157 results about "Driver amplifier" patented technology

A polar modulation transmitter circuit provides reduced ACPR in its output signal by controlling the relative delay between its envelope and phase modulation operations based on direct or indirect feedback measurement the output signal's ACPR. Such measurement and associated control may be based on a delay controller that includes an ACPR measurement circuit and a delay control circuit. Additionally, or alternatively, the polar modulation transmitter circuit provides a greatly extended transmit power control range by using a staged amplifier circuit that includes a driver amplifier circuit operating in combination with a power amplifier circuit to impart desired envelope modulation. In an exemplary embodiment, the driver amplifier circuit is implemented as differential transistor pairs responsive to tail current modulation. As such, the driver amplifier circuit is suited in particular for economical and space saving integration within a transmitter or transceiver integrated circuit (IC).

A voltage regulator apparatus includes an error amplifier that amplifies a voltage difference between a reference and a sampled output voltage of the voltage regulator apparatus. A driver amplifier has an input that is responsive to the amplified voltage difference to produce a gate driving voltage at its output. An output transistor having a drain, a gate, and a source is also included. The gate is responsive to the gate driving voltage to produce a regulated output voltage at the source. To stabilize the voltage regulator apparatus, a Miller compensation capacitor is provided to feed a sample of the regulated output voltage back to the input of the driver amplifier; and additionally, an Ahuja compensation circuit is provided to feed back a portion of the regulated output voltage back to the input of the driver amplifier.

A Solid State Power Amplifier (SSPA) for powering a single element of a multi-element antenna, the SSPA comprising:

an RF amplifier, having a signal amplifying path that includes preamplifier, driver amplifier and a power output stage;

an Electronic Power Conditioner (EPC) for providing a variable value of DC voltage for powering the power output stage of the RF amplifier;

a control ASIC for receiving an input power signal of the RF amplifier for providing a voltage control signal to the EPC to determine the value of the DC voltage, the control ASIC addressing an EEPROM holding a collection of control words that define output values of a control output signal for varying values of said input power, such that the value of the DC voltage to the power output stage is varied so as to control the gain compression of the RF amplifier for varying values of input power in order to maintain constant amplifier linearity.

An RF transmitter capable of transmitting over a wide range of frequencies includes a mixer, a wideband high-Q balun, a first driver amplifier and a second driver amplifier. The balun has a single primary winding and two secondary windings. A differential output of the mixer is coupled to the primary winding. A first of the two secondary windings is coupled to drive the first driver amplifier. A second of the two secondary windings is coupled to drive the second driver amplifier. One driver amplifier is used when transmitting at lower frequencies whereas the other driver amplifier is used when transmitting at higher frequencies. By appropriate sizing of the inductances of the secondary windings and by switching out one of the secondary windings at certain times, the balun is tunable to operate over the wide frequency range while having a high quality factor Q, thereby facilitating reduced power consumption while simultaneously meeting performance requirements.

An assembly involves an integrated circuit die that is bonded, e.g., flip-chip bonded, to a non-semiconductor substrate by a plurality of low-resistance microbumps. In one novel aspect, at least a part of a novel high-frequency transformer is disposed in the non-semiconductor substrate where the non-semiconductor substrate is the substrate of a ball grid array (BGA) integrated circuit package. At least one of the low-resistance microbumps connects the part of the transformer in the substrate to a circuit in the integrated circuit die. At two gigahertz, the novel transformer has a coupling coefficient k of at least at least 0.4 and also has a transformer quality factor Q of at least ten. The novel transformer structure sees use in coupling differential outputs of a mixer to a single-ended input of a driver amplifier in a transmit chain of an RF transceiver within a cellular telephone.

A driver amplifier in an integrated circuit is suitable for driving a signal onto an output node and through an output terminal, and through a matching network to a power amplifier. A novel Programmable Output Impedance Adjustment Circuit (POIAC) within the integrated circuit is coupled to the output node and affects an output impedance looking into the output terminal. When the output impedance would otherwise change (for example, due to a driver amplifier power gain change), the POIAC adjusts how it loads the output node such that the output impedance remains substantially constant. The POIAC uses a series-connected inductor and capacitor L-C-R circuit to load the output node, thereby reducing the amount of capacitance and die area required to perform multi-band impedance matching with a power amplifier. Multi-band operation is accomplished by changing an effective capacitance in the L-C-R circuit depending on communication band information received by the POIAC.

A parametric audio system having increased bandwidth for generating airborne audio signals with reduced distortion. The parametric audio system includes a modulator for modulating an ultrasonic carrier signal with a processed audio signal, a driver amplifier for amplifying the modulated carrier signal, and an array of acoustic transducers for projecting the modulated and amplified carrier signal through the air along a selected projection path to regenerate the audio signal. Each of the acoustic transducers in the array is a membrane-type transducer. Further, the acoustic transducer array is a phased array capable of electronically steering, focusing, or shaping one or more audio beams.

