Abstract: A power amplifier circuit is a Doherty type. A peak amplifier has a first transistor and a second transistor. A first source terminal is connected to a first constant potential line. A first drain terminal and a second source terminal are connected to a first node. A second drain terminal is connected to a second constant potential line having a higher potential than the first constant potential line. A first control terminal is connected to a first bias voltage application circuit, and an input signal is input to the first control terminal via a first alternating current coupling circuit. A second control terminal is connected to a second bias voltage application circuit and is connected to the first node via a second alternating current coupling circuit. The first node is connected to the first constant potential line via a third alternating current coupling circuit.

Abstract: A level converter and circuit arrangement comprising such level converters. The level converter comprises a transistor, an impedance converter, an input voltage connection, an output voltage connection, and a power supply connection. The input voltage connection is connected to a gate terminal of the transistor. The output voltage connection is connected to a source terminal of the transistor and to the power supply connection. A first input terminal of the impedance converter is connected to the source connection or to the gate terminal of the transistor. An output terminal of the impedance converter is connected to the drain terminal of the transistor. The power supply connection is equipped to receive a current from a constant current source. The impedance converter is equipped to keep a source-drain voltage of the transistor at a predefined value using a reference voltage.

Abstract: A circuit comprises an amplifier network including a first amplifier and a second amplifier and a first transistor having a first base. The first transistor is thermally isolated from the second amplifier. The circuit further comprises a second transistor having a second base. The second transistor is thermally linked to the second amplifier. The circuit further comprises coupling circuitry configured to couple the first base to the second base.

Abstract: An apparatus is disclosed, comprising means for storing reference data indicative of characteristics for each of two or more amplifiers for amplifying signals in two or more respective bands, the reference data including voltage characteristics required by the particular amplifier to achieve a particular output power for a range of output power values for its respective frequency band. The apparatus may comprise means for receiving at least a first required output power for a first amplifier and a second required output power for a second amplifier, and determining, based on the reference data, the voltage characteristics required for the first amplifier to achieve the first required output power and the voltage characteristics required for the second amplifier to achieve the second required output power.

Abstract: Systems and methods including variable power amplifier bias impedance are disclosed. In one aspect, there is provided a power amplifier system including a bias circuit configured to receive a bias voltage and generate a bias signal and a power amplifier stage configured to receive an input radio frequency (RF) signal and generate an output RF signal. The power amplifier system may also include a bias impedance component operatively coupled between the bias circuit and the power amplifier stage. The bias impedance is component configured to receive a control signal and adjust an impedance value of the bias impedance component in response to the control signal.

Abstract: A current detecting circuit includes a first switching element, a second switching element, and a third switching element electrically coupled in series with the first switching element. An output side of the third switching element is electrically coupled to an output terminal. The current detecting circuit includes a current amplifier configured to detect a difference between a first output voltage of the first switching element and a second output voltage of the second switching element. The current amplifier outputs a relative current to be used for detecting an output current that flows out from the output terminal. A ratio of resistance associated with the first switching element to resistance associated with the second switching element is n:1.

Abstract: A multi-gain LNA with inductive source degeneration is presented. The inductive source degeneration is provided via a tunable degeneration network that includes an inductor in parallel with one or more switchable shunting networks. Each shunting network includes a shunting capacitor that can selectively be coupled in parallel to the inductor. A capacitance of the shunting capacitor is calculated so that a combined impedance of the inductor and the shunting capacitor at a narrowband frequency of operation is effectively an inductance. The inductance is calculated according to a desired gain of the LNA. According to one aspect, the switchable shunting network includes a resistor in series connection with the shunting capacitor to provide broadband frequency response stability of the tunable degeneration network. According to another aspect, the LNA includes a plurality of selectable branches to further control gain of the LNA.

