply protection can ensure the normal operation of the equipment, extend the service life of the device, and improve the safety, reliability and stability of the equipment. The existing anti-reverse connection technology on the market is mainly based on diode anti-reverse connection, which has more or less certain disadvantages: the reverse bias voltage of the diode is low, and when the input voltage is large, the diode may be directly broken down, and the reverse leakage current of the diode is large, that is, the power supply is not completely cut off when reverse connection is made, and a small current will still pass through the circuit without playing the role of power supply protection. Most of the existing lightning protection technologies on the market are to conduct the current generated by the lightning strike into the ground when lightning occurs. This requires the ground resistance to be zero, which has certain requirements for electronic equipment scenarios, but in fact the ground resistance is difficult to be zero, so there will still be a part of the current flowing into the protected circuit, causing the circuit current to be too large, resulting in the circuit protected by the protection device still having a high lightning breakdown rate. Summary of the invention

[0003] The present invention is a DC power supply protection device which can prevent reverse connection of positive and negative poles and take into account anti-static and surge. The device can be used at the input end of various retail devices to protect the back-end circuit. The device can also be used in various circuits that need to protect the input DC power supply. The module can prevent reverse connection of positive and negative poles, anti-static and anti-surge. The power supply device includes 2 positive temperature coefficient thermistors (PTC), 1 varistor (MOV), 1 gas discharge tube (GDT), 2 Schottky diodes (SBD), 1 transient voltage suppression TVS tube and 1 high-performance bidirectional TVS tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Attached Figure 1The meaning of the digital symbols in the module composition diagram of the present invention is: 1. Positive temperature coefficient thermistor, 2. Schottky diode, 3. Positive temperature coefficient thermistor, 4. Schottky diode, 5. Gas discharge tube, 6. Varistor, 7. Transient voltage suppression TVS tube, 8. High-performance bidirectional TVS tube. Specific implementation method The working principle of this device is to connect this device to the input end of the DC power supply. When the positive and negative poles of the power supply are accidentally connected in reverse by manual operation, the input power supply and the back-end power supply circuit are separated by the principle of forward conduction and reverse cutoff of Schottky diode (SBD). Due to the existence of gas discharge tube (GDT), the entire circuit is in a disconnected state, thereby playing a protective role. When a surge (lightning) occurs, the nonlinear characteristics of the varistor (MOV) are used. When the circuit is subjected to overvoltage, the varistor can clamp the voltage to a relatively fixed voltage value. At the same time, the transient voltage suppression TVS tube and the high-performance bidirectional TVS tube simultaneously clamp the two-level voltage at a certain specific value to prevent the surge from causing power instability and impacting the back power supply circuit. When static electricity occurs, there are many forms of static electricity. The voltage may be too high instantly, and the protection is similar to that of lightning strikes. The current may be very large instantly, and the PTC current protection device will take effect at this time. The relationship between the resistance value and temperature of the PTC device is used. The resistance value increases with the increase of temperature to prevent circuit overload and short circuit.

Claims

1. A DC power supply protection device for preventing positive and negative pole reverse connection and taking into account anti-static and surge, characterized in that: This device can be applied to the DC power input end of various retail equipment to protect the back-end circuit. This device can prevent users from connecting the positive and negative poles in reverse during installation, which may damage the device and cause unnecessary losses. This device can also prevent surges (lightning strikes). When lightning occurs, the power supply is unstable or a large amount of induced voltage is generated on the power supply line, affecting the normal operation of the power supply. This circuit can also prevent static electricity. When the human body touches electronic equipment, a large amount of static electricity is generated. Sometimes the static electricity voltage can be as high as thousands of volts, which can easily break down components and cause the circuit to malfunction. As electronic products become increasingly diversified and complex, the use environment becomes more diverse and complex, making power protection devices very important.

2. A DC power supply protection device for preventing positive and negative pole reverse connection and taking into account anti-static and surge protection according to claim 1, characterized in that: When the positive and negative power supplies are accidentally connected in reverse by manual operation, the SBD tube uses the principle of forward conduction and reverse cutoff to separate the input power supply from the back-end power supply circuit. Due to the presence of the MOV gas discharge tube, the entire circuit is in an open-circuit state, which plays a role in power supply protection.

3. A DC power supply protection device for preventing positive and negative pole reverse connection and taking into account anti-static and surge protection according to claim 1, characterized in that: When a surge (lightning) occurs, the GDT varistor uses its voltage clamping to absorb excess current to protect sensitive devices when the circuit is subjected to overvoltage. At the same time, the transient voltage suppression diode and the high-performance bidirectional TVS diode clamp the two-level voltage at a certain value to prevent the surge from causing power instability and impacting the subsequent power supply circuit.

4. A DC power supply protection device for preventing positive and negative pole reverse connection and taking into account anti-static and surge protection according to claim 1, characterized in that :When static electricity occurs, static electricity discharge can instantly generate high voltage. This situation is similar to the lightning phenomenon. When static electricity occurs, static electricity discharge instantly generates high current. At this time, the characteristics of the PTC current protection device come into play. The relationship between the resistance value and temperature of the PTC is used. The resistance value increases with the increase of temperature to prevent circuit overload, short circuit, etc.

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