Low-Cost LED Dimmer using LM3578
- Rajkumar Sharma
- 278 Views
- easy
- Tested
- SKU: EL123601
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This Low-cost LED dimer project includes two main parts, an LM3578 chip, and a MOSFET. The LM3578 generates a PWM signal, and Q1 MOSFET helps to drive a high current LED. The project also includes current limit feature. Over current trigger point is set to 1.1A. LED intensity can be set using a board trimmer potentiometer. The compact and low-profile circuit occupies a very small area. PCB has the option to mount DIP8 IC or SOIC8 IC.
Note: Read the datasheet of LM3578 to alter the PWM Duty Cycle, Current Limit, Operating PWM Frequency etc.
Connections
- CN1: Pin 1 + Pin 2 = VCC and Pin 3 + Pin 4 = GND
- CN2: Pin 1 + Pin 2 = VCC and Pin 3 + Pin 4 = -Load
- PR1: Trimmer Potentiometer to adjust the LED Light Intensity
Features
- Supply 12V DC
- Load Up to 1Amp (1 to 10W – 12V LED)
- Over Current Limit 1.1A
- PWM Duty Cycle 0 to 80%
- PWM Frequency 10Khz
- On Board Power LED
- PCB Dimensions 47.94 x 15.56mm
Schematic
Parts List
NO. | QNTY. | REF | DESC. | MANUFACTURER | SUPPLIER | PART NO |
---|---|---|---|---|---|---|
1 | 1 | CN1 | 4 PIN MALE HEADER PITCH 2.54MM | WURTH | DIGIKEY | 732-5317-ND |
2 | 1 | CN2 | 4 PIN MALE HEADER PITCH 2.54MM | WURTH | DIGIKEY | 732-5317-ND |
3 | 1 | C1 | 10uF/25V SMD SIZE 1210 OR 1206 | YAGEO/MURATA | DIGIKEY | |
4 | 1 | C2 | 1KPF SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
5 | 1 | C3 | 20PF SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
6 | 1 | C4 | 10K PF 0.01uF SMD SIZE 1206 OR 1210 | YAGEO/MURATA | DIGIKEY | |
7 | 1 | D1 | LED-PWR | LITE ON INC | DIGIKEY | 160-1427-1-ND |
8 | 1 | PR1 | 250K TRIMMER POTENTIOMETER | CTS ELECTROCOMPONENTS | DIGIKEY | 262UR254B-ND |
9 | 1 | Q1 | FDD8876 | ON SEMI | DIGIKEY | FDD8876CT-ND |
10 | 2 | R1,R7 | 1K 5% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
11 | 1 | R2 | 120K % SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
12 | 1 | R3 | 100K 5% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
13 | 1 | R4 | 200E 5% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
14 | 1 | R5 | 0.1E/2W 1% SMD SIZE 2512 | YAGEO/MURATA | DIGIKEY | |
15 | 1 | R6 | 1E 5% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
16 | 1 | U1 | LM3578 DIP 8 OR SOIC8 | TI | MOUSER | 926-LM3578AN/NOPB |
PCB accepts DIP8 or SOIC8 for U1 |
Connections
Gerber View
Photos
Video
LM3578 Datasheet
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