Patent ID: 7598655

Claim:
A piezoelectric transformer driving apparatus characterized in that the apparatus comprises: a first piezoelectric transformer ( 1 ) which comprises primary electrodes ( 1 a and 1 b ) and a secondary electrode ( 1 c ), and in which an output is obtained from the secondary electrode ( 1 c ) by applying an AC power supply to the primary electrodes ( 1 a and 1 b ); and a second piezoelectric transformer ( 2 ), which comprises primary electrodes ( 2 a and 2 b ) and a secondary electrode ( 2 c ), and in which an output is obtained from the secondary electrode ( 2 c ) by applying an AC power supply to the primary electrodes ( 2 a and 2 b ), being a piezoelectric transformer which outputs a voltage of phases reverse to phases of a voltage which the first piezoelectric transformer ( 1 ) outputs, wherein the primary electrodes ( 1 a and 1 b ) of the first piezoelectric transformer ( 1 ) and the primary electrodes ( 2 a and 2 b ) of the second piezoelectric transformer ( 2 ) are connected in series to where an AC power supply is to be applied, and a load (L) is connected between the secondary electrode ( 1 c ) of the first piezoelectric transformer ( 1 ) and the secondary electrode ( 2 c ) of the second piezoelectric transformer ( 2 ), wherein transmission characteristics of said first piezoelectric transformer ( 1 ) and said second piezoelectric transformer ( 2 ) have only one resonance point f 0 even if there is a variation in input impedances at respective resonance frequencies between said first and second piezoelectric transformers ( 1 , 2 ).