BLF flashlight driver for cheap SRKs, 46 mm, 5.6 A + m

Features

• Intended for the current generation of cheap SRKs where the thermal design is not great. Maximum current can be selected up to 6 A by populating the corresponding number and type of 7135 regulators.
• Dual channel (15+1 7135)
• No OTC - Intended for memory-decay or no-memory firmware.
• R5 to eliminate unintentional Vcc boosting during PWM.
• Cell voltage read upstream of D1.
• Oversized ground ring with good thermal connection to the 7135s.
• Full size SOT-89 electrical pads for the 7135s.
• Generous 0603 pad sizes that will accept 0805 parts as well.
• Accepts Tiny13A-85 package size for MCU.

Revision changes

• New

Suggested parts list

• U1: Atmel Attiny25, SSU or SSN package
• U2-17: 7135 350 mA LED driver
• C1, C3: 10 uF, X5R or better, 0603 or 0805 (C3 is optional)
• C2: 0.1 uF, X7R, 0603
• D1: Schottky diode, 200 mA 20 V or better, 0805 or SOD323
• R1: 300 kohm, 1%, 0603
• R2: 100 kohm, 1%, 0603
• R5: 4.7 ohm, 5%, 0603
• R6: 330 ohm, 5%, 0603 (optional, to drive an indicator LED from MCU pin 3)
• R7: 330 ohm, 5%, 0603 (optional, to drive an indicator LED from MCU pin 7, do not populate R1, R2 if doing this)
• R8: 330 ohm, 5%, 0603 (this one is just a jumper,1R - 10k will work)