A Two-Phase Switching Hybrid Supply Modulator for RF Power Amplifiers With 9% Efficiency Improvement

Wu, Patrick Y.; Mok, Philip K. T.

doi:10.1109/jssc.2010.2076510

Cited by 93 publications

(55 citation statements)

References 21 publications

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“…The phases are operated in an interleaved manner, thus the size of the filter network can be reduced due to the increased equivalent switching frequency and the ripple cancelation effect [49]. However, multiphase MS structure often requires a current-sharing loop to guarantee each phase providing equal power [49], which increases the system complexity and restricts the dynamic response. m-stage filter (m > 1) can also be applied to MS structure to further improve the bandwidth.…”

Section: ) Ms Structurementioning

confidence: 99%

A Review of Envelope Tracking Power Supply for Mobile Communication Systems

2017

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Abstract-In modern mobile communication systems, spectral efficient modulation formats have been widely used, which results in the envelope of the radio frequency (RF) signal is variable and having large peak to average power ratio (PAPR). In order to amplify the RF signal without distortion, the linear power amplifier (LPA) is adopted, which is less efficient when powered by constant voltage. Three popular techniques, i.e., Doherty, envelope elimination and restoration (EER), and envelope tracking (ET) techniques, to greatly improve the efficiency of the power amplifiers are analyzed and compared in this paper, and it is shown that the ET technique is the most suitable for future mobile communication systems. In the ET systems, the ET power supply is the key equipment, which dominates the system efficiency. With the development of the mobile communication systems, the bandwidth and the PAPR of the envelope signals are increasing rapidly, which pose severe challenges on the design of the ET power supply. This paper summarizes and sorts the ET power supplies in the literatures, and a detailed comparison is presented to guide the selection of ET power supplies for different applications. Finally, the methods, including soft-switching, slow envelope, and band separation are proposed for further increasing the efficiency of the ET power supply.Index Terms-Band separation, Doherty, envelope elimination and restoration, envelope tracking, power amplifier, slow envelope, supply modulator, soft-switching. I. IntroductIonT HE mobile communication brings convenience of real-time communicating to people in a mobile state without physical transmission line, and it has been continuously developing ever since its advent in 1970s [1]. The first-generation (1G) mobile communication systems adopted analog electronics technology and can only provide voice service. Furthermore, it suffered poor anti-interference ability and slow data transmission rate. The second-generation (2G) mobile communication systems employed digital electronics technology, and they can transmit and receive voice and text message. With the rapidly increased customers and the demand for multi-media service, the data transmission rate is required to be faster, and the third-generation (3G) and fourth-generation (4G) mobile communication systems emerged in succession, which makes the video calling service and internet surfing into reality [1].With the development of mobile communication, the power consumption increases rapidly, accounting for about 10% of the global power generation. Thus, it is necessary to reduce the power consumption of the mobile communication. In mobile communication systems, the base stations consume the majority of the power. In a base station, about 50% of the power is consumed by the power amplifier, and its loss is dissipated as heat, which requires extra power to cool down. So, increasing the efficiency of the power amplifier is the basis of reducing the overall power consumption of the mobile communication.In 2G mobile communicatio...

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Section: ) Ms Structurementioning

confidence: 99%

A Review of Envelope Tracking Power Supply for Mobile Communication Systems

2017

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“…In switching amplifiers, the output noise is much higher than that of linear amplifier which results in a relatively poor linearity for the PAs. Hybrid supply modulators, which combine linear and switching amplifier in a master-slave configuration, can achieve wide bandwidth, high linearity and [18]- [35]. Various methods have been published to enhance the ET PA systems' efficiency and linearity.…”

Section: Dissertation Outlinementioning

confidence: 99%

“…Various methods have been published to enhance the ET PA systems' efficiency and linearity. In [18], a switching amplifier operating in two phases to reduce current ripple and power loss is proposed. A transistor-resizing technique for the PA to increase its efficiency is described in [24].…”

Section: Dissertation Outlinementioning

confidence: 99%

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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“…Low drop-out regulators and switching regulators are not good choice for the bias modulator due to low efficiency and narrow bandwidth, respectively [3,4]. The hybrid bias modulators, which have a highly efficient switching stage and a broadband linear stage, have been popular for the ET applications [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The switching stage supplies most of the current which are around very low frequency including DC.…”

Section: Introductionmentioning

confidence: 99%

A CMOS Envelope Tracking Power Amplifier for LTE Mobile Applications

Ham¹,

Jung²,

Kim³

et al. 2014

JSTS:Journal of Semiconductor Technology and Science

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Abstract-This paper presents an envelope tracking power amplifier using a standard CMOS process for the 3GPP long-term evolution transmitters. An efficiency of the CMOS power amplifier for the modulated signals can be improved using a highly efficient and wideband CMOS bias modulator. The CMOS PA is based on a two-stage differential common-source structure for high gain and large voltage swing. The bias modulator is based on a hybrid buck converter which consists of a linear stage and a switching stage. The dynamic load condition according to the envelope signal level is taken into account for the bias modulator design. By applying the bias modulator to the power amplifier, an overall efficiency of 41.7 % was achieved at an output power of 24 dBm using the 16-QAM uplink LTE signal. It is 5.3 % points higher than that of the power amplifier alone at the same output power and linearity.

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A Two-Phase Switching Hybrid Supply Modulator for RF Power Amplifiers With 9% Efficiency Improvement

Cited by 93 publications

References 21 publications

A Review of Envelope Tracking Power Supply for Mobile Communication Systems

A Review of Envelope Tracking Power Supply for Mobile Communication Systems

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

A CMOS Envelope Tracking Power Amplifier for LTE Mobile Applications

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