High-efficiency modulating RF amplifier

A technology of amplifiers and power amplifiers, applied in the field of RF amplifiers and signal modulation, can solve problems such as incompatibility of nonlinear power amplifiers, distortion of signal amplitude changes, etc., and achieve the effect of high-power and high-efficiency modulation structures
CN1371545AInactive Publication Date: 2002-09-25APPLE INC
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
APPLE INC
Publication Date
2002-09-25
Estimated Expiration
Not applicable · inactive patent

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Abstract

The present invention provides efficient power control of high efficiency (eg, hard-limited or switched) power amplifiers. By emulating a switching converter with an active linear regulator, the difference between the highest frequency of modulation required and the operating frequency of the switching DC-DC converter is reduced. The linear regulator controls the operating voltage of the power amplifier with sufficient bandwidth to reproduce the desired amplitude-modulated waveform. A linear regulator rejects changes in the input voltage even while changing the output voltage in response to an applied control signal. Amplitude modulation is achieved by changing the operating voltage of the power amplifier. Efficiency is improved by allowing a switching DC-DC converter to vary its output voltage so that the voltage drop across the linear regulator is maintained at a relatively constant low level.
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Description

technical field

[0001] This invention relates to RF amplifiers and signal modulation. Background technique

[0002] In wireless communication devices such as cellular telephones, pagers, wireless modems, and the like, battery life is of great concern. In particular, radio frequency transmission consumes a large amount of power. Contributing to this power dissipation is inefficient power amplification operation. Typical RF power amplifiers for wireless communications operate at about 10% efficiency. Undoubtedly, low-cost techniques to significantly increase the efficiency of amplifiers will satisfy the above pressing needs.

[0003] Additionally, most modern digital wireless communication devices operate on packets. That is, the transmitted information is sent in short bursts of one or more, with the transmitter active only during the burst time and inactive at all other times. Therefore, control of pulse firing and cessation in an energy-efficient manner is required in ...

Claims

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