数字控制电压调整器模块的建模分析

Modeling of Digitally Controlled Voltage Regulator Module

近年来,数字控制电压调整模块(VRM)因相比于传统的模拟控制电压调整模块有不少优势而得到青睐。但仍存在诸多不足,如量化效应、延时效应等。其中的延时环节多在数字控制器内部,难以知道其确切的模型。本文介绍了一种数字控制12V零电压开关的自驱电压调整模块的小信号模型,分别对主电路、数字控制电路各组成部分进行建模,最后统一成一个完整的小信号模型,并依此对控制电路进行设计。这个模型同样适用于Buck电路和多相交错并联的Buck电路。此外,通过这种方法设计了一个可以实现自适应电压定位(AVP)的数字控制器。文章最后给出了仿真和实验结论,用以证明提出的小信号模型的正确性。

In recent years, compared to conventional analog controlled voltage regulator module(VRM), digital controlled voltage regulator module is more popular because of its advantages. But there still exist several defects, like quantization effects, delay effects and so on. Usually these delays are inside the digital controller and it is hard to know the exact model. This paper proposes a small-signal model for digital controlled 12 V ZVS self-driven voltage regulator module. Each part is modeled one by one in detail, finally making up a complete small signal model to guide the design. The model is also applicable for buck and multiphase interleaving buck converters. With this new model,frequency-domain characteristics are clearly explained. Moreover, a digital controller to achieve adaptive voltage positioning(AVP) function is designed. Simulations and experimental results are presented to prove the proposed small-signal model.