An Anti-interference DC-DC Converter

Abstract

The present invention discloses a DC-DC converter with strong anti-interference ability, including a lightning surge protector, an electromagnetic pulse protector EMP, a surge suppressor, an EMI filter and a voltage conversion circuit electrically connected together, wherein the lightning surge protector includes a varistor, a gas discharge tube G1, an inductor and a TVS tube SMDJ110CA electrically connected together, the electromagnetic pulse protector EMP includes two bidirectional BV-SMBT-15CA TVS tubes, the surge suppressor includes TVS tubes SMCJ150A D3 and D4 electrically connected together, a MOS tube and a surge suppression chip, the EMI filter includes a common mode inductor, a differential mode inductor, an X filter capacitor and a Y filter capacitor electrically connected together, and the voltage conversion circuit includes a power control chip, a transformer, a MOS tube and a feedback loop electrically connected together. The advantages of the present invention compared with the prior art are: it has multiple functions such as lightning protection, surge resistance, electromagnetic pulse interference suppression, EMI filtering, etc., and can be applied to work in a complex electromagnetic environment.

Description

Technical Field

[0001] The invention relates to the technical field of converters, and in particular to an anti-interference DC-DC converter. Background Art

[0002] Complex electromagnetic environment refers to the complex electromagnetic environment of electronic information systems. Complex electromagnetic environment includes the superposition of multiple electromagnetic environments such as lightning surge (1.2 / 50us lightning voltage surge, 8 / 20us lightning current), electromagnetic pulse EMP interference, ±600V / 10us overvoltage spike and 80V / 50ms overvoltage surge, EMI noise, etc. DC-DC converter is a voltage converter that effectively outputs a fixed voltage after converting the input voltage. During operation, the DC-DC converter needs to have anti-interference suppression capability for complex electromagnetic environments. The DC-DC converter in the prior art can achieve anti-interference suppression capability for a certain electromagnetic environment, such as surge suppression or EMI filtering, on the basis of converting the input voltage into a fixed voltage output, but does not have the ability to suppress interference in complex electromagnetic environments. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the above technical defects and provide an anti-interference DC-DC converter with multiple functions such as lightning protection, surge resistance, electromagnetic pulse interference suppression, EMI filtering, etc., which can be used to work in complex electromagnetic environments.

[0004] To solve the above technical problems, the present invention provides a technical solution: an anti-interference DC-DC converter, comprising a lightning surge protector, an electromagnetic pulse protector EMP, a surge suppressor, an EMI filter and a voltage conversion circuit electrically connected together, the lightning surge protector comprising a varistor, a gas discharge tube G1, an inductor and a TVS tube SMDJ110CA electrically connected together, the electromagnetic pulse protector EMP comprises two bidirectional BV-SMBT-15CA TVS tubes, the surge suppressor comprises TVS tubes SMCJ150AD3 and D4 electrically connected together, a MOS tube and a surge suppression chip, the EMI filter comprises a common mode inductor, a differential mode inductor, an X filter capacitor and a Y filter capacitor electrically connected together, and the voltage conversion circuit comprises a power control chip, a transformer, a MOS tube and a feedback loop electrically connected together.

[0005] Preferably, the lightning surge protector can discharge a 1.2 / 50us lightning voltage surge and an 8 / 20us lightning current.

[0006] Preferably, the electromagnetic pulse protector EMP can suppress 2.5 / 23ns electromagnetic pulses.

[0007] Preferably, the surge suppressor can suppress ±600V / 10us overvoltage spikes and 80V / 50ms overvoltage surges, and suppress the output voltage within 36V.

[0008] Preferably, the varistor is of model 14D121K, and is provided with three varistor elements R1, R2, and R3, and the gas discharge tube G1 is of model BX091N.

[0009] Compared with the prior art, the advantages of the present invention are: it has multiple functions such as lightning surge protection, electromagnetic pulse interference suppression, ±600V / 10us overvoltage spike suppression and 80V / 50ms overvoltage surge suppression, EMI filtering, etc., and can be used in complex electromagnetic environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The invention discloses a lightning surge protector circuit diagram of an anti-interference DC-DC converter.

[0011] Figure 2 The invention discloses an electromagnetic pulse protector EMP circuit diagram of an anti-interference DC-DC converter.

[0012] Figure 3 The invention discloses a surge suppressor circuit diagram of an anti-interference DC-DC converter.

[0013] Figure 4 The invention discloses an EMI filter circuit diagram of an anti-interference DC-DC converter.

[0014] Figure 5 The invention discloses a circuit diagram of a voltage conversion circuit of an anti-interference DC-DC converter. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0016] An anti-interference DC-DC converter comprises a lightning surge protector, an electromagnetic pulse protector EMP, a surge suppressor, an EMI filter and a voltage conversion circuit which are electrically connected together. The lightning surge protector comprises a varistor, a gas discharge tube G1, an inductor and a TVS tube SMDJ110CA which are electrically connected together. The electromagnetic pulse protector EMP comprises two bidirectional BV-SMBT-15CA TVS tubes. The surge suppressor comprises TVS tubes SMCJ150AD3 and D4 which are electrically connected together, a MOS tube and a surge suppression chip. The EMI filter comprises a common mode inductor, a differential mode inductor, an X filter capacitor and a Y filter capacitor which are electrically connected together. The voltage conversion circuit comprises a power control chip, a transformer, a MOS tube and a feedback loop which are electrically connected together.

