The TLE4309 is an integrated adjustable constant current source for driving loads up to 500 mA. The output current level can be adjusted with an external shunt resistor. Supplying high power LEDs with the TLE4309 ensures constant brightness independent from supply voltage or LED forward voltage spread. Therefore, LED lifetime is extended by protecting from overcurrent and overtemperature The PWM/EN input permits LED brightness regulation by pulse width modulation. Setting the pin to "low" switches off the IC entirely. Due to the high impedance of the PWM/EN input, the TLE4309 can be used as a protected high side switch. Protection circuits prevent from damage to the IC in case of overload, short circuit, and reverse polarity. A chip temperature monitoring circuit shuts off the power stage and prevents the IC from destruction under fault conditions. In case of negative input voltage, a leakage current is flowing only from the output to the input, hence the LED are protected against reverse supply. Input voltage peaks up to 45 V are absorbed by the IC, preventing the LEDs from overcurrent. The TLE4309G is provided in the surface mounted PG-TO-263 package with excellent thermal resistance.