有源钳位的钳位MOSFET功耗巨大

LM5025做的低端有源钳位,带载时钳位MOSFET功耗巨大,TO-252封装的管子没散热器最多几分钟就崩溃了.
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输入:输入12V,输出24V2A,变压器4T:17T,工作频率400K
图中元件参数:C12=104,R14=10K,D3=CD4148,Q3=IRFR9220(200V3.6A1.5R),C13=100V0.1uF,R12=5.1R,C11=103,R13=10K,Q2=IRFR530

那位高人指点一下?

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驱动波形

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漏极波形