A 8.9W/mm2, 95.4%-Efficiency, CP-Length Tracking Switching Supply Modulator for 5G New Radio mmWave PA Arrays

Abstract

This paper presents a switching supply modulator that enables the implementation of highly challenging cyclic-prefix (CP)-length, supply/load (S/L) tracking on a single power stage, demanded by emerging 5G new radio applications. To break the design tradeoffs between tracking speed, reliability, efficiency and power density, a nonlinear Δ-T dual-zone control is introduced. Meanwhile, in the same controller, a clock-injected switching spectrum regulation scheme is integrated to regulate switching noise against supply, power or process variation in highly noise-sensitive and space-restricted power amplifier (PA) arrays. Implemented on a low-cost 350nm CMOS process, an IC prototype of this work achieves a peak efficiency of 95.4% and a maximum power density of 8.9W/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 10MHz. At a full load of 3.45W, it accomplishes the S/L tracking speeds of 810ns/V and 327ns/A, respectively, which are among the fastest for single power stage implementations.