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High-efficiency composite amplifier

A technology of amplifiers and maximum voltage, applied in the direction of amplifiers, power amplifiers, radio frequency amplifiers, etc., can solve problems such as imperfect composite amplifiers

Inactive Publication Date: 2012-08-08
TELEFON AB LM ERICSSON (PUBL)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

A problem that has remained unsolved so far is how to obtain maximum efficiency (i.e. the best possible under such conditions) from an imperfect composite amplifier.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0108] Example 1: Detuned Chireix Amplifier

[0109] By making the sum of the transmission line lengths slightly different from 1 / 2, we have a "detuned" Chireix amplifier. Such as Figure 16 As shown, in the case mentioned here, the electrical lengths are 0.30λ (from PA1 to common output) and 0.18λ (from PA2 to common output), totaling 0.48λ (instead of the exact value of 0.5λ). This can be seen when the Chirexi amplifier is operating below 4% of its rated frequency. On the input side, linear drive signal components are generated directly from the input signal via amplifiers / phase shifters 26 and 32 . Likewise, non-linear drive signal components are generated by non-linear element 38 and amplifier / phase shifters 28 and 30 . For example, unit 38 is implemented as a combination of a lookup table followed by a D / A converter in which the digital input signal amplitude is converted to the appropriate drive signal (assuming the input signal amplitude proportional to the composit...

example 2

[0114] Example 2: Detuned Doherty Amplifier

[0115] The Doherty amplifier can be constructed with transmission lines of electrical length λ / 4 and λ / 2 from the constituent amplifiers to the common output [16]. In the case presented, this Doherty amplifier was detuned to 19% below its rated frequency. Thus, the length of the transmission line is changed to 0.21λ (from PA1 to common output) and 0.42λ (from PA2 to common output), for a total of 0.63λ. Figure 23 Such a detuned Doherty amplifier is illustrated. Figure 24-27 The amplitude and phase of the amplifier output node voltage and output current are shown.

[0116] and Figure 9 Compared to the Doherty amplifier, the main features of this new solution are in Figure 24 The voltage plot of , appears as a middle or transition region in the upper end, where both amplifiers are at constant voltage. As in the case of the detuned Chireix amplifier, this can be seen as inserting an additional transition point T2, but this ti...

example 3

[0120] Example 3: Current Limit at Low Output

[0121] This example of a detuned asymmetric (in terms of transistor size) Chireix amplifier illustrates the need for additional transition points, ie more regions with different operating conditions. The transmission line impedances are 1.4 (from PA1 to common output) and 3.5 (from PA2 to common output), respectively. This means that the maximum output current from PA1 is 1 / 1.4=5 / 7 and the maximum output current from PA2 is 1 / 3.5=2 / 7. Such as Figure 30 As shown, the wire lengths are 0.33λ (from PA1 to the common output) and 0.19λ (from PA2 to the common output), for a total of 0.52λ. Figure 31-34 The amplitude and phase of the output node voltage and output current of the amplifier are shown.

[0122] The point of this example is to show the extra transition that occurs due to current limitation at zero (at 0.36 times the maximum output voltage). As previously stated, one amplifier (PA2) alone optimally takes care of the fi...

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Abstract

A detuned composite amplifier includes a nonlinear drive function (22) that has a phase that varies with the composite amplifier output voltage amplitude. The nonlinear drive function (22) is configured to transform the output voltage transition point of the prior art into an extended output voltage transition region to increase the efficiency of the composite amplifier.

Description

technical field [0001] This invention relates to composite amplifiers, and more particularly to methods and apparatus for increasing the efficiency of such amplifiers. Background technique [0002] In many wireless communication systems, the power amplifier (PA) in the transmitter is required to be very linear in addition to being able to simultaneously amplify many radio channels (frequencies) distributed over a fairly wide broadband range. This must be done efficiently in order to reduce power consumption and cooling requirements, and to increase its lifetime. High linearity is required because nonlinear amplifiers cause leakage of interfering signal energy between channels. [0003] The amplitude probability density of a mixture of sufficiently many independent Radio Frequency (RF) channels or of a multi-user CDMA (Code Division Multiple Access) signal tends to approach a Rayleigh distribution with a large peak-to-average power ratio. Since a conventional RF power ampli...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03F1/02H03F3/21
CPCH03F1/0294H03F3/602H03F2200/543H03F3/24H03F1/0288H03F2200/451
Inventor R·赫尔伯格M·克休伯格
Owner TELEFON AB LM ERICSSON (PUBL)