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Hybrid Envelope Tracking Supply Modulator Analysis and Design for Wideband Applications

abstract: A wideband hybrid envelope tracking modulator utilizing a hysteretic-controlled three-level switching converter and a slew-rate enhanced linear amplifierer is presented. In addition to smaller ripple and lower losses of three-level switching converters, employing the proposed hysteresis control loop results in a higher speed loop and wider bandwidth converter, enabling over 80MHz of switching frequency. A concurrent sensor circuit monitors and regulates the flying capacitor voltage VCF and eliminates conventional required calibration loop to control it. The hysteretic-controlled three-level switching converter provides a high percentage of power amplifier supply load current with lower ripple, reducing the linear amplifier high-frequency current and ripple cancellation current, improving the overall system efficiency. A slew-rate enhancement (SRE) circuit is employed in the linear amplifier resulting in slew-rate of

over 307V/us and bandwidth of over 275MHz for the linear amplifier. The slew-rate enhancement circuit provides a parallel auxiliary current path directly to the gate of the class-AB output stage transistors, speeding-up the charging or discharging of out-

put without modifying the operating point of the remaining linear amplifier, while maintaining the quiescent current of the class-AB stage. The supply modulator is fabricated in 65nm CMOS process. The measurement results show the tracking of LTE-40MHz envelope with 93% peak efficiency at 1W output power, while the SRE is disabled. Enabling the SRE it can track LTE-80MHz envelope with peak efficiency of 91%. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2019

Identiferoai:union.ndltd.org:asu.edu/item:55465
Date January 2019
ContributorsMahmoudidaryan, Parisa (Author), Kiaei, Sayfe (Advisor), Bakkaloglu, Bertan (Committee member), Kitchen, Jennifer (Committee member), Mehdizad Taleie, Shahin (Committee member), Arizona State University (Publisher)
Source SetsArizona State University
LanguageEnglish
Detected LanguageEnglish
TypeDoctoral Dissertation
Format64 pages
Rightshttp://rightsstatements.org/vocab/InC/1.0/

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