Title :
1.8 W, 19 MHz envelope amplifier for envelope tracking and envelope elimination and restoration
Author :
Hietakangas, S. ; Hietanen, M. ; Rahkonen, Timo
Author_Institution :
Dept. of Electr. & Inf. Eng., Univ. of Oulu, Oulu, Finland
Abstract :
This paper presents an efficient envelope amplifier targeted to wideband Envelope Tracking (WBET) and wide-band Envelope Elimination and Restoration (EER). The design combines a Buck DC-DC converter with wideband operational amplifier. The goal is to achieve high operating frequency with good efficiency. The paper revisits some design features like the effect of slew rate limitation of switch current, comparator hysteresis on the operation of the envelope amplifier and the effect of propagation delay of the switch loop. The designed and implemented envelope amplifier achieved a measured 1.8 W of true output power with peak efficiency of 65%. The measured 1 dB frequency response reached up to 19 MHz and the measured spurious levels with sinusoidal signal were below 48 dBc.
Keywords :
DC-DC power convertors; HF amplifiers; current comparators; network synthesis; operational amplifiers; switching convertors; wideband amplifiers; EER; WBET; buck DC-DC converter; comparator hysteresis; efficiency 65 percent; envelope amplifier; frequency 19 MHz; frequency response; gain 1 dB; power 1.8 W; propagation delay effect; slew rate limitation effect; switch loop current; wideband envelope elimination and restoration; wideband envelope tracking; wideband operational amplifier; Current measurement; Field effect transistors; Frequency measurement; Hysteresis; Propagation delay; Switches; Switching frequency;
Conference_Titel :
NORCHIP, 2013
Conference_Location :
Vilnius
DOI :
10.1109/NORCHIP.2013.6702003
