Power supply and electronic ballast with low-cost inverter bootstrap power source

摘要

A power supply (10) for powering a load (500) includes an inverter (100), a series resonant output circuit (200), and a bootstrap power source (300) for supplying operating power to an inverter driver circuit (110). The bootstrap power source (300) is coupled in series with the load (500) via a dc blocking capacitor (240) and provides automatic shutdown of the inverter (100) by ceasing to supply operating power to the inverter driver circuit (110) when the load (500) fails to conduct current or is removed.