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

Inactive Publication Date: 2002-09-25
APPLE INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As explained in the state of the art, signals with information realized in amplitude variations are incompatible with high-efficiency, non-linear power amplifiers, since changes in signal amplitude can be severely distorted

Method used

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  • High-efficiency modulating RF amplifier
  • High-efficiency modulating RF amplifier
  • High-efficiency modulating RF amplifier

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Embodiment Construction

[0067] Reference is now made to FIG. 7, which is a schematic diagram of a power amplifier that overcomes many of the above-mentioned disadvantages. A switched (or saturated) non-linear amplifier has applied to it the voltage generated by the power control stage. In a typical implementation, essentially according to the formula V = PR Controls the voltage V applied to the nonlinear amplifier, where P is the desired power output level of the amplifier and R is the resistance of the amplifier. In the case of a switching or saturated amplifier, the resistance R can be considered constant. The power control stage receives a DC input voltage (for example, from a battery), receives a power level control signal, and outputs a voltage according to the above equation.

[0068] use Figure 8 illustrates the efficiency of directly controlling the output power of a nonlinear amplifier over a wide dynamic range by varying the operating ...

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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.

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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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03F3/68H03C5/00H03F1/02H03F3/193H03G3/00
CPCH03C5/00H03F1/0227H03F1/0244H03F3/1935H03F3/2176H03G3/004H03F2201/3215
Inventor 温德尔·桑德小厄尔·W·麦丘恩罗纳德·A·迈克
Owner APPLE INC
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