Abstract: A gate drive circuit that drives a power device by controlling charge and discharge of gate capacitance of the power device includes: a first semiconductor switch that charges the gate capacitance by being brought into conduction according to a first control signal; a second semiconductor switch that discharges the gate capacitance by being brought into conduction according to a second control signal; and a slew rate control circuit that is connected between a gate of the power device and a ground line, and controls a slew rate during discharge. The slew rate control circuit includes a capacitor and a third semiconductor switch connected in series. The third semiconductor switch is brought into conduction according to the second control signal.

Abstract: An electromagnetic resonance coupler includes a first transmission line on a top surface of a first dielectric layer, and a second transmission line on a top surface of a second dielectric layer. The first transmission line includes first and second resonance lines and first and second input-output lines. The second transmission line includes third and fourth resonance lines and third and fourth input-output lines. Third and fourth ground parts are provided separated from each other on the top surface of the second dielectric layer or the top surface of the first dielectric layer. The first resonance line and the third ground part are connected via a third connector, and the fourth resonance line and the fourth ground part are connected via a fourth connector.

Abstract: A gate driving circuit that controls a switching element includes: a startup switch which is provided between a gate voltage source and an output terminal; a termination switch which is provided between the output terminal and an output ground terminal; a startup resistor provided between a gate and a source of the startup switch; and a termination resistor provided between a gate and a source of the termination switch. At least one of the startup resistor or the termination resistor is configured to adjust a resistance value.

Abstract: A power amplifier includes an amplification transistor which performs power amplification, a bias circuit which outputs a bias voltage to a base of the amplification transistor, a control terminal to which a control voltage is applied for controlling switching between an operating state and a stopping state of the bias circuit, and a bias voltage adjustment circuit connected to the control terminal. The bias voltage adjustment circuit includes a variable capacitance element which is connected to the control terminal and whose capacitance value decreases as the control voltage increases, a discharge circuit which discharges electric charge accumulated in the variable capacitance element to the control terminal, and a control circuit which is connected to the bias circuit and controls the bias voltage. The bias voltage adjustment circuit outputs, to the bias circuit, a bias voltage adjustment signal which increases the bias voltage for a predetermined period after the control voltage is applied.

Abstract: A power amplifier includes an amplification transistor which performs power amplification, a bias circuit which outputs a bias voltage to a base of the amplification transistor, a control terminal to which a control voltage is applied for controlling switching between an operating state and a stopping state of the bias circuit, and a bias voltage adjustment circuit connected to the control terminal. The bias voltage adjustment circuit includes a variable capacitance element which is connected to the control terminal and whose capacitance value decreases as the control voltage increases, a discharge circuit which discharges electric charge accumulated in the variable capacitance element to the control terminal, and a control circuit which is connected to the bias circuit and controls the bias voltage. The bias voltage adjustment circuit outputs, to the bias circuit, a bias voltage adjustment signal which increases the bias voltage for a predetermined period after the control voltage is applied.

Abstract: Provided is a compact high frequency power amplifier having a high degree of freedom of design with respect to a gain fluctuation immediately after start-up of an amplifier. The high frequency power amplifier includes a speed-up circuit that transiently increases a reference voltage during rise of a control voltage to increase an amount of bias supplied to an amplification transistor from a bias circuit. The speed-up circuit includes a capacitor and an overshoot control circuit. The overshoot control circuit determines an increasing amount of the reference voltage when the reference voltage is transiently increased according to a charge amount charged in the capacitor, and the overshoot control circuit also determines a time constant in charging and discharging the capacitor.

Abstract: Provided is a compact high frequency power amplifier having a high degree of freedom of design with respect to a gain fluctuation immediately after start-up of an amplifier. The high frequency power amplifier includes a speed-up circuit that transiently increases a reference voltage during rise of a control voltage to increase an amount of bias supplied to an amplification transistor from a bias circuit. The speed-up circuit includes a capacitor and an overshoot control circuit. The overshoot control circuit determines an increasing amount of the reference voltage when the reference voltage is transiently increased according to a charge amount charged in the capacitor, and the overshoot control circuit also determines a time constant in charging and discharging the capacitor.

