Automotive LED driver simplifies rear lighting designs

Expanding its portfolio of automotive-compliant devices for automotive exterior illumination, Diodes Inc. has released the AL5873Q three-channel linear LED driver with PWM dimming and analog dimming control that simplifies rear lamp cluster designs. Rated for 125°C ambient temperature operation, the device is AEC-Q100 Grade 1 qualified.

Each of the AL5873Q’s channels can drive up to 250 mA, and is set via two reference resistors, which are connected to the driver IC’s REF1 and REF2 pins. Support for two different LED current levels enables more streamlined lighting systems, said the company, because the same LEDs can be used in rear lamp clusters for tail and brake lamps, lowering the bill-of-materials (BOM) cost substantially.

The AL5873Q features analog and PWM dimming control functionality, supporting a maximum PWM frequency of 1 kHz. Diodes said “the PWM dimming function is pivotal in improving current accuracy when LEDs are being driven at low current levels. The current on each channel is regulated to within a ±4% tolerance, which allows better channel-channel matching in the rear combination lamps.” The AL5873Q goes into standby mode if no PWM signal is detected in order to save power. The device also provides a wide input voltage range from 5 V to 55 V.

AL5873Q functional block diagram (Diodes Inc.)

The LED driver offers built-in protection features with a bidirectional (input/output) fault pin, which flags any faults and allows up to four devices to have their fault pins connected together. The device also includes an internal junction temperature monitoring circuit that reduces the LED current if its defined threshold temperature is exceeded, thermal shutdown, LED string-open/-short protection mechanisms, and input undervoltage lockout.

The AL5873Q is supplied in a 16-pin TSSOP package and supports PPAP documentation. The device is priced at $0.50 in quantities of 10,000.

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