A circuit includes a capacitor-drop power supply including a series combination of a resistor and a first capacitor. The capacitor-drop power supply includes an output and is adapted to be coupled to a light source. The circuit also includes a second capacitor, a switch, and an active clamp circuit. The second capacitor couples to the output of the capacitor-drop power supply. The switch couples in parallel with the series combination of the resistor and the first capacitor. The switch is configured to cause the light source to illuminate. The active clamp circuit couples to the capacitor-drop power supply. The active clamp circuit has an output coupled to the capacitor-drop power supply. The active clamp circuit is configured to cause current to continuously flow through at least one of the switch or the series combination of resistor and first capacitor regardless of a magnitude of the voltage across the second capacitor.