应用于CMOS图像传感器的带保护LDO电路的设计

Design of LDO with Protection Circuit Based on CMOS Image Sensor

摘要:

随着CMOS图像传感器(CIS)的广泛应用,低功耗、高集成化、高稳定性成为其发展趋势,低压差线性稳压器(LDO)因体积小、功耗低、噪声低及电源抑制比高等优点而满足芯片供电需求。为了避免传统电源在芯片异常时仍持续工作致使功耗增加或芯片烧毁,设计了一种可应用于CMOS图像传感器的LDO电路,并加入了LDO的保护电路结构。该保护电路具有欠压保护与过流保护的功能,并能够通过数字电路对LDO进行使能控制。基于0.11μm CMOS工艺平台对LDO及其保护电路进行仿真与分析,完成了该工艺下电路版图的绘制和验证。

Abstract:

With wide applications and technology development of CMOS image sensor(CIS), low power dissipation, high integration and high stability become the development trends of CIS. Low dropout voltage regulator (LDO) owns the characteristics of small area, low power dissipation, low noise and high PSRR, thus it can meet the requirement of power supply. To achieve the goal of CIS onchip power system with high integration, low power dissipation and high stability and to avoid the increase of power dissipation or damage of the chips caused by continue working under irregular conditions, in this paper, a design of LDO for CMOS image sensor is presented, and a protection circuit is added. This protection circuit includes two functions of undervolatge protection and over current protection, and it can control the enable signal of LDO by digital circuits. The schematic of LDO and its protection circuit based on 0.11μm CMOS process were also simulated and analyzed, and the layout of the whole LDO is finished under the same process.