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Design Power for Smart Tracking Watch

manh ngo van
Prodigy 10 points
Other Parts Discussed in Thread: BQ2970

Hello everyone,

I am designing wearable device that can tracking GPS and send coordinator of user to server using GPRS and may call/sms when user need it

My question is how to design power for this device?

I use Quectel module that have 2 part is GSM part and GNSS part:

- My battery: 540mAh

- GSM part need 3.3V to 4.6V and about 500mA

- GNSS part need 3.3V and 40mA (at peak current)

I see reference of Quectel, they suggest to use LDO to supply for GNSS. 

Do you have any suggestion for me?

Thank you

  • 0
    TI__Mastermind 27135 points
    Hi Manh,

    We have a reference design for smartwatches that might be helpful to you: www.ti.com/.../TIDA-00712.

    For your battery solution, you will likely want a charger, gauge and protector.

    1. For gauges, take a look at bq27421 to see if it fits your needs. Using an integrated sense resistor would save you some space on your pcb.
    2. For protectors, take a look at the bq2970 family of devices. They control two low side fets which are turned off in the event of a safety related event.
    3. If your device recommends an LDO, look into some of the linear battery chargers. www.ti.com/.../battery-charger-ic-applications.page

    One thing you may want to look into is if your GSM part needs 500mA and your battery is only 540mAh, you will only have a little over an hour of operation.

    Best Regards,
    Ben Lough