Abstract: A system and method for amplifier gain measurement and compensation. A method for compensating a signal gain of an amplifier circuit includes determining a desired gain for the amplifier circuit, determining an operating temperature of the amplifier circuit, adjusting a set of signal gains based on the operating temperature to produce a set of adjusted signal gains, determining a desired gain setting based on the desired gain and the set of signal gains, and providing the desired gain setting to the amplifier circuit.

Abstract: A method for tuning a filter is provided. The method includes: enabling a VCO circuit, wherein at least a portion of the VCO circuit is selected from the filter; generating an oscillation signal by the VCO circuit according to a driving signal; comparing the oscillation signal with a reference signal and generating a comparison result; and adjusting the driving signal according to the comparison result.

Abstract: A thermal calibration circuit for adjusting the gain of a variable gain amplifier, the thermal calibration circuit comprising an interface for receiving a signal that varies with temperature and for providing a signal related to the variation of the temperature; a variable gain amplifier having an input and an output; the signal related to the variation of the temperature being selectively coupled to the input; a circuit at the output of the variable gain amplifier for developing a first current proportional to a difference between a current developed at the output of the variable gain amplifier and a reference current; and the first circuit driving a further circuit to produce a gain control signal for adjusting the gain of the variable gain 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: A transconductance control circuit, comprising: a test transconductance circuit for providing an output current from a reference voltage; apparatus for deriving a bias current for the test transconductance circuit from the output current, the bias current including a component that varies with temperature and a component that varies with process; and apparatus for providing the bias current to other transconductance circuits.

Abstract: The present invention alters the frequency response of an optoelectronic device to match a driver circuit that drives the optoelectronic device. The optoelectronic device is formed on a first substrate. A matching circuit is also formed on the first substrate and coupled to the optoelectronic device to change its frequency response. The matching circuit provides a precise and repeatable amount of inductance to an optoelectronic device.

Abstract: A multi-mode RF amplifier is described having at least a higher and a lower power path coupling an input to an output. At a pre-selected output power level, the higher power path is enabled while the lower power path is disabled when more output power is required. The process is reversed when less power is needed. The present invention matches the power gain variation over temperature characteristic of each path such that, especially at the cross over point, the gain delta (the difference in power gain between the two paths) has minimal variation over temperature. Such power gain characteristic is required for meeting the test requirements, specifically the inner loop power control, for third generation (3G) cellular handsets.

Abstract: A solid state power amplifier (SSPA) system may include a radio frequency (RF) input, an RF waveguide split block, multiple monolithic microwave integrated circuit (MMIC) power amplifier modules, and/or a heat spreader. An MMIC power amplifier module may include a backing, a board, at least one MMIC, and/or a cover. A method for dissipating heat within an SSPA may include receiving an RF signal, splitting the RF signal, amplifying multiple RF signals, combining the multiple RF signals, generating heat, and/or dissipating heat.

Abstract: In a power amplifier, a serial bus interface is provided for sending and receiving information to other devices, such as a baseband controller. The power amplifier includes several control pins that can be used as a serial interface, or alternately, with a direct pin control interface. The power amplifier uses various techniques to address noise problems related to the use of a serial bus with a power amplifier.

Abstract: A voltage-controlled current source includes a current source having temperature dependency, a voltage source having process dependency, a first signal conversion circuit which generates second voltage having temperature dependency and process dependency by use of current of the current source and first voltage of the voltage source, a second signal conversion circuit which converts a first control signal used to control transfer conductance into a second control signal by using the second voltage as a reference, and a voltage-controlled current source circuit whose transfer conductance is controlled according to the second control signal.

Abstract: A waveform processing system may include a compensation circuit to adjust a voltage supplied to an output stage, wherein a supplied voltage is controlled to substantially maintain constant power dissipation in the output stage, and wherein the compensation circuit is configurable independently from the amplification stage. In an illustrative embodiment, a control circuit may be independently configurable with respect to an amplifier that generates a signal for the output stage, and the control circuit may bias a compensation circuit that provides thermal tail compensation for an output stage transistor. In some embodiments, the bias may operate the compensation circuit (i) to maintain a substantially constant power condition in the output stage transistor to substantially reduce thermal tail effects, and (ii) to maintain the output stage transistor in an unsaturated operating condition.

