Peavey Electronics Corporation

Lee Carlos Santillano

Larry E Hand

James W Brown, Sr

Brian E Attwood

Michael Shawn Craynon

An audio amplifier is provided that adjusts the supply voltage rails communicated to a power amplifier circuit according to the circuit's output. The amplifier compares the output voltage from the power amplifier to a predetermined voltage range to determine if the output voltage is or is not within a predetermined range. If so, the audio amplifier reduces the supply voltage rails for the power amplifier circuit to reduced values. When the output voltage from the power amplifier moves outside the predetermined range, the supply voltage rails return to maximum levels. Whenever the output voltage from the power amplifier is not within the predetermined range, the audio amplifier maintains the supply voltage rails at maximum levels. By reducing the supply voltage rails for the power amplifier circuit, less power is dissipated by the power amplifier circuit, thereby generating less heat in the audio amplifier.

Smart voltage rail reduction audio amplifier

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.

Digital amplifier with pulse insertion circuit

In a digitally controlled amplifier circuit a dc power source is modulated by an oscillator signal for producing a reference square wave signal. A sawtooth signal, double the frequency of the reference signal and synchronized therewith, is compared with a variable input signal to be amplified. When the sawtooth exceeds the input signal a phase shifted version of the reference signal, shifted in phase in accord with the instantaneous amplitude of the variable signal is produced. A switching circuit logically governed by the reference and phase shifted signals produce a pulse width modulated output signal of a selected polarity. An output filter smooths the pulse width modulated output signal and steering diodes control the polarity of the switching circuit.

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Meridian, MS, United States of America

Lee Carlos Santillano