Diodes has is aiming at automotive LED strings with a boost and SEPIC (single-ended primary-inductance converter) controller, that can also be wired as a voltage regulator.

Diodes automotive SEPIC LED driver
Called AL8853AQ, it is qualified to AEC-Q100 and implements current-mode and fixed-frequency (400khz) PWM control. Slope-compensation is included to prevent sub-harmonic oscillation at duty cycles >50%.

The IC requires an external n-channel power switching mosfet. Mosfet and LED current is sensed through an external grounded current-sense resistor whose voltage is compared with a 200mV internal reference. Via a potentiometer instead of a single resistor, the same 200V reference is when the converter is used as a voltage regulator.

A separate input provides output over-voltage protection (for example against open-circuit LEDs) by comparing a potentiometer connected to the output with a 2V threshold.

Another input allows an incoming PWM signal to control analogue dc LED dimming down to 1%, and provides an enable-disable function. PWM input frequency can range across 5 to 50kHz and the input’s logic thresholds are 1.3V and 2.5V.

Other protections include: external mosfet over-current, diode short, inductor short, LED cathode-to-ground short, IC power rail under-voltage lock-out, output voltage short and over-temperature.

Intended to nominal 12V systems, the IC can accept power between 6 and 40V. Packaging is SO-8.