Abstract: A coupler structure includes a main signal line, a first coupling line, a second coupling line and a spacer element. The main signal line is located on a first plane, the first coupling line is located on a second plane, and the second coupling line is located on a third plane, wherein the second plane and the third plane are both in parallel with the first plane, and the second plane and the third plane are both different from the first plane. The spacer element is connected to the main signal line. The projection of the spacer element on the first plane is located between the projection of the first coupling line on the first plane and the projection of the second coupling line on the first plane. The main signal line, the first coupling line and the second coupling line extend along a virtual line.

Abstract: A system includes a primary coil, a series combination having a first conducting wire and a first capacitor coupled in series, a second conducting wire, and a secondary coil. A first end of the series combination is coupled to a first end of the primary coil. A first end of the second conducting wire is coupled to the first end of the primary coil. A second end of the second conducting wire is coupled to the second end of the series combination. A first end of the secondary coil is coupled to an output end.

Abstract: A radio frequency circuit is provided. The radio frequency circuit includes a first terminal, a second terminal, a power amplifier, and a coupling circuit. The power amplifier is coupled between the first terminal and the second terminal. The power amplifier is configured to receive a first signal. The coupling circuit includes a first coupling terminal, a second coupling terminal, and at least one transistor. The first coupling terminal is coupled to the power amplifier and the second terminal. The at least one transistor is connected in series between the first coupling terminal and the second coupling terminal. In a coupling mode, the at least one transistor is in an at least partial cut-off state, and the at least one transistor provides a coupling signal at the second coupling terminal through capacitive coupling. The first signal is controlled according to the coupling signal.

Abstract: An amplifier circuit includes an amplifier, a detector and an adjustment circuit. The amplifier includes a first transistor and a bias voltage terminal. The first transistor includes a first terminal coupled to a first reference voltage terminal, a second terminal coupled to a second reference voltage terminal, and a control terminal coupled to the bias voltage terminal of the amplifier. The second transistor includes a first terminal coupled to a third reference voltage terminal and the detector, and a second terminal coupled to the second reference voltage terminal. The detector outputs a detection signal related to a characteristic parameter of the second transistor. The adjustment circuit is coupled to the detector and the bias voltage terminal of the amplifier for performing an adjustment operation according to the detection signal.

Abstract: A voltage controlled circuit includes a tracking circuit, an operational amplifier, a transistor, a feedback circuit and a sample and hold circuit. The tracking circuit generates an updated enabling voltage according to an enabling voltage, a sample enabling voltage and a sample reference voltage. The operational amplifier includes a first input terminal used to receive an input voltage, a second input terminal used to receive a feedback voltage, and an output terminal used to output a control voltage. The transistor includes a control terminal used to receive the control voltage, a first terminal used to receive a reference voltage, and a second terminal used to output a regulated voltage. The feedback circuit generates the feedback voltage according to the regulated voltage. The sample and hold circuit is used to sample the input voltage to generate the sample enabling voltage, and sample the feedback voltage to generate the sample reference voltage.

Abstract: A power supply includes a voltage regulator, a transistor, a current-to-voltage transform circuit, and a comparator. The voltage regulator receives a control signal, a source voltage, and a control voltage, and outputs a supply voltage according to the control voltage and the control signal. The transistor has a first terminal receiving the source voltage, and a control terminal coupled to the voltage regulator. The current-to-voltage transform circuit has a first terminal coupled to a second terminal of the transistor, a second terminal for receiving a reference voltage. The comparator has a first input terminal for receiving a comparison signal, a second input terminal coupled to the first terminal of the current-to-voltage transform circuit, and an output terminal for outputting the control voltage.

Abstract: An amplification circuit includes a first amplifier circuit and a second-stage amplifier. The second-stage amplifier is connected to the amplifier to form a multi-stage amplification circuit. The first amplifier circuit includes a first-stage amplifier and a bypass circuit. The bypass circuit includes a first transistor. A first end of the first transistor is coupled to the input end of the first amplifier circuit, a second end of the first transistor is coupled to the output end of the first amplifier circuit, and a third end of the first transistor is coupled to a supply voltage. The first end of the first transistor is further coupled to a first control terminal to receive a control signal for controlling a bias voltage of the first transistor, so as to make the amplification circuit work in different operation modes.

Abstract: A power supply includes a voltage regulator, a transistor, a current-to-voltage transform circuit, and a comparator. The voltage regulator receives a control signal, a source voltage, and a control voltage, and outputs a supply voltage according to the control voltage and the control signal. The transistor has a first terminal receiving the source voltage, and a control terminal coupled to the voltage regulator. The current-to-voltage transform circuit has a first terminal coupled to a second terminal of the transistor, a second terminal for receiving a reference voltage. The comparator has a first input terminal for receiving a comparison signal, a second input terminal coupled to the first terminal of the current-to-voltage transform circuit, and an output terminal for outputting the control voltage.

Abstract: An amplification circuit includes a first amplifier circuit and a second-stage amplifier. The second-stage amplifier is connected to the amplifier to form a multi-stage amplification circuit. The first amplifier circuit includes a first-stage amplifier and a bypass circuit. The bypass circuit includes a first transistor. A first end of the first transistor is coupled to the input end of the first amplifier circuit, a second end of the first transistor is coupled to the output end of the first amplifier circuit, and a third end of the first transistor is coupled to a supply voltage. The first end of the first transistor is further coupled to a first control terminal to receive a control signal for controlling a bias voltage of the first transistor, so as to make the amplification circuit work in different operation modes.