What are the common design considerations for overcurrent and overvoltage protection?

Power Circuit Protection
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Question: What common design elements should I keep in mind when designing overcurrent and overvoltage protection into my system?
Answer: " For overcurrent: voltage, operating current, ambient temperature, lightning strike requirements, short - circuit current, surge impact, etc.; For overvoltage: lightning strike requirements, operating voltage, ambient temperature, etc."

Design considerations for overcurrent protection:

  1. Voltage: The voltage range that the circuit or device can withstand during normal operation needs to be considered to ensure that the overcurrent protection device can work effectively within this voltage range.
  2. Operating current: The threshold of overcurrent protection must be designed according to the actual operating current of the device or circuit. Ensure that the protection is not triggered accidentally under normal operating current, and the circuit can be cut off in a timely manner when the current exceeds the safe value.
  3. Ambient temperature: Ambient temperature can affect parameters such as resistance and capacitance of the circuit or device, thus affecting the current. Therefore, the impact of ambient temperature on overcurrent protection needs to be considered during the design.
  4. Lightning strike requirements: In environments prone to lightning strikes, overcurrent protection also needs to consider the instantaneous large current generated by lightning strikes to ensure that the device can work safely during lightning strikes.
  5. Short-circuit current: An overcurrent protection device that can withstand and cut off the short-circuit current needs to be designed to prevent fires or device damage caused by short circuits.
  6. Surge impact: Surge currents may occur in the circuit due to reasons such as switch operations and sudden load changes. This needs to be considered in the overcurrent protection design to ensure that the device can handle surge impacts.

Design requirements for overvoltage protection:

  1. Lightning strike requirements: Similar to overcurrent protection, overvoltage protection also needs to consider the instantaneous high voltage generated by lightning strikes to ensure that the device is not damaged during lightning strikes.
  2. Operating voltage: The threshold of overvoltage protection is designed according to the normal operating voltage range of the device or circuit. Ensure that the protection is not triggered accidentally under normal voltage, and the circuit can be cut off in a timely manner when the voltage is too high.
  3. Ambient temperature: Ambient temperature can also affect the voltagebearing capacity of the device. Therefore, the impact of ambient temperature on overvoltage protection needs to be considered during the design.

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