TPS61221: CR2025 to 3.3V converter

MIT SHAH

Part Number: TPS61221
Other Parts Discussed in Thread: TPS61261

Hello

urgent help required

I have designed a power supply using TPS61221 Booster IC, Input supply is 3V and required output voltage is 3.3V , 7mA.

CR2025 coin cell is used to drive circuit, cell draws 250mA while connecting it to the device and it dubs the input voltages to 0.9V

I have checked without booster IC , direct supply to circuit it works properly , Kindly find schematic design of power supply and give your comments for the same or suggest good IC to boost voltages from 3 to 3.3

Our circuit includes LED(HSMF-C116), sensor(MAX30205MTA+T) and BLE module (BGM13S32F512GN-V2),kindly find attached datasheets for your reference.

LED is driving 1mA current in our circuit.
MAX30205-1020988.pdf pub-005255_DS_HSMF-C116_2019-10-04-1828243.pdf bgm13s-datasheet-1666253.pdf

over 3 years ago

0 Minqiu Xie over 3 years ago

TI__Mastermind 21565 points

HI MIT:

May you use a DC power as input supply for the boost circuit? Can it work well?

0 MIT SHAH over 3 years ago in reply to Minqiu Xie

Intellectual 715 points

Sure we will check the booster on other DC supply

Directly without booster the circuit works proper with coin cell supply, But we need to maintain the 3.3V.

0 MIT SHAH over 3 years ago in reply to MIT SHAH

Intellectual 715 points

Additionally,

As per my further exploration I found TPS61261

In this datasheet, there is mentioned that it can be used for coin cell batteries.

So i doubt that the minimum switching current of 200mA in tps61221 causing the issue

I honestly do not understand the switching current so can you please guide me on that?

Also please check the TPS61261 for our application if it is suitable or not?

0 Minqiu Xie over 3 years ago in reply to MIT SHAH

TI__Mastermind 21565 points

Hi MIT:

TPS61221 has the capability to support 3.3V from Vin=3V. But I'm not sure if the battery can handle the current, expecially the inrush current during the startup. That's why I recommend you to do a test with a DC power supply. And be care about the voltage drops in cables.

I think the "the switching current" you mentioned is the current of the inductance. It looks like a triangle wave while the Low-side switch turn on/turn off. The maximum current through the power FET is equals to the peak current of the inductance.

0 MIT SHAH over 3 years ago in reply to Minqiu Xie

Intellectual 715 points

Please share your views on TPS61261

0 Minqiu Xie over 3 years ago in reply to MIT SHAH

TI__Mastermind 21565 points

Hi MIT:

I would like to check the capability about the input source at first. We have some solution to deal with such case, but I'm not sure if it's the root cause till now.

I'll check the inrush current of TPS61261 during startup.

0 Minqiu Xie over 3 years ago in reply to Minqiu Xie

TI__Mastermind 21565 points

Hi MIT:

Is there any update?

As long time no hear from you, I assume you have solved the issue. If not, just reply below. Thank you!

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TPS61221: CR2025 to 3.3V converter