TPS56221: Low current max.

Jeremy howell

Part Number: TPS56221

When i try use a circuit i got from the WEBENCH that is supposed to able to source 25A the maximum current i can get is 500mA.

Design ID: 11

Part Number: TPS56221DQPR

Design Name: TPS56221DQPR 5V-5V to 1.50V @ 25A

The ouput voltage is correct but the current is low.

Thank you.

over 3 years ago

0 Young Zhao over 3 years ago

TI__Genius 9280 points

Hi,

Do you mean the max loading current is 0.5A on your application ?

What's the clamp current of your sourcing ?

BRs,

Young

0 Jeremy howell over 3 years ago in reply to Young Zhao

Prodigy 20 points

The max current of the dummy load i am using should be around 12 A but all i am getting is 500 mA. I am using a 5A power supply for the source at the moment.

0 Gerold Dhanabalan - Online Design Tools over 3 years ago in reply to Jeremy howell

TI__Genius 14455 points

Hi Jeremy

The average input current with Vout=1.5V and 25A is 8.19A. So the input power supply will definitely limit it. Also, the input caps need to supply peak Iout of 29A when the load is 25A. If the input capacitors are not sufficient it would cause the input to drop.

When you powered up with 0 load, did you get 1.5V at the output?

When you increased the load current beyond 500mA, did the Vout drop or did the device shutdown?

Can you please send us scope shots of the SW node and Vout when this is happening?

Can you try replacing the source with something that is capable of supplying a higher current?

Regards,

Gerold

0 Young Zhao over 3 years ago in reply to Jeremy howell

TI__Genius 9280 points

Hi ,

5A supply current can not support your out put on this condition .

Assume eff=~87%, you can get the input current IVIN=VOUT*IOUT/Eff/VIN=8.6A > 5A .

Please use a higher capacity source and check the output . thanks .

And please also check the other component whether they can support on this application . thanks .

BRs,

Young

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TPS56221: Low current max.