Selvam_Perumal
Junior Member level 2
HI,
I am using ICE2HS01 LLC controller for converting 300V to 50V @30A using half bridge LLC converter.
I am driving the secondary FET s with the gate driver for channel conduction to reduce the power dissipation.
IC has secondary gate pulse signals which is not giving the control signals at higher switching frequency of 1MHz.So,I given primary gate drive control to both primary and secondary FETs through separate isolated gate driver.
We had a failure in Primary top and bottom FET.
During start up,while probing the resonant current,the current waveform is not as intended and the SW node waveform resembles the wave form of capacitive region.
My converter will never operate in capacitive region because my minimum switching frequency limitation is kept above the resonant frequency.
Due to the channel conduction of secondary without sensing its diode current.I thought that it can be due to current from the secondary side which is changing my resonant current waveform.
So,I disabled the channel conduction and made it operate in diode conduction alone and I verified the resonant current waveform.
Now the waveform looks proper and the rise time is faster(50us) than later(200us) at no load.
Can anyone tell me the reason for current reversal from secondary to primary during start up.
With regards,
P.Selvam
P.Selvam.
I am using ICE2HS01 LLC controller for converting 300V to 50V @30A using half bridge LLC converter.
I am driving the secondary FET s with the gate driver for channel conduction to reduce the power dissipation.
IC has secondary gate pulse signals which is not giving the control signals at higher switching frequency of 1MHz.So,I given primary gate drive control to both primary and secondary FETs through separate isolated gate driver.
We had a failure in Primary top and bottom FET.
During start up,while probing the resonant current,the current waveform is not as intended and the SW node waveform resembles the wave form of capacitive region.
My converter will never operate in capacitive region because my minimum switching frequency limitation is kept above the resonant frequency.
Due to the channel conduction of secondary without sensing its diode current.I thought that it can be due to current from the secondary side which is changing my resonant current waveform.
So,I disabled the channel conduction and made it operate in diode conduction alone and I verified the resonant current waveform.
Now the waveform looks proper and the rise time is faster(50us) than later(200us) at no load.
Can anyone tell me the reason for current reversal from secondary to primary during start up.
With regards,
P.Selvam
P.Selvam.