Linear Current Source LED Driver with Dimmer Input

Rajkumar Sharma
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SKU: EL136285
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The compact module shown here is a linear current source for LED driver and it’s ideal for automotive LED lighting applications. The project is built using a TLD1211 chip from Infineon. The board provides supply to LEDs under the severe condition of automotive applications resulting in constant brightness and extended LED lifetime. The project is capable to drive high current, high brightness LEDs. The circuit features overload, short circuit, over-voltage, and over-temperature protections. It also has the option to control the LED brightness control by an external PWM signal.

The project can provide an output current of up to 2.5A. You will need to choose the appropriate booster transistor Q1 and sunt resistor R5 to achieve this output. Please refer to the datasheet of the chip for more info.

Dimmer: LED brightness control is possible with an external PWM signal. In this case, you can use the enable pin to feed a PWM signal to control the brightness of the LED. For full current/full brightness apply 5V to Enable Pin or change resistor R1 to 12K and connect it to a 24V LED supply to enable the output.

Features

Operating Voltage 8 to 24V (Maximum 28V)
Load Current 300mA
Constant Current Output
Enable Input for PWM Brightness or ON/OFF
Over Voltage Protection
Very low Standby Current
PCB Dimensions 36.04 x 22.54mm
2 x 2.5mm Mounting Holes

Connections and Other Details

CN1: Pin 1,2 = VCC, Pin 3, 4 = GND
CN2: Pin 1 = Enable or PWM Enput, Pin 2 = GND
CN3: Pin 1, 2 = +LED , Pin 3,4 = -LED

Schematic

Parts List

NO.	QNTY.	REF.	DESC	MANUFACTURER	SUPPLIER	SUPPLIER'S PART NO
1	2	CN1,CN3	4 PIN MALE HEADER PITCH 2.54MM	WURTH	DIGIKEY	732-5317-ND
2	1	CN2	2 PIN MALE HEADER PITCH 2.54MM	WURTH	DIGIKEY	732-5315-ND
3	1	C1	100nF/50V CERAMIC SMD SIZE 0805	YAGEO/MURATA	DIGIKEY
4	1	C2	10uF/35V CERAMIC SMD 1206 OR 1210	YAGEO/MURATA	DIGIKEY
5	1	Q1	MJD3055	ONSEMI	DIGIKEY	MJD3055-ND
6	1	R1	1.8K 5% SMD SIZE 0805	YAGEO/MURATA	DIGIKEY
7	1	R2	1K 5% SMD SIZE 0805	YAGEO/MURATA	DIGIKEY
8	1	R3	820E 5% SMD SIZE 0805	YAGEO/MURATA	DIGIKEY
9	1	R4	100E 5% SMD SIZE 0805	YAGEO/MURATA	DIGIKEY
10	1	R5	0.5E/2W 1% SMD SIZE 2512	YAGEO/MURATA	DIGIKEY
11	1	U1	TLD1211 SOIC8	INFINEON	DIGIKEY	TLD1211SJFUMA1TR-ND