An amplifier system is provided that switches between a linear mode of operation, an envelope tracking mode of operation and a polar mode of operation. The amplifier system switches between modes of operation based upon a characteristic of an input signal relative to a first threshold level and a second threshold level. A mode selector selects the operation mode by transmitting an amplitude modulated signal plus a variable headroom voltage to a supply terminal of a power amplifier during the envelope tracking mode, an amplitude modulated signal to the supply terminal and phase modulated input signal during the polar mode and a substantially constant amplitude signal to the supply terminal during the linear mode.

Multi-mode amplifier system

The present invention, generally speaking, incorporates the power amplifier as a fundamental constituent of a modulator, using polar modulation techniques. Thus, it is possible to achieve the combination of precision signal generation (including envelope variations) along with high energy efficiency in combinations not possible heretofore. In accordance with one embodiment of the invention, a modulated radio (passband) signal generator produces high quality signals of general type, which specifically includes signals with varying envelopes. Signals are generated with high energy efficiency in the conversion of applied DC power to output RF signal power. The result is longer battery life for products such as mobile phone handsets. Dramatically improved efficiency also allows for a dramatic reduction (10 to 1 or greater) in the size of any required heatsink for the radio transmitter, which significantly lowers both cost and size. Furthermore, continuous operation of these radio transmitters is made possible with small temperature rises using small heatsinks, or even without any heatsink components. This provides for high operating reliability, as well as for greater throughput due to the longer operating time allowed. Another aspect of the invention allows the generation of high quality signals with wide bandwidth, without the need for continuous feedback during operation. This further reduces costs by greatly simplifying the design, manufacturing, and complexity of the transmitter circuitry.

High-efficiency power modulators

A transceiver comprises an amplifying circuit for amplifying an input signal to produce an output signal A power supply is operable for varying the level of power supplied to the amplifying circuit in response to variation of an input signal envelope directed to the power supply A processing circuit is operable for digitally detecting the input signal envelope to provide variation of the power supply level The processing circuit is further operable for digitally delaying the digital input signal envelope to time align the power supply level with the input signal

Integrated transceiver with envelope tracking

A power amplifier controller for adjusting a supply voltage to a power amplifier. The power amplifier controller adjusts the supply voltage so that distortion in an RF output signal corresponds to a predetermined limit. An amplitude error signal is generated by the power amplifier controller which represents a difference between an RF output signal and an attenuated RF output signal. The AC components of the amplitude error signal are processed to generate a deviation signal that represents the distortion in the RF output signal. The supply voltage to the power amplifier is increased when the deviation signal exceeds a distortion level control signal, and decreased when the deviation signal drops below the distortion level control signal.

Error driven rf power amplifier control with increased efficiency

Systems and methods are provided for determining and providing an appropriate variable voltage supply to a power amplifier. A power amplifier is operative to amplify an input signal. A digital buffer stores a copy of the input signal representing a predetermined interval of time. An envelope profiler analyzes the buffered interval of the input signal and determines an appropriate supply signal profile for the power amplifier over the predetermined time interval. A supply control provides a supply signal according to the determined profile.

Variable supply amplifier system

A method (200) and device (100) provide an efficient linear power amplifier that generates a variable-envelope radio frequency RF signal. The method includes the steps of: A) using an efficient envelope-following unit to output a supply voltage in accordance with a variable envelope of an input baseband signal, wherein using the efficient envelope-following unit includes: 1) using a bandwidth-limiting mapping unit to determine a reference signal based on the baseband signal; and 2) using an envelope-tracking power converter to output a supply voltage, responsive to the reference signal, to the linear RF power amplifier; B) providing an RF input signal with amplitude and phase information to a linear RF power amplifier; and C) using the linear RF power amplifier to output a power-efficient amplified variable-envelope RF signal with substantially a same amplitude and phase information as the RF input signal.

Method, device, phone and base station for providing envelope-following for variable envelope radio frequency signals

The system mechanism (122) provides an effective, linear power amplifier, generating a HF-RF variable signal. An effective envelope curve tracking converter (102) receives a base band signal and transmits a supply voltage in coincidence with a variable envelope curve of the base band signal. The tracking converter contains a wide band limiting imaging unit (108) receiving the base band signal for determining a reference signal, and an envelope curve tracking converter (110) receives the reference signal and is coupled to a current source (120) to transmit a supply voltage to the linear RF power amplifier (106) as a reaction to the reference signal. An RF signal generator (104) is incorporated in the system. Independent claims are included for a method for providing a linear power amplifier, a cellular telephone, a portable radio apparatus, a satellite telephone, a radio telephone and a base station.

Steven F. Gillig

Papers

Method, device, phone and base station for providing envelope-following for variable envelope radio frequency signals

System with telephone and base station

Method and device for providing envelope-following for variable envelope radio frequency signals

Procede, dispositif, telephone et station de base pour fournir un suivi d'enveloppe a des signaux radiofrequence a enveloppe variable