Other Parts Discussed in Thread: , TPS631010
Hello TI Support Forum,
Some facts about the wearable product we are working on:
1) Product is powered by a standard 3V7 1000mAH Li-po / LiFePo rechargable battery. This represents an input voltage range of 3V to 4V2.
2) 3V3 power is required for 3 wireless modules, a 2.4GHz module, a 865MHz – 867MHz module and a 1.2GHz - 1.7GHz module, some LEDs, a 17ohm magnetic buzzer, an accelerometer, etc.
3) Worst case current required is below 600mA peak, the average current is much lesser.
4) When the product is in sleep mode, the current required is around 200-350uA average. In deep-sleep the current is less than 10uA.
5) The battery is charged with a the cheap and common TP4056 battery charger IC.
6) As this is a wearable, we are also space constrained on our 2 layer PCB. Also, our PCB is a 0.8mm thick 2 layer board only!
We have tested a prototype by powering it with the above mentioned battery and the standard AP2114 LDO. It works fine but we cannot utilize the full battery capacity.
We have been looking for a good buck-boost DC-DC converter that will take in 3 to 4V2 and output 3V3@ at least 600mA. We require the converter itself to consume as less current as possible on no-load while still switching since it will always be powered and never off throughout the products lifetime. After spending time on-line we have decided to use the TPS63802DLA. We have looked at the datasheet, ordered (it's still on it's way) the TPS63802EVM. It's relatively a new chip. We also had a look at the Webench design.
Please let us know of any important points that we should consider and bear in mind while designing / working with the TPS63802 as this will be a new design and we can still change it if need be.
We intend for the TPS63802 to directly power the application in place of the LDOs. Is this ok?
Based on the info given above, do you think the TPS63802 would be the right choice for an application such as ours. If not, why?!
We are open to alternate, better suited converter chip suggestions that you may recommend / suggest for this application.
Thanks in advance,