Abstract: Various methods and circuital arrangements for biasing one or more gates of stacked transistors of an amplifier are presented, where the amplifier can have a varying supply voltage. According to one aspect, the gate of the input transistor of the amplifier is biased with a fixed voltage whereas the gates of the other transistors of the amplifier are biased with variable voltages that are linear functions of the varying supply voltage. According to another aspect, the linear functions are such that the variable voltages coincide with the fixed voltage at a value of the varying supply voltage for which the input transistor is at the edge of triode. According to another aspect, biasing of the stacked transistors is such that, while the supply voltage varies, the drain-to-source voltage of the input transistor is maintained to a fixed value whereas the drain-to-source voltages of all other transistors are equal to one another.

Abstract: A differential power amplifier includes an input matching network, a first-stage amplification circuit, a first inter-stage matching network, a second-stage amplification circuit, a second inter-stage matching network, a third-stage amplification circuit, and an output matching network. The first-stage amplification circuit and the second-stage amplification circuit are single-ended input single-ended output circuits. The third-stage amplification circuit is a dual input dual output circuit. The second inter-stage matching network includes a first transformer T1, a first capacitor C1, a second capacitor C2, a first inductor L1, and a second inductor L2. The output matching network includes a second transformer T2. The inter-stage matching networks and the output matching network are realized by the first transformer T1 and the second transformer T2, which reduces an inter-stage matching difficulty, optimizes input return loss and gain, and improves output power.

Abstract: Systems and methods for controlling a signal amplifier unit configured with an electronic communication device are disclosed. The signal bar level on the electronic communication device is determined, and the signal amplifier unit is turned on based on the determined signal bar level. The signal level of the signal amplifier unit may be measured, and attenuation may be added based on the measured signal level. The measured signal level may be compared to a target level.

Abstract: A power amplifying module includes a first input terminal, a second input terminal, a first power amplifier, a stage matching circuit, a bypass line, and a second power amplifier. The first input terminal receives a first input signal in a first operation mode. The second input terminal receives a second input signal in a second operation mode which is different from the first operation mode. The first power amplifier amplifies the first input signal and outputs a first amplified signal. The stage matching circuit is disposed downstream of the first power amplifier and receives the first amplified signal. The bypass line outputs the second input signal to the inside of the stage matching circuit not through the first power amplifier. The second power amplifier is disposed downstream of the stage matching circuit, and amplifies the first amplified signal or the second input signal and outputs a second amplified signal.

Abstract: Thermal temperature sensors for power amplifiers are provided herein. In certain implementations, a semiconductor die includes a compound semiconductor substrate, and a power amplifier including a plurality of field-effect transistors (FETs) configured to amplify a radio frequency (RF) signal. The plurality of FETs are arranged on the compound semiconductor substrate as a transistor array. The semiconductor die further includes a semiconductor resistor configured to generate a signal indicative of a temperature of the transistor array. The semiconductor resistor is located adjacent to one end of the transistor array.

Abstract: A radio frequency power amplifier circuit includes a controllable attenuation circuit, an input matching circuit, a drive amplification circuit, an inter-stage matching circuit, a power amplification circuit and an output matching circuit connected in sequence, and respectively configured to switch between a negative gain mode and a non-negative gain mode of the radio frequency power amplifier circuit based on a mode control signal, match the impedance between the controllable attenuation circuit and the drive amplification circuit, amplify a signal, configured to match the impedance between the drive amplification circuit and the power amplification circuit, amplify a signal, and match the impedance between the radio frequency power amplifier circuit and a post-stage circuit. A feedback circuit is connected across the drive amplification circuit, and is configured to adjust a gain.

Abstract: An integrated circuit includes an oscillator and a power amplifier. The oscillator includes a first node, a second node, and a network of one or more reactive components coupled between the first node and the second node. The power amplifier includes a first input coupled to the first output of the oscillator, a second input coupled to the second output of the oscillator, and an output. The power amplifier includes a coarse gain control circuit, a first amplifier stage, and a second amplifier stage.

