请教IR1150高手,软启动的问题

第一次用这个PFC芯片,我把栅极电阻取了(管子不工作),然后用AC调压器从0V升压到约80V,1150工作,发现8脚驱动波形前一段很怪,这段波形过了才是正常的软启动过程
但是如果我调压器设好80V,直接开通开关,1150的8脚驱动又没有软启动过程了,是怎么回事,我是用VIPER22做了个小电源给1150供15V电
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缓慢上升输入电压的波形
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下面是直接设好调压器80VAC,然后开开关
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