Abstract: The frequency detector includes a first impedance circuit and a second impedance circuit. The first impedance circuit has a first terminal for receiving an input signal, and a second terminal for outputting a divisional signal. The second impedance circuit has a first terminal coupled to the second terminal of the first impedance circuit, and a second terminal coupled to a first system voltage terminal. The frequency response of the first impedance circuit is different from a frequency response of the second impedance circuit. The resistance of the first impedance circuit, a resistance of the second impedance circuit, and the divisional signal change with a frequency of the input signal.

Abstract: An amplification device includes an amplification circuit, an inductor, a regulator, and a impedance circuit. The amplification circuit has an input terminal for receiving a radio frequency signal, and an output terminal for outputting an amplified radio frequency signal. The inductor has a first terminal, and a second terminal coupled to the output terminal of the amplification circuit. The regulator is coupled to the first terminal of the inductor and generates a steady voltage and/or a steady current. The impedance circuit has a first terminal coupled to the output terminal of the amplification circuit, and a second terminal coupled to a first system voltage terminal. The impedance circuit provides a low frequency impedance path to suppress a beat frequency signal in the amplified radio frequency signal.

Abstract: The frequency detector includes a first impedance circuit and a second impedance circuit. The first impedance circuit has a first terminal for receiving an input signal, and a second terminal for outputting a divisional signal. The second impedance circuit has a first terminal coupled to the second terminal of the first impedance circuit, and a second terminal coupled to a first system voltage terminal. The frequency response of the first impedance circuit is different from a frequency response of the second impedance circuit. The resistance of the first impedance circuit, a resistance of the second impedance circuit, and the divisional signal change with a frequency of the input signal.

Abstract: An amplification device includes an amplification circuit, an inductor, a regulator, and a impedance circuit. The amplification circuit has an input terminal for receiving a radio frequency signal, and an output terminal for outputting an amplified radio frequency signal. The inductor has a first terminal, and a second terminal coupled to the output terminal of the amplification circuit. The regulator is coupled to the first terminal of the inductor and generates a steady voltage and/or a steady current. The impedance circuit has a first terminal coupled to the output terminal of the amplification circuit, and a second terminal coupled to a first system voltage terminal. The impedance circuit provides a low frequency impedance path to suppress a beat frequency signal in the amplified radio frequency signal.

Abstract: An amplification device includes an amplification circuit and a protection circuit. The amplification circuit includes a transistor having a first terminal for outputting an amplified radio frequency signal, a second terminal, and a control terminal coupled to the input terminal of the amplification circuit for receiving a radio frequency signal to be amplified. The protection circuit has a first terminal coupled to the output terminal or the input terminal of the amplification circuit, and a second terminal. The protection circuit includes a switch and a first voltage clamping unit. The switch unit is turned on or turned off according to a control signal. The first voltage clamping unit is coupled to the switch unit for clamping a voltage at the first terminal of the protection circuit within a predetermined region when the switch unit is turned on.

Abstract: A control circuit with a bypass function includes a first signal terminal, a second signal terminal, an output terminal, a first switch unit to a fourth switch unit, an output switch unit and a bypass unit. The first signal terminal is used for receiving a first signal. The second signal terminal is used for receiving a second signal. The first switch unit is coupled to the first signal terminal. The second switch unit is coupled between the first switch unit and the output switch unit. The third switch unit is coupled to the second signal terminal. The fourth switch unit is coupled between the third switch unit and the output switch unit. The output switch unit is coupled between the second switch unit and the output terminal. The bypass unit is coupled between the first switch unit and the output terminal to provide a bypass path corresponding to the first signal.

Abstract: An amplification device includes an amplification circuit and a protection circuit. The amplification circuit includes a transistor having a first terminal for outputting an amplified radio frequency signal, a second terminal, and a control terminal coupled to the input terminal of the amplification circuit for receiving a radio frequency signal to be amplified. The protection circuit has a first terminal coupled to the output terminal or the input terminal of the amplification circuit, and a second terminal. The protection circuit includes a switch and a first voltage clamping unit. The switch unit is turned on or turned off according to a control signal. The first voltage clamping unit is coupled to the switch unit for clamping a voltage at the first terminal of the protection circuit within a predetermined region when the switch unit is turned on.

Abstract: A control circuit with a bypass function includes a first signal terminal, a second signal terminal, an output terminal, a first switch unit to a fourth switch unit, an output switch unit and a bypass unit. The first signal terminal is used for receiving a first signal. The second signal terminal is used for receiving a second signal. The first switch unit is coupled to the first signal terminal. The second switch unit is coupled between the first switch unit and the output switch unit. The third switch unit is coupled to the second signal terminal. The fourth switch unit is coupled between the third switch unit and the output switch unit. The output switch unit is coupled between the second switch unit and the output terminal. The bypass unit is coupled between the first switch unit and the output terminal to provide a bypass path corresponding to the first signal.

Abstract: A bias circuit includes a first transistor, a second transistor, a first resistor and a second resistor. The first end of the first transistor is coupled to a first voltage source. One end of the first resistor is coupled to the second end of the first transistor, and the other end of the first resistor is coupled to the control terminal of the first transistor. The first end of the second transistor is coupled to a second voltage source, and the second end of the second transistor is coupled to the control terminal of the first transistor. One end of the second resistor is coupled to the other end of the first resistor, and the other end of the second resistor is coupled to the control terminal of the second transistor.

Abstract: A semiconductor structure includes a first well, a semiconductor element, a second well and a first isolation layer. The semiconductor element is formed on or contacts the first well. The first well is formed on the second well. The first isolation layer is used to reduce a parasitic effect between the first well and the second well. The bottom of the first isolation layer is at least as deep as the bottom of the first well. The first isolation layer substantially forms a first ring structure around the first well. The doping type of the second well is different from the doping type of the first well.

Abstract: A bias circuit includes a first transistor, a second transistor, a first resistor and a second resistor. The first end of the first transistor is coupled to a first voltage source. One end of the first resistor is coupled to the second end of the first transistor, and the other end of the first resistor is coupled to the control terminal of the first transistor. The first end of the second transistor is coupled to a second voltage source, and the second end of the second transistor is coupled to the control terminal of the first transistor. One end of the second resistor is coupled to the other end of the first resistor, and the other end of the second resistor is coupled to the control terminal of the second transistor.

Abstract: A semiconductor structure includes a first well, a semiconductor element, a second well and a first isolation layer. The semiconductor element is formed on or contacts the first well. The first well is formed on the second well. The first isolation layer is used to reduce a parasitic effect between the first well and the second well. The bottom of the first isolation layer is at least as deep as the bottom of the first well. The first isolation layer substantially forms a first ring structure around the first well. The doping type of the second well is different from the doping type of the first well.