Abstract: An amplifier includes a semiconductor die and a substrate that is distinct from the semiconductor die. The semiconductor die includes a III-V semiconductor substrate, a first RF signal input terminal, a first RF signal output terminal, and a transistor (e.g., a GaN FET). The transistor has a control terminal electrically coupled to the first RF signal input terminal, and a current-carrying terminal electrically coupled to the first RF signal output terminal. The substrate includes a second RF signal input terminal, a second RF signal output terminal, circuitry coupled between the second RF signal input terminal and the second RF signal output terminal, and an electrostatic discharge (ESD) protection circuit. The amplifier also includes a connection electrically coupled between the ESD protection circuit and the control terminal of the transistor. The substrate may be another semiconductor die (e.g., with a driver transistor and/or impedance matching circuitry) or an integrated passive device.

Abstract: A radio frequency module includes: a transmission power amplifier that includes a plurality of amplifying elements that are cascaded; a reception low noise amplifier; and a module board on which the transmission power amplifier and the reception low noise amplifier are mounted. The plurality of amplifying elements include: an amplifying element disposed most downstream; and an amplifying element disposed upstream of the amplifying element, and in a plan view of the module board, a conductive member is physically disposed between the amplifying element and the reception low noise amplifier.

Abstract: A transistor stack can include a combination of floating and body tied devices. Improved performance of the RF amplifier can be obtained by using a single body tied device as the input transistor of the stack, or as the output transistor of the stack, while other transistors of the stack are floating transistors. Transient response of the RF amplifier can be improved by using all body tied devices in the stack.

Abstract: Various embodiments are directed to apparatuses and methods to generate a first signal representing modulation data and a second signal representing an amplitude of the modulation data, the first signal and the second signal to depend on an output signal and vary a power supply voltage to a gain stage in proportion to the amplitude of the modulation data.

Abstract: The present disclosure provides for process and temperature compensation in a transimpedance amplifier (TIA) using a dual replica via monitoring an output of a first TIA (transimpedance amplifier) and a second TIA; configuring a first gain level of the first TIA based on a feedback resistance and a reference current applied at an input to the first TIA; configuring a second gain level of the second TIA and a third TIA based on a control voltage; and amplifying a received electrical current to generate an output voltage using the third TIA according to the second gain level. In some embodiments, one or both of the second TIA and the third TIA include a configurable feedback impedance used in compensating for changes in the second gain level due to a temperature of the respective second or third TIA via the configurable feedback impedance of the respective second or third TIA.

Abstract: A power amplifier circuit includes an amplifier transistor having a base, a collector, a bias circuit, and a first resistance element connected between the base of the amplifier transistor and the bias circuit. The bias circuit includes a voltage generation circuit, a first transistor having a base to which a first direct-current voltage is supplied, and an emitter from which the bias current or voltage is supplied, a second transistor having a base to which a second direct-current voltage is supplied, and an emitter connected to the emitter of the first transistor, a signal supply circuit disposed between the base of the amplifier transistor and the base of the second transistor, and an impedance circuit disposed between the base of the first transistor and the base of the second transistor.

Abstract: A power amplifier circuit includes a power amplifier including a first transistor having a first terminal connected to a reference potential, a second terminal to which a first current and a radio-frequency signal are input, and a third terminal connected to a first power supply potential via a first inductor; a capacitor connected to the third terminal of the first transistor; a second transistor including a first terminal connected to the capacitor and the reference potential via a second inductor, a second terminal to which a second current is input and is connected to the reference potential, and a third terminal connected to the first power supply potential via a third inductor and outputs signal; and an adjustment circuit that outputs a third current corresponding to the first power supply potential or a second power supply potential to the second terminal of the second transistor.

Abstract: A power amplifier module includes a first transistor that amplifies and outputs a signal, a second transistor that supplies a bias current to a base of the first transistor, and a ballast resistor circuit that is disposed between the base and an emitter of the second transistor and that includes first and second resistive elements and a switching element. The first resistive element is arranged in series on a line connecting the base and the emitter. The first and second resistive elements are series-connected or parallel-connected. When the second resistive element is series-connected to the first transistor, the switching element is parallel-connected to the second resistive element. When the second resistive element is parallel-connected to the first transistor, the switching element is series-connected to the second resistive element. The switching element is switched on/off based on a collector current of the second transistor.

