LED Dimmer for Super High Brightness LEDs

  • Rajkumar Sharma
  • 37 Views
  • easy
  • Tested
  • SKU: EL125039
  • Quote Now

This is a high-efficiency and reliability DC/DC converter with a dimming feature for super high brightness LEDs.  The project is built using L6902D chip. L6902 is a complete and simple step-down switching regulator with adjustable current limit. The current control loop with external sense resistors R6, R7, and R8 are able to work in constant current mode providing up to 350mA output current with an accuracy of 5%.  Potentiometer PR1 helps to control the dimming of the LEDs. PR1 is connected to the 3.3V reference pin of the chip. When the dimming (CS+) pin is grounded (0V) the maximum output current is provided (350mA) and vice versa when 3.3V is applied to the pin, the current provided is zero and so the LED is off.

Features

  • Supply 24V DC (Range 8 to 24V DC)
  • Load 6 x LEDs in Series (High Brightness LEDs)
  • Output Current Adjustable 0 to 350mA
  • Short Circuit or Over Current Protection
  • Switching Frequency DC-DC Converter 250Khz
  • 4 x 2.5MM Mounting Holes -PCB
  • PCB Dimensions 40.64 x 26.04 mm

Schematic

Parts List

NO.QNTY.REF.DESC.MANUFACTURERSUPPLIERPART NO
11CN12 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5315-ND
21CN22 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5315-ND
31C122uF/50VPANASONICDIGIKEYPCE4797CT-ND
41C210uF/35VYAGEO/MURATADIGIKEY
51C322KPF/50V SMD SIZE 0805YAGEO/MURATADIGIKEY
61C4220PF/50V SMD SIZE 0805YAGEO/MURATADIGIKEY
71D1MBRS360ONSEMIDIGIKEYMBRS360T3GOSCT-ND
81L1100uH/1AMPTDKDIGIKEY445-180842-1-ND
91PR15K TRIMMER POTENTIOMETERAMPHENOL PHIERDIGIKEY1993-1136-ND
101R12.2K 5% SMD SIZE 0805YAGEO/MURATADIGIKEY
111R28.2K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
121R31K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
131R49.1K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
141R527K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
153R6,R7,R81E 1% SMD SIZE 1206YAGEO/MURATADIGIKEY
161R9510E 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
171R105.1K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
181U1L6902 SOIC8STDIGIKEY497-5330-1-ND
191D2LED RED SMD SIZE 0805LITE ON INCDIGIKEY160-1427-1-ND

Connections



Gerber View

Photos

Video

L6902D Datasheet

L6902D

PCB

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