Design of the Dual-output Piezoelectric Transformer based on Load Current Balance

When a piezoelectric transformer (PT) connected with two slight different loads, the load currents will not be equal, especially in the case with large loading currents. The current balance issue is thus one of significant issues on the design of dual-output PT which expected to deliver equal current to external loads. The condition of the load currents balance and imbalance for dual output PT will be discussed in this paper. The inherent equivalent circuit components of PTs could be adopted to replace external reactive component in conventional balanced circuit. By setting the operating frequency and designing the parameters in the equivalent circuit of PTs, the current balance condition can be accomplished by itself. A dual-output Rosen-type piezoelectric transformer with size 53x15x2.6mm was adopted as the testing specimen to verify the theoretical prediction. The experimental verification will also be detailed in this paper.