Hi,
I designed a 2-trans. forward converter for a battery charger. It is designed for 8A at 30V. It uses a PIC 16F877A controlling a IR2110 driver and IR840 MOSFETs.
The problem is that at moderate currents (>4A) the ferrite transformer (ETD59) starts emitting a crackling noise. tho it continues to work OK upto about 7.5A, after which the overload circuit trips (possibly due to interference).
Thinking it may be a feedback stability problem, I ran it in open loop. But amazingly at about 4A, the PIC started behaving erratically (display went beserk), and this blew out the power circuits.
Not having a 'scope, I cant seem to figure out what the problem is, esp. since it worked far better in closed loop.
Anyone has any suggestions?
Thanks,
vkj.