Overvoltage surge protection circuit

Abstract

The utility model provides an overvoltage surge protection circuit. A first end of a resistor R1 is connected with Vin +, a second end is connected with a negative electrode of a Zener diode D1, a positive electrode is connected with Vin-, the second end is connected with a base electrode of a triode V2 through a resistor R2, an emitter electrode is connected with Vin +, and a collector electrode is connected with a first end of a resistor R5; the cathode of the voltage stabilizing diode D2 is connected with Vin +, and the anode is connected with the collector of the triode V2; the second end of the resistor R5 is connected with the Vin-through a resistor R6 and is connected to the grid electrode of the PMOS tube V1 through a resistor R4, the source electrode is connected with the Vin +, and the drain electrode is connected with the Vout +; the drain electrode of the PMOS tube is connected with the first end of a resistor R8, and the second end of the resistor R8 is connected with Vin-through a resistor R10; the two ends of the resistor R10 are connected with a capacitor C5 and a voltage stabilizing diode D4 in The overvoltage protection circuit has good overvoltage protection, surge suppression and reverse connection protection functions.

Description

TECHNICAL FIELD

[0001] The utility model mainly relates to the protection circuit technical field, especially relates to a overvoltage surge protection circuit. BACKGROUND

[0002] With the application demand of domesticization, miniaturization, high power density power supply, in order to meet the high reliability power supply equipment safety and stability of operation, it is necessary to involve overvoltage, reverse connection, surge protection and other measures in power supply equipment to improve the reliability and stability of power supply.

[0003] When the output voltage of switching power supply is too high and is higher than the maximum voltage that the power equipment can bear, it may cause serious damage to the output load power equipment, such as burning circuit board, burning element or causing device failure, etc. The overvoltage protection circuit can monitor that the power supply voltage exceeds the rated safety range, and take protective measures quickly to avoid abnormal failure of the power equipment.

[0004] Reverse connection protection is mainly to prevent the positive and negative poles of the power supply from being connected in reverse, to ensure that the components in the power supply equipment and the power equipment are not damaged. When the positive and negative poles of the power supply are connected in reverse, the diode will be reverse-biased and cut off the power supply circuit to prevent current from passing through, so as to protect the safety of the power supply and the power equipment.

[0005] Surge current suppression is mainly to protect the power equipment from damage caused by surge current at the moment of starting, to protect electronic components and prolong the service life. When there is a large capacitive load at the power supply load end, the surge suppression resistor at the input end suppresses the current amplitude and absorbs excess energy, thereby protecting the power equipment. When the output starts to charge the capacitive load device, the output starting moment current is large, which may cause the input switch to trip, the output voltage to drop, a high peak current to be generated, and the power supply equipment to output overcurrent protection, thereby interrupting the power supply of the equipment and stopping the output load.

[0006] The output voltage of the switching power supply running for a long time at the rated maximum voltage of the power equipment will shorten the service life of the electrical equipment. The overvoltage protection circuit can detect the overvoltage condition in time and cut off the power supply connection to prevent the equipment from running in a high voltage environment for a long time, thereby prolonging the service life of the equipment. High voltage may cause line overload and overheating of power equipment components, increasing the risk of failure. Surge protection suppresses the output starting moment current to protect the line from failure risk caused by overload and overheating, thereby prolonging the service life of the power supply and the power equipment.

[0007] How to optimize the protection circuit, improve the performance of the protection circuit and prolong the service life of the protection circuit has been the goal pursued by the field. UTILITY MODEL CONTENTS

[0008] The utility model wants to solve the technical problem to provide a kind of overvoltage surge protection circuit, it has good overvoltage protection, surge suppression and reverse connection protection function.

[0009] To solve the above technical problem, the utility model provides an overvoltage surge protection circuit, comprising: resistance R1, its first end is connected Vin+, second end is connected the negative pole of stabilizing voltage diode D1, the positive pole of stabilizing voltage diode D1 is connected Vin-, the second end of resistance R1 is connected triode V2 base through resistance R2, the emitter of triode V2 is connected Vin+, the first end of resistance R5 is connected the collector of triode V2, be provided with stabilizing voltage diode D2, the negative pole of stabilizing voltage diode D2 is connected Vin+, the positive pole is connected the collector of triode V2, the second end of resistance R5 is connected Vin- through resistance R6, is connected to PMOS tube V1 gate through resistance R4, the source of PMOS tube is connected Vin+, the drain is connected Vout+, the drain of PMOS tube is connected the first end of resistance R8, the second end of resistance R8 is connected Vin- through resistance R10, the both ends of resistance R10 are connected capacitor C5 and parallel stabilizing voltage diode D4, wherein the positive pole of stabilizing voltage diode D4 is connected Vin-, the positive pole of stabilizing voltage diode D4 is connected to the first end of resistance R7, the second end of resistance R7 is connected the positive pole of diode D5, the negative pole of diode D5 is connected Vout-, the node between resistance R8 and resistance R10 is connected to NMOS tube V3 gate through resistance R11, the source of NMOS tube is connected Vin-, the drain is connected Vout-.