Abstract: Provided in the present invention are a power control apparatus for a radio-frequency power amplifier and a radio-frequency transmission system for a magnetic resonance imaging system. The power control apparatus comprises: a power control module used to receive a control voltage so as to control an output power of the radio-frequency power amplifier; a voltage detection module used to detect an operating voltage provided to the radio-frequency power amplifier and to output a detected voltage; and a voltage adjustment module used to adjust, on the basis of the detected voltage, the control voltage received by the power control module so as to adjust the output power of the radio-frequency power amplifier.

Abstract: A bias circuit includes first to fourth transistors and a phase compensation circuit. In the first transistor, a reference current or voltage is supplied to a first terminal, and the first terminal and a second terminal are connected. In the second transistor, a first terminal is connected to the first transistor, and a third terminal is grounded. In the third transistor, a power supply voltage is supplied to a first terminal, a second terminal is connected to the first transistor, and a bias current or voltage is supplied from a third terminal to an amplifier transistor. In the fourth transistor, a first terminal is connected to the third transistor, a second terminal is connected to the second transistor, and a third terminal is grounded. The phase compensation circuit is provided in a path extending from the fourth transistor to the third transistor through the second and first transistors.

Abstract: One aspect of this disclosure is a power amplifier system that includes a control interface, a power amplifier, a passive component, and a bias circuit. The power amplifier and the passive component can be on a first die. The bias circuit can be on a second die. The control interface can operate as a serial interface or as a general purpose input/output interface. The power amplifier can be controllable based at least partly on an output signal from the control interface. The bias circuit can generate a bias signal based at least partly on an indication of the electrical property of the passive component. Other embodiments of the system are provided along with related methods and components thereof.

Abstract: An compensation circuit for an Amplitude Modulation-Amplitude Modulation (AM-AM) of a Radio Frequency (RF) power amplifier, including: a first biasing circuit, a power amplifier, and a compensation circuit located between the first biasing circuit and the power amplifier; herein, the compensation circuit includes a diode detection circuit and a feedforward amplifier for compensating AM-AM distortion.

Abstract: An RF amplifier for implementation in SiGe HBT technology is described. The RF amplifier has a cascode stage comprising a common base (CB) transistor and a common emitter (CE) transistor arranged in series between a first voltage rail and a second voltage rail. An RF input is coupled to the base of the CE transistor and an RF output is coupled to the collector of the CB transistor. The RF amplifier includes a CB power-down circuit arranged between the base of the CB transistor and the second voltage rail and a CE power-down circuit arranged between the base of the CE transistor and the second voltage rail. In a power-down mode the CE power-down circuit couples the base of the common-emitter-transistor to the second voltage rail. The CB power-down mode circuit couples the base of the CB transistor to the second voltage rail via a high-ohmic path.

Abstract: A circuit comprises an amplifier network including a first amplifier and a second amplifier and a first transistor having a first base. The first transistor is thermally isolated from the second amplifier. The circuit further comprises a second transistor having a second base. The second transistor is thermally linked to the second amplifier. The circuit further comprises coupling circuitry configured to couple the first base to the second base.

Abstract: A temperature dependent correction circuit includes a first supply source, a second supply source, a rectifying circuit, and a reference. The first supply source is configured to supply a first signal that varies with temperature along a first constant or continuously variable slope. The second supply source is configured to supply a second signal that varies with temperature along a second constant or continuously variable slope. The rectifying circuit is configured to receive the first and second signal, rectify the first signal to produce a first rectified signal, and add the first rectified signal to the second signal to produce a correction signal. The reference is configured to receive the correction signal.

