一种高效的源线补偿电路

A High Efficiency Source Line Voltage Compensation Circuit

提出了一种适合于嵌入式闪存的高效的源线补偿电路,本电路根据需要进行编程的存储单元的数目,自动调整电荷泵的输出来补偿源线译码路径上的由于编程电流造成的压降,最后实现源线电压不随输入数据的不同而变化,以达到最优的编程效率和最小的编程串扰。为了补偿由于温度变化引起的源线电压变化,文中提出利用亚阈值电流对源线电压进行温度补偿。同时,为了解决工艺偏差造成的源线电压误差,还提出了一种测试电路及其方法。将这个源线补偿电路在0.13μm的FLASH工艺平台上实现。测试结果表明：对于32位的数据输入,从0X00000000变化到0XFFFFFFFF,源线上的电压浮动范围为±50mV,从-40~125°C,源线上的电压浮动范围为±100mV,再通过每个芯片单独微调,所有温度、输入数据情形下,源线上电压浮动范围小于±200mV。

A high efficiency source line voltage compensation circuit with several fine trimming techniques for embedded flash memory is introduced in this paper.The source line voltage compensation circuit controls the output voltage of the charge pump according to the number of cells to be programmed with data‘0＇to compensate the IR drop on the source line decoding path.Thus,a stable source line voltage is obtained and high program efficiency with low program disturbance is realized.In order to compensate the source line variations caused by temperature,a temperature compensation circuit driven by sub-threshold current is proposed.Furthermore,a testing circuit and testing methodology are proposed to do the individual trimming,thus to reduce the source line distributions caused by process variations.All these techniques are implemented with 0.13μm flash technology.Testing results show that：with the input data from 0x00000000 to 0xFFFFFFFF,the source line voltage variation range is±50mV;with the temperature ranges from-40°C to 125°C,the variation range is±100mV.By combining these techniques,the whole variation range is±200mV in all cases of process,temparature and data pattern.