An integrated circuit arrangement is provided for converting a high-frequency bandpass signal to a low-frequency quadrature signal with a first in-phase component and a first quadrature-phase component, which has: an amplifier arrangement, which is designed to generate an amplified signal and has a first amplifier stage for amplifying the high-frequency bandpass signal, a mixer unit with a first mixer to provide the first in-phase component and a second mixer to provide the first quadrature-phase component, and a driver amplifier, which is designed to generate a local oscillator signal. According to the invention, between the amplifier arrangement and the mixer unit a polyphase filter is disposed, which converts the amplified signal to a complex-valued polyphase signal with a second in-phase component and a second quadrature phase component. Furthermore, according to the invention each mixer is connected to the driver amplifier, and the first mixer is designed to multiply the second in-phase component by the local oscillator signal, and the second mixer is designed to multiply the second quadrature-phase component by the local oscillator signal.

An RF power amplifier circuit is disclosed. A driver amplifier stage includes a first set of a plurality of amplifier transistors in a cascode configuration, a driver amplifier stage input, and a driver amplifier stage output. A final amplifier stage includes a second set of a plurality of amplifier transistors in a cascode configuration, a final amplifier stage input connected to the driver amplifier stage output, a final amplifier stage output, and a power supply input. An envelope signal amplifier has an input connectible to an envelope signal source, and an output capacitively coupled to the power supply input. A power converter input is connected to the power supply input to provide supplemental power to the final amplifier stage based on an envelope signal from the envelope signal source that corresponds to an input RF signal.

A variable impedance load (104) is provided at the output of a radio frequency (RF) driver amplifier (102) having a variable gain. In an exemplary embodiment, the variable load (104) comprises a resistor (R) in series with a semiconductor device (M₁). The semiconductor device (M₁) has an impedance level determined by a drive current. The value of the drive current is related to the gain of the RF driver amplifier (102).

Provided are a circuit and method for driving a liquid crystal display device using low power. The circuit includes a display data latch, a gamma decoder, and a driver cell circuit. The display data latch latches display data from a memory. The gamma decoder receives a plurality of gray scale voltages, and selects and outputs one of the plurality of gray scale voltages in response to the display data. The driver cell circuit receives an output voltage of the gamma decoder and generates an output voltage applied to the liquid crystal display device. The driver cell circuit controls a slew rate in response to comparison result of current data and previous data of the display data. The driver cell circuit includes a previous data latch, a bias control voltage generator, and a driver amplifier. The previous data latch receives a portion or the whole of the display data and outputs the portion or the whole of the display data as the previous data. The bias control voltage generator compares the current data and the previous data of the display data and generates a control signal. The driver amplifier receives the output voltage of the gamma decoder, generates the output voltage applied to the liquid crystal display device, and controls the slew rate in response to the control signal.

A multi-mode multi-band power amplifier (PA) module is described. In an exemplary design, the PA module includes multiple power amplifiers, multiple matching circuits, and a set of switches. Each power amplifier provides power amplification for its input signal when selected. Each matching circuit provides impedance matching and filtering for its power amplifier and provides a respective output signal. The switches configure the power amplifiers to support multiple modes, with each mode being for a particular radio technology. Each power amplifier supports at least two modes. The PA module may further include a driver amplifier and an additional matching circuit. The driver amplifier amplifies an input signal and provides an amplified signal to the power amplifiers. The additional matching circuit combines the outputs of other matching circuits and provides an output signal with higher output power. The driver amplifier and the power amplifiers can support multiple output power levels.

The present invention, generally speaking, provides an RF power amplifier that exhibits high PAE at high output powers. The design of the power amplifier is based on the observation that the switching transistor is controlled by either voltage (for a FET) or current (for bipolar transistors), but not both. Thus, it is not necessary to develop power from the driver amplifier in order to operate the final stage as a switch. This recognition runs exactly counter to conventional wisdom, i.e., the concept of impedance matching for interstage design of high efficiency power amplifiers. It is impossible to develop solely a voltage waveform or a current waveform in a passband (resonant) network such as an RF power amplifier—both voltages and current must exist. In accordance with one aspect of the invention, however, instead of maximizing power transfer, power consumption is reduced while maintaining the magnitude of the voltage (or current) waveform. In accordance with another aspect of the invention, the driver is designed to, along with the final stage, operate in switch mode. In this instance, the design of the interstage network is similar to that of a Class E output stage. In the case of the interstage network, however, the objective is not to develop maximum power across the load (as in the case of the Class E output stage). Rather, the objective is to develop the maximum voltage across the driver's load (which is the switch input). In this arrangement, the input drive of the switch may be sufficiently high that the operating voltage of the driver stage may be reduced. This reduction further reduces the DC supply power to the driver, enhancing PAE.

