eem2am
Banned
In push pull smps (offline), i am worried that my transformer will saturate due to the non balanced switching, -i mean the "flux-walking" effect.
it is said i may use current mode to solve this.....but how do i have my overcurrent trip only trip due to magnetising current, and not due to the "transformer current" or load current ?
transformer primary "load" current will need to ba able to rise to 166mA. -Of course , this current will not saturate the ferrite as it's field is cancelled.
However, the saturation current for the core is just 100mA in the primary.
my max on_time is 4us and will not normally allow magnetising current to build up to 100mA.....but with flux-walking effect the saturation could occur.
i cannot set my primary current sense trip to 100mA , as then the load current would not get through, so what should i do ?
thanks in advance of any thoughts at all.
it is said i may use current mode to solve this.....but how do i have my overcurrent trip only trip due to magnetising current, and not due to the "transformer current" or load current ?
transformer primary "load" current will need to ba able to rise to 166mA. -Of course , this current will not saturate the ferrite as it's field is cancelled.
However, the saturation current for the core is just 100mA in the primary.
my max on_time is 4us and will not normally allow magnetising current to build up to 100mA.....but with flux-walking effect the saturation could occur.
i cannot set my primary current sense trip to 100mA , as then the load current would not get through, so what should i do ?
thanks in advance of any thoughts at all.