The AL5801″s open-drain output operates between 1.1V and 100V, ensuring common 12V, 24V and 48V power rails are supported, while the LED current is set using an external low value resistor. By generating a 0.56V reference voltage across the resistor, the driver”s internal control transistor helps minimize power losses and ensures sufficient supply voltage margin.
Due to the reference voltage”s negative temperature coefficient, the output current is automatically reduced at higher temperatures, helping to protect the LED chain from any damage, thus improving overall circuit reliability. In addition, 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.
For applications requiring simple LED dimming, the driver supports PWM output-current regulation, achieved by driving its bias pin with a PWM signal via an external open-collector NPN transistor or open-drain N-channel MOSFET.