Abstract
Recent studies have shown that functional electrical stimulation can be used to treat neurological disorders, like cardiac dysrhythmia, sensorineural hearing loss, Parkinson's disease, and other diseases. A high voltage neuron stimulator is used in biomedical implantable devices. The chip size is considered to achieve an implantable device. High efficiency of the converter is also important to have long operating life. In this thesis, a neuron stimulator, which provides a functional electrical stimulation, consists of a voltage multiplier and a high voltage driver circuit. A novel hybrid architecture is proposed and analyzed with a mathematical model. The circuit supplies a wide range output voltage of high efficiency with the proposed switching stages circuit operation. The hybrid architecture allows the use of different types of on chip capacitor to minimize the chip area. The proposed circuit technique of parasitic auxiliary path improves the efficiency of the whole circuit. The voltage multiplier with 1V input can achieve 3V to 6V output voltage under the loading current from 30uA to 240uA using a standard 0.18um CMOS process technology. The measurement results demonstrate that the efficiency of the overall system reaches 48% to 58% over a wide range of output voltages. A constant voltage output circuit is transformed into a constant current output circuit. The simulation shows that the 60us pulse width and 120uA constant current functional electrical stimulation is provided by an integrated voltage multiplier and high voltage driver.