Abstract: The present invention is related to an improved power amplifier and a method for restraining power of the improved power amplifier. The improved power amplifier has an output power restraint unit, and the output power restraint unit is capable of restraining output power of the improved power amplifier when the output power is exceedingly large. A method for restraining power of a power amplifier, the method comprises the steps of: determining whether power of output powers signal are exceedingly large through a power signal transformation unit, if yes, adjusting two variable resistor of an input amplifier unit for adjusting the power of the power signals, and outputting the adjusted power signals for driving a load via output terminals of the power amplifier.

Abstract: An improved self-oscillating audio amplifier and a method for restraining audio distortion of the self-oscillating audio amplifier are disclosed. The improved self-oscillating audio amplifier comprises a distortion restraint unit configured to detect whether modulated audio signals outputted from the self-oscillating audio amplifier is distorted and, if so, to restrain the distortion. The method for restraining audio distortion of the self-oscillating audio amplifier includes the following steps of: determining whether the modulated audio signals outputted from an audio amplifier positive output terminal is distorted by a first flip-flop set, and if yes, restraining the distortion of the modulated audio signals outputted from the audio amplifier positive output terminal; and outputting the modulated audio signals to drive a speaker by the audio amplifier positive output terminal and an audio amplifier negative output terminal.

Abstract: A Class D amplifier capable of setting restraint power is provided, which comprises: an audio amplification unit, a pulse width modulation (PWM) unit, a first pre-drive unit, a second pre-drive unit, a first power transistor set, a second power transistor set and a power restraint unit. The power restraint unit has a comparator circuit and a power restraint circuit. The comparator circuit is configured to compare the level of first/second amplified audio signals against the level of a first reference voltage that is externally settable. When the high level of the first/second amplified audio signals is higher than the level of the first reference voltage, the comparator circuit outputs a first comparison signal and a second comparison signal to the power restraint circuit to restrain the power.

Abstract: A class D amplifier including a PWM circuit, a buffer amplifying circuit, a low-pass filter, and two current sources is provided. The PWM circuit transfers an analog signal into a PWM signal. The buffer amplifying circuit amplifies the PWM signal and generates an amplified signal. The low-pass filter will filter high frequency components out from the amplified signal and then transmit the filtered signal to a loading of the class D amplifier. The two current sources provide currents flowing into and out from a feedback node in the PWM circuit, respectively. The charging and discharging provided by the two current sources can generate a triangular signal for the PWM circuit.

Abstract: A Class D amplifier capable of setting restraint power is provided, which comprises: an audio amplification unit, a pulse width modulation (PWM) unit, a first pre-drive unit, a second pre-drive unit, a first power transistor set, a second power transistor set and a power restraint unit. The power restraint unit has a comparator circuit and a power restraint circuit. The comparator circuit is configured to compare the level of first/second amplified audio signals against the level of a first reference voltage that is externally settable. When the high level of the first/second amplified audio signals is higher than the level of the first reference voltage, the comparator circuit outputs a first comparison signal and a second comparison signal to the power restraint circuit to restrain the power.

Abstract: An improved self-oscillating audio amplifier and a method for restraining audio distortion of the self-oscillating audio amplifier are disclosed. The improved self-oscillating audio amplifier comprises a distortion restraint unit configured to detect whether modulated audio signals outputted from the self-oscillating audio amplifier is distorted and, if so, to restrain the distortion. The method for restraining audio distortion of the self-oscillating audio amplifier includes the following steps of: determining whether the modulated audio signals outputted from an audio amplifier positive output terminal is distorted by a first flip-flop set, and if yes, restraining the distortion of the modulated audio signals outputted from the audio amplifier positive output terminal; and outputting the modulated audio signals to drive a speaker by the audio amplifier positive output terminal and an audio amplifier negative output terminal.

Abstract: The present invention is related to an improved power amplifier and a method for restraining power of the improved power amplifier. The improved power amplifier has an output power restraint unit, and the output power restraint unit is capable of restraining output power of the improved power amplifier when the output power is exceedingly large. A method for restraining power of a power amplifier, the method comprises the steps of: determining whether power of output powers signal are exceedingly large through a power signal transformation unit, if yes, adjusting two variable resistor of an input amplifier unit for adjusting the power of the power signals, and outputting the adjusted power signals for driving a load via output terminals of the power amplifier.

Abstract: The invention discloses a class-D amplifier, which is used for driving a two-terminal load according to a set of analog signals. The D-class amplifier includes a pulse-width modulation (PWM) circuit, a signal processing circuit and a driving amplifier circuit. The PWM circuit receives the set of analog signals and converts them into a set of PWM signals with identical phase. The signal processing circuit generates a set of pulse signals which are attached to the set of PWM signals respectively. The driving amplifier circuit is coupled between the signal processing circuit and the two-terminal load. The driving amplifier circuit receives and amplifies the set of PWM signals. According to the set of PWM signals, the driving amplification circuit drives the two-terminal in a filterless way.

Abstract: A Class-D power amplifier having a distortion-suppressing function includes a gain control unit, a first PWM unit, a second PWM unit, a current control unit, and a level control unit. The level control unit includes at least one D flip-flop and at least one XNOR gate. The D flip-flop has an output end coupled with the gain control unit and an R end coupled with an output end of the XNOR gate. When the Class-D power amplifier has its positive output end and negative output end respectively and simultaneously outputting a high-level signal and a low-level signal to the XNOR gate, the XNOR gate outputs the high-level signal to the D flip-flop. Then the D flip-flop outputs the high-level signal to the gain control unit as feedback for controlling the gain control unit to reduce audio gain, thereby suppressing audio distortion.

Abstract: The invention discloses a class-D amplifier, which is used for driving a two-terminal load according to a set of analog signals. The D-class amplifier includes a pulse-width modulation (PWM) circuit, a signal processing circuit and a driving amplifier circuit. The PWM circuit receives the set of analog signals and converts them into a set of PWM signals with identical phase. The signal processing circuit generates a set of pulse signals which are attached to the set of PWM signals respectively. The driving amplifier circuit is coupled between the signal processing circuit and the two-terminal load. The driving amplifier circuit receives and amplifies the set of PWM signals. According to the set of PWM signals, the driving amplification circuit drives the two-terminal in a filterless way.

Abstract: A class D amplifier including a PWM circuit, a buffer amplifying circuit, a low-pass filter, and two current sources is provided. The PWM circuit transfers an analog signal into a PWM signal. The buffer amplifying circuit amplifies the PMW signal and generates an amplified signal. The low-pass filter will filter high frequency components out from the amplified signal and then transmit the filtered signal to a loading of the class D amplifier. The two current sources provide currents flowing into and out from a feedback node in the PWM circuit, respectively. The charging and discharging provided by the two current sources can generate a triangular signal for the PWM circuit.