Princeton Technology Corporation

Yung-Ming Lee

Ming-Chung Li

Tzu-Fei Han

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

A voltage clamping module is disposed at an output terminal of a gain amplifying module, so that a voltage level of an amplifying signal outputted by the gain amplifying module can be clamped within a predetermined range. The voltage clamping module includes an upper bound voltage clamping module, which is utilized for limiting the voltage level of the amplifying signal to be lower than an upper bound voltage level, and a lower bound voltage clamping module, which is utilized for limiting the voltage level of the amplifying signal to be higher than a lower bound voltage level.

Voltage controlling circuit

A voltage-controlled amplifier for a signal processing system includes an input voltage reception end, a first voltage-to-current converter, a reference current generator, a gain adjustment circuit, a first current mirror, and an output circuit. The voltage-controlled amplifier adjusts a gain according to a variable control voltage, so as to transfer an input voltage to an output voltage according to the adjusted gain. When adjusting the gain, the present invention changes only an alternating current part of the input voltage, and can decrease noise, the production cost, and increase integration degree.

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Taipei, Taiwan

Yung-Ming Lee