Linear LED driver from Diodes Incorporated simplifies low power LED control

The LED current is set via an external low value resistor, the one additional component required by the driver. By generating a reference voltage of 0.65V across the resistor, the internal high gain transistor helps minimize power losses and ensures supply voltage headroom. The negative temperature coefficient of the reference voltage means that LED current is automatically reduced at high temperatures, thereby helping to protect LEDs and improve circuit reliability.

PWM dimming of the LED string is also simple to achieve by either driving the device bias pin with a low impedance voltage source or driving its enable pin with an external open collector NPN transistor or open drain N-Channel MOSFET. The AL5802’s wide ambient temperature operating range of -40ºC to +125ºC enables it to be circuit mounted very close to the LEDs in space limited lighting applications.