Abstract: To provide a high-frequency power amplifier capable of improving the linearity and efficiency of a high-frequency power amplifier by stabilizing, at high frequencies, the bias voltage of a bias circuit featuring the temperature compensating effect of a high-frequency amplifying transistor, a capacitor 61 is connected between the base of a bias supply transistor 41 and a reference potential. It is thus possible to possible to suppress variations in the base voltage of the bias supply transistor 41 in particular when the high-frequency power amplifier is at high output and improve the linearity of the high-frequency power amplifier.

Abstract: Operational transconductance amplifiers have a natural signal capacity format in which signal performance can be expressed in terms of fixed percentages. Input signal can be applied to Operational transconductance amplifiers in this natural signal capacity format in order to optimize performance. A signal which drives a given Operational transconductance amplifier architecture to produce an output current which is at 50% of it's maximum available output current can be thought of as applying an input voltage which is at 50% of an Operational transconductance amplifier's maximum input voltage capacity. In this input/output channel capacity format, dc offset, distortion, and noise all are temperature independent.

Abstract: A gain compensation circuit, applied to a microwave transceiver, includes a gain adjuster, a first attenuator and a second attenuator. The gain adjuster is disposed between a first amplifier and a filter for adjusting a nominal gain of the microwave transceiver. The first attenuator is disposed between the filter and a second amplifier for providing a first gain compensation. The second attenuator is electrically connected to the output of the second amplifier for providing a second gain compensation. The first and second gain compensations keep the gain of the microwave transceiver at a constant value under varying temperature conditions, and the first and second attenuators are used to reduce the degradation of return loss and noise figure of the microwave transceiver.

Abstract: A gain compensation circuit comprises a first amplifier, a second amplifier, a filter, a first attenuator, a second attenuator and a third attenuator. The first amplifier is configured to amplify an input signal of the microwave signal processor. The filter is disposed between the first and second amplifiers. The first attenuator is disposed between the first amplifier and the filter for reducing return loss of the microwave signal processor. The second attenuator is disposed between the second amplifier and the filter for reducing return loss of the microwave signal processor. The third attenuator is electrically connected to the output of the second amplifier for reducing noise figure of the microwave signal processor and providing first and second gain compensations. The first gain compensation keeps the gain of the microwave signal processor constant under various temperatures, and the second gain compensation adjusts a nominal gain of the microwave signal processor.

Abstract: Precision and reliability of a current limited mode output power control of an RF amplifier is enhanced by sensing the base current of the current controlled output power transistor. The base current is compared to a control current that is normalized by scaling it as a function of the current gain of a bipolar junction transistor of similar characteristics as the output power transistor. Fabrication process spread of current gain figures of bipolar junction transistors is effectively compensated. Moreover, by using a band-gap temperature compensation control current that is eventually ?-scaled before comparing it with the sensed base current of the output power transistor, the output power may be effectively controlled and maintained constant over temperature as well as process spread variations.

Abstract: The invention provides a wide-band, low-noise, and small-sized high frequency power amplifier that has small temperature dependence of the gain and is excellent in input matching. A parallel circuit consisting of a resistor whose resistance depends strongly on temperature and a conventional resistor is inserted serially into a signal path in an input matching circuit of an amplification unit, and resistances of the resistors are set to appropriate values, for example, about 2/3 times an input impedance of the amplification unit.

Abstract: A thermal calibration circuit for adjusting the gain of a variable gain amplifier, the thermal calibration circuit comprising an interface for receiving a signal that varies with temperature and for providing a signal related to the variation of the temperature; a variable gain amplifier having an input and an output; the signal related to the variation of the temperature being selectively coupled to the input; a circuit at the output of the variable gain amplifier for developing a first current proportional to a difference between a current developed at the output of the variable gain amplifier and a reference current; and the first circuit driving a further circuit to produce a gain control signal for adjusting the gain of the variable gain amplifier.

