分布式CPU内核电压调节模块

Distributed Voltage Regulator Module, VRM, for CPU Core Voltage

随着PC工业的发展,预计到2007年将急需能够在0.95V时供应200A电流的DC/DC电源变换器。为了能如期实现这种需求,从现在开始就必须对现有的各种技术方案进行审核并提出新的设计思路。文中仔细研究了各类损耗机理,尤其是在每相电流达到30～40A大电流条件下的主要损耗情况。结果表明,该目标是能够实现的。基于这种想法,研制了一种分布式电压调节模块(VRM)。该模块由几路单相供电可达40A,且效率超过80%的子模块构成。采取集成5个子模块的设计方式就能实现200A的总供应电流。多相DC/DC变换器的研究工作包含以下几项:①PWM控制器及其相关组件;②功率MOSEFET、MOSFET驱动器、输出电感及相关组件;③输入/输出电容器组。包括陶瓷电容和电解电容两种类型。文中就第②项设计中存在的问题展开讨论(如功率的处理),这是因为第①,③项已有成熟的标准,并且可以在相关技术文献中找到。在第②项设计中,调节模块每一相的全部元件是集中在一块1.15英寸×0.85英寸的小插板上的,它能供应40A电流,同时还负责接收来自控制器的脉宽调制的TTL电平信号。这个小插板只需占用0.85英寸×0.25英寸的主板空间。它可以放在主板上的任何地方,尤其是贴近CPU的地方,这样便可以减小导通阻抗和损耗,也可使主板的设计者灵活安排功率模块和充分利用PCB空间。另外,每个模块还可以装备单独的散热片。

As the PC industry pushes for DC-DC converters that can deliver up to 200 Amp at 0. 95V by the year 2007, we must begin to examine the ramifications and propose new ideas to fulfill this need when the time comes. I firmly believe that this is an achievable goal right now if we carefully take into account all the loss mechanisms specially those that most pronounced at high currents say 30 - 40 A per phase. Toward that end we have developed a distributed VRM in the form of several modules each is capable of delivering up to 40 Amps per phase at efficiency over 80% . This would allow us to deliver 200 Amps with five-phase design. The approach we have taken in this work is to divide the multi-phase DC-DC converter into the following sections:(1)PWM controller and its associated components;(2) Power MOSFETs, MOSFET driver, Output inductor and associated components;(3)Input and output capacitors bank comprising ceramic and electrolytic type. In this paper,I will address only point (2)above i. e. the power train. The selection of the controller and the output and input capacitors is fairly standard and may be found in the technical literatures. For each phase,the components on point(2) above which constitute all the power components are placed on a small plug-in board of 1.15'×0. 85' that delivers 40 Amps and receives the PWM TTL signal from the controller. This module has a footprint of about 0. 85'×0. 25'of the motherboard space and may be placed anywhere on the board as close as possible to the CPU reducing the transmission impedance and losses and giving the Motherboard designer the flexibility to optimize the power and PCB space utilization. Each modular board may be fitted individually with its own heat sink.