FEDEVEL
Platform forum

Paras , 02-20-2024, 07:12 PM

can anyone please help me, how to find switching frequency before selecting switching power convertor, only load is known. What parameter have to be taken care in datasheet of load? Let suppose I have a load of Vin 3.3v and Iload to be 2 Amp my main supply coming to board is 12v, I have to choose buck regulator but from where and what calculation i will define my switching frequency ?

Sniper2 , 02-20-2024, 07:41 PM

datasheet

Sniper2 , 02-20-2024, 07:41 PM

generaly u chose it based on the inductor used/wanted

Sniper2 , 02-20-2024, 07:42 PM

yes Cout changes too but not as noticeble when it comes to the circuit

Sniper2 , 02-20-2024, 07:43 PM

TLDR: Fsw * L = constant so adjust either one to get where u want

Sniper2 , 02-20-2024, 07:44 PM

i would go with 1MHz then see that is available around that , then u can start optimiseing

Sniper2 , 02-20-2024, 07:44 PM

ICs are either fixed Fsw or with a wide range set by a resistor

Sniper2 , 02-20-2024, 07:44 PM

@Paras

Sniper2 , 02-20-2024, 07:45 PM

questions:

QDrives , 02-20-2024, 09:21 PM

As @Sniper2 mentioned, the inductor and switching frequency have a relation.
Higher frequency = more EMC noise and lower efficiency in switching losses. But also smaller inductor and higher bandwidth.

Sniper2 , 02-20-2024, 09:43 PM

more EMC may still be ok if it is under the limit
regarding efficiency (overall) yea it is marginal up to a point but like all things it is a drade off