LiPo Power Rails
Closed this issue · 3 comments
Describe the solution you'd like
Create a 3.3V power rail for the glove PCB, powered with the 3.7V Li-Po battery.
- Find a buck/boost converter that will allow a single cell Li-Po battery to power the glove hardware from 3.7V down to 3.0V (the full battery life).
- What is the DC-DC circuit for on the VCORE and VSW pins in the MSP432 schematic pg. 36?
Describe alternatives you've considered
Was originally planning to use a 3.3V linear voltage regulator, but I realized that the voltage dropout was too high (~300 mV). This would mean that the battery could only power the circuit from 3.7-3.6V.
Additional context
TPS63020 Buck/Boost Converter will allow use of the battery from 3.7V down to 3.0V.
Using the TPS63020DSJT set to output 3.3V. I have added a header that will need to be shorted in order to make the buck/boost converter the 3.3V power rail for this system. This will be useful for debugging because I can make the DAD board the power supply while debugging board issues.
In order to estimate the battery's Open Circuit Voltage (OCV), the microcontroller needs to be able to power other hardware on/off. My solution to this is to include a P-channel power MOSFET that supplies the buck/boost output voltage to the rest of the circuit. The FET gate can be toggled with a uC GPIO pin.
When the uC powers off the rest of the hardware, only the MSP432 and the TPS63020 buck/boost converter will be using the battery voltage. I believe this is about as close to OCV that I can get while still having my microcontroller running.
Right now, I am using a 4P03L04 for this purpose.
Added in a high power MOSFET where the output is the source of the glove's 3.3V power rail. The gate can be controlled by an MSP432 GPIO to enable/disable power from the rest of the circuit.
