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LED Driver Using the LM317

Here is another electronic circuit of a driver for Led, this project is identical to the previously published, to Current Regulator for LED High Brightness 1 Watt tipo estrela ( Led Driver). He is part of a series of publications on Led Driver.

This driver uses the famous voltage regulator LM317, which in this case is configured as a current regulator or Current limiter. This circuit can be easily constructed, low cost and ideal for those with no knowledge of electronics or getting in Hobby.

LED Driver Using the LM317

In the LM317 regulator driver is used as a voltage source 1.25V, where the pin is output with 1.25 Volts relative to the adjustment. The calculation for this drive is simple resistor, V is the voltage regulator output, R is the resistor limiter and Iout is the output current.


Knowing the voltage (In) as we speak is already 1.25 Volts and the current that the LED 1 Watts needs is about 330 mA (+OR-) , the calculation is simple resistor, 1.25 x 330 = R . The result is 4.12 Ohms, rounding the resistor may be one of 4R2 1 Watts. Since this resistor is not standard commercial, We can do this as follows, associating in parallel 3 resistors 12 Ohms por 1/2 Watt.

A resistor 3.9 ohm por 1 Watt will also work perfectly. Do not forget to put the necessary Led and the regulator on a heat sink to prevent overheating, Led does not support high temperatures, the regulator has already a shield and its power decreases with increasing temperature. Soon I will be publishing more for LED driver circuits with different power ratings.

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