Linear LED driver from Diodes for display and lighting applications
Diodes has introduced a new 36-channel automotive-compliant linear LED current driver. The AL5887Q, with its ability to drive RGB configurations as well as individual LEDs, addresses the need for OEMs to differentiate their brands by enabling designers to create different animated lighting patterns and colour depths for interior and exterior lamps. This dual-role control capability simplifies the design of these once-complex LED-based modules and, coupled with its high efficiency, saves valuable power. Applications include interior ambient lighting, rear lighting, exterior EV charging status indicators, infotainment systems, and more.
The AL5887Q supports up to 12 RGB LED modules with three programmable banks (A, B, C) for software control of each colour. An external resistor sets the output current of all 36 channels. Using the hardware-selectable digital interface (INT_SEL pin), lighting designers have the option to select either I²C or SPI for full system programming flexibility. Each channel current is configurable up to 70mA, enabling full optimisation of the visual clarity of the LEDs, which avoids the need for paralleling. Designers also benefit from the device’s automatic power-saving mode of 15µA and ultra-low quiescent shutdown of 1µA when all LEDs are off for more than 30ms, helping minimise unnecessary energy draw from the car’s battery.
The device has multiple protection features, including an open drain FAULT pin for fault reporting and overtemperature protection (OTP) with pre-OTP warning. The individually addressable fault mask registers and open/short registers allow designers to enable and disable fault reporting for each of the 36 channels within the lighting system. Any unused RGB channels can be disabled by the LED configurable registers.
The AL5887Q features a built-in 16MHz oscillator for PWM dimming, eliminating the need for an external clock, which reduces the PCB footprint of the lighting modules, eases design and layout, and lowers bill-of-material (BOM) costs. To optimise colour mixing and minimise audible noise, it uses a 12-bit PWM addressable register along with a 30kHz internal PWM generator. The device supports deep PWM dimming by modulating the duty cycle of the constant current from 100% to 3%. Once the duty cycle is below 3%, the internal circuitry transitions the PWM signal to analog dimming to maintain the overall linearity. The AL5887Q has 3% device-to-device and channel-to-channel current accuracy, which enables designers to create precise colour mixing and uniform colour distribution across their lighting modules and displays.
The AL5887Q is specified for an operating temperature range of -40°C to +125°C and is available in the small-footprint wettable W-QFN6060-52/SWP (Type A1) package, occupying only 6mm x 6mm.
