Title :
Design of H-Bridge Class-D Power Amplifiers for Digital Pulse Modulation Transmitters
Author :
Hung, Tsai-Pi ; Rode, Jeremy ; Larson, Lawrence E. ; Asbeck, Peter M.
Author_Institution :
Univ. of California at San Diego, La Jolla
Abstract :
This paper presents an H-bridge class-D power amplifier (PA) for digital pulse modulation transmitters. The class-D amplifier can be driven by two-or three-level digital signals generated by a delta-sigma modulator (DSM) and provides a linear microwave output after filtering. Within the amplifier, the pull-up and pull-down devices are driven separately to improve the amplifier efficiency by minimizing the loss associated with shoot-through current. The H-bridge class-D PA system was tested with code-division multiple-access IS-95 signals at 800 MHz. Using binary DSM signals, a drain efficiency of 31% was achieved with an output power of 15 dBm and an adjacent channel power ratio of -43 dBc. With three-level DSM signals, a drain efficiency of 33% was achieved at same output power. An analysis of the factors governing amplifier efficiency is provided.
Keywords :
UHF power amplifiers; bridge circuits; code division multiple access; delta-sigma modulation; pulse modulation; transmitters; H-bridge class-D power amplifiers; adjacent channel power ratio; code-division multiple-access; delta-sigma modulator; digital pulse modulation transmitters; drain efficiency; frequency 800 MHz; pull-down devices; pull-up devices; Delta modulation; Digital modulation; Microwave amplifiers; Microwave generation; Power amplifiers; Power generation; Pulse amplifiers; Pulse modulation; Signal generators; Transmitters; Bandpass delta–sigma modulation (BPDSM); class-D amplifier; code-division multiple access (CDMA); complementary metal–oxide semiconductor (CMOS); radio-frequency power amplifier (RF PA);
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2007.909881