On Track for Efficiency: Concurrent Multiband Envelope-Tracking Power Amplifiers

Kwan, Andrew; Younes, Mayada; Darraji, Ramzi; Ghannouchi, Fadhel M.

doi:10.1109/mmm.2016.2525118

Cited by 19 publications

(8 citation statements)

References 34 publications

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“…Operating such an RF power amplifier with a fixed supply is no longer a viable option, as it reduces the overall efficiency as well as battery lifetime between charges. Envelope tracking is an assuring supply modulation technique [1][2][3][4] that helps improving the efficiency of such an RF power amplifier. Envelope Tracking Power Supply (ETPS) is a vital block of an Envelope Tracking Power Amplifier (ETPA), since the overall efficiency of the ETPA [5] depends on the efficiency of the ETPS as given by:…”

Section: Introductionmentioning

confidence: 99%

Efficiency Analysis and Design Considerations of a Hysteretic Current Controlled Parallel Hybrid Envelope Tracking Power Supply

Babu¹,

Shivaleelavathi²,

Yatnalli³

2023

Eng. Technol. Appl. Sci. Res.

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This paper presents the realization of an Envelope Tracking Power Supply (ETPS), for a sinusoidal envelope input signal. A parallel hybrid topology is chosen for the implementation. In this topology, a voltage-controlled Class-AB linear amplifier stage and a current-controlled switching converter stage operate in parallel. A hysteretic current control scheme is employed to control the operation of the switching converter. Block-level implementation of the ETPS is done using Simulink 2017b, continuous mode simulation. Simulations are performed using a sinewave input envelope signal = 1.94+ 1.2 sin(ω∙t). The input frequency varied from 1MHz to 60MHz. As the input frequency is increased, the ETPS moves from the linear to the non-linear region of operation. During the transition, the slew rates of the load current and the switching current match at a particular input frequency of 2MHz while the efficiency peaks. The maximum obtained efficiency while tracking the sinewave input signal is 82.3%. The way the efficiency can be optimized by focusing on the matching of the slew rates of load and switching currents is explained. Also, an insight into the study of various circuit parameters and the trade-offs that the designer needs to consider while designing an ETPS, is provided.

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Section: Introductionmentioning

confidence: 99%

Efficiency Analysis and Design Considerations of a Hysteretic Current Controlled Parallel Hybrid Envelope Tracking Power Supply

Babu¹,

Shivaleelavathi²,

Yatnalli³

2023

Eng. Technol. Appl. Sci. Res.

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“…Meanwhile, the peak‐to‐average power ratio (PAPR) of wideband‐modulated signal is usually high, 5–8 leading to low efficiency of the stand‐alone power amplifier 9 . To improve the efficiency of a PA, envelope‐tracking architecture is one of the most promising candidates 9–14 …”

Section: Introductionmentioning

confidence: 99%

“…Such a wide bandwidth of envelope signal will not only degrade the efficiency of the supply modulator but also bring serious nonlinear distortion 15 . On the other hand, the PA will show severe nonlinearity when its supply voltage is below the knee voltage, 12 therefore the original envelope should be mapped to a proper voltage range.…”

Section: Introductionmentioning

confidence: 99%

“…9 To improve the efficiency of a PA, envelope-tracking architecture is one of the most promising candidates. [9][10][11][12][13][14] Figure 1 shows a general block diagram of envelope tracking (ET), where the x(n) and jx(n)j represent the baseband input signal and the original envelope, respectively. The original envelope is processed by the envelope generation block, amplified by the supply modulator and then applied as the supply voltage of the PA. 14 Therefore, the PA keeps working in a saturated state to achieve high efficiency.…”

Section: Introductionmentioning

confidence: 99%

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High‐accuracy filtering‐based envelope generation and digital predistortion for wideband envelope tracking power amplifier

Chen

Zhu

et al. 2022

Int J RF Mic Comp-Aid Eng

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A high‐accuracy filtering‐based envelope generation technique for wideband envelope tracking power amplifiers (ET PAs) is proposed to improve PA efficiency with limited envelope bandwidth. It is achieved by optimizing the envelope generation block by employing three generalized rectification functions. The proposed envelope can be obtained by finding the proper coefficients in these generalized rectification functions. Furthermore, the digital predistortion can be employed to compensate for the nonlinearity and memory effect introduced by the proposed envelope. Experiments have been carried out on an ET system that is operated with the center frequency of 3.5 GHz, which have shown that the proposed technique can improve the PA efficiency by more than 2.2% with only 1.2× the modulated bandwidth compared to the state‐of‐the‐art methods. The normalized mean square error can achieve −44.8 dB, and the adjacent channel leakage ratio can achieve better than −52 dBc. The proposed technique can improve the PA efficiency with limited envelope bandwidth compared to the state‐of‐the‐art techniques, and the PA supplied by the proposed envelope can be linearized well, while it may cost more resources to find the proper coefficients of these three generalized rectification functions.

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“…Introduction: Owing to the increasingly high peak-to-average power ratio (PAPR) of modern-day modulated signals, power amplifiers (PAs) need to have the capability to operate efficiently overextended power back-off. In comparison with a conventional power amplifier (PA), envelope tracking (ET) PA can significantly reduce power dissipation by modulating the supply voltage in response to the instantaneous modulation envelope magnitude [1][2][3][4]. Bandwidth (BW) reduction techniques can be used to alleviate the BW requirement and thus reduce the necessary switching speed in supply modulators needed to improve the overall power efficiency.…”

mentioning

confidence: 99%

Flexible bandwidth reduction technique for envelope tracking using low‐pass finite impulse response filters

et al. 2020

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In this Letter, low-pass finite impulse response filters are proposed to flexibly reduce the envelope bandwidth (BW) requirements for envelope tracking (ET) supply modulators. A second-order power ET (PET) approach is used as a comparative study, and a 'design zone' for shaping function coefficients is identified for the first time. Proposed 20 and 10 MHz low-pass filters (LPFs) are used to reduce the effective envelope BW in response to a 20 MHz long-term evolution signal applied to a 10 W power amplifier (PA). Experimental results verify that in comparison with PET, the proposed LPF method has the benefit of allowing arbitrary BW reduction and is compatible with the use of customised shaping functions. It is also shown that significant memory effects can be introduced when the effective envelope BW is reduced to less than the RF BW. To investigate the linearisability of the ET PA, the linearity before and after digital pre-distortion is also measured.

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On Track for Efficiency: Concurrent Multiband Envelope-Tracking Power Amplifiers

Cited by 19 publications

References 34 publications

Efficiency Analysis and Design Considerations of a Hysteretic Current Controlled Parallel Hybrid Envelope Tracking Power Supply

Efficiency Analysis and Design Considerations of a Hysteretic Current Controlled Parallel Hybrid Envelope Tracking Power Supply

High‐accuracy filtering‐based envelope generation and digital predistortion for wideband envelope tracking power amplifier

Flexible bandwidth reduction technique for envelope tracking using low‐pass finite impulse response filters

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