Patent ID: 7675489

Claim:
A passive matrix display panel comprising: a plurality of rows adapted to be scanned at a predetermined scanning frequency of said display; a row driver for scanning said plurality of rows at said predetermined scanning frequency; a plurality of columns which intersect said rows to form a plurality of pixels characterized by a varying panel capacitance (C p ); a column driver having output buffers configured as voltage followers for applying output voltages to respective ones of said columns to provide gray-scale control of said pixels; a resonant energy recovery circuit incorporating a step down transformer to reduce the effective panel capacitance (C p ) of said display, for receiving electrical energy and in response generating a sinusoidal voltage to power said display at a resonance frequency which is substantially synchronized to the scanning frequency of said display; and a circuit for switching said output buffers to a high output impedance while said panel capacitance (C p ) is discharging so that substantially all discharge current from said panel capacitance (C p ) flows back through a secondary winding of said step-down transformer of the resonant energy recovery circuit.