Abstract: A low noise method and apparatus for driving electroluminescent (EL) panels provides reduction in EL panel noise, and in the preferred embodiment, voltage compensation as the EL panel ages. The output of a high voltage power supply is applied to the EL panel through a circuit having an optimized time-constant, producing a waveform that reduces EL panel vibration. Additionally, if the time constant is derived in part from the capacitance of the EL panel, the time constant may be chosen such that aging of the EL panel maintains the time constant in the proper range to maintain noise reduction over the life of the panel and compensate for brightness reduction due to aging of the EL panel.

Abstract: A low noise method and apparatus for driving electroluminescent (EL) panels provides reduction in EL panel noise, and in the preferred embodiment, voltage compensation as the EL panel ages. The output of a high voltage power supply is applied to the EL panel through a circuit having an optimized time-constant, producing a waveform that reduces EL panel vibration. Additionally, if the time constant is derived in part from the capacitance of the EL panel, the time constant may be chosen such that aging of the EL panel maintains the time constant in the proper range to maintain noise reduction over the life of the panel and compensate for brightness reduction due to aging of the EL panel.

Abstract: A method for improving the efficiency of H-bridge electrical switching devices that drive a capacitive load such as electroluminescent lamps, liquid crystal devices and piezoelectric transducers. The method provides for discharge steps that first discharge the capacitive load to a difference in voltage potential of zero (0) volts before re-charging from the opposite side. By implementing the method, the DC power supply will only be required to charge the capacitive load from zero (0) volts to +Vcs volts, rather than +Vcs volts to -Vcs volts as in prior art. With less energy required from the DC power supply to accomplish the same result, a more efficient switching network is achieved.