Abstract: A front end module includes a first radio frequency (RF) terminal, a second RF terminal, a third RF terminal, a transmission path and a reception path. The transmission path is formed between the first RF terminal and the third RF terminal. The reception path is formed between the first RF terminal and the second RF terminal. The reception path includes a first set of switches, a second set of switches, a third set of switches and an amplifier. An amplifier is coupled to the second set of switches and the second RF terminal. The third set of switches is coupled to the first set of switches and the second RF terminal. When a transmission signal is transmitted to the first RF terminal via the transmission path, the first set of switches, the second set of switches and the third set of switches are turned off.

Abstract: A radio frequency switch has an antenna end, a first signal end for transmitting a first radio frequency signal, a second signal end for transmitting a second radio frequency signal, a third signal end for transmitting a third radio frequency signal, a first series path having a first switch, a second series path having a second switch, a third series path having a third switch, a first shunt path coupled between the first signal end and a node, a second shunt path coupled between the second signal end and the node, a common path coupled between the node and a first reference voltage end, and a third shunt path coupled between the third signal end and a second reference voltage end. The first series path and the second series path are connected to a common ground pad via the common path.

Abstract: A switch device includes a first node, a switch unit, an adjustment switch, an impedance element, a second node and a detection unit. A first terminal of the switch unit is coupled to the first node. A first terminal and a second terminal of the adjustment switch are respectively coupled to a second terminal of the switch unit and a reference voltage terminal. A first terminal and a second terminal of the impedance element are respectively coupled to the first terminal and the second terminal of the adjustment switch. The detection unit is coupled to the second node, and a control terminal of the switch unit and a control terminal of the adjustment switch. The detection unit detects a node signal at the second node to accordingly control the switch unit and the adjustment switch.

Abstract: A switch device includes a first node, a switch unit, an adjustment switch, an impedance element, a second node and a detection unit. A first terminal of the switch unit is coupled to the first node. A first terminal and a second terminal of the adjustment switch are respectively coupled to a second terminal of the switch unit and a reference voltage terminal. A first terminal and a second terminal of the impedance element are respectively coupled to the first terminal and the second terminal of the adjustment switch. The detection unit is coupled to the second node, and a control terminal of the switch unit and a control terminal of the adjustment switch. The detection unit detects a node signal at the second node to accordingly control the switch unit and the adjustment switch.

Abstract: A power amplifier has an amplifying transistor, a first resistor, a bias circuit, a second resistor, and a compensation circuit. The amplifying transistor amplifies a radio frequency (RF) signal to output an amplified RF signal. A control end of the amplifying transistor receives the RF signal. The first resistor provides a first resistance, and a second end of the first resistor is coupled to the control end of the amplifying transistor. The bias circuit has a bias transistor and is coupled to a first end of the first resistor. The second resistor provides a second resistance less than the first resistance, and a second end of the second resistor is coupled to the control end of the amplifying transistor. The compensation circuit has a compensation transistor, and an output end of the compensation circuit is coupled to a first end of the second resistor.

Abstract: The switch device includes a first circuit. The first circuit has a first end coupled between a first terminal and a second terminal, and the first circuit has the second end coupled between the first terminal and the second terminal or coupled to a third terminal. The first circuit includes a first switch and a second switch. The first switch is coupled between the first end and the second end of the first circuit and is turned on or off according to a first control signal. The second switch is connected to the first switch in parallel and is turned on or off according to a second control signal. The first switch and the second switch include transistors of the same type. In a surge protection mode, the second switch is turned on to dissipate the surge current.

Abstract: A voltage state detector includes an input terminal, a voltage drop circuit, a pull-down circuit, a load circuit, a transistor, a pull-up circuit, a first output terminal, and a second output terminal. The voltage drop circuit is coupled to the input terminal. The pull-down circuit is coupled to the voltage drop circuit and a first reference terminal. The load circuit is coupled to a second reference terminal. The transistor has a first terminal coupled to the load circuit, a second terminal coupled to the first reference terminal, and a control terminal coupled to the voltage drop circuit. The pull-up circuit is coupled to the second reference terminal and the voltage drop circuit. The first output terminal is coupled to the first terminal of the transistor for outputting a first state determination signal. The second output terminal is coupled to the voltage drop circuit for outputting a second state determination 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: A switch device structure includes RF1-st and RF2-nd input terminals, RFA-th, RFB-th and RFC-th output terminals, P2A-th, P1B-th and P1C-th paths, and first and second common paths. The P2A-th path includes a first terminal, and a second terminal coupled to the RFA-th output terminal. The P1B-th path includes a first terminal, and a second terminal coupled to the RFB-th output terminal. The P1C-th path includes a first terminal, and a second terminal coupled to the RFC-th output terminal. The first common path is coupled to the RF2-nd input terminal and the first terminal of the P2A-th path. The second common path is coupled to the RF1-st input terminal, the first terminal of the P1B-th path, and the first terminal of the P1C-th path. The first and second common paths cross each other on different planes to form a crossover.

Abstract: A device of measuring a duty cycle includes a resistor-capacitor circuit and a control circuit. The resistor-capacitor circuit is used to generate a first voltage when a reference signal is in a first state, and generate a second voltage and a third voltage when the reference signal is in a second state. The control circuit is coupled to the resistor-capacitor circuit, and configured to acquire an ON-time according to the first voltage, the second voltage and the third voltage. The ON-time is a time interval during which the reference signal is in the first state.

