BLF flashlight driver, 17 mm, DD+m

Features

• 17 mm direct drive + 350 mA regulator LED driver
• No OTC - Intended for e-switch, memory-decay or no-memory firmware.
• R5 to eliminate unintentional Vcc boosting during PWM.
• R3 to eliminate unintentional flashing during mode changes.
• Oversized heat plane for the 7135 with good thermal link to the ground ring.
• Generous 0603 pad sizes through-out that will accept 0805 parts as well.
• ‘SS’ SOIC package size for MCU. Tiny85 requires pin-bending to fit.

Revision changes

• Move MCU and 7135 slightly for better programming clip clearance

Suggested parts list

• U1: Atmel Attiny25, SSU or SSN package
• U2: 7135 350 mA LED driver
• Q1: Vishay SiR800DP
• C1: 10 uF, X5R or better, 0603 or 0805
• D1: Schottky diode, 200 mA 20 V or better, 0805 or SOD323
• R1: 22 / 330 kohm, 1%, 0603 (R1, R2 larger values for e-switch lights)
• R2: 4.7 / 100 kohm, 1%, 0603
• R3: 100 kohm, 5%, 0603
• R5: 4.7 ohm, 5%, 0603