I want to make small (~cigarette pack size) oscillometric blood pressure monitor (with arm cuff). The device will be powered by single cell 3.7V LiPo battery with USB charger circuit, without LCD display or physical buttons.
- ATmega32u4 microcontroller with Arduino bootloader,
- single supply amplifiers,
- 5V or 3V pressure sensor (mpx5050 or mp3v5050),
- 3V air pump + 3V solenoid valves, powered directly from battery, controlled via transistors,
- 3.3V HM-10 BLE module (based on CC2540).
I'm not sure how to power microcontroller, sensor and filtering circuit. The current draw shouldn't be more than 250mA. It can operate on 3.3V or 5V, I would prefer 5V, becouse uC will run faster (16MHz vs 8MHz at 3.3V). I think about TPS61232 boost converter as it offers undervoltage protection and over 90% efficiency. At 5V, p-p output voltage (taken from TI WEBENCH) is acceptable: value at 0.3A is 4.94mV, at 0.2A 3.52mV and at 0.1A 7.53mV.
Is using step-up converter in this case a good solution or are there any better options?