A synchronous rectification using a digital PLL technique for contactless power supplies

Transcutaneous energy transmission systems for the artificial heart with synchronous rectifiers were developed. The input voltage is 24 V and the output voltage is 9 to 18 V. This paper shows the efficiency of the system with synchronous rectifier using a digital PLL technique achieved 92% DC-DC efficiency at 5 mm coil distance. Using the ferrite core and a digital PLL technique, inductor and capacitor were eliminated from the rectifier circuit. And the circuit was mounted to the back of the secondary coil. And we developed the control systems for stable output voltage and apply this result to other contact power supply system.