Patent ID: 6304039
Filing Date: 2001-10-16
Classification: H05B,Y02B

Abstract:
A power supply for illuminating an EL lamp with a constant current and frequency drive signal having a predetermined limiting voltage level for compensating changes in the EL lamp characteristics, said power supply comprising:means for providing an input voltage power source signal to said power supply, said power supply having EL lamp voltage drive circuit means for generating an EL lamp alternating voltage drive signal having a substantially constant current and frequency;electronic ground fault current interrupter circuit means coupled to said input voltage power supply signal for transferring said input voltage power source signal to said EL lamp voltage drive circuit means, said EL lamp drive circuit means having means for generating a first and second DC high voltage supply signals;PWM low power controller circuit means for generating an alternating voltage pulse signal having a selectable predetermined frequency;transformer logic circuit means coupled to said PWM controller circuit means for receiving said alternating voltage pulse signal and having a first and second transformer logic circuit output means for producing a first and second output alternating voltage signal, said first and second output alternating voltage signal having a 180 degree phase relationship with respect to each other;first electronic switching means having a conductive and non-conductive state coupled to said first transformer logic circuit output means and responsive to said first output alternating voltage signal;second electronic switching means having a conductive and non-conductive state coupled to said second transformer logic circuit output means and responsive to said second output alternating voltage signal;said first electronic switching means and said second electronic switching means connected in series with one another and a resonant circuit means including said EL lamp, one of said first and second electronic switching means further being connected to said first DC high voltage supply signal, the other of said first and second electronic switching means further being connected to said second DC high voltage supply signal, said first and second electronic switching means alternately connecting and disconnecting said first and second DC supply voltage signals respectively to said EL lamp to power said EL lamp with a peak-to-peak AC voltage drive signal at said selectable predetermined frequency and constant current.