低功耗高性能能量自激型电源管理集成电路

Wireless transmission of power is more and more popular in applications where batteries cannot be used due to size, lifetime, or cost constraints. Passive radio frequency identification (RFID), implantable microelectronic devices, and wireless sensor nodes are some of the examples. These so-called energy-autonomous systems usually induce an AC power carrier signal through a pair of tuned inductively-coupled coils. A rectifier follows the receiver LC-tank circuit to convert the AC carrier signal to a DC voltage, which supplies the rest of the system after being regulated by a low-power low-dropout (LDO) regulator. The small coupling coefficient between the two coils, particularly when they are misaligned, is the bottleneck in inductive power transmission. On the other hand, the performances such as transient response and power supply ripple rejection (PSRR) of LDO regulator are often limited by its ultra-low quiescent current. This project targets for low-voltage high-efficiency rectifier and fully integrated low-power LDO regulator with fast transient response and high PSRR. Different state-of-the-art topologies of rectifier will be analyzed and the power efficiency will be modelled with mathematical methods. Digital-controlled dynamic biasing technique will be proposed and implemented to enhance the transient response of LDO regulator without large RC components, which can save large chip area. Embedded power supply ripple feed-forward path will be proposed and implemented to improve the PSRR under wide bandwidth, while even no any more static power is consumed. All circuits will be designed and verified in (deep) sub-micro CMOS process, and target for industrial applications with the intellectual property (IP) of these energy-autonomous power management ICs.

无线电源传输越来越广泛应用于电池因尺寸、使用寿命及成本控制等因素而无法或不便使用的系统中，如医疗植入器件、无源射频识别标签及无线传感器节点等。在这些称之为能量自激型的无线供电设备中，电源管理成为影响系统性能的关键因素。围绕实现低输入电压、高转换效率这一目标，对AC-DC整流器电路各种拓扑结构进行深入细致的理论研究，总结影响转换效率及输入电压受限等问题，设计出新型低电压高效率的整流电路。针对超低功耗的DC-DC稳压电路，研究无需外部电容补偿的全集成线性稳压电路。通过数字化检测动态偏置电路，使稳压电路能够在极低功耗下获得良好的瞬态响应能力，且无需RC高通滤波电路，大大节省了芯片面积。采用嵌入式电源纹波前馈通路，在无额外静态功耗下获得高电源纹波抑制（PSRR）能力。设计的低电压高效率整流器及全集成快速高PSRR线性稳压器将在（深）亚微米CMOS下流片验证，并形成电源芯片IP，直接面向产业界应用。

应用日益广泛的医疗植入器件、无源射频识别标签及无线传感器节点等需要极低的静态功耗以维持较长时间的工作能力。因此，电源管理电路需具备高效率、低功耗等性能。本项目主要研究高效AC-DC及低功耗低压差线性稳压器（LDO）中的相关技术问题。.通过结合传统整流器和LDO，设计了高度集成的AC-DC稳压器，减少了输出电容大小及数量，提高了转换效率。0.18-μm CMOS下的仿真结果表明13.56 MHz下转换效率可达80%。.详细分析了LDO的电源纹波抑制（PSR）性能，总结了提升PSR的基本方法。提出一种简单独到的电源纹波前馈技术，跟传统电路相比，只需多采用两个无源低通滤波器，通过复用误差放大器缓冲输出级，在不增加电路静态功耗前提下有效改善了LDO低频至中频段PSR。基于0.18-μm CMOS的流片测试结果表明，25mA负载下2.5MHz时PSR可达到–85dB，5MHz内PSR优于–55dB。通过带宽扩展技术，进一步的设计可实现10MHz以内PSR性能优于–63dB。.主要从三方面针对低功耗LDO瞬态响应增强技术展开了研究。（1）采用先进补偿技术提升了环路增益、扩展了环路带宽。将共源共栅电流源电路嵌入到全集成的FVF-LDO中去，直流增益提升了33%，环路带宽增加了56%。（2）采用先进放大器结构扩展了带宽并增大了压摆率。通过将六级具备低阻特性的小增益放大级进行级联，在24μA静态电流下即使驱动15nF的大电容负载，也可以获得接近100dB的直流增益、1.46MHz的单位增益带宽、以及0.47 V/μs的压摆率。（3）提出了数字检测技术用于提高LDO瞬态性能。由于无需采用无源高通滤波器进行尖峰检测，电路面积大为减小。.在光电能量获取等应用中研究通过使用单电感多输出（SIMO）DC-DC来减少电感数目，减小板级空间，降低元件成本。目前阶段，定位于针对通用型DC-DC开展研究。提出了自动升降压型SIMO DC-DC电路，采用一阶锁相环和相位自动分配技术，有效解决了多路负载不平衡的难题，并将电感电流锁定时间大大缩短，减小了平均电感电流，提升了转换效率。.针对具体应用，研发了一个适用于无线传感器节点的锁相环发射机电路，提出了一种环路带宽校准技术，有效校准了数字预加强滤波器和锁相环之间的数模误差。后续工作还将结合高PSR的LDO稳压器，研究电源电路PSR性能对射频电路的影响。