用于开关DC-DC变换器的高精度片上电流检测电路

High Accuracy On-Chip Current Sensor for Switch Mode DC-DC Converter

设计了一种应用于开关DC-DC变换器的高精度片上电流检测电路。与传统方法相比,该电流检测方式采用无运算放大器的结构,去除了无运算放大器结构中的电流共享,从而提高了电流检测精度。将该电流检测电路应用于一款同步降压型DC-DC变换器,芯片采用0.35μm标准CMOS工艺。实验结果显示,电流检测精度在轻负载时可达98.7%,在大负载时高达99.7%。

A high accuracy on-chip current sensor was designed for switch mode DC-DC converter.Operational amplifier current sensing technique for conventional current sensor was not used in the circuit.With current sharing eliminated,the proposed current sensing technique achieved high accuracy.The new sensor was applied to a synchronous buck DC-DC converter,which was fabricated in standard 0.35μm CMOS process.Simulation results showed that the proposed circuit had a current sensing accuracy of 98.7%and 99.7%for light load and heavy load, respectively.