Acta Scientiarum Naturalium Universitatis Pekinensis

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A Current-Sensing Circuit with High Accuracy and Fast Response

JIANG Mei, WANG Xin'an, MA Xinwen, ZHANG Xing   

  1. The Key Laboratory of Integrated Microsystems of Computer &Information Engineering institute in Shenzhen Graduate School of Peking University,Shenzhen 518055;
  • Received:2008-02-29 Online:2009-03-20 Published:2009-03-20



  1. 北京大学深圳研究生院信息工程学院集成微系统科学工程与应用重点实验室,深圳518055;

Abstract: A current-sensing circuit using senseFETs as current sensing devices in a current mode PWM DC-DC Converter system is presented.It is easy to be integrated because of the simple structure and it owns excellent frequency response, low power dissipation.The accuracy of this circuit is high in a wide range of the load current,and it will be elevated with the using of the cascade-common-gate amplifiers' structure.The test chip is fabricated in CSMC 0.5 μm 2p3M 3.3 V CMOS process.The measurement results show that the buck converter can operate from 1.2 to 2 MHz with supply voltage from 2.5 to 5.5 V for lithium ion battery application,and the output voltage is 1.5 V.The highest accuracy of proposed current sensing circuit is 97.75% for the load current from 50 to 600 mA.

Key words: current-sensing, current-mode, SMPC, common-gate-amplifier, sensing resistor, senseFET

摘要: 提出一种应用于电流模的PWMDC-DC转换器系统、利用senseFET作电流检测器件的新颖的电流检测电路。该电路结构简单,易于集成,具有功耗低、频率特性好、响应速度快、不降低电源系统的工作效率等优点。同时,该电路在很大的负载电流范围内实现高精度的电流检测功能。芯片利用CSMC0.5μm 2p3M 3.3V CMOS工艺实现。这款降压芯片能够在1.2~2MHz的频率范围内将输入的2.5~5.5V的直流电源电压转换为1.5V的稳定直流电压输出,完全适用于单节锂电池电源的系统。在50~600mA的负载电流范围内,测试检测电流的精度最高可达到97.75%。

关键词: 电流检测, 电流模, SMPC, 共栅放大器, 检测电阻, 检测晶体管

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