Modulated Triangular Wave Amplifier

Abstract

The invention is a power amplifier circuit for providing a signal acceptable for use in audio amplifiers or similar applications without requiring a stable power supply free from fluctuations. An alternating current power supply signal rectified to a direct current signal is processed by two voltage multipliers. A voltage divider establishes a unity gain level, and the variance from this voltage is squared by the first voltage multiplier. This squared voltage is then multiplied with a triangular wave signal to generate a modulated triangular wave signal. The modulated triangular wave signal and a signal to be amplified, typically an audio signal, are processed by an internal comparator to generate a pulse width modulated signal. This modulated signal is processed by a power transistor network and filter to provide an amplified signal to a load device. By modulating the triangle wave signal to compensate for fluctuations in the power supply to the amplifier circuit, noise or ripples present in the power supply are demodulated, eliminating the requirement for a regulated power supply.

I claim: 
     
         1 . A power amplifying device processing an input alternating current power signal comprising:
 a rectifier that produces a direct current power signal from the input alternating current power supply signal;   a first voltage multiplier receiving a first input signal and a second input signal derived from voltage division of the direct current power signal, and producing a first output signal;   a second voltage multiplier receiving a third input signal from the first output signal and a fourth input signal, and producing a second output signal;   a pulse width modulation controller receiving a fifth input signal from the second output signal and a sixth input signal from an audio input signal, and producing a third output triangular wave signal as the fourth input signal, and producing a fourth output signal; and,   whereas the power amplifying device produces an output power signal based on the fourth output signal and the direct current power signal.