A method and system to use voltage isolated and floating differential output amplifiers wired in series and parallel to achieve arbitrary output drive voltage and current for the applications load. A second embodiment uses multiple matched voltage-isolated and floating differential output amplifiers in a single chassis to enable selection between a multi-channel amplifier and a high current and/or high voltage mono amplifier. A third embodiment uses a step-up transformer and paralleled unity-gain buffer amplifiers, on input and/or output stages, to produce a zero feedback, high performance, high drive amplifier. A fourth embodiment uses a high voltage unity-gain driver amplifier to bias a unity-gain buffer amplifier and its power supply to achieve an ultra low distortion high voltage buffer amplifier. A fifth embodiment uses multiple voltage-isolated and linearized devices to enable dynamically modifiable, Class A, Class B, and Class AB topologies of predetermined voltage and current performance. A sixth embodiment corrects an output by linearizing one or more devices in a circuit by utilizing a linearization module (e.g., including one or more digital lookup tables, an error simulation circuit, or an equivalent) to linearize at least one parameter of at least one device in the circuit.

An apparatus for detecting abnormal masses such as breast cancer includes a measurement sensor configured to obtain a voltage at a first area of a first breast of a subject; a reference sensor configured to obtain a voltage at a second area of a second breast of the subject, a position of the first area corresponding to a position of the second area; and a detector, wherein the detector includes a differential amplifier configured to amplify a voltage input from the at least one of the measurement sensor and the reference sensor; an active low pass filter configured to pass a signal frequency of a low frequency band among signals transmitted from the differential amplifier; a driver amplifier configured to amplify a signal passed through the active low pass filter; and an analog-to-digital (AD) converter configured to convert the signal amplified by the driver amplifier into a digital signal.

A source driver circuit in which a slow rate is adjusted according to a frame frequency and a method for adjusting a slew rate according to a frame frequency in the source driver circuit, wherein the source driver circuit includes a plurality of driver amplifiers, a frequency-current converting unit, and a bias current outputting unit. The driver amplifiers receive input voltages, generate output voltages, and adjust slew rates of the output voltages according to an amount of a bias current. The frequency-current converting unit receives a frame frequency and outputs a control current having an amount of the control current adjusted according to the frame frequency. The bias current outputting unit adjusts an amount of a bias current according to the amount of the control current and outputs the adjusted bias current to the driver amplifiers. Therefore, in the source driver circuit and the method for controlling the slew rate in the source driver circuit, by adjusting a slew rate of an output voltage of a driver amplifier according to a frame frequency, it is possible to reduce power consumption while ensuring a time required for displaying gradation data.

An integrated voltage controlled current source device is provided, that extends the high accuracy, low drift output current over a large current range, and provides more headroom and better power efficiency than the standard shunt resistor and INA (instrumentation amplifier) current source arrangement. The device has a control voltage input, a load current output and a current set terminal for a connection of a current set resistor. It contains a selected leg biasing set voltage, corresponding to a control voltage applied to the control voltage input of a regulating driver amplifier providing a regulated voltage to be applied across the current set resistor, thereby causing a reference current to flow through the current set resistor and selected leg(s) of a current mirror. Furthermore, the device contains a dynamically matched current mirror that mirrors the reference current to the load output current. The algorithm for selecting the current mirror legs may be a pseudo-random or a defined pattern.

A transmission power control device which amplifies in a driver amplifier 2, and in a power amplifier 4 to which the output from the driver amplifier is inputted, so that the power of a signal to be transmitted may become predetermined target transmission power, detects an electric-current which flows to the power amplifier 4 from a power supply, and adjusts the gain of the driver amplifier 2 based on this detected electric-current.

A wireless transmitter includes an RF signal generation circuit, a driver amplifier, and a class-D amplifier. The RF signal generation circuit detects an amplitude signal and a phase signal based on a digital baseband signal subjected to orthogonal modulation, thus generating a pulse phase signal which is High in response to the phase ranging from 0° to 180° but is Low in response to the phase ranging from 180° to 360°. The amplitude signal is subjected to sigma-delta modulation in synchronism with the pulse phase signal and further mixed with the pulse phase signal, thus producing an RF pulse signal. The RF pulse signal is input to the class-D amplifier via the driver amplifier, thus outputting a pulse voltage signal based on a reference voltage. Thus, it is possible to achieve a small-size wireless transmitter with good noise/distortion characteristics and high power efficiency.

Disclosed is a duobinary optical transmitter, which includes a laser source for outputting light with a predetermined wavelength; a Mach-Zehnder interferometer-type optical intensity modulator for modulating the intensity of the light according to a three-level data signal inputted through a modulation terminal; a low-pass filter for converting an inputted two-level binary data signal into a three-level data signal through an interference among codes; and, a modulator driver/amplifier for amplifying the three-level data signal and then outputting it to the modulation terminal, wherein the overall bandwidth of the low-pass filter, the modulator driver/amplifier, and the optical intensity modulator corresponds to approximately ¼ of the clock frequency of the two-level binary data signal.