Patent application number | Description | Published |
20110140784 | Amplifier Circuit - An amplifier circuit includes a pair of amplifying devices, a first balun coupled between an input port of the amplifier circuit and RF input ports of the pair of amplifying devices and a second balun coupled between RF output ports of the pair of amplifying devices and an output port of the amplifier circuit wherein the first and second baluns are configured such that the amplifier circuit operates under open condition for signals at a second harmonic frequency even when the second harmonic frequency is within an operating frequency band of a fundamental frequency of the amplifier circuit. In one embodiment, the amplifier circuit includes a bypass circuit which selectively couples balun ports to ground such that in response to a first control signal, the amplifier circuit operates in an amplifying mode and in response to a second control signal, the amplifier circuit operates in a bypass mode. | 06-16-2011 |
20110241755 | High Power Radio Frequency (RF) Switch - A radio frequency (RF) switch circuit includes switching devices coupled at a common node and a floating control signal circuit (CSS) coupled to the control electrodes of the switching devices and the common node and configured to isolate RF signals from the CSS and configured to provide differential voltage signals to the common node and each of the control electrodes. | 10-06-2011 |
20130207721 | Envelope Tracking Amplifier - An envelope tracking power amplifier uses signal cancellation techniques to provide isolation between RF signals and envelope signals, without the use of filters. In this manner, the envelope tracking power amplifiers are capable of operating with envelope signals that are at or near the frequency of the corresponding RF signals. In at least one embodiment, a double balanced power amplifier is provided that includes a balanced RF input port, a balanced RF output port, and a balanced envelope input port. The balanced nature of the amplifier results in ports of the amplifier forming virtual grounds with respect to signals at other ports. In some other embodiments, a single balanced amplifier is provided that provides isolation between ports thereof. | 08-15-2013 |
20130241655 | Linearization Circuit and Related Techniques - Circuits and techniques to linearize the operation of an RF power amplifier are described. A linearizer circuit may include a non-amplification signal path which includes a delay line and an amplification signal path which includes at least one amplifier stage. In some embodiments, the amplification signal path may include an odd number of amplification stages. The linearizer may be used to precondition an input signal of an RF power amplifier in a manner that improves the overall linearity of operation. | 09-19-2013 |
20130241656 | Power Amplification System Using Doherty Amplifier with Linearization Circuit and Related Techniques - A power amplification system includes a linearizer circuit feeding a power amplifier to linearize the operation of the power amplifier. The linearizer circuit may shape the input signal of the power amplifier in a manner that complements the output power versus input power characteristic of the power amplifier. In some embodiments, the linearizer may increase the relative magnitude of higher power portions of the input signal while decreasing the relative magnitude of lower power portions of the input signal to provide an overall increase in the linearity of the power amplification system. The power amplifier may include a Doherty amplifier in some implementations. | 09-19-2013 |
20140253245 | Interference Tolerant, Broadband Radio Frequency Amplifier - A distributed RF amplifier includes filter circuits to band limit input signal components applied to corresponding amplifiers. Different amplifiers in the distributed amplifier may be band limited to different pass bands. The different pass bands may collectively cover an operational frequency range of the distributed amplifier. In this manner, band-limited interference within an input signal of the distributed amplifier may only effect the gain performance of the distributed amplifier within corresponding band(s) | 09-11-2014 |
20140368268 | Load Tuning Circuit For Pulse-Width / Pulse-Position Modulation Amplifier And Related Techniques - A pulse width modulated/pulse modulated PWM/PPM power amplification circuit includes a load modulation circuit coupled between an output of the amplification circuit and a load. In one embodiment, the load modulation circuit comprises a plurality of capacitor elements switchably coupled such that in response to a control signal provided the load modulation circuit presents one of a plurality of different capacitance values at a terminal thereof. By changing capacitance values associated with the plurality of capacitor elements in accordance with the output of the amplification circuit and the load, improved (and “optimum”) power levels that exhibit a desired (and best) efficiency can be selected. Such results in an amplification circuit having an efficiency level which is relatively high compare with efficiency levels of conventional amplifier circuits over a wide dynamic range of output power. | 12-18-2014 |
20140368278 | Using Multiple-Driver Stages to Realize Fast Rise/Fall Time And Large Current Capability - A driver circuit includes a first sub-driver circuit having an input coupled to receive a first pulsed signal, the first sub-driver circuit being configured to generate a first driver signal at an output thereof in response to the first pulsed signal, the first driver signal having relatively fast edge transitions and a low current capability. Also included is a second sub-driver circuit having an input coupled to receive a second pulsed signal, the second sub-driver circuit being configured to generate a second driver signal at an output thereof in response to the second pulsed signal, the second driver signal having edge transitions that are slower than those of the first driver signal and a current capability that is higher than that of the first driver signal. Further included is a combiner to combine the first driver signal and the second driver signal to generate a combined driver signal having fast edge transitions associated with the first driver signal and higher current capability associated with the second driver signal. A corresponding method is also provided. | 12-18-2014 |
20140368279 | Direct Biasing A Gate Electrode Of A Radio Frequency Power Amplifier Through a Driver Stage - A radio frequency (RF) circuit includes an amplifier circuit comprising at least one transistor amplifier having first, second, and third terminals. The RF circuit additionally includes a driver circuit comprising an enhancement-mode transistor and a depletion-mode transistor coupled in a cascade configuration having an upper portion and a lower portion, the driver circuit having an output coupled to an input of the amplifier circuit such that the driver circuit is capable of providing pulsed signals as well as a direct-current (DC) bias current to at least one terminal of a transistor amplifier of the amplifier circuit. A corresponding method is also provided. | 12-18-2014 |