Patent ID: 7768213

Claim:
A circuit for driving a predominantly capacitive load, the circuit comprising: a primary circuit; a secondary circuit connected to the predominantly capacitive load; and a transformer device with a primary side and a secondary side connecting the primary circuit with the secondary circuit, wherein the primary circuit comprises: a source device supplying power via the transformer device for operating the predominantly capacitive load, a drain device or absorbing at least a part of said power, which is reflected back from the predominantly capacitive load during operation, a switch for switching a current on the primary side of the transformer device, and a diode reverse connected across the switch so as to conduct a reverse current through the primary side of the transformer when the switch is turned off, wherein the transformer device is of a transformer type with a gap for transforming an input voltage-current-signal on the primary side to an output voltage-current-signal for supplying the predominantly capacitive load on the secondary side, wherein the source device is in serial connection with the transformer device, the drain device, and the switching device, and wherein the transformer device comprises means for forming a resonant tank circuit with the predominantly capacitive load.