Patent ID: 8306448

Claim:
A fuser for a printing system, comprising: at least one fuse roller operative to fuse marking material onto a printable media moving along a path proximate the at least one fuse roller; a heating element operative to heat at least a portion of the at least one fuse roller; and an AC-AC power conversion circuit operative to provide electrical power to the heating element, the AC-AC power conversion circuit comprising: an input receiving AC input power from an AC power source, an output coupled with a first terminal of the heating element, an inductance coupled in series with the heating element, first and second rectifiers, the first rectifier being coupled between the input and a first internal node, and the second rectifier being coupled between the input and a second internal node, first and second high speed switching devices, the first high speed switching device being coupled between the first internal node and a third internal node, and the second high speed switching device being coupled between the second and third internal nodes, the high speed switching devices being alternatively turned on in complementary fashion in each cycle of a pulse width modulation period to provide current from the input to the heating element using one of the rectifiers, and first and second low speed switching devices, the first low speed switching device being coupled between the heating element and the first internal node, and the second low speed switching device being coupled between the heating element and the second internal node, one of the low speed switching devices being turned on in at least a portion of each half cycle of the AC input power to provide a conductive path to conduct flyback current from the inductance.