Design of high-efficiency current-mode class-D amplifiers for wireless handsets

• Published in: IEEE transactions on microwave theory and techniques Vol. 53; no. 1; pp. 144 - 151
• Main Authors: Tsai-Pi Hung, Metzger, A.G., Zampardi, P.J., Iwamoto, M., Asbeck, P.M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.01.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplifiers; Applied sciences; Bond-wire inductor; Bonding; Circuit properties; class-D; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Frequency; Gallium arsenide; high efficiency; High power amplifiers; Inductors; Mathematical analysis; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; Operational amplifiers; Parasitic capacitance; Power amplifiers; Power generation; Radiofrequency amplifiers; Resonators; Simulation; Switching; Telephone sets; Voltage; Inductance; D class; Circuit design; Current mode; Simulation; Wireless telecommunication; Bond-wire inductor; high efficiency; Portable equipment; power amplifiers; Power amplifier; class-D
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2004.839327

Design considerations are discussed for current-mode class-D (CMCD) microwave power amplifiers. Factors affecting amplifier efficiency are described analytically and via simulation. Amplifiers are reported that incorporate parallel LC resonators alongside the switching transistors. To reduce parasitic resistance, bond-wires were utilized to implement a high Q inductor in the LC resonator. An experimental CMCD amplifier based on GaAs HBTs is reported, with collector efficiency of 78.5% at an output power of 29.5 dBm (0.89 W) at 700 MHz.