A Low-Power 0.8% Sensing Error On-Chip Current Sensor with Auto-Accuracy Adjustment

In this paper, an on-chip low-power current sensor with auto-accuracy adjustment is proposed for current monitor applications, which is composed by a sensing element and a quantizer. The sensing element is designed as a current mirror with auto-adjustable current ratio of K determined by the value of sensing current. When the current is larger than a threshold value, K changes from 1000 to 2000 to reduce the power consumption. The quantizer includes a comparator, two current-source arrays and two successive approximation register (SAR) logic circuits. The main 8-bit SAR logic is adopted to control a current-source array to realize current quantized range, the auxiliary 4-bit SAR logic is employed to control another current.