Abstract
Floating-gate devices have been widely used in many commercial products as memory cells. In this paper, a bidirectionally-programmable non-volatile analog storage cell has eight effective resolutions to write or erase information. The memory cell, which stores the analog information in the MOS transistor floating-gate device, is written and erased by means of hot-electron injection and hot-hole injection. The memory circuit can write or erase the target value to the floating-gate devices and it is achieved by a simple, on-chip comparator. By using a comparator, the circuit controls the programming mechanisms automatically that the storage analog information can be programmed to the target value precisely under negative feedback. Errors due to the effects of device mismatches or trapping can be eliminated by the feedback control. By modeling the programming mechanisms, the proposed analog memory circuit is designed and can be used in analog neural networks. The proposed analog memory circuit has the storing voltage range from 0.6V to 2.2V and the error voltage less than 5mV. In this experiment, data-retention should be tested after the design of the memory cell was finished. the data-retention test results can be used to estimate the storage time in which the memory cell holds the storage information. In the end, a memory-cell array is designed by using floating-gate technique to store analog information.