TPS61021A: Large startup current spike issue

lakshmikanth satyavolu

Part Number: TPS61021A

Hi,

I am using TPS61021DSG in my design which is a data acquisition system using BLE. I am using 1.4V Zinc-air battery to power up my circuit to generate 3VDC at output.

I am facing a problem that the circuit is not being powered up when using Zinc-air 1.4V. After I investigate more by testing it with DC power supply, I realized that the initial current when we apply 1.4V to the circuit goes upto 53mA and settles down at 20mA which is causing my battery to not support that initial surge.

Attached is my power supply section and the video I have captured which explains the scenario. Can someone please review the design and help me understand why is this happening?

Best

Lakshmikanth

over 4 years ago

0 Helen chen over 4 years ago

TI__Mastermind 40080 points

Dear Sir,

Thanks for the post. Did you ever try to start up the circuit with no load? For the TPS61021, to make it work properly, it should be startup at no load condition, after the Vout rise to the target value, then add the load.

0 lakshmikanth satyavolu over 4 years ago in reply to Helen chen

Expert 1670 points

Hi Helen,

Thanks for your response. I have removed the load by putting all the peripherals and processor into the sleep mode. But still seeing the inrush current. I have also replaced 100uF output cap with 22uF.

I suspect the MOSFET at input is creating this inrush spike. Do you think using MOSFET for this design is appropriate?

Best

Lakshmi

0 Helen chen over 4 years ago in reply to lakshmikanth satyavolu

TI__Mastermind 40080 points

Dear Sir,

You can directly connects the battery with the TPS61021A. Not sure whether this is caused by the input FET, but if the FET turns on suddenly, there will be some inrush at the input side.

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TPS61021A: Large startup current spike issue