A Multiple-Input Digitally Controlled Buck Converter for Envelope Tracking Applications in Radiofrequency Power Amplifiers

Rodrı́guez, Miguel A.; Miaja, Pablo F.; Rodríguez, Alberto; Sebastián, J.

doi:10.1109/tpel.2009.2028732

Cited by 80 publications

(51 citation statements)

References 16 publications

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“…Their use for applications that require bandwidth in the MHz range is however limited. For example, a buck converter with 1 MHz bandwidth should operate at a switching frequency of at least was 2.2 W. In [12], a solution based on multiple input buck converter is presented and it enables an easier design of the output filter due to pulse width modulation with various voltage levels.…”

Section: (T) Arct G (F|) a { T)mentioning

confidence: 99%

Envelope Amplifier Based on Switching Capacitors for High-Efficiency RF Amplifiers

Vasić¹,

García²,

Oliver³

et al. 2012

IEEE Trans. Power Electron.

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Abstract-Modern transmitters usually have to amplify and transmit signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, linear power amplifiers (class A, B, or AB) are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has high peak-to-average power ratio. The Kahn envelope elimination and restoration technique is used to enhance the efficiency of RF transmitters, by combining highly efficient, nonlinear RF amplifier (class E) with a highly efficient envelope amplifier in order to obtain a linear and highly efficient RF amplifier. This paper presents a solution for the envelope amplifier based on a multilevel converter in series with a linear regulator. The multilevel converter is implemented by employing voltage dividers based on switching capacitors. The implemented envelope amplifier can reproduce any signal with a maximum spectral component of 2 MHz and give instantaneous maximum power of 50 W. The efficiency measurements show that when the signals with low average value are transmitted, the implemented prototypes have up to 20% higher efficiency than linear regulators used as a conventional solution.

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Section: (T) Arct G (F|) a { T)mentioning

confidence: 99%

Envelope Amplifier Based on Switching Capacitors for High-Efficiency RF Amplifiers

Vasić¹,

García²,

Oliver³

et al. 2012

IEEE Trans. Power Electron.

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“…This fast-response DC/DC converter is often known as an Envelope Modulator or Envelope Amplifier. Over the years, several designs have been proposed for fast-response DC/DC converters conceived to work as Envelope Amplifiers [41][42][43][44][45][46][47][48][49][50]. Most of these designs derive from the Buck converter, as this converter exhibits linearity between the control and the output voltage if it has been designed to operate in Continuous Conduction Mode (CCM).…”

Section: B Fast-response Dc/dc Converters Used To Synthesize the Whomentioning

confidence: 99%

On the Role of Power Electronics in Visible Light Communication

Sebastián

Lamar

Aller

et al. 2018

IEEE J. Emerg. Sel. Topics Power Electron.

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Abstract-The continuous demand of increasing data rates provided by wireless communication systems is contributing to saturating the RF spectrum. Visible Light Communication (VLC) systems aim to alleviate this congestion by using the visible light spectrum. These systems have been proposed to make use of High-Brightness LEDs (HB-LEDs) not only for lighting, but also for transmitting information by rapidly changing the intensity of the emitted light. A critical issue is that VLC requires a fast HB-LED driver in order to reproduce the target light intensity waveforms, which can include components of several MHz. Consequently, the HB-LED drivers proposed to date are based on the use of an RF Power Amplifier (RFPA). These devices provide the required speed, but suffer from very high power losses. To overcome this drawback, different solutions based on the use of fastresponse DC/DC converters are presented in this paper. Several DC/DC converters, either to be used instead of an RFPA or to help an RFPA to achieve high efficiency, are thus analysed. The proposed HB-LED drivers enable the implementation of VLC transmitters without sacrificing one of the most important advantages of HB-LED lighting, namely its high power efficiency.Index Terms-Visible Light Communication (VLC), High-Brightness LEDs (HB-LEDs) and Fast-response DC/DC converters.

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“…A variety of switching-mode dc/dc converters have been proposed to be used as an EA [1]- [20], sometimes with the help of a linear stage to increase the overall bandwidth [13]- [18]. Those derived from the basic Buck converter [1], [3], [5], [6], [8]- [12], [14]- [16], [18] are especially suitable for this application because they have a linear relationship between the duty cycle and the output voltage, when they operate in the continuous conduction mode (CCM) [23].…”

Section: Introductionmentioning

confidence: 99%

Design of a Two-Phase Buck Converter With Fourth-Order Output Filter for Envelope Amplifiers of Limited Bandwidth

Sebastián

Miaja

Ortega-González

et al. 2014

IEEE Trans. Power Electron.

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Abstract-The use of techniques such as envelope tracking (ET) and envelope elimination and restoration (EER) can improve the efficiency of radio frequency power amplifiers (RFPA). In both cases, high-bandwidth DC/DC converters called envelope amplifiers (EA) are used to modulate the supply voltage of the RFPA. This paper addresses the analysis and design of a modified two-phase Buck converter optimized to operate as EA. The effects of multiphase operation on the tracking capabilities are analyzed. The use of a fourth-order output filter is proposed to increase the attenuation of the harmonics generated by the PWM operation, thus allowing a reduction of the ratio between the switching frequency and the converter bandwidth. The design of the output filter is addressed considering envelope tracking accuracy and distortion caused by the side bands arising from the nonlinear modulation process. Finally, the proposed analysis and design methods are supported by simulation results, as well as demonstrated by experiments obtained using two 100-W, 10-MHz, two-phase Buck EAs capable of accurately tracking a 1.5-MHz bandwidth OFDM signal.

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A Multiple-Input Digitally Controlled Buck Converter for Envelope Tracking Applications in Radiofrequency Power Amplifiers

Cited by 80 publications

References 16 publications

Envelope Amplifier Based on Switching Capacitors for High-Efficiency RF Amplifiers

Envelope Amplifier Based on Switching Capacitors for High-Efficiency RF Amplifiers

On the Role of Power Electronics in Visible Light Communication

Design of a Two-Phase Buck Converter With Fourth-Order Output Filter for Envelope Amplifiers of Limited Bandwidth

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