An AC-coupled hybrid envelope modulator for HSUPA transmitters with 80% modulator efficiency

Riehl, Patrick; Fowers, P.; Hong, Hao-Ping; Ashburn, M.

doi:10.1109/isscc.2013.6487771

Cited by 35 publications

(17 citation statements)

References 6 publications

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“…A conventional current mirror OTA with a class AB output stage is employed as the linear amplifier in the ET supply modulator design in [33]. The equivalent transconductance of this amplifier is vwC = #$ R / 6 , where K 1 , K 2 are the transistor size ratios relative to the unit size [40].…”

Section: Linear Amplifier Designmentioning

confidence: 99%

“…3.7. In the constant input biasing scenario, like the linear amplifier used in [33], the maximum slew rate is calculated as:…”

Section: Slew Rate Comparisonmentioning

confidence: 99%

“…where SR con and I B are the slew rate of constant input biasing current linear amplifier in [33] and the biasing current in each input transistor. K 1 and K 2 are the ratios discussed in Fig.…”

Section: Slew Rate Comparisonmentioning

confidence: 99%

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A High Slew-Rate Adaptive Biasing Hybrid Envelope Tracking Supply Modulator for LTE Applications

Yue

Bakkaloglu

2017

IEEE Trans. Microwave Theory Techn.

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As wireless communication enters smartphone era, more complicated communication technologies are being used to transmit higher data rate. Power amplifier (PA) has to work in back-off region, while this inevitably reduces battery life for cellphones.Various techniques have been reported to increase PA efficiency, such as envelope elimination and restoration (EER) and envelope tracking (ET). However, state of the art ET supply modulators failed to address high efficiency, high slew rate, and accurate tracking concurrently.In this dissertation, a linear-switch mode hybrid ET supply modulator utilizing adaptive biasing and gain enhanced current mirror operational transconductance amplifier (OTA) with class-AB output stage in parallel with a switching regulator is presented. In comparison to a conventional OTA design with similar quiescent current consumption, proposed approach improves positive and negative slew rate from 50 V/µs to 93.4 V/µs and -87 V/µs to -152.5 V/µs respectively, dc gain from 45 dB to 67 dB while consuming same amount of quiescent current. The proposed hybrid supply modulator achieves 83% peak efficiency, power added efficiency (PAE) of 42.3% at 26.2 dBm for a 10 MHz 7.24 dB peak-to-average power ratio (PAPR) LTE signal and improves PAE by 8% at 6 dB back off from 26.2 dBm power amplifier (PA) output power with respect to fixed supply. With a 10 MHz 7.24 dB PAPR QPSK LTE signal the ET PA system achieves adjacent channel leakage ratio (ACLR) of -37.7 dBc and error vector magnitude (EVM) of 4.5% at 26.2 dBm PA output power, while with a 10 MHz 8.15 dB PAPR 64QAM LTE signal the ET PA system achieves ACLR of -35.6 dBc and EVM of 6% at 26 dBm PA output power ii without digital pre-distortion (DPD). The proposed supply modulator core circuit occupies 1.1 mm 2 die area, and is fabricated in a 0.18 µm CMOS technology.iii To My Parents and Family iv ACKNOWLEDGMENTS

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Section: Linear Amplifier Designmentioning

confidence: 99%

“…3.7. In the constant input biasing scenario, like the linear amplifier used in [33], the maximum slew rate is calculated as:…”

Section: Slew Rate Comparisonmentioning

confidence: 99%

See 1 more Smart Citation

A High Slew-Rate Adaptive Biasing Hybrid Envelope Tracking Supply Modulator for LTE Applications

Yue

Bakkaloglu

2017

IEEE Trans. Microwave Theory Techn.

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“…2(b)) has recently been proposed to improve efficiency [3,5] by modulating V IN . A switching converter typically achieves peak efficiency of 80-95% [14], surpassing the efficiency limit of a linear regulator.…”

Section: Envelope Modulator Topologiesmentioning

confidence: 99%

“…However, compared to conventional protocols, they have significantly higher peak-to-average-power ratio (PAPR). This results in dramatically lower efficiency in RF power amplifiers (PAs) [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Switching-Converter-Only Multiphase Envelope Modulator With Slew Rate Enhancer for LTE Power Amplifier Applications

Sankman

Song

2016

IEEE Trans. Power Electron.

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With ever-growing energy crisis in wireless communication, effective envelope tracking solutions are in high demands for efficient operations in power amplifiers (PAs). Conventionally, a linear regulator is utilized to assist a switching converter to achieve fast tracking performance, but is highly inefficient. To overcome such an efficiency limitation, a dualphase switching-converter-only topology is proposed in this paper. Synchronized adaptive voltage tracking control is introduced, which enables both clock synchronization and fast response for high speed envelope tracking. To mitigate the inductor current slew rate limit of the switching converter, a push-pull slew rate enhancer (SRE) is designed. The SRE only operates when the switching converter reaches its inductor current slew rate limit, thereby maximizing the efficiency. The proposed envelope modulator is fabricated with a 0.18-µm CMOS process, achieving 85.8% peak efficiency at 1.5 W, tracking a 10 MHz LTE envelope.Index Terms-Envelope tracking, envelope modulator, switching converter, synchronized adaptive voltage tracking, slew rate enhancer.

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An AC-Coupling Parallel Hybrid Supply Modulator Achieving 100MHz Envelope Tracking Power Amplifiers for Wireless Communications

Hsiung

Tsai

Chen

et al. 2022

2022 IEEE Applied Power Electronics Conference and Exposition (APEC)

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An AC-coupled hybrid envelope modulator for HSUPA transmitters with 80% modulator efficiency

Cited by 35 publications

References 6 publications

A High Slew-Rate Adaptive Biasing Hybrid Envelope Tracking Supply Modulator for LTE Applications

A High Slew-Rate Adaptive Biasing Hybrid Envelope Tracking Supply Modulator for LTE Applications

Switching-Converter-Only Multiphase Envelope Modulator With Slew Rate Enhancer for LTE Power Amplifier Applications

An AC-Coupling Parallel Hybrid Supply Modulator Achieving 100MHz Envelope Tracking Power Amplifiers for Wireless Communications

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