Patent ID: 6847175

Claim:
A lighting ballast circuit comprising: a lamp portion that includes contacts for receiving a light source; a switching portion including: a first transistor; a second transistor in series with the first transistor, the first and second transistors being conductive in alternating periods of time; a first diode in an anti-parallel combination with the first transistor that helps prevent reverse current flow through the first transistor; a second diode in an anti-parallel combination with the second transistor that helps prevent reverse current flow through the second transistor; a third diode connected to an input bus voltage in forward series combination with a collector of the first transistor that further helps prevent reverse current flow through the first transistor; a fourth diode connected to a circuit ground in forward series combination with a collector of the second transistor that further helps prevent reverse current flow through the second transistor; and, a drive portion configured to supply signals to the switching portion.