A low ripple switched capacitor charge pump applied to phase change memory (PCM) is proposed. Compared with the conventional switched capacitor charge pump, the flying capacitor of the proposed charge pump is charged to the difference between the prospective output voltage and the input voltage during the charge phase. In the discharge phase, the flying capacitor is connected between the input and output of the charge pump to transfer energy to output, so the output is regulated at prospective voltage. This new operation mode can reduce the output ripple caused by charge redistribution. A simulation was implemented for a DC input range of 2.8~4.4 V in a SMIC standard 0.18 μm CMOS process. Result shows the new operation mode can regulate the output about 5 V with a load condition from 0 to 10 mA, the ripple voltage is lower than 3 mV and the highest power efficiency reaches 88%.%针对相变存储器编程操作对电荷泵低输出纹波与高瞬态响应速度的要求,提出了一种超低输出电压纹波的开关电容型电荷泵.相比于传统开关电容型电荷泵,在充电阶段,由电压比较器控制泵电容充电时间,泵电容被充电至预先设定的电压值Vo-Vin后停止充电,其中Vo为预期输出电压,Vin为输入电源电压；放电阶段,泵电容串联在输入电源Vin与电荷泵输出端,泵电容上极板电压自然地被提升互Vo并向外部负载输出电流.通过该方法固定电荷泵输出电压,可有效地消除由于电容间电荷分享所造成的输出纹波,并兼顾了高瞬态响应速度.使用中芯国际0.18 μm标准CMOS工艺模型进行仿真验证,结果表明新结构的电荷泵在输入电压为2.2～4.8 V间,输出5V电压,10 mA负载电流,榆出纹波低于3mV,电源效率最高可达88％.
展开▼
