Reasons:
① The power supply system is abnormal, causing the input voltage to exceed the design range.
② The input filter or voltage regulator fails and cannot effectively regulate the voltage.
③ External voltage interference, such as the power line being affected by high-frequency interference signals.
Solutions:
① Check and calibrate the power supply system to ensure that its output voltage is within the design range.
② Replace the failed filter or voltage regulator to restore normal voltage regulation function.
③ Use appropriate protection circuits, such as overvoltage protection circuits (OVP), to prevent excessive input voltage from damaging the power converter.