Princeton Technology Corporation

Ming-Chung Li

Ming-Hsiung Chen

Shang-Shu Chung

Yung-Ming Lee

I-Chi Lin

Yi-Fan Shih

A gain controlling system, a sound playback system, and a gain controlling method thereof are disclosed. The gain controlling system includes a main gain control unit, a sub gain control unit, and a logic control unit. The main gain control unit has a first step-by-step adjusting magnitude; the sub gain control unit has a second step-by-step adjusting magnitude; wherein the second step-by-step adjusting magnitude is smaller than the first step-by-step adjusting magnitude. The logic control unit is used for controlling the main and the sub gain control unit to transform an analog signal into a converted signal according to an adjustment command signal and further determining whether an adjusting magnitude required by the adjustment command signal is larger than a maximum gain range of the sub gain control unit. If yes, the logic control unit controls the main control unit and the sub gain control unit repeatedly.

Gain controlling system, sound playback system, and gain controlling method thereof

An amplifying circuit capable of suppressing spikes of an audio signal includes an integration module, a comparison module, an output module, a feedback module, and a limiting module. The integration module is used for receiving an input signal and generating a first voltage signal corresponding to the input signal. The comparison module is coupled to the integration module for receiving the first voltage signal and a reference signal, and generating a comparison signal. The output module is coupled to the comparison module for generating an audio signal according to the comparison signal. The feedback module is coupled between the output module and the integration module for feeding back an output signal to the integration module. The limiting module is coupled between the feedback module and the integration module for limiting the comparison signal to be within a predetermined range.

Amplifying circuit capable of suppressing spikes of an audio signal

A class-D power amplifier capable of reducing electromagnetic interference includes an integrator, a triangular wave generator, a comparator, a gate driver, a feedback circuit, and an output stage circuit. The integrator is used for receiving an input signal and potential of ground, and outputting a first voltage. The comparator is used for comparing the first voltage with a triangular wave generated by the triangular wave generator to output a pulse-width modulation signal. The gate driver is used for driving the output stage circuit to output an output voltage according to the pulse-width modulation signal. Therefore, the class-D power amplifier reduces the electromagnetic interference by the triangular wave.

Class-D power amplifier capable of reducing electromagnetic interference and triangular wave generator thereof

An audio playback apparatus is disclosed. The audio playback apparatus processes an audio signal and provides at least one output signal to at least one speaker or an earphone connected to a phone-jack. The audio playback apparatus comprises a clock generating module, a processing module, an amplifier module, and a detecting module. The processing module is connected to the clock generating module and processes the audio signal to generate a processed signal according to a clock signal generated by the clock generating module. The amplifier module amplifies the processed signal to generate an output signal. The detecting module detects whether the earphone is plugged in the phone-jack. If the earphone is plugged in the phone-jack, the amplifier module provides the output signal to the earphone. If not, the amplifier module provides the output signal to the speaker.

Audio playback apparatus

An audio control apparatus. The audio control apparatus comprises a processing module, an amplification module, and a control module. The processing module receives and processes an audio signal according to a control signal, and generates a processed signal. The amplification module coupled to the processing module, amplifies the processed signal to generate an output signal. The control module coupled to the processing module and the amplification module, receives the output signal to generate the control signal.

Audio control apparatus

An audio signal processing apparatus is provided. The audio signal processing apparatus comprises a clock generator, a processing module, an amplifying module and an output module. The clock generator is used for generating a clock signal. The processing module is coupled to the clock generator for processing the clock signal and generating a processing signal. The amplifying module is coupled to the processing module for amplifying the processing signal and generating an amplifying signal. The output module is coupled to the amplifying module for outputting the amplifying signal.

Audio signal processing apparatus

An audio amplifier includes a plurality of sub-audio amplifier sets, a clock source, and a speaker. When the audio amplifier is under an audio amplify mode, the plurality of sub-audio amplifier sets is operated under a synchronic operating frequency with a same clock signal generated by the clock source. When the audio amplifier is under a self-oscillation mode, the clock signal is isolated from being input to the plurality of sub-audio amplifier sets. A higher distortion is prevented by repeatedly charging and discharging an oscillating capacitor of a sub-audio amplifier in a sub-audio amplifier set.

Audio amplifier capable of performing self-oscillation

In a speaker system, pulse width modulation signals are utilized for driving said speaker system, and duty cycles of both left audio channel signals and right audio channel signals of an earphone in said speaker system are modulated by said pulse width modulation signals. When the left audio channel or the right audio channel of the earphone has no inputted audio signals with the abovementioned modulated duty cycles, the speaker system may be prevented from unnecessary power consumption. Besides, audio signals from both the left audio channel and the right audio channel of the earphone and outputted from the speaker system may thus be synchronized further by both the pulse width modulation signals and a sawtooth wave source for generating said pulse width modulation signals, for reducing noise and increasing an output audio quality of the speaker system. The abovementioned speaker system is preferably utilized for a Class D amplifier.

Speaker system of utilizing pulse width modulation signals for saving idling power consumption

After coupling a first voltage source to a voltage supply circuit, a second voltage source having a same electrical level but an opposite electrical pole with said first voltage source is generated. An audio amplifier is then driven by both the first voltage source and the second voltage source, where said audio amplifier requires a pair of voltage sources having the same electrical level but opposite electrical poles to be driven. The voltage supply circuit generates the second voltage source from the first voltage source by simultaneously switching two sets of switches, where said both sets of switches have non-synchronous statuses in switching.

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Taipei, Taiwan

Ming-Chung Li