TPS54331: inductor ripple current with 0.8 ?

kingson zhang

Prodigy 165 points

Part Number: TPS54331
Other Parts Discussed in Thread: TPS54561,

Hello TI,

why there is 0.8 in eq(9) of tps54331 datasheet? it's different from tps54561.

10 months ago

0 Miranda Gu 10 months ago

TI__Genius 15137 points

Hello Kingson,

I will check and reply you soon.

+1 Miranda Gu 10 months ago in reply to Miranda Gu

TI__Genius 15137 points

Hello Kingson,

I think the 0.8 factor is considering 80% efficiency or 80% effective inductance. But agree with you, I more often to see this equation without this factor. I would say it's not good to add it without any explanation.

Thanks for point out! I will add it into our backlog.

+1 kingson zhang 10 months ago in reply to Miranda Gu

Prodigy 165 points

Hello Miranda

Because the actual duty cycle is related with efficiency, duty cycle =Vout/(Vin*n), normally efficiency n is thought as 80% ?

0 Miranda Gu 10 months ago in reply to kingson zhang

TI__Genius 15137 points

Hello Kingson,

Yes, it's a rough estimation.

0 kingson zhang 10 months ago in reply to Miranda Gu

Prodigy 165 points

Thanks Miranda ^-^

Power management

Power management forum

TPS54331: inductor ripple current with 0.8 ?