用于电压岛式功耗管理的无运放结构高精度电流采样电路

High Accuracy Current Sampling Circuit for Power Management without OPA in Multi-voltage Island SoC

电压岛式的功耗管理在大规模SoC芯片中的应用越来越广泛,由于负载电流是反映功耗最直接的物理量,因此对负载电流的实时、精确采样是对功耗进行精确管理和控制的基础,而低压大电流又是当前大规模芯片的基本特征。在分析了几种常用的电流采样技术的基础之上,提出了一种基于电流镜采样的高精度的电流采样方案,适合于低电源电压供电,并且不需要使用运算放大器,结构简单。基于0.18μm CMOS工艺实现了该电流采样电路,各种条件下的版图模拟结果表明,对于60-1300mA的负载,该电路的采样精度最高可达99.1%,并且自身功耗不超过4mW。利用该电流采样电路,可以对负载电流进行实时有效的高精度侦测,用以作为功耗管理的依据。

In multi-voltage island SoC, power management is one of the most important fields. The current of workload is the firsthand information of power dissipation, so, the current sampling is the first step in the cycle for high accuracy real-time power management. In this paper, we presented a kind of high accuracy current sampling technology. The circuit is based on current mirrors without operation amplifier, and the voltage of power supply can be ultra low. We designed this circuit with 0.18μm CMOS process. It is shown that the accuracy of this circuit can be 99.1% according to the Hspice simulation and power consumption is less than 4mW for workload in 60 -1300mA.