Abstract: An amplifier device includes an amplifying unit and a bias module. The amplifying unit has a first end coupled to a voltage source configured to receive a source voltage, a second end configured to receive an input signal, and a third end coupled to a first reference potential terminal configured to receive a first reference potential. The first end of the amplifying unit is configured to output an output signal amplified by the amplifying unit. The bias module is coupled to the second end of the amplifying unit, and configured to receive a voltage signal to generate a bias current according to a first counter-gradient and a second counter-gradient, and provide the bias current to the amplifying unit. The voltage signal is a variable voltage. A supply current flowing into the amplifying unit and is adjusted in accordance with the voltage signal to stay within a predetermined range.

Abstract: A power amplifier system is disclosed that includes a power amplifier having a first signal input, a first signal output, second signal input, and a second signal output. The power amplifier system further includes cross-coupled bias circuitry having a first transistor with a first collector coupled to the first signal input, a first base coupled to the second signal input, and a first emitter coupled to a fixed voltage node, a second transistor with a second collector coupled to the second signal input, a second base coupled to the first signal input, and a second emitter coupled to the fixed voltage node.

Abstract: A power amplification system includes a Power Amplifier (PA) for amplifying an input RF signal. An adaptive bias circuit is configured to adaptively set a bias of the PA. The adaptive biasing circuit includes a gain expansion circuit, a gain compression circuit and a biasing circuit. The gain expansion circuit derives a gain-expansion control signal from the input RF signal. For a first sub-range of the input RF signal, the gain-expansion control signal has a larger dynamic range than the input RF signal. The gain compression circuit derives a gain-compression control signal from the input RF signal. For a second sub-range of the input RF signal having higher power levels than the first sub-range, the gain-compression control signal has a smaller dynamic range than the input RF signal. The biasing circuit sets the bias of the PA responsively to the gain-expansion control signal and the gain-compression control signal.

Abstract: A system for adjusting bias power provided to a radio-frequency amplifier to increase plurality of figures of merit based on sensed characteristics of the amplifier and/or characteristics of the input or output power.

Abstract: Disclosed is a voltage protection circuit for preventing power amplifier burnout in an electronic device. The electronic device includes a power amplifier (PA) configured to amplify a transmission signal, a switch configured to set a path of a signal outputted from the PA, a bias control circuit configured to control the supply of a bias current driving the PA, and a voltage protection circuit configured to provide a main control signal for turning off the PA earlier than turning off the switch based on a battery voltage providing a driving power of the electronic device, and forward the main control signal to the bias control circuit, wherein, in response to receiving the main control signal instructing to turn off the PA from the voltage protection circuit, the bias control unit stops the supply of the bias current driving the PA.

Abstract: Embodiments of a temperature compensation circuit and a temperature compensated amplifier circuit are disclosed. In an embodiment, a temperature compensation circuit includes a bias reference circuit having serially connected transistor devices and a driver transistor device connected to the bias reference circuit. At least one of the serially connected transistor devices includes a resistor connected between two terminals of the at least one of the serially connected transistor devices. The driver transistor device is configured to generate a drive current based on a resistance value of the resistor.

Abstract: The invention relates to powering one or more devices, in particular in the context of Power-over-Ethernet (PoE). In an embodiment of the invention, it is proposed to equip each node (11) with a PD interface (22) that can signal multiples of the standard defined unity load (25 k? with tolerances) during the detection process and increase the load during a sequence of detection attempts. In that way, several nodes (11) can share one PSE outlet and determine the number of neighboring loads (11). At the same time, each node (11) will offer full functionality during “normal” stand-alone wiring. This powering concept can be combined with full or limited data communication capabilities.

Abstract: Disclosed are a radiofrequency power amplifier module having high linearity and power-added efficiency and an implementation method. The radiofrequency power amplifier module comprises a bias circuit, a linearization circuit, and a power amplifier circuit. The power amplifier circuit is connected to the linearization circuit. The linearization circuit is connected to the bias circuit. The bias circuit is connected to the power amplifier circuit. In the present invention, the linearization circuit is utilized to capture a radiofrequency signal inputted from a radiofrequency signal input end of the power amplifier circuit, the captured radiofrequency signal is fed back to the bias circuit, a corresponding bias current is generated by the bias circuit on the basis of the radiofrequency signal fed back, and the bias current is inputted to the power amplifier circuit, thus increasing the linearity and power-added efficiency of an output signal of the radiofrequency power amplifier.

