Analysis and Design of a Two-Loop Controlled Switching Power Amplifier

Hisahito ENDO  Takashi YAMASHITA  Toshiyuki SUGIURA  

IEICE TRANSACTIONS on Communications   Vol.E76-B   No.9   pp.1193-1201
Publication Date: 1993/09/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Power Supply
switching power amplifier,  portable telephone,  switching regulator,  two-loop control,  small-signal transfer functions,  

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This paper analyses the amplification characteristics of a two-loop controlled switching power amplifier for a digital portable telephone and presents the amplifier which has a flat gain and small phase delay from dc to 100kHz. This amplifier is a modification of a switching regulator and it uses two-loop control to achieve a wideband amplification characteristic. Optimum amplification characteristics, however, can't be designed by using the conventional method for designing a switching regulator because a flat gain and small phase delay in an amplification characteristic has not been considered for most switching regulators. This paper analyses in detail the small-signal transfer functions of the switching power amplifier and shows the behaviour of zero and poles. It also shows the boundary condition of large-signal operation. A new design procedure of a switching power amplifier is presented, and the analytical results are verified by experiments.