一种基于电荷泵的衬底电位选择器设计

Design of a substrate potential selector based on charge pump

为避免电荷泵中PMOS开关管的衬底发生闩锁现象,设计了一款高效低功耗的衬底电位选择器。选择器由偏置电路、比较电路、输出级3部分组成,电荷泵输出电压不仅作为独立偏置电路的电源,而且作为源端输入带迟滞功能的电压比较器的输入信号。与电源电压相比较,通过比较电路产生一对控制信号,用以控制由2组PMOS对管构成的输出级,使选择器始终输出芯片中的最高电压,并能在低电压下正常工作。仿真结果表明,该选择器能够较准确地选择电路中的最高电压值,并具有0.3V滞回区间,满足设计要求。

In order to avoid latch phenomenon of PMOS switch tube substrate in the charge pump,a efficient and low power substrate potential selector is designed.The selector is composed of bias circuit,comparator and output level.The output voltage of charge pump not only acts as power supply of an independent bias circuit,but also input signal of the voltage comparator with a source input and hysteresis function.Compared with the power supply voltage,a pair control signal is produced by the comparison circuit to control the output stage consisting of two groups of PMOS,so that selector always supplies the highest voltage of chip and can normally work under the low voltage.The simulation results show that the selector can select the highest voltage of the circuit accurately and has 0.3 V hysteresis interval,and meets the design requirements.