Switching capacities based envelope amplifier for high efficiency RF amplifiers

Vasić, Miroslav; García, O.; Oliver, J. A.; Alou, P.; Diaz, Daniel; Cobos, J.A.

doi:10.1109/apec.2010.5433590

Cited by 10 publications

(9 citation statements)

References 12 publications

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“…The switched regulator can be implemented in many different ways [25,26] (Figure 3 shows just one possible way how to do it). The multilevel converter operates in open-loop and its output will be only certain discrete voltage levels.…”

Section: E Multilevel Converter In Series With a Linear Regulatormentioning

confidence: 99%

“…The multilevel converter operates in open-loop and its output will be only certain discrete voltage levels. These levels are achieved by stacking cells (see figure 3) or by an analog multiplexor [26] The main advantage is that the average switching frequency of these cells is much smaller than the frequency of the envelope (it depends on the probability density of the envelope), obtaining a high efficiency. In [18] it is explained how the average switching frequency could be estimated for a signal described by its probability function.…”

Section: E Multilevel Converter In Series With a Linear Regulatormentioning

confidence: 99%

“…In [23] a flyback converter with three outputs has been used. In [25] a bidirectional flyback in a combination with a buck converter was implemented as a first stage, while in [26] the first stage is composed of simple voltage dividers implemented with switched capacitors. The last example offers very high efficiency and power density of the first stage and it does not need any bulky magnetic component, which opens a possibility for the integration of this stage.…”

Section: E Multilevel Converter In Series With a Linear Regulatormentioning

confidence: 99%

“…Including a parallel linear regulator (group A.2) makes easier to achieve a high bandwidth [15,16]. The solution that presents a good trade-off between power and bandwidth is the one based on the multilevel with series regulator [23][24][25][26][27]0 (group D).…”

Section: Trade-off Bandwidth-out Trade-offmentioning

confidence: 99%

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Survey of architectures and optimizations for wide bandwidth envelope amplifier

Vasić

García

Oliver

et al. 2012

2012 15th International Power Electronics and Motion Control Conference (EPE/PEMC)

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-In the last years, RF power amplifiers are taking advantage of the switched dc-dc converters to use them in several architectures that may improve the efficiency of the amplifier, keeping a good linearity. The use of linearization techniques such as Envelope Elimination and Restoration (EER) and Envelope Tracking (ET) requires a very fast dc-dc power converter to provide variable voltage supply to the power amplifier but theoretically the efficiency can be much higher than using the classical amplifiers belonging to classes A, B or AB. The purpose of this paper is to analyze the state of the art of the power converters used as envelope amplifiers in this application. The power topologies will be explored and several important parameters such as efficiency, bandwidth will be discussed.

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Section: E Multilevel Converter In Series With a Linear Regulatormentioning

confidence: 99%

Section: E Multilevel Converter In Series With a Linear Regulatormentioning

confidence: 99%

Section: E Multilevel Converter In Series With a Linear Regulatormentioning

confidence: 99%

Section: Trade-off Bandwidth-out Trade-offmentioning

confidence: 99%

See 2 more Smart Citations

Survey of architectures and optimizations for wide bandwidth envelope amplifier

Vasić

García

Oliver

et al. 2012

2012 15th International Power Electronics and Motion Control Conference (EPE/PEMC)

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“…In this case it is possible to obtain high efficiency because the major part of the output power is managed by the buck converter, while the fast dynamic response is guaranteed by the linear regulator. A solution that exhibits a fast dynamic response and high output power is presented in [5,6]. The main idea is to exploit good dynamic characteristics of the multilevel converter and to increase its efficiency.…”

Section: Introductionmentioning

confidence: 99%

Multiphase buck converter with minimum time control strategy for RF envelope modulation

Cheng

Vasić

García

et al. 2011

2011 Twenty-Sixth Annual IEEE Applied Power Electronics Conference and Exposition (APEC)

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Power amplifier supplied with constant supply voltage has very low efficiency in the transmitter. A DC-DC converter in series with a linear regulator can be used to obtain voltage modulation. Since this converter should be able to change the output voltage very fast, a multiphase buck converter with a minimum time control strategy is proposed. To modulate supply voltage of the envelope amplifier, the multiphase converter works with some particular duty cycle (i/n, i=l, 2 ... n, n is the number of phase) to generate discrete output voltages, and in these duty cycles the output current ripple can be completely cancelled. The transition times for the minimum time are pre-calculated and inserted in a look-up table. The theoretical background, the system model that is necessary in order to calculate the transition times and the experimental results obtained with a 4-phase buck prototype are given. I.

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