NCP1653手册上也是这么说的:
When the product (IS⋅Ivac) goes above 3 nA2, OPL is activated and the Drive Output duty ratio is reduced
by pulling down Vcontrol indirectly to reduce the input power.
但是:
1:Ivac的取值
实际上,pin3
被设计成来接受与输入电压vac 的平均值成比例的一个电流值。 这个电流信息主
要是用来过功率保护,对于保护需要适当的调整,当输入电压最低的时候,感应
到得输入电流必须在15uA以下。
2:IS的取值
This pin sources a current IS which is proportional to the inductor current IL. The sense current
IS is for overcurrent protection (OCP), overpower limitation (OPL) and PFC duty cycle
modulation. When IS goes above 200 A, OCP is activated and the Drive Output is disabled.
这样的话不是不能保证
IS⋅Ivac< 3 nA2
本人英语不好,可能是手册没看明白,请大家帮帮忙,不尽感谢激!先谢谢了!