Abstract: A power amplifier includes a class-D amplifier and an input signal supplier. The class-D amplifier includes an input portion and a switching device. The switching device is switched according to an input signal that is input to the input portion so that a current is supplied to a load from a power source via the switching device. The input signal supplier supplies the input signal to the input portion of the class-D amplifier, calculates a virtual output voltage to be output from a virtual power source having a prescribed internal impedance characteristic when a current to flow through the load is output from the virtual power source, and adjust an amplitude of the input signal according to the virtual output voltage.

Abstract: A power amplifier includes a class D amplification section and a load current feedback circuit. The class D amplification section includes an input section and a switching section serving as an output stage and switched depending on a signal input to the input section, and outputs current from a power source to a load via the switching section. The load current feedback circuit negatively feeds back the current flowing in the load to the input section of the class D amplification section.

Abstract: A power amplifier includes a class D amplification section and a load current feedback circuit. The class D amplification section includes an input section and a switching section serving as an output stage and switched depending on a signal input to the input section, and outputs current from a power source to a load via the switching section. The load current feedback circuit negatively feeds back the current flowing in the load to the input section of the class D amplification section.

Abstract: A power amplifier includes a class-D amplifier and an input signal supplier. The class-D amplifier includes an input portion and a switching device. The switching device is switched according to an input signal that is input to the input portion so that a current is supplied to a load from a power source via the switching device. The input signal supplier supplies the input signal to the input portion of the class-D amplifier, calculates a virtual output voltage to be output from a virtual power source having a prescribed internal impedance characteristic when a current to flow through the load is output from the virtual power source, and adjust an amplitude of the input signal according to the virtual output voltage.

Abstract: A power amplifier includes a class D amplification section and a load current feedback circuit. The class D amplification section includes an input section and a switching section serving as an output stage and switched depending on a signal input to the input section, and outputs current from a power source to a load via the switching section. The load current feedback circuit negatively feeds back the current flowing in the load to the input section of the class D amplification section.

Abstract: The present invention provides a D/A converter circuit which enables D/A conversion with a high precision and can prevent occurrence of a limit cycle component in the case where an input signal is low, and can also prevent the effect of dither signal from occurring in an analog signal which is a D/A conversion result. A dither signal generation section 505 outputs a dither signal (DITHER) which is an alternating current signal and a reversal dither signal (DITHER_N) inverted from the dither signal. A DEM decoder 502 processes an input digital signal including a component of the dither signal (DITHER), and outputs a plurality of lines of time-series digital signals having a density of “1” or “0” conforming to the input digital signal to be processed. An analog addition section 503 converts a plurality of lines of time-series digital signals and the reversal dither signal (DITHER_N) into an analog signal respectively and adds them, and outputs an analog signal which is a D/A conversion result.

Abstract: The present invention provides a D/A converter circuit which enables D/A conversion with a high precision and can prevent occurrence of a limit cycle component in the case where an input signal is low, and can also prevent the effect of dither signal from occurring in an analog signal which is a D/A conversion result. A dither signal generation section 505 outputs a dither signal (DITHER) which is an alternating current signal and a reversal dither signal (DITHER_N) inverted from the dither signal. A DEM decoder 502 processes an input digital signal including a component of the dither signal (DITHER), and outputs a plurality of lines of time-series digital signals having a density of “1” or “0” conforming to the input digital signal to be processed. An analog addition section 503 converts a plurality of lines of time-series digital signals and the reversal dither signal (DITHER_N) into an analog signal respectively and adds them, and outputs an analog signal which is a D/A conversion result.