Effect of dimension on characteristics of Rosen-type piezoelectric transformer

Characteristics of a Rosen-type piezoelectric transformer (PT) were analyzed by combining an equivalent circuit with piezoelectric equations, and the relation between the characteristics and the dimension of the PT was studied. The analyzed results showed that the voltage step-up ratio, efficiency, and power transfer per the square of input voltage depend on the ratio of length to width, l/sub L//l/sub W/, as well as the ratio of length to thickness, l/sub L//l/sub T/, of the PT. The calculated step-up ratio vs. load resistance curve was divided into four regions depending on the value of load resistance, and a suitable dimension of the PT was derived for each region. Then it was concluded that a wide PT has superior characteristics for a small value of load resistance and that a long PT is suitable for a large value of load resistance. The analytical results were also confirmed by experiments.