Patent ID: 7977893

Claim:
An IC for controlling a power supply circuit for delivering power to a load circuit including an output stage, comprising: ballast control and driver circuitry that provides drive signals to the power supply circuit, receives current sense signals indicative of current in said output stage, and responds to the current sense signals by modifying the drive signals; the ballast control and driver circuitry including: drive circuitry that provides the drive signals; and fault detection circuitry that receives the current sense signals and provides a detect signal in response to a fault in the output stage, and in response to said detect signal, causes the drive circuitry to cease providing the drive signals, wherein said fault detection circuitry comprises an internal fault counter that delays termination of said drive signals until a predetermined number of consecutive detect signals have been counted; and wherein said ballast control and driver circuitry is configured to discharge a DC bus voltage from said power supply circuit through an internal MOSFET down to a ballast power off (UVLO-) threshold and said drive signals are latched low when said IC is in a run mode and when said DC bus voltage decreases below 3.0V.