By LEIDITECH | 11 March 2024 | 0 Comments
Surge protection in circuit design
one、A headache for hardware engineers-Surge in the circuit
Surges may cause the following hazards to electronic devices and circuits：
1. Damaged electronic components：Surge overvoltage may exceed the rated voltage of electronic components，Causing component breakdown、Burnt or damaged。
2. Shorten equipment lifespan：Repeated surges may accelerate equipment aging，Shorten its service life。
3. Data loss and system failure：Surges may interfere with or damage data transmission in circuits，Causing data loss or system failure。
4. Affects device performance：Surge may cause equipment misoperation、Reset or unstable operation，Affects its performance and reliability。
5. Security risks：In certain situations，Surges may pose a risk of electric shock to personnel。
To protect electronic devices from the hazards of surges，The following protective measures can be taken
two、circuit designHow to add surge protection devices in China
Shanghai Leimao recommends the following common methods to add appropriate onesSurge protection circuit：
1. apply TVS（Transient Voltage Suppressor）diode：TVS Diodes are components specifically designed to protect circuits from surge voltage effects。They have fast response time and low breakdown voltage，Capable of diverting overvoltage to ground，So as to protect other components in the circuit。At the power input terminal、On signal lines and other locations susceptible to surges，Can be connected TVS 二极管。
2. Using ceramic gas discharge tubes：Ceramic gas discharge tube is a component that uses the principle of gas discharge to protect circuits。When the voltage exceeds the set threshold，Gas discharge tubes will discharge，Shunt overvoltage to ground。Gas discharge tubes are commonly used for protection of AC/DC power input。
3. Using varistors：Varistor is a nonlinear resistor element，The resistance value sharply decreases with the increase of voltage。When the surge voltage exceeds the threshold of the varistor，It will conduct，Shunt overvoltage to ground，So as to protect the circuit。Varistors are commonly used for protection of AC and DC power input。
4. Add current limiting resistors and inductors：Adding current limiting resistors and inductors to a circuit can limit the rate of surge current rise，So as to reduce the impact on the circuit。Current limiting resistor can limit the current，And inductance can suppress sudden changes in current。
5. Using filters：Filters can be used to suppress high-frequency noise and surges。Add a filter to the power input or signal line，Can reduce the impact of surges，And provide protection for the circuit。
Suitable surge protection circuit components and methods need to be selected based on specific circuit characteristics and application environments。During the design process，The layout of surge protection circuits should also be considered、Factors such as grounding and wiring，To ensure its effectiveness and reliability。
three、Recommend specific surge protection circuit design cases
Shanghai Leimao recommends the following specific surge protection circuit design cases，For reference：
1. TVS（Transient Voltage Suppressor）Diode protection circuit：TVS Diodes are commonly used for the protection of power and signal lines。Here is a simple example TVS Example of diode protection circuit：
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- Connect at the power input or signal line TVS diode，Connect its positive pole to the signal or power line，Negative grounding。
- TVS Diodes divert overvoltage energy to ground，Protect the circuit from the impact of surges。
2. Ceramic gas discharge tube protection circuit：Gas discharge tube is a gas discharge type overvoltage protection element，Commonly used for protection of AC/DC power sources。The following is a simple example of a gas discharge tube protection circuit：
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- Connect a gas discharge tube to the AC power input terminal，Connect both ends to the power cord and ground wire respectively。
- When the voltage exceeds the breakdown voltage of the gas discharge tube，Gas discharge tubes will discharge，Divert overvoltage energy to ground，protection circuit 。
3. Varistor protection circuit：Commonly used for protection of AC and DC power supplies。The following is a simple example of a varistor protection circuit：
- Connect a varistor to the DC power input terminal，Connect both ends to the power cord and ground wire respectively。
- When the voltage exceeds the threshold of the varistor，The resistance value of the varistor will sharply decrease，Divert overvoltage energy to ground，protection circuit 。Refer to the above picture
These are just some common surge protection circuit design cases，The specific design should be selected and adjusted according to the actual application requirements and circuit characteristics。meanwhile，Follow relevant design standards and specifications，Conduct sufficient testing and validation，To ensure that the surge protection circuit can effectively protect the circuit from the impact of surges。If you have more requirements for specific circuit design，Can apply Shanghai Leimao to electromagnetic compatibility professionalsEMCLittle brother consultation。
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