Single shot with pulse width controlled by reference oscillator

Abstract

A one-shot structure for controlling pulse widths on integrated circuit chips by using a reference oscillator to compensate the rate at which a capacitor is discharged through a transistor in a reference pulse generator. Compensation is accomplished by using a feedback circuit to control the voltage applied to the transistor in the reference pulse generator. The reference oscillator is used with the reference pulse generator to generate a control voltage which matches the reference pulse to the reference oscillator. The same control voltage is then applied to a desired pulse generator. The desired pulse generator has the same one-shot structure as the reference pulse generator, namely a capacitor and a discharge transistor. The pulse width of the desired pulse generator is determined by scaling the geometry of the capacitor and the discharge transistor in the desired pulse generator relative to the geometry of the corresponding components in the reference pulse generator. These relative geometries remain consistent within relatively small tolerances for a chip in a typical integrated circuit process, compared to relatively large variances between design values and absolute chip geometries.