Piezoelectric transformer wrapped by wrapping member of soft insulating sheet material

An electric power supply device comprising a piezoelectric transformer device, other circuit elements to be connected to said piezoelectric transformer device, and a circuit board having a transformer region on which said piezoelectric transformer device is mounted, an adjacent region on which said other circuit elements are mounted, and a wiring pattern formed thereon to connect said piezoelectric transformer device with said other circuit elements, wherein said piezoelectric transformer comprises:

• a piezoelectric transformer element comprising a piezoelectric rectangular plate having an input region and an output region, primary electrode means formed on said input region of said rectangular plate for receiving a driving voltage as a primary voltage to drive vibration of said rectangular plate by the piezoelectric effect, and secondary electrode means formed on the output region of said rectangular plate for taking out a secondary voltage generated by the vibration of said rectangular plate due to the piezoelectric effect;
• primary lead means connected to said primary electrode means for feeding said driving voltage to said primary electrode means, said primary lead means being connected to said wiring pattern;
• and
• secondary lead means connected to said secondary electrode means for leading out said secondary voltage, said secondary lead means also being connected to said wiring pattern;
• and wherein said electric power supply device further comprises:
• wrapping means of soft insulating sheet material wrapping and grasping said piezoelectric transformer element, said primary lead means, said secondary lead means, and said transformer region of said circuit board together therein.