TPS82140: Switch current limit

Kazuki Itoh

Part Number: TPS82140

Hi team,

Could you please let me know about the switch current limit of TPS82140?
My customer wonders how the switch current limit works when Iout is >2A (above recommended operating condition).
From the datasheet, I guess Iout flows even if it is >2A when the ripple is enough small.
Is it just high-side cycle-by-cycle current limit with 30ns?
I'd appreciate if you share digestive figure to help my customer to understand.

Regards,
Itoh

over 2 years ago

0 Nancy Zhang over 2 years ago

TI__Mastermind 47000 points

Hi Itoh,

TPS82140 high-side FET current limit is 3A min in the datasheet page 5. Due to the internal propagation delay, the actual current can exceed the static current limit during that time, especially if the input voltage is high and very small inductances are used. The dynamic high-side FET peak current can be calculated as below equation.

Ipeak=Ilim+((Vin-VOUT)*30ns)/L

Hope this helps,

Thanks,

Nancy

0 Kazuki Itoh over 2 years ago in reply to Nancy Zhang

TI__Genius 9635 points

Hi Nancy-san,

Thank you for the clarification about the Ipeak.
How about the average output current?
Can TPS82140 output 2A average Iout if Ipeak<3A?

Regards,
Itoh

0 Shuai Fan over 2 years ago in reply to Kazuki Itoh

TI__Genius 13451 points

Hi Itoh!

Nancy will reply you soon!

BSR-MV

Shuai

+1 Nancy Zhang over 2 years ago in reply to Shuai Fan

TI__Mastermind 47000 points

Hi Itoh,

It is a little bit confusing. It is impossible that current limit happens less than average current 2A. TPS82140 has a max 2A operating output current. The min average current limit is 3A which is higher than 2A. Because of a typical 30ns propagation delay, the actual current is even higher than 3A depending on Vin/Vout/inductor.- Hope this is clear.

Thanks,

Nancy

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TPS82140: Switch current limit