The project used UC3843 with 12V power supply. Now the power supply is changed to 5V, So IC changed to UCC 3803.Only the IC is changed, and the peripheral circuit is not changed, The Circuit as follows:
1>When used 5V power supply, The output of the sixth pin is abnormal, and the third pin is the waveform above， the waveform as follows：
2>When used 5.5V power supply, The output of the sixth pin is normal，the waveform as follows：
3>There is a board, the input voltage must reach 8.5V, and the sixth pin can be switched normally，the waveform as follows：
4>modify the working frequency from 100K to more than 900 K，the output of the sixth pin is abnormal，the waveform as follows：
