A high frequency electronic ballast for main loads, such as an HID lamp, includes a regulated low voltage output to drive auxiliary loads. A low voltage microcontroller generates a low voltage drive signal in response to voltage and frequency of a high voltage power supply. A switch operably connected to the high voltage power supply and responsive to the low voltage drive signal provides the regulated low voltage output to drive the auxiliary devices, such as a back-up incandescent lamp and/or an insulation detector. In one embodiment, the low voltage output may be responsive to the HID lamp power, e.g., a control signal from a ballast microcontroller, so that the back-up incandescent lamp is energized when the HID lamp is not providing sufficient illumination.