Abstract: A communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT) are provided. The disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. An amplifier includes a first transistor for amplifying the fundamental signal applied to a gate terminal, and a second transistor having a source terminal electrically connected to the drain terminal of the first transistor and a drain terminal electrically connected to a bias voltage. The current flowing through the second transistor may be determined based on the current flowing in the drain terminal of the first transistor.

Abstract: A second main electrode of a first transistor is connected to a first main electrode of a sixth transistor, a second main electrode of the sixth transistor is connected to a first main electrode of a fifth transistor at a first node, a second main electrode of the fifth transistor is connected to a second main electrode of a second transistor, a control electrode of the fifth transistor is connected to the second main electrode of the fifth transistor, a second main electrode of a third transistor is connected to a first main electrode of a fourth transistor at a second node, and a control electrode of the fourth transistor is connected to the control electrode of the fifth transistor. A gain control amplifier controls a voltage supplied to a control electrode of the sixth transistor such that the first node and the second node are equal in voltage.

Abstract: The present disclosure relates to devices and methods for detecting and preventing occurrence of a saturation state in a power amplifier. A power amplifier module can include a power amplifier including a cascode transistor pair. The cascode transistor pair can include a first transistor and a second transistor. The power amplifier module can include a current comparator configured to compare a first base current of the first transistor and a second base current of the second transistor to obtain a comparison value. The power amplifier module can include a saturation controller configured to supply a reference signal to an impedance matching network based on the comparison value. The impedance matching network can be configured to modify a load impedance of a load line in electrical communication with the power amplifier based at least in part on the reference signal.

Abstract: An amplification circuit includes: a power supply terminal that is connected to a power supply; a first transistor that has a first source terminal, a first drain terminal, and a first gate terminal to which a high-frequency signal is inputted; a second transistor that has a second source terminal that is connected to the first drain terminal, a second drain terminal that outputs a high frequency signal, and a second gate terminal that is grounded; a capacitor that is serially arranged on a second path that connects the second gate terminal and the power supply terminal; and a switch that is serially arranged on a first path, which connects the second drain terminal and the power supply terminal, or the second path. The second drain terminal and the second gate terminal are connected to each other via the switch and the capacitor.

Abstract: A wideband envelope modulator comprises a direct current (DC)-to-DC switching converter connected in series with a linear amplitude modulator (LAM). The DC-DC switching converter includes a pulse-width modulator that generates a PWM signal with modulated pulse widths representing a time varying magnitude of an input envelope signal or a pulse-density modulator that generates a PDM signal with a modulated pulse density representing the time varying magnitude of the input envelope signal, a field-effect transistor (FET) driver stage that generates a PWM or PDM drive signal, a high-power output switching stage that is driven by the PWM or PDM drive signal, and an output energy storage network including a low-pass filter (LPF) of order greater than two that filters a switching voltage produced at an output switching node of the high-power output switching stage.

Abstract: A power amplification module includes a first transistor which amplifies and outputs a radio frequency signal input to its base; a current source which outputs a control current; a second transistor connected to an output of the current source, a first current from the control current input to its collector, a control voltage generation circuit connected to the output and which generates a control voltage according to a second current from the control current; a first FET, the drain being supplied with a supply voltage, the source being connected to the base of the first transistor, and the gate being supplied with the control voltage; and a second FET, the drain being supplied with the supply voltage, the source being connected to the base of the second transistor, and the gate being supplied with the control voltage.

