Microchip's HV9805 driver integrated circuit (IC) is targeted at general LED lighting products, such as LED lamps and LED lighting fixtures with a maximum power rating of about 25 W at 120 V_AC and about 50 W at 230 V_AC.

A two-stage topology provides true constant current drive for the LED load while drawing mains power with high power factor. The first stage, a boundary conduction mode boost converter, transfers power from the AC line to a second stage with high power factor and high efficiency. The second stage, a linear regulator arranged for operation with low overhead voltage, transfers power from the first stage to the LED load with true constant current and protects the LED load from overvoltage that may pass from mains to the output of the first stage.

The IC is particularly geared to drive a high voltage LED load. An LED load arranged as a high-voltage load is capable of offering cost advantages in terms of heat management and optics. The boost converter employs a cascode switch for high-speed switching and convenient generation of the V_DD supply. The control device of the cascode switch is an integral part of the HV9805 and is rated at 700 mA peak. Current for powering the V_DD supply is derived by way of an internal connection to the cascode switch. Applications with low output voltage can be accommodated using the SEPIC topology.