Abstract:
An apparatus (1000) and method for sensing load current of an envelope tracking (ET) modulator (1150) enables load impedance of a power amplifier (130) to be measured. Impairments associated with the load impedance characteristic can be suppressed by calibration and pre-distortion instead of by feedback. The ET modulator (1150) provides a switching regulator that can be reconfigured as a linear regulator for the purpose of sensing the load current. This allows the ET modulator (1150) to be operated open-loop, thereby eliminating the power consumption overhead resulting from utilization of a loop filter and error amplifier and achieving a higher overall efficiency.
Abstract:
The present disclosure includes circuits and methods for power amplifiers. In one embodiment, a main and peaking amplifier receive dynamic power supply voltages to operate an RF power amplifier in a high efficiency range for a particular output voltage. The power supply voltages may be changed based on an output voltage so that the power amplifier operates within a high efficiency plateau. In one embodiment, different discrete power supply voltage levels are used for different output voltage ranges. In another embodiment, a continuous time varying power supply voltage is provided as the power supply voltage. A dynamic supply voltage may be generated having a lower frequency than a signal path of the power amplifier.
Abstract:
Exemplary embodiments of the invention include a request received to change a TX output power setting or a frequency channel setting. In response, the requested TX output power setting is used to generate a TX output signal in the proper frequency channel. Handset circuitry makes OOB power measurements, the results of which are used to determine a VCC2 setting. The VCC2 setting is a setting that results in an MPS requirement just being met. The VCC2 setting is stored in association with the TX output power and frequency channel setting. The determined VCC2 setting is also used to set the VCC2 supply voltage for the power amplifier. Once set, VCC2 remains fixed until the next request. Each individual handset uses this Adaptive Average Power Tracking (AAPT) method, thereby reducing its VCC2 voltage during operation and conserving power. Because each handset uses AAPT, factory calibration to account for unit-to-unit variations in transmitter circuitry performance is avoided.
Abstract:
An amplifier 100 has an input 108 for receiving a signal to be amplified and an output 110 for outputting an amplified signal. The amplifier 100 comprises a main amplification stage 102, an auxiliary amplification stage 104 and a controller 106. The main amplification stage 102 comprises a main amplification circuit 200 and the auxiliary amplification stage 104 comprises an auxiliary amplification circuit 202. Each of the main amplification circuit 200 and the auxiliary amplification circuit 202 comprises a p-channel metal oxide semiconductor (PMOS) transistor T1, T3 and an n-channel metal oxide semiconductor (NMOS) transistor T2, T4. The PMOS and NMOS transistors T3, T4 of the auxiliary amplification circuit 202 are either identical to the PMOS and NMOS transistors T1, T2 of the main amplification circuit 200 or are scaled down copies of the PMOS and NMOS transistors T1, T2 of the main amplification circuit 200. The auxiliary amplification circuit 202 amplifies the input signal to generate a control signal and the controller 106 controls a function of the amplifier 100 based on the control signal.
Abstract:
The present invention relates to a line termination unit (1') comprising: - a line driver (10) for driving a transmission line, with a first supply voltage input terminal (11) and a second supply voltage input terminal (12); - a power supply means (20), with an analog supply voltage output terminal (22) for feeding an analog part of the line termination unit, and at least one digital supply voltage output terminal (23a, 23b, 23c) for feeding a digital part of the line termination unit, and - a ground voltage reference (30). In accordance with a first aspect of the invention, the analog supply voltage output terminal is coupled to the first supply voltage input terminal, and the line termination unit further comprises a selector (40) for selectively coupling one of the at least one digital supply voltage output terminal or the ground voltage reference to the second supply voltage input terminal.
Abstract:
A power supply system uses improved Class G amplifier architecture for high bandwidth operation with low distortion. The power supply system switches between multiple power supply rails, depending on the signal level handled by the power supply system. The lowest usable supply rail voltage is chosen to minimize power dissipation in the output driver, thus optimizing efficiency. Each supply rail has an associated driver capable of sourcing current to the amplifier output. When a supply rail is selected, its associated driver is enabled and other driver(s) not associated with the selected supply rail are disabled via separate disable control signals. The disabling of the deselected driver may be delayed until current above a predetermined threshold is sensed at the output of the enabled driver. In addition, the frequency of switching between the power rails may be limited via various means designed to limit distortion in the power supply system.
Abstract:
A two-(or multi-) stage power amplifier receives a variable RF input signal, and outputs an optimized RF output signal from, for example, a mobile handset. The output power level from the handset is predetermined, as known in the art, by the re- ceived control signal from a base station. The first power amplifier stage amplifies the variable RF input signal and outputs an RF signal, Vin, to a power detector circuit and an RF signal to the second or next amplifier stage. The power detect circuit amplifies the Vin signal and rectifies that signal with a linearly biased diode and provides a detect signal to a DC to DC converter. The converter responds by providing an optimum voltage bias, which is linearly related to the DC voltage detect signal from the power detector, to the output stage, and, if desired, to the first and/or other stages of the power amplifier that optimizes the output power level while meeting the required linearity specification. The battery current consumption is optimized through this automatic, dynamically control of the supply voltage for the power amplifier at each output power level through the DC to DC converter.
Abstract:
Devices and methods for correcting for start-up transients in integrated power amplifiers are disclosed. A delay element (116) is arranged to produce a delay waveform signal that is responsive to an input voltage signal. A transconductance element (118) has an input that receives the delay waveform signal and is arranged to provide an output boost current (102) that is based on the delay waveform signal and a gain of the transconductance element. A reference element (104) provides an output bias current (108) that is responsive to a static reference current (106) and the boost current (102). A bias element (110) has an input that receives the bias current (108) and is arranged to provide a bias control output (112). A power amplifier (114) is responsive to the bias control output (112) and is arranged to provide an amplified power output (RF OUT ).