How to optimized design for 3.8V/4A with inn3694C. i am facing problem . kindly advise and 5V/4A CKT is working fine.

Hi Pradeep,

This will be a challenging specification since our InnoSwitch device needs BPS voltage around 4.4V. BPS is supplied via FWD pin and Vout pin. If your output voltage is less than 4.4V, Vout pin can't help supplying charge current towards BPS and FWD pin charge current will not be enough to maintain BPS at 4.4V.

Regards,

Jedidiah

One approach (though not optimum in cost or simplicity) would be to start with a higher output voltage and regulate down using using a commercially available synchronous buck controller.

Thanks for your reply. can we add some turn in output winding to supply volt 4.4v to ic.

Another approach that might work is to feed the BPS pin from a supply derived from a separate higher voltage winding. 

please share TRX Design.

Attached is a rough schematic markup showing use of an extra higher voltage winding to drive the Vo pin, as well as the possibility of using an extra resistor from the higher voltage winding to prop up  the BPS supply.

Thanks.