Abstract: A high frequency switch circuit including: a first rectifier circuit including at least one rectifier element having one end connected between the gate terminal of a first MOSFET circuit and a first control terminal and the other end connected to ground, and a second rectifier circuit including at least one rectifier element having one end connected between the gate terminal of a second MOSFET circuit and a second control terminal and the other end connected to ground. The circuit further includes a connecting section connecting the forward-current input terminal side of at least one of the rectifier elements of the first rectifier circuit and one of the main terminal sides of the first MOSFET circuit, and connecting the forward-current input terminal side of at least one of the rectifier elements of the second rectifier circuit and one of the main terminal sides of the second MOSFET circuit.

Abstract: A wireless transmission device includes a RF power amplification section for amplifying a transmit RF signal and outputting the amplified signal to a transmission antenna, a detector section, and a control section. The RF power amplification section includes a plurality of stages of amplification, the transmit RF signal is input to an input of a first one of the plurality of stages of amplification, and an output of a last one of the plurality of stages of amplification is output to the transmission antenna. The detector section includes a plurality of detectors provided so as to correspond to the plurality of stages of amplification, each for detecting an input level of a corresponding one of the stages of amplification, and a synthesizer for synthesizing together detection outputs from the plurality of detectors. The control section controls, in a feedback control, an output level of the RF power amplification section based on an output level of the synthesizer.

Abstract: A differential amplifier circuit is connected to the input node and the output node of the final amplification stage through detection circuits. The signal level difference output from the differential amplifier circuit does not change even if the input power varies. Because a change in the power gain at the output node does not travel back to the input node when the load impedance of the wireless frequency power amplifier varies, it is possible to detect only the change in the load impedance. Damage to the final stage can be prevented by controlling the operating current of the final stage and the gain of the drive stage according to the detected load variation. Nonlinear distortion in the wireless frequency power amplifier output can also be reduced by detecting and canceling the change in the gain of the drive stage by changing the gain of the adjustment stage.

Abstract: A wireless transmission device includes a RF power amplification section for amplifying a transmit RF signal and outputting the amplified signal to a transmission antenna, a detector section, and a control section. The RF power amplification section includes a plurality of stages of amplification, the transmit RF signal is input to an input of a first one of the plurality of stages of amplification, and an output of a last one of the plurality of stages of amplification is output to the transmission antenna. The detector section includes a plurality of detectors provided so as to correspond to the plurality of stages of amplification, each for detecting an input level of a corresponding one of the stages of amplification, and a synthesizer for synthesizing together detection outputs from the plurality of detectors. The control section controls, in a feedback control, an output level of the RF power amplification section based on an output level of the synthesizer.

Abstract: A differential amplifier circuit is connected to the input node and the output node of the final amplification stage through detection circuits. The signal level difference output from the differential amplifier circuit does not change even if the input power varies. Because a change in the power gain at the output node does not travel back to the input node when the load impedance of the wireless frequency power amplifier varies, it is possible to detect only the change in the load impedance. Damage to the final stage can be prevented by controlling the operating current of the final stage and the gain of the drive stage according to the detected load variation. Nonlinear distortion in the wireless frequency power amplifier output can also be reduced by detecting and canceling the change in the gain of the drive stage by changing the gain of the adjustment stage.

Abstract: An electronic device includes: a plurality of RF power amplifiers; and an impedance converting circuit. The RF power amplifiers amplify RF signals having different frequencies. The impedance converting circuit receives RF signals output from output terminals of the respective RF power amplifiers at a plurality of input terminals disposed to face the respective output terminals, and performs impedance conversion.

Abstract: An RF amplifier includes a transistor for an RF signal amplification; and a diode which is connected at one of two terminals thereof to an input terminal of the transistor and receives the RF signal at the other terminal. This structure enables the RF amplifier to operate stably.

Abstract: In a high-frequency power amplifier of the present invention, when a short circuit occurs between a gate or source or between a base and emitter in one of unit cells comprising a multi-cell, influence on the operations of the other normal unit cells is suppressed by a direct-current interrupting characteristic of a diode disposed for each of the unit cells.

Abstract: An integrated dielectric substrate has a dissipating plate for dissipating the heat generated by an exothermic element mounted above the surface of the dielectric substrate. Either a cavity or a groove is cut through the surface of the dielectric substrate, preferably from one end to the other end of the dielectric substrate, the dissipating plate being fitted in the cavity or groove, both ends of the dissipating plate extending beyond the corresponding ends of the dielectric substrate to form extending end portions, and the exothermic element being mounted on the surface of the dissipating plate.

Abstract: A high-frequency composite part includes a high-frequency switch and an amplifier in a transmission circuit side among high-frequency parts constituting a PHS portable telephone. In the telephone, the high-frequency switch is used for switching between the connection of the transmission circuit Tx and an antenna, and the connection of a receiving circuit Rx and the antenna. The amplifier at the Tx side amplifies a signal to be transmitted which has been converted into an RF signal and passes through a filter at the Tx side, and sends it to the high-frequency switch.