一种用于AMOLED驱动的多模式高效电荷泵

A Multi-Mode High Efficiency Charge Pump for AMOLED Driving

设计了一种用于AMOLED驱动芯片的多模式高效低纹波电荷泵。该电荷泵通过模式选择,使输出电压可配置,实现多模式功能。针对电压建立和模式切换过程中电荷损耗的问题,利用初始化电路和电压检测电路来保证电荷泵中电荷单向传输,同时利用衬底选择开关来解决电荷泵的体效应问题,提高了电压转换效率。采用双边对称的泵电路结构,减小了输出电压纹波。采用UMC 80 nm CMOS工艺进行仿真。结果表明,负载电流为4 mA时,输出电压为8.4~17 V,四种工作模式下电压转换效率均在90%以上,电压纹波均小于1 mV。

A multi-mode high efficiency low ripple charge pump circuit of AMOLED driver chips was designed for pixel circuits in AMOLED screens.The charge pump allowed the output voltage to be configurable through mode selection,so the multi-mode functionality was achieved.To solve the problem of charge losing during voltage establishment and mode switching,the initialization circuit and the voltage detection circuit ensured the one-way transmission of charge in the charge pump,and the substrate selection switch was used to solve the body effect in the charge pump.Therefore,the voltage conversion efficiency was improved.Meanwhile,a symmetric pump circuit structure was presented to reduce the output voltage ripple.The circuit was simulated in UMC 80 nm CMOS process.The simulation results showed that the output voltage range was 8.4~17 V when the load current was 4 mA.The voltage conversion rate could be maintained above 90%at four working modes,and the voltage ripple was less than 1 mV.