Part Number: PMP20289
Team,
There need your help about PMP20289.
There have some new questions about PMP20289 which is a 500W(400V – 12V/42A) high frequency resonant converter using high voltage GaN devices.
PMP20289
http://www.ti.com/tool/PMP20289
power : 500W
output : 12V 42A
Structure : primary side is LLC with GaN, Secondary side SR with FET (2mohm)
fo=370kHz, fs=400~500kHz (above)
resonant capacitor: MLCC 6* 8.2nF
separate trans structure : Lk 3.71uH ( separate inductor L = 2.05uH + tran Lk 1.66uH)
Lp =67.5uH ( 16 : 1)
Questions :
Q1 : Normally, MLCC vendor don’t provide current ripple specification. Which current specification of MLCC be used for calculation ?
Q2 : As we know, for high frequency, it should reduce inductor value or reduce capacitor value. For PMP20289, What’s the key reason about increase capacitor value significantly and reduce inductor ?
Dose this structure for SR stability due to high current(42A) in secondary side ?
Dose it like LLC bobbin structure (increasing primary side Lp value for reduce GaN temperature and decreasing Lk for SR stability) ?
Dose this structure for low output voltage application normally ?
Q3 : Why fs above fo ? (Secondary side have FET. If fs above fo, It seems there have higher switching loss. )
thanks,