Power supply for use with switched anode field emission display

Abstract

A switching power supply 38 for use in a switched anode, field emission flat panel display includes energy recovery modules 48.sub.R, 48.sub.G and 48.sub.B for recovering energy from each anode electrode 50.sub.R, 50.sub.G and 50.sub.B of the display as the voltage on the anode V.sub.A is switched from a high level to a low level, and for restoring this energy to the anode as the voltage is returned from the low level back to the high level. Each energy recovery module 48 includes a capacitor 62 for storing charge and an inductor 60 for storing energy. During the deactivation period of each anode electrode 50, dc source 40 is uncoupled from anode electrode 50 and energy is transferred from the anode electrode 50 to inductor 60, and subsequently from inductor 60 to storage capacitor 62. During the re-activation period, energy transfers from storage capacitor 62 to inductor 60 and anode electrode 50, and subsequently from inductor 60 to anode electrode 50. All of the recovered energy (minus the circuit losses) is returned to anode electrode 50. At this time, dc source 40 is recoupled to anode electrode 50, providing current thereto. The transfer and storage of energy, and its reuse when the anode electrode 50 is switched back to its high voltage state, allows the recovery of as much as eighty percent of the energy applied to the anode electrodes.