The Microchip HV9861A is a patented, average-mode, constant-current control LED driver IC operating in a constant off-time mode. Unlike the HV9910B, this control IC does not produce a peak-to-average error, and therefore greatly improves the accuracy, line, and load regulation of the LED current without any need for loop compensation or high-side current sensing. The output LED current accuracy is ±3%. The IC is equipped with a current-limit comparator for hiccup-mode output short circuit protection. Internal over-temperature protection is provided.

The internally regulated voltage (V_DD) for the HV9861A is 7.5 V. The IC can be powered from a 15 V to 450 V supply. A PWM dimming input that accepts an external control TTL-compatible signal is provided. The output current can be programmed by an internal 270 mV reference, or controlled externally through a 0 V to 1.5 V dimming input. The IC is pin-to-pin compatible with the Supertex HV9910B and HV9961, and can be used as a drop-in replacement for many applications to improve the LED current accuracy and regulation.