Digital amplifier with pulse insertion circuit

Abstract

A digital amplifier having an input for receiving an input signal employs an oscillator for producing a reference pulse signal and a sawtooth signal. A first generating circuit coupled to the oscillator is responsive to the reference pulse signal for producing a first pulse signal of a first polarity. A second generating circuit coupled to the first generating circuit is responsive to said first pulse signal for producing a second pulse signal of a polarity opposite the first polarity. A comparator responsively coupled to the input and said oscillator compares the input signal and the sawtooth signal and produces a comparator output signal operable between first and second states, for toggling the comparator output signal between the first and second states each time the input signal equals the sawtooth signal. The comparator output is maintained in the first or second state when the input signal exceeds the sawtooth signal. A pulse insertion circuit responsively coupled to the comparator and the first and second generating circuits produces an insertion signal during intervals when the comparator output is maintained in either of the first or second states.