A direct power output digital to analog conversion of digital audio signals operates to directly convert digital audio signals into an analog power audio output signal capable of driving a speaker, such that there is no need for further amplification or modification of the audio output signal after the direct power output digital to analog conversion of the digital audio signals. The direct power output digital to analog conversion incorporates a digital-to-analog converter within the same feedback circuit as a current-to-voltage power amplifier by using a single resistive feedback network to supply the feedback signal from the output terminal of the current-to-voltage power amplifier to the summing junction of the same current-to-voltage power amplifier.

A D/A converter comprises a bias circuit including a series circuit of a drain-source of a bias FET and a bias resistor connected between a power source terminal and a reference potential point, the bias circuit includes a negative feedback amplifier to which a reference voltage is supplied, a digital to analog converting section includes a plurality of constant-current source FETs having a current value substantially equal to the current value of the bias FET of the bias circuit, and includes a plurality of current switches for selectively supplying currents of the constant-current source FETs to an output terminal in response to a digital input signal. An output resistor with resistance value Ro is connected to the output terminal to produce an analog output voltage across the output resistor and the resistance of the bias resistor is varied so as to adjust the full scale voltage across the output resistor while maintaining the relationship that the resistance value of the bias resistor is selected by (2.sup.n-1)Ro such that the full scale value of the output voltage is substantially equal to the reference voltage.

A method and system is provided for a digital audio system to reconstruct a digital audio signal using time domain interpolation and direct power digital-to-analog conversion. A signal processor performs the time domain interpolation on an original digital audio signal to allow for the proper recreation of the original audio signal and a direct power output digital-to-analog converter generates an analog power audio output signal from the interpolated digital audio signal that can directly drive a speaker to produce the sound waves represented by the audio output signal. The signal processor and direct power output digital-to-analog converter allow a digital audio system to more precisely reconstruct an analog power output audio signal from a digital audio signal such that there is no need for further amplification of the audio output signal and such that there will be no perceptible difference between the reconstructed digital signal and the original analog signal.

A drive circuit which can drive an IGFET in a non-saturated region over a long period time without reduction in level is disclosed. The drive circuit comprises a series circuit of a plurality of directional elements connected between a power supply terminal and an output terminal, a plurality of control terminals receiving repetitional signals and a plurality of capacitors coupled between the control terminals and intermediate junctions of the series circuit.

A pair of equilibrium output signals P(+) and P(-) from a 1-bit D/A converter IC, which is made up of an oversampling filter, noise shaper and a pulse converter, are supplied to a pair of field effect transistors connected in a common drain configuration. A constant current I.sub.0 is supplied to the common drain from a constant current source and at least one of the source output currents is converted by an output circuit into a voltage. In this manner, a 1-bit D/A converted output signal freed of fluctuations of the power source is provided at an output terminal.