CAREER: High Frequency Integrated Voltage Regulator to Support Dynamic Voltage and Frequency Scaling for Mobile Devices

电压调节器已广泛应用于计算系统中，用于从电池等能源向微处理器输送电力。今天的电压调节器通常是使用分立元件和组装在主板上。分立无源元件，如电感器和电容器体积庞大，在主板上占据相当大的占地面积。此外，从稳压器到微处理器的功率传递路径相对较长。近年来，人们对高频集成稳压器的需求很大，这种稳压器可以放置在非常靠近微处理器的位置，以支持动态电压和频率缩放，这是微处理器非常有效的功耗降低技术。这将导致电源电压根据微处理器工作负载动态变化（工作负载越低，电源电压越低；电源电压越低，时钟频率也越低）。因此，微处理器的动态和静态功耗都可以大大降低。然而，由于稳压器和微处理器之间的高寄生互连阻抗，传统的离散稳压器无法足够快地调制电源电压，因此无法实现动态电压和频率缩放的全部潜力。本项目重点开发用于智能手机等移动设备的20-50MHz三维集成稳压器。该研究预计将对智能手机和其他移动应用的电源管理解决方案产生重大影响。这项工作将有助于使集成稳压器成为显著降低移动设备功耗的可行方法，这将大大延长电池寿命并降低电力消耗。通过快速将高频电源转换器设计纳入课程，并通过短期课程对工业电力电子工人进行再培训，综合教育计划将有助于保持美国电力电子劳动力的竞争活力。计划中的教育活动还包括向K-12年级的学生和代表性不足的群体提供服务，以增加对电力电子领域的熟悉和吸引力。该项目的研究目标是开发一种20-50MHz的三维集成多相稳压器，可以支持智能手机等移动设备的动态电压和频率缩放。将采用独特的横向磁通电感结构，将多个电感集成到单片磁芯中。所提出的单芯多相横向磁通电感结构可以同时实现低轮廓、高密度、低绕组电阻和受限磁通。它还可以具有可控的非线性电感（电感电流越小，电感越大），以提高稳压器轻载效率，这对智能手机应用非常重要。这种独特的磁性元件将作为衬底与半导体器件堆叠，以实现三维集成。将使用两种不同的技术来实现集成。一是印制电路板嵌入。这种技术与今天的印刷电路板制造工艺兼容，这将有助于加快工业采用集成电压调节器。第二种技术是三维打印。能够共同分配不同浆料的三维打印机将用于构建电感基板，其包括磁性层和非磁性层。磁性层用于构建多相横向磁通电感器；非磁性层用于构建金属走线，以实现集成稳压器所需的电气连接。该技术将实现非常复杂的电感结构的集成，这将带来电源转换器封装和集成的范式转变。此外，针对所提出的集成多相电压调节器，将开发一种高带宽非纹波的恒准时控制。这种新的控制将具有相位重叠和开启时间扩展能力，以实现快速瞬态速度。

Voltage regulators have been used widely in computing systems to deliver power from energy sources such as batteries to microprocessors. Today's voltage regulator is usually constructed using discrete components and assembled on the motherboard. The discrete passive components such as inductors and capacitors are bulky and occupy a considerable footprint on the motherboard. Furthermore, the power delivery path from the voltage regulators to the microprocessors is relatively long. Recently there has been great demand for a very high-frequency integrated voltage regulator that can be placed very close to the microprocessor to support dynamic voltage and frequency scaling, which is a very effective power consumption reduction technique for microprocessors. This would entail the supply voltage changing dynamically according to the microprocessor workload (a lower workload leads to a lower supply voltage; a lower supply voltage also leads to a lower clock frequency). As a result, both the dynamic and static power consumption of the microprocessor can be greatly reduced. However, traditional discrete voltage regulators are not able to realize the full potential of dynamic voltage and frequency scaling since they are not able to modulate the supply voltage fast enough due to the high parasitic interconnect impedance between the voltage regulators and the microprocessors. This project focuses on developing a 20-50MHz three-dimensional integrated voltage regulator for mobile devices such as smartphones. The research is expected to have a significant impact on power management solutions for smartphones as well as other mobile applications. The work will help to make the integrated voltage regulator a feasible approach to significantly reduce power consumption in mobile devices, which will greatly extend battery life and reduce electricity consumption. The integrated education plan will help to maintain the competitive vitality of the United States power electronics workforce by quickly incorporating high-frequency power converter design into the curriculum, and by retraining industry power electronics workers through short courses. The planned education activities also include outreach to students in grades K-12 and underrepresented groups to increase familiarity and attractiveness of the area of power electronics.The research goal of this project is developing a 20-50MHz three-dimensional integrated multi-phase voltage regulator that can support dynamic voltage and frequency scaling for mobile devices such as smartphones. A unique lateral flux inductor structure will be used to integrate multiple inductors into a single-piece magnetic core. The proposed single-core multi-phase lateral flux inductor structure can simultaneously achieve low-profile, high-density, low winding resistance and confined-flux. It can also have controllable nonlinear inductance (the smaller the inductor current, the larger the inductance) to increase voltage regulator light-load efficiency, which is very important for the smartphone application. This unique magnetic component will serve as a substrate stacked with semiconductor devices to realize three-dimensional integration. Two different technologies will be used to realize integration. One is printed circuit board embedding. This technique is compatible with today's printed circuit board fabrication process, which will help to speed industry's adoption of integrated voltage regulators. The second technology is three-dimensional printing. A three-dimensional printer capable of co-dispensing different pastes will be used to construct the inductor substrate which includes both a magnetic layer and a non-magnetic layer. The magnetic layer is used to build a multi-phase lateral flux inductor; the non-magnetic layer is used to build metal traces to realize a necessary electrical connection for the integrated voltage regulator. This technique will enable the integration of a very complicated inductor structure, which will bring a paradigm shift in power converter packaging and integration. Furthermore, a high bandwidth non-ripple-based constant on-time control will be developed for the proposed integrated multi-phase voltage regulators. This new control will have phase overlapping and turn-on-time extension capability for fast transient speed.