Pulse-Shaping Feed-Forward-Compensated Generator

A typical electrical stimulator has a battery, step-up converter, voltage regulator, pulse generator with a micro-controller providing the clocking signal. This outputs a step response with a specified amplitude and pulse-width. In this work, Single-Ended Primary Inductance Converter (SEPIC) and Cúk converters are built to output a step response without the requirement of a voltage regulator and a pulse generator. The transfer function of both instruments predict a step response that will overshoot but settle to steady-state. This is true when the drive is of a fixed duty cycle. The main contribution of this manuscript is to show that the overshoot can be reduced or completely removed by sending an irregular pulse waveform to the switch, determined from the transfer function of the converters. Sufficiently adjusting the duty cycles of drive pulses forces the converter to rapidly reach steady-state value. As a result, a programmable converter delivers a well-formed pulse of specific length without the need for additional circuitry.