基于低压CMOS工艺的新型负电压型电荷泵电路

New Regulated Negative Charge Pump in Low Voltage CMOS Process

采用UMC 0.18μm 1.8 V/3.3 V CMOS工艺设计并流片验证了一个应用于生医刺激器的新型负电压型电荷泵电路。介绍了几种典型的负电压型电荷泵电路,比较其优缺点,在此基础上设计了一个新型4级交叉耦合型负电压电荷泵。和现有的结构相比,该电路在启动过程和工作过程中都不存在过压问题,器件任意两端口之间的电压均小于电源电压VDD,同时降低了MOS器件衬底效应、反向漏电流对电荷泵效率的影响。电荷泵的电容采用MIM电容,升压电容为50 p F,输出电容为100 p F。芯片面积为2.3 mm×1.3 mm,测试结果表明负电压型电荷泵电路输出电压为!10.3 V,系统最高效率为56%。当输出电流为3.5 m A时,输出电容为100 p F时,纹波电压为150 m V。

A new regulated charge pump for biomedical applications was proposed and realized in UMC 0. 18 μm 1. 8 V /3. 3 V CMOS process. Some typical negative voltage charge pump circuits were summaried with an analyse and comparison their advantages and disadvantages,and then a new 4-level cross-coupled negative voltage charge pump circuit was designed. Compared with the existing structure,the electrical overstress issues in the curcuit are fully eliminated in the start-up and working processes.The device voltage,across any two ports of devices,is less than the normal operating power supply voltage（ VDD）,and the body effect and return leakage current in the circuit are eliminated. The capacitors in charge pump are realized with MIM capacitor,the boost capacitor and output capacitor are 50 p F and100 p F,respectively. Chip area of the proposed charge pump is 2. 3 mm × 1. 3 mm. The experimental results show that the proposed new regulated negative charge pump can provide !10. 3 V output voltage with the maximum power efficiency of 56%. The ripple voltage is 150 m V when the output current and output capacitor are 3. 5 m A and 100 p F,respectively.