Surge voltage-withstanding dual-protection circuit

Abstract

The invention relates to the technical field of power supply protection, and discloses a surge voltage-withstanding dual-protection circuit. The invention provides a surge voltage-withstanding dual-protection circuit. The surge voltage-withstanding dual-protection circuit comprises a TVS diode, a rectifier diode, a protected circuit and a protection ground, a TVS diode and a rectifier diode are connected between the protected circuit and the protected ground, the first end of the TVS diode is located on the protected circuit, the other end of the TVS diode is located on the anode of the rectifier diode, and the cathode of the rectifier diode is connected with the protected ground. According to the protection circuit, the TVS diode is connected with the rectifier diode in series, and the rectifier diode and the TVS diode are reasonably selected, so that surge electrostatic impact can be prevented, and a very high withstand voltage value can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of power supply protection, in particular to a surge withstand voltage dual protection circuit. Background Art

[0002] TVS (Transient Voltage Suppressor) diode is a high-efficiency circuit protection component in the form of a diode, also known as transient voltage suppression diode, which can be divided into unidirectional and bidirectional. When the two ends of the TVS diode are subjected to a transient high-energy impact, it changes the impedance between the two ends from high impedance to low impedance at a PS-level speed, has a considerable surge discharge capacity, and clamps the voltage at both ends to a predetermined value to protect the subsequent components from the impact of transient high-voltage spike pulses. Conventional protection circuits connect one end of the TVS to the protection circuit and the other end to the protection ground. This conventional design can indeed achieve protection against transient high-voltage pulses, but it cannot pass the withstand voltage and insulation tests in safety tests. Because if the TVS diode is selected in a unidirectional manner, the cathode of the unidirectional TVS is connected to the protection circuit line, and the anode of the unidirectional TVS is directly connected to the protection ground. In this way, in the withstand voltage or insulation test, the voltage applied to the shell will flow directly to the protection circuit, resulting in test failure. Bidirectional TVS does not need to distinguish the direction, and its reverse shutdown voltage VRWM (Peak Reverse Working Voltage) should be greater than or equal to the maximum working voltage of the protected circuit. If the selected VRWM is too low, the TVS diode may enter an avalanche state or affect the normal operation of the circuit due to excessive reverse leakage current. Common DC working voltages include 3.3V, 5V, 12V, 24V, 110V, etc., and AC 220V, so the VRWM voltage will not be too high, but the withstand voltage or insulation test voltage of conventional safety tests basically exceeds 500V, exceeding the VRWM value. Similarly, the surge can pass, but the withstand voltage and ground resistance tests fail. Summary of the invention

[0003] 1. Technical issues to be solved

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide a power supply protection circuit, which can achieve protection against transient high-voltage pulses through TVS diodes and safely pass the withstand voltage insulation test through rectifier diodes.

[0005] (II) Technical solution

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a surge withstand voltage dual protection circuit, comprising: a TVS diode, a rectifier diode, a protected circuit and a protection ground; the TVS diode and the rectifier diode are connected between the protected circuit and the protection ground, wherein a first end of the TVS diode is located at the protected circuit, and the other end is located at the anode of the rectifier diode, and a cathode of the rectifier diode is connected to the protection ground.

[0008] As a preferred solution of the present application, when there are one or more TVS diodes and rectifier diodes, their connection order can be changed: from the protected circuit to the TVS diode, then to the rectifier diode and finally to the protection ground; or from the protected circuit to the rectifier diode, then to the TVS diode and finally to the protection ground.

[0009] As a preferred solution of the present application, the TVS diode may be a single TVS diode or a plurality of TVS diodes connected in series or in parallel.

[0010] As a preferred solution of the present application, the rectifier diode can be a single rectifier diode or multiple rectifier diodes connected in series or in parallel. If there are multiple rectifier diodes connected in parallel, a current-sharing resistor can be added as needed.

[0011] As a preferred solution of the present application, the TVS diode may be a unidirectional or bidirectional TVS diode.

[0012] (III) Beneficial effects

[0013] Compared with the prior art, the present invention provides a surge withstand voltage dual protection circuit, which has the following beneficial effects:

[0014] 1. The protection circuit can prevent surge electrostatic shock and have a high withstand voltage value by connecting the TVS diode and the rectifier diode in series and selecting the rectifier diode and the TVS diode in a reasonable manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention provides a protection circuit schematic diagram.

[0016] Figure 2 This is another protection circuit schematic diagram provided by the present invention.

[0017] Figure 3 It is a schematic diagram of a circuit structure in which multiple TVS diodes are connected in parallel provided by the present invention.

[0018] Figure 4 It is a schematic diagram of a circuit structure in which a plurality of rectifier diodes are connected in parallel provided by the present invention.