Abstract: A tuned low-noise amplifier is disclosed. A device in accordance with the present invention comprises a first current source, a second current source, a comparator, coupled to the first current source and the second current source, for providing a control signal, and a third current source, receiving the control signal and coupled to the tuned low-noise amplifier, wherein a current in the third current source is proportional to a current in the first current source and the second current source, where values of the first current source, the second current source, and the third current source are based on a quasi-Proportional-To-Absolute-Temperature (PTAT) curve.

Abstract: A configurable LNA architecture for a multi-band RF receiver front end comprises a bank of LNAs, each optimized to a different frequency band, wherein each LNA has a configurable topology. Each LNA comprises a plurality of amplifier stages, each stage including an RF transistor having a different width. The transistor widths in adjacent amplifier stages may be binary weighted, or may be sized to achieve a constant gain step. By selectively enabling and disabling RF transistors, the effective transistor width of the LNA can be controlled with a fine granularity. A DAC generates a bias voltage with a small quantization step, additionally providing a fine granularity of gain control. The LNAs are protected by overvoltage protection circuits which shield transistors from a supply voltage in excess of their breakdown voltage. A source degeneration inductor presents a real resistance at inputs of the LNAs, without introducing thermal noise.

Abstract: A semiconductor indicator for quantitatively diagnosing voltage conditions in high power transistor devices is provided. The semiconductor indicator includes a first transistor and a second transistor, where an electrically active periphery of the second transistor is less than an electrically active periphery of the first transistor. The transistors are thermally coupled to one another and may be in close proximity. The second transistor detects the voltage of a node on the first transistor and may be monitored by infrared imaging. The breakdown voltage characteristic of the second transistor may not substantially change as the temperature in the first transistor increases. An optional control circuit monitors and detects the output voltage of the first transistor.

Abstract: An amplifier circuit includes an amplifier input, an amplifier output, a control terminal for adjusting a gain of the amplifier circuit, and a feedback path between the amplifier output and the control terminal, wherein a variable-impedance means, the impedance of which depends on a temperature so that a variation of the gain depending on the temperature is reduced, is connected in the feedback path.

Abstract: A method for generating a temperature-compensated control signal is provided. The method includes receiving a constant control signal. A temperature-compensated control signal is generated based on the constant control signal. The temperature-compensated control signal is provided to a variable gain amplifier. The temperature-compensated control signal is operable to cause the variable gain amplifier to function independently of temperature.

Abstract: A high-frequency power amplifier with a temperature compensation function for power amplifying a high-frequency signal, includes: a power amplifying transistor having an emitter grounded; a high power output bias circuit that supplies a high power output current corresponding to a high power output of the high-frequency power amplifier to the power amplifying transistor; and a low power output bias circuit that supplies a low power output current corresponding to a low power output of the high-frequency power amplifier to the power amplifying transistor.

Abstract: A method for tuning a filter is provided. The method includes: enabling a VCO circuit, wherein at least a portion of the VCO circuit is selected from the filter; generating an oscillation signal by the VCO circuit according to a driving signal; comparing the oscillation signal with a reference signal and generating a comparison result; and adjusting the driving signal according to the comparison result.

Abstract: Variable gain amplifiers with controllable gain gradient over temperature. A variable gain amplification circuit comprises an input terminal receiving an input signal, an output terminal outputting an output signal, and a control terminal receiving a first gain control signal. The relationship between gain of the variable gain amplification circuit and temperature is programmable rather than temperature independent, and is controlled by the first gain control signal obtained by a second gain control signal and a third gain control signal.

Abstract: A transconductance control circuit, comprising: a test transconductance circuit for providing an output current from a reference voltage; apparatus for deriving a bias current for the test transconductance circuit from the output current, the bias current including a component that varies with temperature and a component that varies with process; and apparatus for providing the bias current to other transconductance circuits.

Abstract: The systems and methods described herein provide for composite transistor circuit having a bipolar transistor and a compensation unit. The compensation unit can be configured to stabilize the DC biasing point of the bipolar transistor. The compensation unit can compensate for the self-heating effect in the bipolar transistor and/or improve the linear performance of the bipolar transistor. The compensation unit can include a nonlinear resistor in series with a switch and can be configured to increase the base current into the bipolar transistor as the output voltage of the circuit increases.

