Richwave Technology Corp.

Yi-Fong Wang

Wei-Kung Deng

The present invention discloses an amplifier. The bias amplifier includes a signal input end, for inputting an input signal; a voltage input end, for inputting a source voltage; an amplifying circuit, for generating an amplified input signal according to the input signal, and the amplified input signal comprises a fundamental signal, a first harmonic signal and a second harmonic signal, wherein the first harmonic signal is a second order harmonic of the fundamental signal, and the second harmonic signal is a third order harmonic of the fundamental signal; a harmonic filter, coupled between the voltage input end and the amplifying circuit, for filtering the first harmonic signal and the second harmonic signal; and a signal output end, coupled to the harmonic filter, for outputting an output signal according to the amplified input signal.

Power amplifier with harmonic filter

A bias device includes a transistor, a bias circuit, and an impedance unit. The transistor has a first terminal, a second terminal for providing a first bias voltage to an input terminal of an amplifier, and a control terminal. The bias circuit has a first terminal, a second terminal coupled to a first system voltage terminal for receiving a first system voltage, and a third terminal coupled to the control terminal of the first transistor for providing a second bias voltage to the control terminal of the first transistor. The impedance unit has a first terminal for receiving a first reference voltage, a second terminal coupled to the first terminal of the bias circuit. The first impedance unit adjusts the input impedance looking into the second terminal of the first transistor according to a frequency of a radio frequency signal received from the input terminal of the amplifier.

Bias device

A bias circuit includes a current sensor, a transistor, and a low pass filter circuit. The current sensor has a first terminal coupled to a voltage terminal, and a second terminal. The transistor has a first terminal coupled to the second terminal of the current sensor, a second terminal coupled to a radio frequency signal path for providing a bias signal, and a control terminal for receiving a reference voltage. The low pass filter circuit is coupled between the second terminal of the current sensor and the control terminal of the transistor.

Bias circuit

A protection circuit for use in an RF active circuit includes a signal strength detecting circuit, a current detecting circuit, a logic circuit, and a switching unit. The signal strength detecting circuit is coupled to the signal input end or the signal output end of the RF active circuit and configured to generate a first detecting signal according to the signal strength of the RF signal. The current detecting circuit is configured to detect the VSWR of the RF signal based on the driving current of the RF active circuit, thereby generating a corresponding second detecting signal. The logic circuit is configured to generate a switch control signal according to the first detecting signal and the second detecting signal. The switching unit is configured to lower the driving current of the RF active circuit according to the switch control signal.

Power amplifier and protection circuit for use in RF active circuit

A calibration circuit includes at least two compensation circuits and a comparator. The at least two compensation circuits are coupled to an input signal for outputting at least a first compensation signal and a second compensation signal respectively. The comparator is coupled to the first compensation signal and the second compensation signal for outputting a calibration signal, where the calibration signal is used for determining an oscillation frequency of a crystal oscillator to achieve a purpose of frequency compensation with a temperature.

Calibration circuit of a frequency generator, and compensation circuit thereof

A multi-band electronic apparatus and method thereof is provided. The method comprises outputting a first output signal in the first band by a first voltage controlled oscillator according to a switch control signal and a control voltage, outputting a second output signal in the second band by a second voltage controlled oscillator according to the switch control signal and the control voltage, the second band being not completely overlapped by the first band, performing frequency division selectively on the first output signal or the second frequency divided signal according to the switch control signal, and outputting a first frequency divided signal, determining a phase difference between the first frequency divided signal and a reference signal to output a phase difference signal, outputting the control voltage according to the phase difference signal, and selectively driving the first or the second voltage controlled oscillators by the control voltage according to the switch control signal.

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Taipei, Taiwan

Yi-Fong Wang