[0017] As the instruction manual Figure 1 As shown, the lightning surge protector: the lightning surge protection includes varistors R1, R2, R3 (14D121K), gas discharge tube G1 (BX091N), inductor, TVS tube SMDJ110CA, varistor R1 is used to discharge differential mode lightning surge, varistors R2, R3 and gas discharge tube G1 are used to discharge common mode lightning surge;

[0018] When the DC-DC converter is working normally, the voltage at the input end is less than the varistor's varistor voltage, and the varistor is in a high-resistance state. When a common-mode lightning surge occurs at the input end, the voltage of the lightning surge is greater than the varistor voltage of the varistor R2 or R3, and the varistor R2 or R3 is in a low-resistance state. The varistor R2 or R3 is turned on, and then the voltage at both ends of the gas discharge tube is greater than the breakdown voltage. The gas discharge tube is turned on, discharging the common-mode lightning surge and clamping the voltage at about 200 to 300 V. Similarly, when a differential-mode lightning surge occurs at the input end, the varistor R1 is turned on to discharge the differential-mode lightning surge.

[0019] D1 is a bidirectional TVS tube, SMDJ110CA, which is used to further clamp the output surge voltage. The voltage after clamping is about 100V.

[0020] Inductor L1 is used to prevent sudden changes in current in the circuit;

[0021] It can discharge 1.2 / 50us lightning voltage surge and 8 / 20us lightning current, so that the lightning surge energy is instantly discharged through the earth, reducing the output voltage within a certain voltage range, and the reaction speed is at the us level.

[0022] According to the national standard GB / T17626-5, the voltage peak of the 1.2 / 50us lightning voltage surge and the current peak of the 8 / 20us lightning current are different according to different protection levels. Taking level 3 lightning surge protection as an example, the voltage peak of the lightning voltage surge is 2kV, and the current peak of the lightning current is 1kA.

[0023] As the instruction manual Figure 2 As shown, the EMP circuit of the electromagnetic pulse protector includes two bidirectional TVS tubes, BV-SMBT-15CA, which are used to clamp the ns-level electromagnetic pulse input in the circuit. The TVS tube of BV-SMBT-15CA can clamp the voltage output at its rear end to about 15V. It can suppress 2.5 / 23ns electromagnetic pulses and clamp the output voltage, and the reaction speed is at the ns level.

[0024] As the instruction manual Figure 3As shown, the surge suppressor mainly includes TVS tubes D3 and D4 (SMCJ150A), MOS tubes and surge suppression chips. The main working principle is that when a ±600V / 10us overvoltage spike is input into the circuit, TVS tubes D3 and D4 are turned on, and most of the energy is discharged to the ground through D3 and D4, and the voltage is clamped at about 150V. Then, the surge control chip controls the MOS tube to be in an incompletely turned-on state, and its rear-end output voltage is clamped at about 36V.

[0025] When an overvoltage pulse of 80V / 50ms is input into the circuit, the surge control chip controls the MOS tube to be in an incompletely turned-on state, and the surge suppressor clamps the output voltage at about 36V to ensure the stability of the EMI output voltage.

[0026] The surge suppressor can suppress ±600V / 10us overvoltage spikes and 80V / 50ms overvoltage surges, and clamp the output voltage within a certain voltage range. Usually, the surge suppressor can suppress the output voltage within 36V when ±600V / 10us overvoltage spikes and 80V / 50ms overvoltage surges are input.

[0027] As the instruction manual Figure 4 As shown, the EMI filter includes a common-mode inductor, a differential-mode inductor, an X filter capacitor and a Y filter capacitor, which are used to filter out EMI noise interference at the input end of the voltage conversion circuit and can suppress electromagnetic interference in the circuit.

[0028] As the instruction manual Figure 5 As shown, the voltage conversion circuit mainly includes a power control chip, a transformer, a MOS tube and a feedback loop. The power control chip generates a PWM control signal according to the difference between the current voltage and the controlled output voltage, controls the conduction time of the MOS tube, and then controls the charging and discharging time of the transformer, so that the current output voltage meets the controlled output voltage.

[0029] The voltage conversion circuit is used to convert the input voltage under normal working state of the circuit into a fixed output voltage.

[0030] It has multiple functions such as lightning surge protection, electromagnetic pulse interference suppression, ±600V / 10us overvoltage spike suppression and 80V / 50ms overvoltage surge suppression, and EMI filtering, and can be used in complex electromagnetic environments.

[0031] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. An anti-interference DC-DC converter, characterized in that: The invention comprises a lightning surge protector, an electromagnetic pulse protector EMP, a surge suppressor, an EMI filter and a voltage conversion circuit which are electrically connected together. The lightning surge protector comprises a varistor, a gas discharge tube G1, an inductor and a TVS tube SMDJ110CA which are electrically connected together. The electromagnetic pulse protector EMP comprises two bidirectional BV-SMBT-15CA TVS tubes. The surge suppressor comprises TVS tubes SMCJ150AD3 and D4 which are electrically connected together, a MOS tube and a surge suppression chip. The EMI filter comprises a common mode inductor, a differential mode inductor, an X filter capacitor and a Y filter capacitor which are electrically connected together. The voltage conversion circuit comprises a power control chip, a transformer, a MOS tube and a feedback loop which are electrically connected together.

2. The anti-interference DC-DC converter according to claim 1, characterized in that: The lightning surge protector can discharge a 1.2 / 50us lightning voltage surge and an 8 / 20us lightning current.

3. The anti-interference DC-DC converter according to claim 1, characterized in that: The electromagnetic pulse protector EMP can suppress 2.5 / 23ns electromagnetic pulses.

4. The anti-interference DC-DC converter according to claim 1, characterized in that: The surge suppressor can suppress ±600V / 10us overvoltage spikes and 80V / 50ms overvoltage surges, and suppress the output voltage within 36V.

5. The anti-interference DC-DC converter according to claim 1, characterized in that: The varistor is 14D121K model, and has three components R1, R2, and R3. The gas discharge tube G1 is BX091N model.

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