TPS62130A-Q1: frequency setting and result

Hi Viola!

This device does has such wide frequency. Pls see below figure in DS.

I suggest you directly choose 2.2uH L and 22uH Cout. This solution has been validated a lot.

Shuai

did you know how to calculate the frequency @Vin=8V, Vout=1.09V? did there have any fomula can share?

and

from datasheet it shown the duty will larger than 20%.

but from my EVM board test, it was 16%@Vin=8V, Vou=1.09V, Iout=2.6A, L=2.2uH

why the duty can less than 20%?

thank you.

BR,

Viola

Hi Shuai,

Although the fomula on datasheet shows the minimum duty is 20% isn't consider the IR drop caused by Rds_on and inductor DCR... 

if consider the factor, duty will less than 20%, right?

thank you.

BR,

Viola 

hi

Even we don’t consider it drop，1.09/8 is still less than 20%

hi

that's my confuse. because on datasheet is shows " an absolute minimum on-time of about 80ns is kept to limit switching losses".

and the fomula is ton =Vout/Vin*400ns=> Vout/Vin will more than 20%