Abstract: Disclosed are methods for biasing amplifiers and for manufacturing bias circuits bias for biasing amplifiers. A power amplifier bias circuit can include an emitter follower device and an emitter follower mirror device coupled to form a mirror configuration. The emitter follower device can be configured to provide a bias signal for a power amplifier at an output port. The power amplifier bias circuit can include a reference device configured to mirror an amplifying transistor of an amplifying device of the power amplifier. The emitter follower mirror device can be configured to provide a mirror bias signal to the reference device. A node between the emitter follower device and the emitter follower mirror device can have a voltage of approximately twice a base-emitter voltage (2Vbe) of the amplifying transistor.

Abstract: In one example an amplifier includes a bias circuit, an open-loop gain stage including a first PMOS having a gate coupled to a first node, a source coupled to a second node, a drain coupled to a third node, and a bulk coupled to the bias circuit, a second PMOS having a gate coupled to a ground node, a source coupled to the second node, a drain coupled to a fourth node, and a bulk coupled to the bias circuit, a first NMOS having a drain and a gate coupled to the third node and a source coupled to a fifth node, a second NMOS having a drain coupled to the fourth node, a gate coupled to the third node, and a source coupled to the fifth node, an adjustable resistor coupleable between the third and fourth nodes, and a buffer stage coupled to the open-loop gain stage.

Abstract: Disclosed is an apparatus including a radio frequency amplifying circuit, a power supply circuit, and a bias generating circuit. The power supply circuit includes: a first power supply terminal coupled to a first ground terminal via a first capacitor and coupled to/decoupled from the radio frequency amplifying circuit through a first switch; and a second power supply terminal coupled to a second ground terminal via a second capacitor and coupled to/decoupled from the radio frequency amplifying circuit through a second switch, wherein the first capacitor and second capacitor are coupled to/decoupled from the radio frequency amplifying circuit through the first switch and second switch respectively, the supply voltages outputted from the two power supply terminals are different, and the two switches are not concurrently turned on. The radio frequency amplifying circuit operates according to a bias voltage provided by the bias generating circuit and one of the two supply voltages.

Abstract: Certain aspects of the present disclosure provide methods and apparatus for current-limiting protection of an amplifier, such as a power amplifier in a radio frequency (RF) front-end. One example current-limiting circuit generally includes a node coupled to a current source, a plurality of current-sinking devices coupled to the node, one or more switches coupled between the node and at least one of the plurality of current-sinking devices, and a bias circuit having an input coupled to the node and an output for coupling to an input of the amplifier.

Abstract: There has been a problem that linearity is degraded in the conventional amplifier when the idle current is reduced in order to lower the power consumption. An amplifier of the present invention includes: a bias circuit to cause a bias current to flow; an amplifying element to amplify a signal by causing an output current corresponding to the bias current to flow; a bias current subtracting circuit to detect the signal and subtract, from the bias current, a current based on an amplitude of the signal detected; and a bias current adding circuit having an operation starting point higher than an operation starting point of the bias current subtracting circuit, and to detect the signal and add, to the bias current, a current based on an amplitude of the signal detected.

Abstract: Circuits, devices and methods related to amplification with active gain bypass. In some embodiments, an amplifier can include a first amplification path implemented to amplify a signal, and having a cascode arrangement of a first input transistor and a cascode transistor to provide a first gain for the signal when in a first mode. The amplifier can further include a second amplification path implemented to provide a second gain for the signal while bypassing at least a portion of the first amplification path when in a second mode. The second amplification path can include a cascode arrangement of a second input transistor and the cascode transistor shared with the first amplification path. The amplifier can further include a switch configured to allow routing of the signal through the first amplification path in the first mode or the second amplification path in the second mode.

Abstract: The present disclosure relates to a power amplifier circuit. The power amplifier circuit includes a voltage-controlled current source and a current mirror. The voltage-controlled current source is configured to receive a first voltage and to generate a first current. The current mirror is connected to the voltage-controlled current source and to generate a second current in response to the first current. The second current continuously changes from 0 mA to about 120 mA as the first voltage continuously changes from 0 V to about 1 V.