Abstract
Development of internal rechargeable battery for totally implantable artificial organs is major problem for transcutaneous energy transmission systems (TETS). Also their charging systems have to be considered. Lithium ion batteries were charged in the constant current (CC), constant voltage (CV) method. A switching mode converter is used for this charge control. However devices are suffered from high frequency and ripple current and voltage. Their risks of failure are relatively high, also size and temperature rise are great concerns. In this study, we examined a new internal rechargeable battery charge system. In which the battery is directly connected to the output of the internal rectifying circuit of TETS, and the charging current is controlled by the external circuit.Our TETS has a series resonant property therefore, by changing driving frequency, the output can be controlled. The input current is sensed and controlled to be a constant current by changing frequency. When the frequency reaches the lower limit, the maximum output voltage is induced. Therefore the rechargeable battery is connected via an overvoltage protective circuit.