Abstract: The present invention offers a radio frequency module having a radio frequency power amplifier and a directional coupler integrated in a multi-layer board, and in particular, a small, inexpensive, and high-performance radio frequency module, and a small and inexpensive wireless device equipped with the radio frequency module. The radio frequency module includes: a multi-layer board; a radio frequency power amplifier formed on top of the multi-layer board; a directional coupler having two layers vertically arranged in the multi-layer board; an internal ground pattern provided between the radio frequency power amplifier and the directional coupler; and thermal vias used for the radio frequency power amplifier and provided (i) between the internal ground pattern and a rear surface ground pattern and (ii) between the directional coupler and a bias line which is (i) provided in the same layer as the directional coupler and (ii) used for the radio frequency power amplifier.

Abstract: It is an object of the present invention to provide a high-frequency power amplifier capable of improving the linearity at the time of high output by preventing decrease in power of bias supply transistor. The high-frequency power amplifier is a high-frequency power amplifier including high-frequency power amplifier transistors and connected in multiple stages and bias supply transistors and each of which supplies bias current to a base of a corresponding one of said high-frequency power amplifier transistors, and each of which is connected to a common power supply terminal which is further connected to a collector of the high-frequency power amplifier transistor at a first stage among said high-frequency power amplifier transistors, and a passive element connected between the common supply terminal and a collector of the corresponding one of said bias supply transistors connected to the high-frequency power amplifier transistor at the first stage.

Abstract: It is an object of the present invention to provide a high-frequency power amplifier capable of improving the linearity at the time of high output by preventing decrease in power of bias supply transistor. The high-frequency power amplifier is a high-frequency power amplifier including high-frequency power amplifier transistors and connected in multiple stages and bias supply transistors and each of which supplies bias current to a base of a corresponding one of said high-frequency power amplifier transistors, and each of which is connected to a common power supply terminal which is further connected to a collector of the high-frequency power amplifier transistor at a first stage among said high-frequency power amplifier transistors, and a passive element connected between the common supply terminal and a collector of the corresponding one of said bias supply transistors connected to the high-frequency power amplifier transistor at the first stage.

Abstract: A radio frequency signal RF is input to a base of each of transistors TR1 through TRn via a corresponding capacitor among capacitors C1 through Cn, is amplified, and is output from a collector of each of the transistors TR1 through TRn. An emitter of each of the transistors TR1 through TRn is grounded. A bias voltage DC given from a bias circuit Bias is supplied to the base of each of the transistors TR1 through TRn via a corresponding resistor among resistors Ra1 through Ran. A signal line for the bias voltage DC is connected to an input line for the radio frequency signal RF via the bridge resistor R in a direct current manner.

Abstract: An emitter of a transistor (1) for high frequency amplification and a cathode of a diode (5) for generating reference voltage are grounded via an inductance (20). Anode electric potential of the diode (5) decreases with increase in output power of the transistor (1) and thus the operation of the transistor (1) is limited. Since the diode is an on linear element, it is possible to quickly limit the operation of the transistor (1) in response to an increase in output current, thereby preventing a breakdown caused by overcurrent.

Abstract: A radio frequency signal RF is input to a base of each of transistors TR1 through TRn via a corresponding capacitor among capacitors C1 through Cn, is amplified, and is output from a collector of each of the transistors TR1 through TRn. An emitter of each of the transistors TR1 through TRn is grounded. A bias voltage DC given from a bias circuit Bias is supplied to the base of each of the transistors TR1 through TRn via a corresponding resistor among resistors Ra1 through Ran. A signal line for the bias voltage DC is connected to an input line for the radio frequency signal RF via the bridge resistor R in a direct current manner.

Abstract: An emitter of a transistor (1) for high frequency amplification and a cathode of a diode (5) for generating reference voltage are grounded via an inductance (20). Anode electric potential of the diode (5) decreases with increase in output power of the transistor (1) and thus the operation of the transistor (1) is limited. Since the diode is an on linear element, it is possible to quickly limit the operation of the transistor (1) in response to an increase in output current, thereby preventing a breakdown caused by overcurrent.