Digital V2 Controller IC Using Delta Operator and Improved Average Predictive Control for DC–DC Converters With Fast Transient Response

Abstract

Owing to its fast transient response, the V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> control technique for switching converters has wide potential application prospects. In this article, we present a digital V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> controller integrated circuit (IC) for dc–dc switching converters to improve the transient response. The controller IC consists of two compensators and some ancillary circuits, specifically a proportion-integral-differential (PID) compensator and a predictive control compensator, as well as an analog-to-digital converter (ADC) and a digital pulsewidth modulator (DPWM). The PID compensator is designed based on the delta operator instead of the conventional shift operator, which can improve the stability of the converter and reduce hardware costs. The predictive control compensator uses an improved average predictive control strategy to enhance the transient response. A 6-b delay-line window ADC with a differential bias circuit is proposed to improve the ADC linearity. An 11-b hybrid DPWM, which consists of a counter and a segmented delay line with a delay-locked loop (DLL), is proposed to relieve the conflict between the die area and DPWM linearity. A prototype of the digital V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> controller IC was fabricated using the 180-nm CMOS process, which was applied to a buck dc–dc switching converter to verify its performance. The experimental results show that an excellent transient response was achieved.