To drive a totally implantable artificial heart for a long period with trauscutaneous energy transmission, it is necessary that the temperature rise of the devices implanted inside the human body be minimized. In this paper we study the properties of a transcutaneous DC-DC converter which transfers energy from an external source to a vibrating flow pump within the body. The temperature rise of the internal rectifying circuit has been reduced by as much as 30 % to 50 % by employing synchronous rectifiers rather than Schottky diodes. In addition, we have investigated a method for controlling the vibrating flow pump(VFP). This pump would be a constituent part of a totally implantable artificial heart. Also, the use and current limitation of an implanted rechargeable battery for emergency use is discussed.