Diodes AL5802 linear LED driver

Integrating a high gain NPN transistor with a 30 V rated pre-biased NPN output transistor, the AL5802 linear LED driver from Diodes provides a low EMI solution for controlling current in up to nine low-power, series-connected LEDs.

With an open collector output capable of operating between 0.8 to 30 V, the SOT26 packaged driver will support 12 and 24 V power supplies and deliver LED currents ranging from 20 to 100 mA for LED signs, lamps and motor vehicle interior displays.

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 0.65 across the resistor, the internal high gain transistor helps minimise power loss 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 wide ambient temperature operating range of -40 to 125ºC enables it to be circuit mounted very close to the LEDs in space-limited lighting applications.