| 摘要 |
PROBLEM TO BE SOLVED: To enable a piezoelectric transformer inverter to operate over a wide input voltage range and output current range, by outputting the control voltage corresponding to the phase difference between the output current and voltage of a piezoelectric transformer and, in addition, a pulse voltage signal the frequency of which is controlled based on the control voltage from a phase difference detecting means. SOLUTION: The DC voltage inputted to a piezoelectric transformer inverter through an input terminal 8 connected to an external DC power source 7 is inputted to a driving voltage control means 3 from the terminal 8. The control means 3 connects the input terminal 8 to the source electrode of a p-type FET Q1. The drain and gate electrodes of the FET Q1 are respectively connected to a driving means 2 and a frequency control circuit 5. A diode D1 is connected between the drain electrode and a ground potential so that the direction of the ground potential may be inverted and, in addition, a resistor R1 and a capacitor C1 are also connected in series between the drain electrode and ground potential. The diode D1 is used for holding current by switching the FET Q1 based on a pulse voltage signal from the frequency control circuit 5 by means of a driving voltage control circuit composed of the resistor R1, capacitor C1, and resistors R2 and R3. |
