Patent ID: 6144139
Filing Date: 2000-11-07
Classification: H01L,H05B

Abstract:
A piezoelectric transformer inverter comprising:a piezoelectric transformer having a pair of primary electrodes, one of which primary electrodes is grounded, which performs voltage conversion of an alternating input voltage or a direct current input voltage applied between the primary electrodes to supply an output voltage to a load connected to a secondary electrode of the piezoelectric transformer;a drive unit for supplying the alternating input voltage or the direct current input voltage between the primary electrodes of the piezoelectric transformer;a low-pass type resonance circuit unit inserted between an output of the drive unit and the primary electrodes of the piezoelectric transformer;a duty control unit for controlling an ON-Duty of the drive unit so that a value of a current flowing into the load coincides with a targeted current value;a phase-difference detection unit for detecting a phase difference between the input voltage and the output voltage of the piezoelectric transformer; anda frequency control unit for controlling a driving frequency of the drive unit so as to give the phase difference a specified value.