[0010] Optionally, further comprising capacitor C4, the capacitor C4 is connected in parallel at the both ends of the stabilizing voltage diode D1.

[0011] Optionally, further comprising resistance R3 and capacitor C1 constitute parallel branch, and the parallel branch is connected in parallel at the both ends of the stabilizing voltage diode D2.

[0012] Optionally, further comprising diode D3, the positive pole of diode D3 is connected to Vout+, and the negative pole is connected to the first end of resistance R8.

[0013] Compared with prior art, the utility model has the following beneficial effects: the protection circuit has good overvoltage protection, surge suppression and reverse connection protection and other functions, compared with the application diode protection under the same function has the advantages such as small pressure drop, high efficiency and large output power. BRIEF DESCRIPTION OF DRAWINGS

[0014] The accompanying drawings are included to provide a further understanding of the utility model, and they are incorporated and constitute a part of the utility model, and the accompanying drawings show the embodiments of the utility model, and together with the specification, they play the role of explaining the principle of the utility model.The accompanying drawings are as follows:

[0015] Figure 1 is a structural schematic view of an overvoltage surge protection circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some examples or embodiments of the present application, and for those skilled in the art, the present application can also be applied to other similar scenarios without creative labor on the basis of these drawings. Unless it is obvious from the language environment or otherwise stated, the same reference numerals in the drawings represent the same structure or operation.

[0017] It should be understood that when a component is referred to as being "on", "connected to", "coupled to", or "contacting" another component, it can be directly on, connected to, coupled to, or contacting the other component, or intervening components can be present. In contrast, when a component is referred to as being "directly on", "directly connected to", "directly coupled to", or "directly contacting" another component, there are no intervening components present. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows electrical current to flow. The electrical path can include capacitors, coupled inductors, and / or other components that allow electrical current to flow, even if there is no direct contact between conductive components.

[0018] Reference Figure 1As shown, the overvoltage surge protection circuit provided by the embodiment includes: a resistor R1, a first end of which is connected to Vin+, a second end of which is connected to a negative electrode of a voltage stabilizing diode D1, and a positive electrode of the voltage stabilizing diode D1 is connected to Vin-; the second end of the resistor R1 is connected to a base of a triode V2 through a resistor R2, an emitter of the triode V2 is connected to Vin+, and a collector is connected to a first end of a resistor R5. A voltage stabilizing diode D2 is arranged, a negative electrode of the voltage stabilizing diode D2 is connected to Vin+, and a positive electrode is connected to a collector of the triode V2. A second end of the resistor R5 is connected to Vin- through a resistor R6 and to a gate of a PMOS V1 through a resistor R4, a source of the PMOS is connected to Vin+, and a drain is connected to Vout+. The drain of the PMOS is connected to a first end of a resistor R8, and a second end of the resistor R8 is connected to Vin- through a resistor R10. Capacitors C5 and voltage stabilizing diodes D4 are connected in parallel across the resistor R10, and a positive electrode of the voltage stabilizing diode D4 is connected to Vin-. The positive electrode of the voltage stabilizing diode D4 is connected to a first end of a resistor R7, a positive electrode of a diode D5 is connected to a second end of the resistor R7, and a negative electrode of the diode D5 is connected to Vout-. A node between the resistor R8 and the resistor R10 is connected to a gate of an NMOS V3 through a resistor R11, a source of the NMOS is connected to Vin-, and a drain is connected to Vout-.

[0019] In the embodiment, the overvoltage protection mainly prevents the output voltage from exceeding the maximum safe voltage value of the power consuming device, thereby protecting the power consuming device in the rear stage from being damaged and improving the reliability of the power supply device. The input voltage is clamped by the voltage stabilizing diode D1, and when the output voltage exceeds the conduction voltage of the voltage stabilizing diode D1, the triode V2 is used as a switch to turn off the PMOS, start the overvoltage protection circuit, and turn off the output, so as to limit the output voltage within a safe voltage range.

[0020] The surge protection can effectively inhibit the sudden current impact, guarantee the stable operation of the circuit, prevent the current from being too large at the starting moment to cause the current limiting protection of the power supply device or the input switch tripping and other abnormalities. The series connection of the cement resistor or the wire-wound resistor in the power loop can effectively inhibit the current impact at the starting moment of the input voltage, protect the power consuming device from being damaged, and interrupt the power supply of the power supply device.

[0021] More preferably, the protection circuit of the embodiment further includes a capacitor C4 connected in parallel across the voltage stabilizing diode D1.

[0022] More preferably, the protection circuit of the embodiment further includes a parallel branch composed of a resistor R3 and a capacitor C1, and the parallel branch is connected in parallel across the voltage stabilizing diode D2.

[0023] More preferably, the protection circuit of the embodiment further includes a diode D3, a positive electrode of which is connected to Vout+, and a negative electrode of which is connected to a first end of the resistor R8.

