Power amplifying apparatus

Abstract

A power amplifying apparatus which is of a switching type and capable of efficiently amplifying a power of an input AC signal such as an acoustic signal, includes a first switch circuit (11) and a second switch circuit (12) to which a power supply voltage Vc is applied, an inductor (13) and a load (14) which are connected between the switch circuits, and a control circuit (15) which receives an input AC signal Vi, sets a predetermined ratio of ON/OFF periods, and drives the switch circuits. The control circuit (15) includes an arithmetic circuit (20) which multiplies a modulation sensitivity (for example, an amplitude of a triangular wave voltage used for generation of a pulse signal for driving a switch circuit) by a ratio (Vc/Ec) of the power supply voltage Vc and a DC component Ec thereof. This configuration can compensate for distortion caused by a ripple variation of the power supply voltage due to regenerated power or the like, and enable a gain control by the power supply voltage.

Dependencies are inferred from the claim text.