DIGITAL CONTROL ELECTRONIC BALLAST EMPLOYING PIEZOELECTRIC TRANSFORMER

摘要

PROBLEM TO BE SOLVED: To obtain a digital control electronic ballast employing a piezoelectric transformer for applying stabilized voltage and current to a lamp. SOLUTION: The digital control electronic ballast comprises a section 41 for rectifying low frequency AC power to produce DC power, a section 42 for compensating loss of power factor due to variation of low frequency AC power supply to sustain DC output power from the rectifying section 41 at a constant level, an inverter section 43 for switching a constant DC output power from the power factor compensating section 42 to produce a high frequency power supply signal, a resonance section comprising a coil (L) coupled with the output of the inverter section 43 and a high output piezoelectric transformer (T) and transmitting high frequency power from the inverter section 43 to a lamp, and a digital control section 48 for controlling iluminance of the lamp by modulating the frequency for controlling the switching period at the inverter section 43 when the lamp is lighted/unlighted wherein the input electrode has rhombic or diamond shape and the lamp capacitor is eliminated.