regarding TPS54617, I have read through the information from the link that was recomended and it's suggested that the ripple should be around 10-30% of full load current. Currently, I am using 0.82uH inductor for TPS54617 while applying 3.3V as Vin and Vout is targeted at 1.0V. According to datasheet of tps54617, F(switching)=1.6Mhz. while applying the formula from TPS53311, I(ripple)=1/(LXSWITCHING FREQUENCY)X[(Vin-Vout)xVout]x[1/Vin]
=1/(0.82u x 1.6M) x [(3.3-1) x 1 ] x [1/3.3]
=0.53A (which is 8% of 6A of full load current) From the above calculation, do you think I should change my inductor to have a lower inductance such as 0.68uH? would you foresee any problems if my ripple current to be less than 10-30% of 6A(full load current). thanks for your reply and much appreciated..
The amount of ripple current is somewhat arbitrary. 10-30% is the typically recommended value. You can go over or under, depending on your other requirements. In some cases, you may even be able to go over 100% ripple. In general though, lower is better with voltage mode control devices such as TPS54617. I don't see any problem with keeping your present inductor value, but you can decrease it if you want.
John Tucker
Consumer DC/DC Applications