AL5801 linear LED driver allows for simplification of auto interiors

Published:2012/7/13 3:18:00 Author:Ecco From:SeekIC

The AL5801 linear LED driver allows designers to simplify automotive interior, signage, and general lighting control circuits by adding two additional components. By integrating a 100V rated N-channel MOSFET with a pre-biased NPN transistor, the AL5801 can drive chains of up to 30 low-power, series-connected LEDs with currents from 20mA to 350mA. The device is available in small footprint SOT26 package.

The AL5801 has an open-drain output which operates between 1.1V and 100V. And the output ensures common 12V, 24V and 48V power rails are supported, while the LED current is set using an external low value resistor. The driver’s internal control transistor helps minimize power losses and ensures sufficient supply voltage margin by generating a 0.56V reference voltage across the resistor.

The output current can be automatically reduced at higher temperatures because of the reference voltage’s negative temperature coefficient. Therefore, it helps to protect the LED chain from any damage and improve overall circuit reliability. What’s more, the AL5801's wide operating temperature range of -40°C to +150°C means it can be mounted immediately adjacent to LEDs where PCB space is limited.

The driver also supports PWM output-current regulation in the applications required simple LED dimming. The regulation can be achieved by driving its bias pin with a PWM signal via an external open-collector NPN transistor or open-drain N-channel MOSFET.

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