Abstract: A multi-mode RF amplifier is described having at least a higher and a lower power path coupling an input to an output. At a pre-selected output power level, the higher power path is enabled while the lower power path is disabled when more output power is required. The process is reversed when less power is needed. The present invention matches the power gain variation over temperature characteristic of each path such that, especially at the cross over point, the gain delta (the difference in power gain between the two paths) has minimal variation over temperature. Such power gain characteristic is required for meeting the test requirements, specifically the inner loop power control, for third generation (3G) cellular handsets.

Abstract: Disclosed is a system and method for compensating for the effects of aging and temperature on the performance of transistors in an RF transmitter. The system and method use a temperature-based polynomial and a feedback control loop to correlate the drain current of each transistor with the desired performance characteristics of each transistor. The present invention measures drain current and temperature of the transistor; compares the measured drain current with the desired drain current, which corresponds to the desired performance characteristics; computes a transistor bias voltage based on the temperature and a control parameter, wherein the control parameter is adjustable based on the measured drain current; and applies the bias voltage to the transistor. The process may be repeated, with the control parameter adjusted with each iteration, until the desired drain current is reached.

Abstract: A combined bias circuit in which a voltage drive bias circuit and a current drive bias circuit are provided in parallel with each other has a configuration in which a linearizer including a first resistor is connected between an amplifying transistor and a second resistor. This configuration ensures that even when a low voltage of 2.4 to 2.5 V is supplied as an external reference voltage, the amplifying operation can be performed while generally constantly maintaining an idling current in a temperature range from a low temperature to a high temperature, and that degradation in distortion characteristics during low-temperature operation can be limited.

Abstract: A power amplification controlling apparatus and method in a mobile communication system are provided. An amplifying part amplifies an input Radio Frequency (RF) signal with a power supply voltage. A bias adaptation part detects a change in at least one an operation and an environment of the amplifying part, attenuates the RF signal according to the detected change, detecting the envelope of the attenuated signal, and generates a supply voltage control signal according to the envelope. A power supply part changes the power supply voltage in response to the supply voltage control signal.

Abstract: A tuning method and a tuning apparatus for tuning a filter are disclosed. The tuning method includes: configuring the filter as a VCO; utilizing the VCO to generate an oscillation signal according to a driving signal; comparing a frequency of the oscillation signal with a reference frequency to generate a comparison result; converting the comparison result into the driving signal in order to establish a feedback mechanism. Therefore, the inner components such as the gm and capacitance inside the VCO are completely tuned when the VCO generates an oscillation signal having a wanted frequency. Since the VCO is inside the filter and the components of the filter and the VCO are similar, the driving signal can be utilized to make the filter operate in a desired center frequency under a well-designed relationship between the frequency of the oscillation signal and the center frequency.

Abstract: A bias circuit includes a resistor in parallel with a voltage-drive bias circuit including a GaAs-HBT transistor. This configuration ensures that a current can be supplied from a reference voltage input terminal to the base terminal of a first transistor via the resistor in an idling state in which a voltage applied to the base terminal is lower than a voltage at which a second transistor operates, thereby enabling a desired amplifying operation while maintaining the idling current generally constant in a temperature range, even when the reference voltage is reduced to a value lower than twice the barrier voltage of the GaAs HBT.

Abstract: A gain control circuit capable of keeping a constant gain without being affected by ambient temperature includes a variable resistor element connected to a power supply terminal, a control unit for controlling the resistance value of the variable resistor element on the basis of a gain control voltage, an amplifying transistor that is supplied with a power supply voltage through the variable resistor element, a current detecting resistor that is interposed between the variable resistor element and a collector of the amplifying transistor, and a voltage detecting unit that detects a drop dropped by the current detecting resistor. The dropped voltage detected by the voltage detecting unit is fed back to the control unit to control the resistance value of the variable resistor element such that a current flowing through the current detecting resistor does not vary.

