用于LCD驱动芯片的高精度可调电压产生电路

A High-Precision Adjustable Voltage Generation Circuit for LCD Driver Chips

针对液晶显示器(LCD)芯片中各模块不同的负载与供电需求,同时为了兼容更多同类型LCD驱动控制电路,设计并实现了一种高精度可调电压产生电路。该电路以零温漂基准电压电路为核心,由低压差线性稳压器(LDO)、电荷泵等组成。在温度检测电路与8 bit模数转换器的协同作用下,配合数字模块的设置值得到放大系数,并用于LDO模块得到最终的驱动电压。通过仿真得到,当电源电压(V_(DD))大于1.72 V时,带隙基准电压(V_(ref))可稳定在1.23 V;温度为-20~80℃时,V_(ref)的斜率为±15μV/℃;电荷泵在3.3 V的输入电压下输出电压为19.794 V,满足6倍的升压范围且效率满足既定目标。采用0.18μm CMOS工艺流片并对其进行测试,与仿真结果相比,实测结果存在部分因工艺模型导致的误差,但差值均在±10%的误差许可范围内,表明了此电路的可行性和实用性。

A high-precision and adjustable voltage generation circuit has been designed and implemented to meet the different load and power supply requirements of each module in the liquid crystal display(LCD)chip.The designed circuit is based on a zero temperature drift reference voltage circuit and consists of a low dropout regulator(LDO),a charge pump and other components.Under the synergistic effect of temperature detection circuit and 8 bit analog-to-digital converter,the amplification coefficient was obtained by matching the setting value of the digital module,which was used in the LDO module to obtain the final driving voltage.Through simulation,it is found that when the power voltage(V_(DD))is greater than 1.72 V,the bandgap voltage reference(V_(ref))can stabilize at 1.23 V.The slope of V_(ref)at a temperature of-20~80℃is±15μV/℃.The charge pump meets the requirements of a 6-fold boost range with an output voltage of 19.794 V at an input voltage of 3.3 V,and the efficiency meets the established target.The chip was fabricated by using 0.18μm CMOS process and was tested.Comparing October 2023 Semiconductor Technology Vol.48 No.10929 with the simulation results,the measurement results have some errors caused by the process model,but the differences are all within the allowable error range of±10%,indicating the feasibility and practicality of this circuit.