Patent ID: 9111743
Filing Date: 2015-08-18
Classification: H01J,H05B

Abstract:
1. A filament preheat module for preheating a filament of a lamp that is powered by a power circuit comprising an inverter for powering the lamp, the inverter comprising an inductively coupled conductor, the filament preheat module comprising: an inductively coupled conductor, the inductively coupled conductor of the filament preheat module magnetically coupled to the inductively coupled conductor of the inverter, to power the filament during preheating; and a switching circuit configured to electrically connect the power from the inductively coupled conductor of the filament preheat module to the filament, wherein the switching module is configured to cutoff the power to the filament from the filament preheat module after a predetermined time period during the preheating, wherein the switching circuit comprises: a first switch coupled to the filament and configured to enable a current flow through the filament from the inductively coupled conductor of the filament preheat module in a conducting state; a second switch configured to control a state of the first switch between the conducting state and a non-conducting state; and a delay circuit coupled to the second switch and configured to control a state of the second switch between a conducting and a non-conducting state.