A LOW POWER HIGH VOLTAGE HIGH FREQUENCY PULSER CIRCUIT DESIGN FOR DENTAL APPLICATION

Abstract

The design of compact high voltage pulser circuits capable of operating at high fre quencies of MHz range remains as a big challenge in modern electronic and biomedi cal engineering fields. Existing pulser circuit design operate at single digit MHz pulse frequency ranges with low repetition rates. Conventional switching and transformer based designs suffer from various switching losses, distorted waveforms and reduced efficiency at high frequencies. This thesis is focused to address this gap of research by presenting the design and simulation results of a voltage pulser circuit design that is ca pable of generating 300V pulses with pulse frequencies ranging from 39kHz to 20MHz with a variable repetition frequency. The design includes a frequency divider circuit, a pulse transformer for transmitting the voltage pulse and analog-digital converters and a microcontroller for further processing the received signal. The proposed design makes use of flip flop based frequency divider circuit to get pulses at various frequencies and a frequency selector topology implemented using ANDlogic. Apulse transformer topology is used to amplify the selected pulse voltage upto 300V. Simulation results show a voltage pulses that has peak voltage above 300V for the required pulse width duration and voltage droop of 20V to 40V. It is also ob served that all the pulse have a 50% duty cycle with rise times of less than 8% of pulse width and fall times of less than 8% of pulse width. Simulation results show an out put current in milliamperes with a power from a 5V DC source. The proposed design serves as a foundation for further study of high voltage high frequency voltage pulser circuit that have uses in dental devices as well as in applications that necessitate such a pulser circuit.