A circuit for operating a high intensity discharge (HID) lamp includes an H-bridge connected between a common terminal and a power line, and a control circuit connected to the H-bridge. The control circuit includes a transformer having a primary winding connected between the common terminal and a power terminal and a secondary winding connected between the common terminal and the power line, and a current sense resistor connected in series between the secondary winding and the common terminal. The HID lamp is connected to the common terminal and to the second winding so as sense a current across the current sense resistor.