Patent application number | Description | Published |
20080238562 | VOLTAGE-CONTROLLED OSCILLATOR - 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. | 10-02-2008 |
20090027130 | POWER AMPLIFIER - 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 μm. 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 μm. | 01-29-2009 |
20090051437 | POWER AMPLIFIER - An emitter follower circuit applies to an input terminal of a second amplifying device a voltage according to a reference voltage applied to a reference terminals. First and second resistors are connected in series between the reference terminal and an input terminal of a first amplifying device. The collector of a first transistor is connected to the reference terminal, and a control voltage is applied to the base of the first transistor. A third resistor is connected between the emitter of the first transistor and a grounding point. A current mirror circuit draws a current proportional to a current input from the collector of the first transistor from a connection point of the first and second resistors. | 02-26-2009 |
20090174474 | POWER AMPLIFIER - 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 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. | 07-09-2009 |
20090174484 | POWER AMPLIFIER - An amplifying transistor for amplifying a radio frequency signal between an input terminal and an output terminal. The cathode of a first diode is connected to the input terminal and the anode of a second diode is connected to the output terminal. A matching and attenuating circuit is connected between the anode of the first diode and the cathode of the second diode. A matching and attenuating circuit reduces impedance mismatches on the input terminal side and the output terminal side, and attenuates the radio frequency signal. In an amplification mode, a bias circuit supplies a bias current to an amplifying transistor and a current mirror circuit turns off the first and second diodes. In an attenuation mode, the bias circuit supplies no bias current to the amplifying transistor and the current mirror circuit turns on the first and second diodes. | 07-09-2009 |
20090295540 | Facsimile machine, facsimile notification system, and communication terminal device - A facsimile machine receives image data, generates a password for received image data, assigns the generated password to the received image data, and stores the received image data. Information indicating a notification destination is extracted from the received image data, and the notification destination is notified of the password. The received image data are output responsive to subsequent input of the password at the facsimile machine. This scheme provides password protection without forcing users to register and remember passwords, and without the risk that a compromised password may be used for unauthorized output of facsimile data received later. | 12-03-2009 |
20090309655 | POWER AMPLIFIER - A power amplifier includes: an amplifying transistor; a bias circuit; a first diode; a second diode; a matching attenuating circuit; a first current mirror circuit; a serial resonant circuit, and a switch. In an amplification mode, the bias circuit supplies a bias current to the amplifying transistor, and the first current mirror circuit turns off the first and second diodes, and the switch. In an attenuation mode, the bias circuit supplies no bias current to the amplifying transistor, and the first current mirror circuit turns on the first and second diodes, and the switch. | 12-17-2009 |
20100127689 | REFERENCE VOLTAGE GENERATION CIRCUIT AND BIAS CIRCUIT - A reference voltage generation circuit comprises: a first depletion mode FET; a second depletion mode FET; a first resistor; a first bipolar transistor; a second resistor; a second bipolar transistor; a third bipolar transistor; a third resistor; a third depletion mode FET having its drain connected to a second end of the first resistor and to the collector of the first bipolar transistor; and a fourth bipolar transistor having its base and collector connected to the gate and the source of the third depletion mode FET, and its emitter grounded, wherein source voltage of the second depletion mode FET is output as a reference voltage. | 05-27-2010 |
20100171564 | DIRECTIONAL COUPLER - A directional coupler includes a main line connected at a first end to an input port and at a second end to an output port, a coupled line connected at a first end to a coupled port and at a second end to an isolated port, and a phase shifter connected at a first end to the isolated port and at a second end to the coupled port. The phase shifter phase shifts a second reflected wave component such that the second reflected wave component is opposite in phase to a first reflected wave component, the second reflected wave component traveling from the output port to the coupled port through the isolated port and the phase shifter, the first reflected wave component traveling from the output port to the coupled port through the coupled line. | 07-08-2010 |
20100301944 | POWER AMPLIFIER - A power amplifier includes: a semiconductor substrate; a preceding-stage amplifying device on the semiconductor substrate, amplifying an input signal; a following-stage amplifying device on the semiconductor substrate, amplifying an output signal of the preceding-stage amplifying device; and an inter-stage matching circuit connecting the preceding-stage amplifying device to the following-stage amplifying device. The preceding-stage amplifying device has a first field effect transistor; the following-stage amplifying device has a heterojunction bipolar transistor; and the inter-stage matching circuit has a capacitance galvanically separating the output terminal of the preceding-stage amplifying device from the input terminal of the following-stage amplifying device. | 12-02-2010 |
20110018639 | POWER AMPLIFIER 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. | 01-27-2011 |
20110057746 | DIRECTIONAL COUPLER - A directional coupler includes capacitive elements electrically connected to a coupled port and an isolated port, respectively, for a coupled line on a chip (on-chip). The capacitive elements serve as matching capacitive elements and may be MIM (Metal Insulator Metal) capacitors on a substrate. A first end of a first of the capacitive elements is connected between the coupled port and the coupled line and a second end is grounded. A first end of a second of the capacitive elements is connected between the isolated port and the coupled line and a second end is grounded. | 03-10-2011 |
