Hey guys,
I am in the process of designing a battery powered circuit and had a couple questions regarding the power supply (more specifically extending battery life to as long as possible).
Quick overview of design:
My plan was to use the batteries in series to create 6.0V, then buck this down to 3.3V as efficiently as possible. This will also be convenient for use with the optional 12V dc power adaptor.
I was considering using one of these chips(they vary in cost, efficiency, and quiescent current):
LTC3103
LT1934
LT3990
LTC1174
LM2596
I am slightly confused regarding the "Quiescent Current" and "Shutdown" modes on buck voltage regulators:
Originally I thought that when my microcontroller shuts down and removes power from sensors and transceiver, that the circuit will be draining roughly 10uA, and the voltage regulator will be draining its "Quiescent Current", which ranges from like 1uA to 150uA depending on the regulator. I am finding out that this is only if the regulator is in "Shutdown" mode, otherwise it will be draining a lot more current. But if I am to wire a GPIO pin from the microcontroller to the Shutdown pin of a regulator, then power will be removed from the microcontroller.... how is this supposed to work?
Should I be using an external timer chip to control the Shutdown mode of the regulator and just have the microcontroller lose power completely for several minutes at a time?
I am a bit confused how I should go about this, any help or advice is greatly appreciated, thanks!
I am in the process of designing a battery powered circuit and had a couple questions regarding the power supply (more specifically extending battery life to as long as possible).
Quick overview of design:
- Powered from 2x CR123 batteries (3.0V, 1500mah per battery).
- Optionally powered by a 12V dc adaptor wall wart
- Parallax Propeller microcontroller, when in standby it will draw roughly 10uA
- Various sensors
- Nordic nRF24L01+ transceiver
My plan was to use the batteries in series to create 6.0V, then buck this down to 3.3V as efficiently as possible. This will also be convenient for use with the optional 12V dc power adaptor.
I was considering using one of these chips(they vary in cost, efficiency, and quiescent current):
LTC3103
LT1934
LT3990
LTC1174
LM2596
I am slightly confused regarding the "Quiescent Current" and "Shutdown" modes on buck voltage regulators:
Originally I thought that when my microcontroller shuts down and removes power from sensors and transceiver, that the circuit will be draining roughly 10uA, and the voltage regulator will be draining its "Quiescent Current", which ranges from like 1uA to 150uA depending on the regulator. I am finding out that this is only if the regulator is in "Shutdown" mode, otherwise it will be draining a lot more current. But if I am to wire a GPIO pin from the microcontroller to the Shutdown pin of a regulator, then power will be removed from the microcontroller.... how is this supposed to work?
Should I be using an external timer chip to control the Shutdown mode of the regulator and just have the microcontroller lose power completely for several minutes at a time?
I am a bit confused how I should go about this, any help or advice is greatly appreciated, thanks!