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TPS61261: Recommendation for boost converter for AAA powered Wi-Fi Sensor

Gary Trehair
Prodigy 10 points
Part Number: TPS61261
Other Parts Discussed in Thread: TPS61322, TPS61099

Hi

I am attempting to create a Temperature sensor that uses WiFi to upload a reading once per minute.

The transmission/upload time period is probably around 5 seconds and then the device sleeps for a minute. 

The transmit power usage peaks at 300mA and then the device sleeps at around 20µA.

The device needs to be as small as possible and the battery needs to be replaceable as recharging isn't an option.

As such I would like to use a AAA battery for this purpose. I am trying to find an appropriate boost converter that can boost the voltage from the AAA battery to 3.3v required by the microprocessor.

There are a large number of boost converters listed in TI's catalogue but I am struggling to find the best fit.

Please can you provide some guidance around what you would recommend for this use case?

TPS61261 and TPS61225 look like good options but I am not sure if they will handle the 300mA peak current when the device is transmitting. 

Since the transmit period is very short (<5s) do you think these chips will be suitable or can you please provide alternative recommendations.

Thank you for your help.

Regards

Gary

  • 0
    TI__Expert 8285 points

    Hi Gary,

    Thanks for reaching out. I think TPS61322, TPS61099 or TPS61021 are suitable for your application. Is there any other features you particularly care about? For example, do you care about the efficiency when the device is sleeping? If that is, I think TPS61099 may be the more suitable because of its ultra low Iq (quiescent current).

    Best Regards,

    Nathan

  • 0
    Prodigy 10 points

    Hi Nathan

    Thank you for your quick and detailed response. This has saved me a lot of time.

    I have gone through the datasheets and the TPS61099 and TPS61021 both look like good options.

    From what I can see the TPS61099 as a much better Iq but it's maximum current limit is very close to what my device will be using, assuming I have calculated it correctly from the equation in the datasheet.

    The TPS61021 has a higher Iq but it looks like it can easily handle the current.

    Have I understood the trade-off's correctly?

    Do you think the TPS61099 will have a problem dealing with brief periods of 300mA current?

    Thanks again for your help!

    Regards,

    Gary

  • 0 in reply to Gary Trehair
    TI__Expert 8285 points

    Hi Gary,

    Yes, TPS61021 has larger current limit but also larger Iq.

    According datasheet, you can see from TPS610994(3.3V fix Vout version) efficiency curve, if Vin = 1.5V, it just can support 300mA output. But if Vin < 1.5V, it may not output 300mA.

    Best Regards,

    Nathan

  • 0
    Prodigy 10 points

    Thanks very much for your feedback Nathan!

    This has been very helpful.