Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Takayuki Matsuzuka

Kazuya Yamamoto

Satoshi Suzuki

Atsushi Okamura

Miyo Miyashita

Tomoyuki Asada

Kazuhiro Iyomasa

Akira Inoue

Teruyuki Shimura

Takayuki Katoh

Tetsuo Kunii

Takao Moriwaki

Hirotaka Amasuga

Kenichiro Chomei

Junichi Udomoto

Hiromitsu Utsumi

Kenji Mukai

Kenichiro Choumei

A power amplifier includes: an amplifier; an input matching circuit connected to an input of the amplifier; an output matching circuit connected to an output of the amplifier; and a low-frequency processing circuit connected to the input matching circuit or the output matching circuit, wherein the low-frequency processing circuit includes a first line having a first end connected to the input matching circuit or the output matching circuit, a first shot stub connected to a second end of the first line and including a second line and a first capacitor connected in series each other, and a second short stub connected to the second end of the first line in parallel with the first short stub and including a third line and a second capacitor which are connected in series each other, the first line has a length of &#x3bb;/8, the second line has a length of &#x3bb;/4, and the third line has a length of &#x3bb;/8 with respect to a wavelength &#x3bb; of a fundamental frequency.

Power amplifier

A power amplifier includes: an amplification element amplifying an input signal; and a bias circuit supplying a bias current to an input of the amplification element. The bias circuit includes a reference voltage terminal to which a battery voltage is applied from a battery, a first resistor having a first end connected to the reference voltage terminal, a second resistor connected between a second end of the first resistor and ground, and a first transistor. The first transistor has a control terminal connected to a connection point between the first resistor and the second resistor, a first terminal connected to a power supply, and a second terminal connected to the input of the amplification element. The first and second resistors are the same material.

A power amplifier includes: an amplifier having a base into which input signals are input, a collector to which a collector voltage is supplied, and an emitter; and a bias circuit for supplying a bias current to the base of the amplifier. The bias circuit includes a first transistor having a first control terminal into which a reference voltage is input, a first terminal to which a power voltage is applied, and a second terminal connected to the base of the amplifier. A capacitance adjusting circuit elevates capacitance between a grounding point and at least one of the first control terminal and the first terminal when the collector voltage of the amplifier is lowered.

A power amplifier includes: a first amplifying element amplifying an input signal; a second amplifying element amplifying an output signal of the first amplifying element; a third amplifying element amplifying the input signal; a first switch connected between an output of the first amplifying element and an input of second amplifying element; a second switch connected between an output of the first amplifying element and an output of the third amplifying element; a third switch connected between an output of the first amplifying element and an output of the second amplifying element; a reference voltage generating a circuit generating reference voltage; a bias circuit supplying a bias current, based on the reference voltage, to inputs of the first, second, and third amplifying elements; and a control circuit controlling the first, second and third switches and the reference voltage generating circuit.

A power amplifier includes a first amplifier unit, a second amplifier unit, and an attenuator. The second amplifier receives a signal from the first amplifier unit and amplifies the signal. The attenuator is provided between the first and second amplifier units. The attenuator has arms, including at least one parallel arm and at least one series arm, and has switches connected to the arms to switch the electrical connection states of the arms with respect to the first and second amplifier units. The at least one parallel arm and the at least one series arm are alternately arranged, in the order named, as viewed in the direction from the first amplifier unit to the second amplifier unit.

A power amplifier includes: an amplifying element having a base into which input signals are inputted, a collector to which a collector voltage is applied, and an emitter; and a bias circuit supplying a bias current to the base of the amplifying element. The bias circuit includes a bias current lowering circuit which lowers the bias current when the collector voltage is lower than a prescribed threshold value.

A power amplifier includes an input matching circuit, an amplifier transistor for amplifying an input signal received through the input matching circuit, an element for varying the collector voltage of the amplifier transistor, a bias circuit for varying the idle current in the amplifier transistor, and a compensation circuit for varying capacitance of the input matching circuit to maintain the phase shift and the input reflection in the power amplifier constant when the collector voltage and the idle current are varied, to prevent a decrease in the efficiency of the power amplifier due to changes in the output power of the amplifier transistor.