Abstract: A transmission amplifier for amplifying a signal to be transmitted includes an amplifying unit that is warmed efficiently when the temperature is low. In a constitution in which an amplifying unit amplifies a signal, a temperature detecting means detects temperature. Amplifying-unit-self-heating-facilitation control means perform control for facilitating self-heating by the amplifying unit when temperature detected by the temperature detecting means is lower than a predetermined threshold value, or equal to or lower than the predetermined threshold value. The amplifying-unit-self-heating-facilitation control means perform, for example, bias control for the amplifying unit as the control for facilitating self-heating by the amplifying unit.

Abstract: A bias circuit is disclosed for use in a temperature compensation system. The bias circuit provides a current that is proportional to a temperature variation raised to an nth power where |n|>1 in accordance with an embodiment. In further embodiments, the bias circuit includes a PTAT current source for providing to a driver-stage amplifier a current that is substantially proportional to absolute temperature, and a CTAT current source for providing a current that is complementary to absolute temperature, wherein the PTAT and CTAT current sources coact to provide a PTAT2 reference current that is proportional to an absolute temperature variation to the nth power wherein |n|>1.

Abstract: A radio transceiver includes circuitry that enables received RF signals to be down-converted to baseband frequencies and baseband signals to be up-converted to RF signals prior to transmission without requiring conversion to an intermediate frequency. The circuitry includes a temperature sensing module that produces accurate voltage level readings that may be mapped into corresponding temperature values. A processor, among other actions, adjusts gain level settings based upon detected temperature values. One aspect of the present invention further includes repetitively inverting voltage signals across a pair of semiconductor devices being used as temperature sensors to remove a common mode signal to produce an actual temperature-voltage curve. In one embodiment of the invention, the circuitry further includes a pair of amplifiers to facilitate setting a slope of the voltage-temperature curve.

Abstract: A linearized bias circuit with adaptation resolves the problem happening to the power amplifier with conventional bias circuit that the DC and AC characteristics of the power amplifier shift or even deteriorate due to a temperature variation. The linearized bias circuit with adaptation has a reference voltage source, a first voltage source, a first resistor, a second resistor, a first NPN transistor, a second NPN transistor, and a third NPN transistor. The present invention has the characteristics of bias current temperature compensation, gain and phase compensations to achieve high linearity for the conventional power amplifier and reducing the DC consumption power. At the same time, the quantity of the required elements and layout area in the present invention are small so that the design complexity can be reduced for improving yield, reducing IC layout area, and reducing cost.

Abstract: A bias circuit includes a voltage stabilizer connected between a control voltage input terminal through a current limit resistor and a ground, a bias supply emitter follower with a base connected to a node between the current limit resistor and the voltage stabilizer through a resistor, and a current limiter connected between the base and an emitter of the bias supply emitter follower.

Abstract: A signal processing circuit includes a circuit stage for operating on signals in a signal path of an input signal, including main circuitry for operating on relatively small-value signals and alternative circuitry for amplifying/processing signals during a condition which otherwise would cause thermal imbalance in the main circuitry. The circuit stage includes switching circuitry for coupling signals in the signal path of the input signal to the main input circuitry during normal small-signal operating conditions and for coupling signals in the signal path of the input signal to the alternative circuitry during the condition which otherwise would cause thermal imbalance in the main circuitry.

Abstract: A waveform processing system may include a compensation circuit to adjust a voltage supplied to an output stage, wherein a supplied voltage is controlled to substantially maintain constant power dissipation in the output stage, and wherein the compensation circuit is configurable independently from the amplification stage. In an illustrative embodiment, a control circuit may be independently configurable with respect to an amplifier that generates a signal for the output stage, and the control circuit may bias a compensation circuit that provides thermal tail compensation for an output stage transistor. In some embodiments, the bias may operate the compensation circuit (i) to maintain a substantially constant power condition in the output stage transistor to substantially reduce thermal tail effects, and (ii) to maintain the output stage transistor in an unsaturated operating condition.

