2 layers55.6 × 71.2 mm
4 layers44.5 × 44.5 mm
Flashlight
engineerbo/flashlight-dev-hw15This repository contains design files for the development board for a flashlight boost driver. The test firmware can be found in the firmware repository.
- Size
- 44.5 × 44.5 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 73
- Nets
- 51
- Pads
- 226
- Tracks, vias
- 367, 131
- Pours
- 242
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 14 Mar 2024
- Updated
- 13 Apr 2025
Overview
Flashlight is an open-source printed circuit board by engineerbo, from the engineerbo/flashlight-dev-hw repository on GitHub, published under the MIT licence. It is a 4-layer board of 44.5 × 44.5 mm with 73 parts on 51 nets, routed with 367 tracks and 131 vias.
It is built around the ATTINY1616-MN, MP3432GL-Z and 2N7002K, with the 3310C-001-104L, DMC2400UV and ISZ065N03L5SATMA1 among its other parts. Its parts include 24 resistors, 18 capacitors, 5 connectors, 4 ICs and 4 transistors. It belongs with the AVR (ATmega, ATtiny) boards of this library.
Main components
6
ATTINY1616-MN
QFN-20-EP(3x3)-40℃~+105℃ 1.8V~5.5V 10bit 16KB 18 20MHz 256Byte 2KB 8 Bit 8bit AVR Built-in FLASH QFN-20-EP(3x3) Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
MP3432GL-Z
QFN-13(3x4)-40℃~+125℃@(TJ) 1 25uA 3.5A 600kHz 800mV~13V 800mV~16V Adjustable Boost Boost Built-in Overcurrent Protection、Light load efficient mode、Adjustable soft-start、Adjustable current limiting、External compensation Yes QFN-13(3x4) DC-DC Converters ROHSMonolithic Power SystemsDC-DC Converters
2N7002K
SOT-23-55℃~+150℃ 1 N-channel 1.2Ω@10V、1.4Ω@5V 1.6V 2.9pF 300pC@4.5V 30pF 380mA 4.2pF 540mW 60V SOT-23 MOSFETs ROHSDiodes IncorporatedMOSFETs3310C-001-104L
插件,P=2.54mm1 100kΩ 250mW ±1000ppm/℃ ±20% 插件,P=2.54mm Potentiometers, Variable Resistors ROHSBournsPotentiometers & Variable Resistors
DMC2400UV
SOT-563-55℃~+150℃ 1 N-Channel + 1 P-Channel 1W 20V 37.1pF 480mΩ@5V 500pC@4.5V 700mA、1.03A N-Channel + P-Channel SOT-563 MOSFETs ROHSDiodes IncorporatedMOSFETs
ISZ065N03L5SATMA1
TSDSON-8-55℃~+150℃ 1 N-channel 10nC@10V 270pF 2V 30V 40A 40pF 670pF 8.6mΩ@4.5V N-Channel TSDSON-8 MOSFETs ROHSInfineon TechnologiesMOSFETs
README
README.mdFlashlight Dev Board Hardware
Introduction
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.
Features
The development board is designed 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
Usage
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.
Hardware Revisions
Revision A
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
Revision B fixes the issues in Revision A:
- GPIO driven N-channel MOSFET for HDR MOSFET gate drive
- Added MP3432 UVLO
Parts
73| Qty | Value | Footprint | References |
|---|---|---|---|
| 8 | 10k | Resistor_SMD:R_0402_1005Metric | R1, R3, R4, R5, R7, R8, R13, TH1 |
| 8 | TestPoint_Probe | TestPoint:TestPoint_Keystone_5000-5004_Miniature | TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8 |
| 7 | Jumper_3_Bridged12 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | JP1, JP2, JP3, JP4, JP5, JP6, JP7 |
| 6 | 22uF | Capacitor_SMD:C_0805_2012Metric | C8, C9, C10, C16, C17, C18 |
| 4 | 100nF | Capacitor_SMD:C_0402_1005Metric | C4, C6, C13, C15 |
| 4 | 4.7uF | Capacitor_SMD:C_0603_1608Metric | C1, C2, C3, C11 |
| 2 | 130k | Resistor_SMD:R_0402_1005Metric | R19, R24 |
| 2 | 20k | Resistor_SMD:R_0402_1005Metric | R2, R17 |
| 2 | 2N7002K | Package_TO_SOT_SMD:SOT-23 | Q2, Q4 |
| 2 | 750k | Resistor_SMD:R_0402_1005Metric | R6, R23 |
| 2 | Conn_01x10_Pin | Connector_PinHeader_2.54mm:PinHeader_1x10_P2.54mm_Vertical | J4, J5 |
| 2 | Screw_Terminal_01x02 | TerminalBlock_Phoenix:TerminalBlock_Phoenix_MKDS-1,5-2_1x02_P5.00mm_Horizontal | J1, J2 |
| 1 | 150k | Resistor_SMD:R_0402_1005Metric | R9 |
| 1 | 1R | Resistor_SMD:R_0805_2012Metric | R14 |
| 1 | 2.2uH | Inductor_SMD:L_Coilcraft_XAL7070-XXX | L1 |
| 1 | 22k | Resistor_SMD:R_0402_1005Metric | R20 |
| 1 | 22nF | Capacitor_SMD:C_0402_1005Metric | C12 |
| 1 | 24k | Resistor_SMD:R_0402_1005Metric | R18 |
| 1 | 27k | Resistor_SMD:R_0402_1005Metric | R21 |
| 1 | 3.3nF | Capacitor_SMD:C_0402_1005Metric | C5 |
| 1 | 3310C-001-104L | footprints:3310C001503L | VR1 |
| 1 | 3k3 | Resistor_SMD:R_0402_1005Metric | R10 |
| 1 | 430k | Resistor_SMD:R_0402_1005Metric | R16 |
| 1 | 5mR | Resistor_SMD:R_0805_2012Metric | R12 |
| 1 | 6.8nF | Capacitor_SMD:C_0402_1005Metric | C14 |
| 1 | 6k8 | Resistor_SMD:R_0402_1005Metric | R22 |
| 1 | ATtiny1616-M | Package_DFN_QFN:VQFN-20-1EP_3x3mm_P0.4mm_EP1.7x1.7mm | U2 |
| 1 | Conn_01x03_Pin | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J3 |
| 1 | DMC2400UV | Package_TO_SOT_SMD_AKL:SOT-563 | Q1 |
| 1 | DNP | Resistor_SMD:R_0402_1005Metric | R15 |
| 1 | DNP | Capacitor_SMD:C_0402_1005Metric | C7 |
| 1 | ISZ065N03L5SATMA1 | Package_SON_AKL:Infineon_PG_TSDSON-8_FL | Q3 |
| 1 | LOGO | Engineer_Bo_Logo:logo_6mm | LOGO1 |
| 1 | MP3432GL-Z | footprints:QFN-13_MP3431_MNP | U4 |
| 1 | NCP114AMX250TCG | Package_DFN_QFN:OnSemi_XDFN4-1EP_1.0x1.0mm_EP0.52x0.52mm | U1 |
| 1 | TLV333/OPA333 | Package_TO_SOT_SMD:SOT-353_SC-70-5 | U3 |
Questions
How big is the Flashlight PCB?
It measures 44.5 × 44.5 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Flashlight use?
73 parts, built around the ATTINY1616-MN, MP3432GL-Z, 2N7002K and 3310C-001-104L. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Flashlight KiCad files?
From the engineerbo/flashlight-dev-hw repository on GitHub, at the commit this page was made from: the board is rev_b/flashlight.kicad_pcb and its schematic rev_a/attiny1616.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Flashlight design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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