Development of film transformer

In order to realize the light and small power supplies, we propose a film shape transformer. This new transformer is constructed by chemical etching process. Experimental works show that this film transformer has about 98% coupling factor over 500 kHz and over 95% efficiency at 1.5 MHz. As an initial test, we applied our film transformer to a push-pull type DC to DC converter and succeeded in obtaining 11 W output power.<>