Abstract: A radio transceiver includes circuitry that enables received RF signals to be down-converted to baseband frequencies and baseband signals to be up-converted to RF signals prior to transmission without requiring conversion to an intermediate frequency. The circuitry includes a temperature sensing module that produce accurate voltage level readings may be mapped into corresponding temperature values. A processor, among other actions, adjusts gain level settings based upon detected temperature values. One aspect of the present invention further includes repetitively inverting voltage signals across a pair of semiconductor devices beings used as temperature sensors to remove a common mode signal to produce an actual temperature-voltage curve. In one embodiment of the invention, the circuitry further includes a pair of amplifiers to facilitate setting a slope of the voltage-temperature curve.

Abstract: In an embodiment of this invention, if a state, in which duty ratio of a PWM signal is kept equal to or greater than a predetermined value, has been maintained for a first time period, the duty ratio of the PWM signal of a digital power amplifier is adjusted downward. Furthermore, the duty ratio of the PWM signal is maintained without change when the duty ratio of the PWM signal is adjusted downward for a second time period, and the duty ratio of the PWM signal is adjusted downward only when volume is set to a maximum value allowable in the power amplifier. Accordingly, the temperature of the power amplifier can be prevented from rapidly increasing, the internal temperature of an electronic apparatus can be efficiently prevented from increasing, and damage to the power amplifier resulting from increased temperature can be prevented.

Abstract: A high frequency power amplifier circuit includes amplifying devices whose control terminals (gate or base terminals) are supplied with a bias voltage. The high frequency power amplifier circuit keeps constant the bias voltage so that the amplifying devices operate in a saturation region. The high frequency power amplifier circuit controls an operating power supply voltage supplied to the amplifying devices in accordance with an output request level to control output power. A device (diode) having temperature dependency is provided for an operating power supply voltage control circuit that controls the operating power supply voltage for the amplifying devices in accordance with the output request level. The operating power supply voltage control circuit is configured to generate the operating power supply voltage corresponding to the device's temperature characteristics and supply it to the amplifying devices.

Abstract: A method for generating a temperature-compensated control signal is provided. The method includes receiving a constant control signal. A temperature-compensated control signal is generated based on the constant control signal. The temperature-compensated control signal is provided to a variable gain amplifier. The temperature-compensated control signal is operable to cause the variable gain amplifier to function independently of temperature.

Abstract: Provided is a temperature-compensated circuit for a power amplifier through diode voltage control, in which a first resistor (Rref), a first diode (D1), and a second diode (D2) are connected to a reference voltage in series. The temperature-compensated circuit includes a second resistor (R1) connected to the reference voltage, a third resistor (R2) connected to the second resistor in series, a fourth resistor (Rc) having one terminal connected to the reference voltage, a fifth resistor (Re) having one terminal connected to ground, a bias transistor having a base terminal connected to a contact point (VS) between the second resistor and the third resistor, a collector terminal connected to the other terminal of the fourth resistor, and an emitter terminal connected to the other terminal of the fifth resistor, and a sixth resistor (Rf) connected between a series connection terminal between the first diode and the second diode, and the collector terminal of the bias transistor.

Abstract: A circuit and a method for nullifying temperature dependence of a circuit characteristic. The circuit includes a plurality of transistors configured such that they generate a gate voltage that includes a threshold voltage as a component. The gate voltage is applied to a transistor to generate a current that is proportional to a process transconductance parameter. The current is applied to a comparator having a differential pair of transistors, wherein each transistor has a process transconductance parameter. The circuit takes the ratios of the process transconductance parameter associated with the current to that of each transistor of the differential pair. By rationing the process transconductance parameters, temperature dependence is nullified or negated. The ratios can be used to set the hysteresis voltage of the comparator.

Abstract: A thermally regulated amplifier system includes an amplifier unit, a temperature-sensing unit and a controller. The amplifier unit includes a power amplifier that has an adjustable gain function. The controller receives temperature readings from the temperature-sensing unit, computes the gain G(n) of the amplifier unit, and provides the computed gain of the amplifier G(n) to the power amplifier unit.

Abstract: An apparatus reducing non-linearity in an output signal presented at an output locus of an amplifier device having an output unit coupled with the output locus, the output unit having at least one first operating characteristic contributing to the non-linearity, includes a compensating unit coupled with the output locus. The compensating unit has at least one second operating characteristic cooperating with the at least one first operating characteristic to effect the reducing.