Abstract: A driving circuit includes a first reference terminal, a second reference terminal, at least one input terminal, an output terminal, a first transistor, a second transistor, a switch module, and at least one control signal terminal. The at least one input terminal receives at least one input signal. The output terminal outputs an output signal in response to the at least one input signal. The first transistor and the second transistor respectively include control terminals coupled to the at least one input terminal. The switch module includes at least one control terminal coupled to the at least one control signal terminal to receive at least one control signal. The at least one input signal has a transition period. The switch module can be turned off according to the at least one control signal.

Abstract: An amplifier circuit having an adjustable gain is provided. The amplifier circuit includes an input terminal, an output terminal, an amplifier, and an attenuation circuit. The input terminal receives an input signal, which is in turn received by an input terminal of the amplifier. An output terminal of the amplifier outputs the input signal that is amplified. The attenuation circuit is coupled between the output terminal of the amplifier and the output terminal to provide a plurality of attenuation to the input signal that is amplified and generate a first attenuation signal, or between the input terminal and the output terminal to provide the plurality of attenuations to the input signal and generate a second attenuation signal. A difference between an impedance value of the input terminal of the attenuation circuit and an impedance value of the output terminal of the attenuation circuit is within a predetermined range.

Abstract: A power amplifier includes a transistor, a temperature sensor and a filter. The transistor is used to receive a bias signal and amplify a radio frequency (RF) signal. The temperature sensor is arranged in proximity to the transistor, and is used to detect a temperature of the transistor to provide a voltage signal at a control node accordingly. The filter is coupled to the temperature sensor and is used to filter the voltage signal to generate a filtered voltage. The bias signal is adjusted according to the filtered voltage.

Abstract: A radio frequency (RF) switch includes a first terminal, a second terminal, a series switch circuit, a shunt switch circuit, an inductor and a reference voltage terminal. An RF signal at the first terminal. The series switch circuit is coupled to the first terminal, the second terminal, and the shunt switch circuit. The shunt switch circuit includes a sub-switch circuit, a transistor coupled to the sub-switch circuit, and a compensation capacitor parallel-coupled to the transistor. The inductor is coupled to the shunt switch circuit and the reference voltage terminal. When the RF signal is operated in a first frequency band, the first transistor is turned on for the shunt switch circuit and the inductor to provide a first impedance. When the RF signal is operated in a second frequency band, the first transistor is turned off for the shunt switch circuit and the inductor to provide a second impedance.

Abstract: A temperature detector is used to detect a temperature of a circuit under test, and includes a temperature coefficient component, a multiplier, an impedance component and a node. The temperature coefficient component is arranged in proximity to the circuit under test. A control terminal of the multiplier is coupled to a second terminal of the temperature coefficient component. The impedance component is coupled between the second terminal of the temperature coefficient component and the control terminal of the multiplier, or between a second terminal of the multiplier and a third voltage terminal. The node is formed between the second terminal of the temperature coefficient component and the control terminal of the multiplier. A voltage at the node and an amplified detection current flowing to a first terminal of the multiplier are positively correlated to the temperature of the circuit under test.

Abstract: An amplification circuit includes a switch circuit, an amplifier, and a control circuit. The switch circuit has a first terminal coupled to a radio frequency signal input terminal or a system voltage terminal, a second terminal coupled to an input terminal of the amplifier, and a control terminal configured to receive a control signal. The amplifier amplifies a radio frequency signal. The control circuit generates the control signal according to a driving current generated by the amplifier. When the control circuit determines that the amplifier operates in a high power mode, the control circuit controls the control signal to adjust a conducting level between the first terminal and the second terminal of the switch circuit according to the intensity of the driving current.

Abstract: A power amplifier includes a transistor, a temperature sensor and a filter. The transistor is used to receive a bias signal and amplify a radio frequency (RF) signal. The temperature sensor is arranged in proximity to the transistor, and is used to detect a temperature of the transistor to provide a voltage signal at a control node accordingly. The filter is coupled to the temperature sensor and is used to filter the voltage signal to generate a filtered voltage. The bias signal is adjusted according to the filtered voltage.

Abstract: The present invention discloses a bias compensation circuit. The bias compensation circuit includes a detecting circuit, including a diode-connected transistor circuit, with a first end for receiving a first current, and a second end coupled to a first reference voltage end; and a first diode circuit, with a first end for receiving a second current, and a second end coupled to the first reference voltage end; wherein the detecting circuit provides a first voltage level according to the diode-connected transistor circuit, and provides a second voltage level according to the first diode circuit; a voltage-current converting circuit, coupled to the detecting circuit, for generating a first reference current according to the first voltage level and the second voltage level; and a bias circuit, coupled to the voltage-current converting circuit, for receiving the first reference current, to provide a bias voltage level according to the first reference current.

Abstract: A sensing electrode includes a first electrode assembly, a second electrode assembly and a sealing component. The first electrode assembly includes an inner tubular body and a reference electrode component installed in the inner tubular body. The second electrode assembly includes an outer tubular body and a working electrode component installed in the outer tubular body. The first electrode assembly is installed in the outer tubular body. The sealing component is located between the inner and outer tubular bodies and provided to inhibit infiltration of an etching solution into the outer tubular body and leakage of an electrolyte from the inner tubular body. Thus, the sensing electrode has a better stability and service life.

Abstract: A temperature detector is used to detect a temperature of a circuit under test, and includes a temperature coefficient component, a multiplier, an impedance component and a node. The temperature coefficient component is arranged in proximity to the circuit under test. A control terminal of the multiplier is coupled to a second terminal of the temperature coefficient component. The impedance component is coupled between the second terminal of the temperature coefficient component and the control terminal of the multiplier, or between a second terminal of the multiplier and a third voltage terminal. The node is formed between the second terminal of the temperature coefficient component and the control terminal of the multiplier. A voltage at the node and an amplified detection current flowing to a first terminal of the multiplier are positively correlated to the temperature of the circuit under test.