Hi,
I use tps54620 for inverting operation with 3.8Vin and -0.9Vout/4A. I apply a 5V on VIN pin. Below is the SCH.The fsw is 950kHz.
The SW(CH3) and output ripple(CH2) are measured as below shows.The load is from 100mA to 4A. It looks like cycle by cycle current limit is triggered, but no overheating of tps54620 was found. And, the Vout average voltage is always in regulation even @ 4A.
Io=100mA
Io=4A
I changed the fsw to 500kHz and Rcomp from 5.76kohm to 800ohm. The fsw looks stable from no load to 2A, but still unstable at 4A.
Could you give suggestion for this?
Thanks