There may be several reasons for the IC to explode:
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1. Overvoltage: If the output voltage of the power supply exceeds the rated voltage of the IC, the IC may be damaged by overvoltage.
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2. Overcurrent: If the output current of the power supply exceeds the rated current of the IC, the IC may be damaged by overcurrent.
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3. Transient voltage: When the power switch is off, a transient voltage may be generated, which may cause the IC to be damaged.
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4. High temperature: If the operating temperature of the IC exceeds its rated temperature, the IC may be damaged.
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It is recommended to check whether the output voltage and current of the power supply are within the rated range of the IC, and check whether there is a transient voltage when the power switch is turned off. In addition, it should also be ensured that the operating temperature of the IC does not exceed its rated temperature.
There is supersaturated voltage in C7, resulting in the failure of C7 to discharge after power failure, IC overcurrent to start and burst at the moment of startup, and U2 will also burst when starting in the cut-off state. There are defects in the circuit design. First of all, when the starting voltage of R5 is short of U2, IC will bear all the current, and the feedback signal from R8 cannot release the residual current of C7 when IC is powered off. C4 no drain circuit, R5 instantaneous IC reaction is cut off when the power supply is short circuited, instead of input zero!