20110187349 | DETECTOR CIRCUIT AND SEMICONDUCTOR DEVICE USING SAME - A detector circuit for detecting degradation in the distortion characteristics of a power amplifier based on signals from both ends of a coupled line of a directional coupler. The detector circuit includes a phase shifter/attenuator for phase shifting and attenuating a signal from a coupled terminal of the coupled line, a differential amplifier for outputting difference between an output signal from the phase shifter/attenuator and a signal from the isolated terminal of the coupled line, a wave detector circuit for converting the difference into a DC signal, and a comparing circuit for determining whether the voltage level of the DC signal exceeds a predetermined level. When degradation in the distortion characteristics of the power amplifier arises, the phase shifter/attenuator phase shifts the signal from the coupled terminal and outputs a signal 180° out of phase with the signal from the isolated terminal. | 08-04-2011 |
20110187459 | EMITTER-FOLLOWER TYPE BIAS CIRCUIT - 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. | 08-04-2011 |
20120062321 | POWER AMPLIFIER - 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. | 03-15-2012 |
20120146733 | POWER AMPLIFIER - 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. | 06-14-2012 |
20120154055 | POWER AMPLIFIER - 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. | 06-21-2012 |
20120300237 | IMAGE FORMATION APPARATUS - An image formation apparatus includes an image reading control unit and a print control unit . The print control unit includes: a first communication control unit connected to the image reading control unit; and a power supply control unit configured to control power supply to the image reading control unit. The image reading control unit includes: a second communication control unit connected to the first communication control unit. When completing a process to transition to a power save mode in accordance with an instruction from the print control unit, the image reading control unit cuts off the communications through the second communication control unit. After sending the image reading control unit the instruction to transition to the power save mode, the print control unit detects the cutoff of the communications and then cuts off the power supply to the image reading control unit through the power supply control unit. | 11-29-2012 |
20120306579 | POWER AMPLIFIER - 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. | 12-06-2012 |
20120326784 | POWER AMPLIFIER - A power amplifier includes: an input terminal at which an input signal is input; a first amplifier element amplifying the input signal; a second amplifier element amplifying an output signal of the first amplifier element; an output terminal from which an output signal of the second amplifier element is output; a matching circuit connected between an output of the second amplifier element and the output terminal; a first switch connected between an output of the first amplifier element and an input of the second amplifier element; and a second switch having a first end connected to the output of the first amplifier element, and a second end. The matching circuit includes a first inductor and a first capacitor connected in series between the output of the second amplifier element and a grounding point. The second end of the second switch is connected to a connecting point of the first inductor to the first capacitor. | 12-27-2012 |
20130249626 | MULTIPLE POWER MODE AMPLIFIER - A multiple power mode amplifier includes: N amplifiers connected in series via switches; and a control circuit for controlling the N amplifiers in accordance with the output modes. P amplifiers out of the N amplifiers constitute a driver amplifier, and constitute a negative feedback amplifier including a feedback circuit for negatively feeding back its own output signal to its own input side. N−P amplifiers constitute a final stage amplifier connected in series to the negative feedback amplifier in a disconnectable manner. The control circuit is configured to: in a first output mode, disconnect the final stage amplifier from the negative feedback amplifier, and disable the feedback circuit; and in a second output mode, connect the final stage amplifier in series to the negative feedback amplifier, and enable the feedback circuit. | 09-26-2013 |
20140132358 | CASCODE AMPLIFIER - A cascode amplifier includes: first transistors; second transistors cascode-connected with respective first transistors; a first line connected at spaced points to control terminals of the first transistors; a second line connected at spaced points to control terminals of the second transistors; and a capacitance connected between one end of the second line and ground. The second line includes at least two lines connected in parallel with each other. | 05-15-2014 |
20140232467 | HIGH-FREQUENCY AMPLIFIER MODULE AND HIGH-FREQUENCY AMPLIFIER MODULE UNIT - A high-frequency amplifier module includes a driver-stage amplifier | 08-21-2014 |
20140292439 | DIRECTIONAL COUPLER - Disclosed is a directional coupler including a broadside coupled line | 10-02-2014 |
20140292440 | DIRECTIONAL COUPLER - Disclosed is a directional coupler including a first hollow portion | 10-02-2014 |
20140306761 | POWER AMPLIFIER - A power amplifier includes: first and second bias terminals to which bias voltages are respectively supplied; a first transistor having a first control terminal connected to the first bias terminal, a first terminal that is grounded, and a second terminal; a second transistor having a second control terminal connected to the second bias terminal, a third terminal connected to the second terminal, and a fourth terminal; a capacitor connected between the second control terminal and a grounding point; and a variable resistor connected in series with the capacitor, between the second control terminal and the grounding point. | 10-16-2014 |
20150048887 | AMPLIFIER CIRCUIT - An amplifier circuit is configured in such a manner that the withstand voltage between the terminals of a FET | 02-19-2015 |
20150054583 | POWER AMPLIFIER - A power amplifier includes: a first transistor having a gate, a drain, and a source that is grounded; a second transistor having a gate, a drain, and a source that is connected to the drain of the first transistor; a capacitor connected between the gate of the second transistor and a grounding point; an idling current control circuit having a positive temperatures coefficient and making an idling current flowing through the first transistor proportional to an ambient temperature; and a drain voltage control circuit having a positive temperature gradient coefficient and making a drain voltage on the first transistor proportional to the ambient temperature. | 02-26-2015 |