[0024] In particular, reference is made to Figure 1

[0025] For the first circuit unit A1, in order to make the voltage stabilizing diode D1 play a voltage stabilizing role, it is usually reversed in the circuit, that is, the negative electrode is connected to the high potential and the positive electrode is connected to the low potential. In this configuration, the voltage stabilizing diode D1 cannot conduct under the forward voltage, and only when the reverse voltage reaches the breakdown voltage value can it conduct voltage stabilizing clamping. In order to protect the voltage stabilizing diode D1 and ensure good voltage stabilizing effect, it is usually necessary to connect a current limiting resistor R1 in series in the circuit to perform current limiting action. When the Vin+ input DC voltage is less than or equal to the conduction voltage Vz of the voltage stabilizing diode D1, the transistor V2 does not conduct, at this time the source (S) voltage of the PMOS transistor V1 is the input voltage, the gate (G) is pulled down to the ground and is low, then the PMOS transistor V1 is fully turned on.

[0026] For the second circuit unit A2, when the Vin+ input DC voltage is greater than the conduction voltage Vz of the voltage stabilizing diode D1, the voltage stabilizing diode D1 makes the transistor V2 conduct through voltage clamping, at this time the gate (G) of the PMOS transistor V1 is high through resistance voltage division, then the PMOS transistor V1 is turned off.

[0027] For the third circuit unit A3, the input voltage is conducted through the PMOS transistor V1, and since the resistance R7 has a small resistance value and the resistances R10 and C5 have an RC delay function, the input voltage first flows through the small resistance value resistance R7, and when the RC delay is completed, the surge NMOS transistor V3 is fully turned on through the power loop.

[0028] For the fourth circuit unit A4, the surge resistance R7 and the diode D5 in series play an input reverse connection protection role, when the positive and negative electrodes of the input Vin+ are reversed, the output is turned off and does not conduct, protecting the input power supply and the subsequent power consumption equipment.

[0029] The overvoltage surge protection circuit of the embodiment can be widely applied to low-voltage DC / DC power supply conversion input and output circuits, protects the power consumption equipment from being damaged due to the input power supply voltage exceeding the specified working range voltage, and suppresses the input current to prevent the switching power supply from being interrupted due to overcurrent protection. When the power supply voltage exceeds the set threshold value, the output overvoltage protection circuit turns off the output, and when the capacitive load at the output load end is large, the starting moment impact current is large, and the current limiting resistor at the output end can suppress the starting current to achieve smooth rising of the output voltage and ensure safe operation of the power supply equipment and the power consumption equipment. The overvoltage surge protection circuit is widely applied in the fields of vehicle-mounted radar power supply, communication power supply, high-reliability military power supply technology, etc.

[0030] ​For those skilled in the art, the above disclosure of the utility model is merely illustrative and does not constitute a limitation of the present utility model. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to the present utility model. Such modifications, improvements, and corrections are suggested in the present utility model and therefore remain within the spirit and scope of the exemplary embodiments of the present utility model.

[0031] Although the present invention has been described with reference to specific embodiments, those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions can be made without departing from the spirit of the present invention. Therefore, any changes or modifications to the above embodiments within the scope of the essential spirit of the present invention will fall within the scope of the claims of the present invention.

Claims

1. An overvoltage surge protection circuit, characterized by, Comprise: The first end of the resistance R1 is connected to Vin+, the second end is connected to the negative electrode of the voltage stabilizing diode D1, the positive electrode of the voltage stabilizing diode D1 is connected to Vin-; the second end of the resistance R1 is connected to the base of the triode V2 through the resistance R2, the emitter of the triode V2 is connected to Vin+, the first end of the resistance R5 is connected to the collector of the triode V2; the voltage stabilizing diode D2 is arranged, the negative electrode of the voltage stabilizing diode D2 is connected to Vin+, the positive electrode is connected to the collector of the triode V2; The second end of the resistance R5 is connected to Vin- through the resistance R6, and is connected to the gate of the PMOS tube V1 through the resistance R4, the source of the PMOS tube is connected to Vin+, and the drain is connected to Vout+; the drain of the PMOS tube is connected to the first end of the resistance R8, the second end of the resistance R8 is connected to Vin- through the resistance R10; the resistance R10 is connected to the capacitor C5 and the voltage stabilizing diode D4 in parallel, wherein the positive electrode of the voltage stabilizing diode D4 is connected to Vin-; The positive electrode of the voltage stabilizing diode D4 is connected to the first end of the resistance R7, the second end of the resistance R7 is connected to the positive electrode of the diode D5, the negative electrode of the diode D5 is connected to Vout-; the node between the resistance R8 and the resistance R10 is connected to the gate of the NMOS tube V3 through the resistance R11, the source of the NMOS tube is connected to Vin-, and the drain is connected to Vout-.

2. The overvoltage surge protection circuit of claim 1, wherein, Further comprising a capacitor C4 connected in parallel across the voltage stabilizing diode D1.

3. The overvoltage surge protection circuit of claim 1, wherein, Further comprising a parallel branch composed of a resistance R3 and a capacitor C1, which is connected in parallel across the voltage stabilizing diode D2.

4. The overvoltage surge protection circuit of claim 1, wherein, Further comprising a diode D3, the positive electrode of the diode D3 is connected to Vout+, and the negative electrode is connected to the first end of the resistance R8.

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