A power amplifier comprises: an amplifying transistor for amplifying an input signal; a reference voltage generating circuit which generates a reference voltage; a bias circuit generating a bias voltage based on the reference voltage and supplying the bias voltage to the amplifying transistor; and a booster elevating an enable voltage input from outside and outputting the enable voltage. The reference voltage generating circuit is turned ON/OFF in correspondence with an output voltage of the booster. The booster includes: an enable terminal to which the enable voltage is applied; a power source terminal connected to a power source; a transistor having a control electrode connected to the enable terminal, a first electrode connected to the power source terminal, and a second electrode that is grounded; and a FET resistor connected between the first electrode of the transistor and the power source terminal. A gate electrode of the FET resistor is open.

An emitter-follower bias circuit supplying a bias voltage to the base of an amplification transistor includes: a depletion mode FET boosting a reference voltage; and an emitter-follower circuit generating the bias voltage in response to the reference voltage boosted by the depletion mode FET.

Emitter-follower type bias circuit

A power amplifier and bias circuit includes a combination circuit in which a voltage drive bias circuit and a current drive bias circuit are connected in a parallel relationship with each other. The power amplifier bias circuit also includes an idle current control circuit which uses the collector voltage of amplifier transistors. When the collector voltage of the amplifier transistors is lower than the threshold voltage of a first transistor (approximately 1.3 V), the first transistor is turned off. At that time, since the reference voltage (2.4-2.5 V) is higher than the voltage for turning on both a second transistor and a diode (namely, approximately 1.3 V plus 0.7 V), a current flows and the first transistor turns on. As a result, a current is drawn from the bases of the amplifier transistors to GND through two resistances, so that the idle currents of the amplifier transistors decrease.

Power amplifier bias circuit

A wave detector circuit includes: a first transistor having its base and collector connected together, the first transistor receiving an AC signal and a reference voltage at its base and collector; a second transistor having its base connected to the base of the first transistor through a resistor, the second transistor outputting a detected voltage at its collector; and a diode-connected temperature compensation transistor connected between ground potential and the base and the collector of the first transistor.

Wave detector circuit

A power amplifier according to the present invention is operated by switching a main power amplifier and a subsidiary power amplifier. The idle current of the subsidiary power amplifier is smaller than the idle current of the main power amplifier. Each of the main power amplifier and the subsidiary power amplifier has a former amplification element for amplifying RF signals, a latter amplification element for amplifying output signals from the former amplification element, a former bias circuit for driving the former amplification elements, and a latter bias circuit for driving the latter amplification elements, respectively. The interval between the latter amplification element of the main power amplifier and the latter amplification element of the subsidiary power amplifier is not more than 100 &#x3bc;m. The interval between the latter amplification element of the main power amplifier and the latter bias circuit of the subsidiary power amplifier is not less than 200 &#x3bc;m.

An amplifier element amplifies RF signals. An emitter follower unit drives the amplifier element at a constant voltage corresponding to a reference voltage supplied to a reference terminal from outside. A current injection unit drives the amplifier element at a constant current corresponding to the reference voltage. An analog control unit analogically controls the output voltage of the emitter follower unit in correspondence with the control voltage supplied to a control terminal from outside. A mode switching unit switches whether the emitter follower unit is operated or not in correspondence with the control voltage.

A voltage-controlled oscillator has an oscillation frequency controlled through a voltage applied across ends of a variable-capacitance element. The voltage-controlled oscillator has a frequency control bias circuit which applies to a first end of the variable-capacitance element a voltage for frequency control according to a control voltage, a first current source which generates a first current according to the control voltage, a second current source which generates a second current according to temperature, independent of the control voltage, a converting resistor which converts a current, obtained by adding together the first and second currents, into a voltage, and a temperature compensation bias circuit which applies to the second end of the variable-capacitance element a voltage for temperature compensation according to the voltage produced by the converting resistor.

Voltage-controlled oscillator

A voltage-controlled oscillator including a voltage-controlled oscillation section, a frequency control bias circuit, a temperature compensation bias circuit, and a temperature compensation bias generation circuit. The temperature compensation bias generation circuit has a transistor having its collector or drain connected to the temperature compensation bias circuit, a first resistor having one end connected to the collector or drain of the transistor and having another end that is grounded, a second resistor having one end connected to the base or gate of the transistor, a base or gate bias application terminal connected to another end of the second resistor, a third resistor having one end connected to the emitter or source of the transistor, and an emitter or source bias application terminal connected to another end of the third resistor.

Growing community of inventors

Tokyo, Japan

Takayuki Matsuzuka