[0019] Figure 5 It is a schematic diagram of the circuit structure of multiple rectifier diodes connected in series provided by the present invention.

[0020] Figure 6 It is a schematic diagram of the circuit structure of multiple TVS diodes connected in series provided by the present invention.

[0021] In the figure: 1-rectifier diode, 2-TVS diode, 3-protective ground. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Reference Figure 1-6 A surge withstand voltage dual protection circuit includes: a TVS diode, a rectifier diode, a protected circuit and a protection ground; a TVS diode and a rectifier diode are connected between the protected circuit and the protection ground, and the TVS diode and the rectifier diode are connected in series, the anode of the rectifier diode is located at the protected circuit, the cathode is located at the cathode of the unidirectional TVS diode, and the anode of the unidirectional TVS diode is connected to the protection ground.

[0024] The specific protection principle and device selection method are as follows:

[0025] Step 101, according to the actual circuit requirements, reasonably select the maximum operating voltage, maximum rated current, directional breakdown voltage, and directional leakage current of the rectifier diode. Utilizing the unidirectional conductivity of the rectifier diode, the transient high-voltage pulse on the protected line is allowed to pass without being damaged.

[0026] Step 102, also using the unidirectional conductivity of the rectifier diode, when the circuit board is subjected to a withstand voltage or insulation test, a voltage is applied to the cathode of the rectifier diode. The reverse breakdown voltage of the selected rectifier diode is greater than the voltage applied in the test, so that the withstand voltage and insulation test are passed.

[0027] Step 103, the cut-off voltage, breakdown voltage, maximum peak pulse power and maximum clamping voltage of the TVS diode are also reasonably selected to ensure the normal operation of the circuit. The TVS diode in the circuit can achieve protection against transient high-voltage pulses.

[0028] Step 104, TVS can realize the circuit protection function in both unidirectional and bidirectional directions. For unidirectional, it is necessary to pay attention to that the cathode is connected close to the protection line end and the anode is connected close to the protection ground end. When there is no transient high-voltage pulse, the TVS diode is in the cut-off state. When there is a transient high-voltage pulse, the TVS diode breaks down in the direction to realize the protection circuit.

[0029] Step 105 , determining the number of TVS diodes and Zener diodes and whether to connect them in series or in parallel according to actual application requirements.

[0030] The electrical components mentioned in this article are all connected to an external main controller and 220V mains electricity, and the main controller can be a conventional known device for controlling a computer or the like.

[0031] In the description of this article, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the description of this article, it should be noted that relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A surge withstand voltage dual protection circuit, comprising a TVS diode, a rectifier diode, a protected circuit and a protection ground, characterized in that: A TVS diode and a rectifier diode are connected between the protected circuit and the protection ground, and the TVS diode and the rectifier diode are connected in series.

2. The surge withstand voltage dual protection circuit according to claim 1, characterized in that: The TVS diode and the rectifier diode form a protection circuit.

3. The surge withstand voltage dual protection circuit according to claim 1, characterized in that: The TVS diode is composed of a single TVS diode or a plurality of TVS diodes connected in series or in parallel.

4. The surge withstand voltage dual protection circuit according to claim 1, characterized in that: The rectifier diode is composed of a single rectifier diode or a plurality of rectifier diodes connected in series or in parallel.

5. The surge withstand voltage dual protection circuit according to claim 2, characterized in that: There is no sequence between the TVS diode and the rectifier diode in the protection circuit from the line to be protected to the protection ground.

6. A surge withstand voltage dual protection circuit according to claim 2, characterized in that: The protection circuit has only one TVS diode and one rectifier diode between the line to be protected and the protection ground, and the TVS diode and the rectifier diode are connected in series.

7. The surge withstand voltage dual protection circuit according to claim 1, characterized in that: The connection sequence of the protection circuit is from the protected circuit to the TVS diode, then to the rectifier diode and finally to the protection ground: the first end of the TVS diode is located at the protected circuit, the other end is located at the anode of the rectifier diode, and the cathode of the rectifier diode is connected to the protection ground.

8. The surge withstand voltage dual protection circuit according to claim 1, characterized in that: The connection order of the protection circuit is from the protected circuit to the rectifier diode, then to the TVS diode and finally to the protection ground: the anode of the rectifier diode is located at the protected circuit, the cathode is located at one end of the TVS diode, and the other end of the TVS diode is connected to the protection ground.

9. The surge withstand voltage dual protection circuit according to claim 1, characterized in that: The TVS diode is a unidirectional TVS diode or a bidirectional TVS diode.

10. The surge withstand voltage dual protection circuit according to claim 1, characterized in that: The cathode of the rectifier diode points to the protection ground, and the anode points to the protected circuit.

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