This repository contains design files for the development board for a flashlight boost driver. The test firmware can be found in the firmware repository.
Also included in the scripts subdirectory are Python scripts used to calculate component values during the design process, as well as generate the look-up table for brightness settings.
For a detailed explanation of this project, check out the video series on the Engineer Bo YouTube channel.
The development board is design in KiCad, and features the following:
- ATtiny1616 microcontroller
- MP3432 boost converter
- LED current regulation
- 1R and 10mR current sense resistances, selectable for high dynamic range (HDR)
- ATtiny1616 DAC controlled current setpoint
- Current regulation using TLV333/OPA333 op-amp and MP3432 feedback pin
- Power switch multi-click counting
- Temperature sensing
- NTC thermistor
- ATtiny1616 internal temperature sensor
- Battery voltage sensing with low current leakage
- Optional potentiometer for current setpoint (highly experimental)
- Test probe hooks
- Headers for all ATtiny1616 pins
- Many jumpers for testing different configurations
This development board is meant to serve as a reference for anybody interested in learning about flashlight boost drivers. It's possible to build these boards, but assembly requires reasonable skill and involves less-than-friendly components e.g. DFN, QFN and many 0402 passives.
Instead, I recommend having a look at the schematics, and leave me a comment on YouTube if you have any questions.
This is the original design built for testing, and includes a couple of issues:
- GPIO driven P-channel MOSFET for HDR MOSFET gate drive
- MP3432 UVLO not configured
- Wrong footprint for NTC thermistor
These issues and their fixes are explained in detail in the video series.
Revision B fixes the issues in Revision A:
- GPIO driven N-channel MOSFET for HDR MOSFET gate drive
- Added MP3432 UVLO