The invention pertains to a switchmode DC-to-AC inverter, and particularly to a self-symmetrized and self-oscillating half-bridge inverter. More particularly, the invention pertains to a high frequency ballast for gas discharge devices, especially for high intensity discharge lamps, including power control,...http://www.google.ca/patents/US5229927?utm_source=gb-gplus-sharePatent US5229927 - Self-symmetrizing and self-oscillating half-bridge power inverter
