Currently the output is using Current doubler with 28951 controller ,SR control to burn SR MOSFETs as soon as they are turned on.
I'd like to ask if you can help me with the confirmation.
hi Yunsheng Qu
PSFB's primary side transformer current generates a ring that can help suggest adjustments to those parameters that have a chance of improvement?
Transformer current is show as CH2 .
Carson,
the resonant ring was caused by resonant ringing between the inductance LS + LLK and stray capacitance in the transformer windings which would otherwise cause high amplitude voltage spikes to appear across the rectifiers.
I suggest you to add D2 and D9 shown in below circuit in your application. The purpose of the diodes D2 and D9 is to clamp the transformer primary winding at either VIN or GND and thus prevent such resonant ring.
Yunsheng
Hi Yunsheng Qu
How are you ?
Is the Clamp diode restricted to the lagging arm or leading arm?
The Lagging Arm will have a negative current when it is switched off.
As shown below
CH2 : Lagging Arm current .
Yunsheng
1.When I add the clamping diode after measuring the switch current. we see the current slope in the opposite direction during conduction ,is it correct?
ch2 is the switching current (Placement on either the leading arm or lagging arm is the same)
2. We adjusted the secondary side SR MOSFET snubber circuit configuration to eliminate the oscillation, but there is still a large PEAK that cannot be cancelled.
