TPS61235P: Output voltage drops to 2V

Danilo A.

Part Number: TPS61235P
Other Parts Discussed in Thread: TPS22965

Hi Team,

According to our customer, the output voltage of TPS61235 drops to 2V when connected to a 2.5A load. Please see the details of his inquiry below.

I'm currently developing a simple circuit with TPS61235 to boost to 5.1V from 18650 battery, and due to my application uses, I do have a heavy load of 2ohms on my output, which I expected to draw 2.5A.

However when I connect this, I measured Vout dropped to only 2V, and I measured my 18650 battery's voltage is at 3.6V, and providing only about 1.1A of current from battery to Vin. Without load, I can see the circuit output normal at 5.1V.

Can you help to check if anything wrong in this circuit? I had CC pin connected to GND as I was thinking I don't need any current limit as my load will be unchanged there.

Regards,

Danilo

over 1 year ago

0 Nathan Ding over 1 year ago

TI__Expert 8905 points

Hi Danilo,

Does the 2ohm resistor connected to the output of TPS61235P before startup or after startup?

If it is connected before startup, sorry that TPS61235P can't support 2ohm load when startup, because the pre-charge current is limited when startup.

Regards,

Nathan

0 Danilo A. over 1 year ago in reply to Nathan Ding

TI__Mastermind 25865 points

Hi Nathan,

Thank you for your response. Please see the feedback of our customer below.

Thanks for checking this. Yes, the 2 ohm load resistor is always there, I think this makes sense and missed that earlier.

As a change in my design, I'm planning to add a power switch TPS22965 at TPS61235's Vout, so that I can control it to be connected to 2ohms load when needed. Can you help to take a quick look if this is correct.

Regards,

Danilo

+1 Nathan Ding over 1 year ago in reply to Danilo A.

TI__Expert 8905 points

Hi Danilo,

I think it should be ok.

Regards,

Nathan

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TPS61235P: Output voltage drops to 2V