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请问LM3489输入电压12V输出电压9VMOS管栅极和漏极波形异常,输入电压25v,输出9V时,带载2.5A左右MOS会击穿,请问什么原因

Other Parts Discussed in Thread: LM3489

请问LM3489输入电压12V输出电压9VMOS管栅极和漏极波形异常,输入电压25v,输出9V时,带载2.5A左右MOS会击穿,请问什么原因

原理图如下,改了上偏电阻输出9V

下图分别为输入12V,输出9V时带载1.4A,2.7A,3.8A,4.7A时MOS管栅极和漏极波形(黄色是漏极,绿色是栅极)

 

1.4A

 

2.7A

3.8A

4.7A