A PWM analog memory programming circuit for floating-gate MOSFETswith 75-μs programming time and 11-bit updating resolution

This paper describes a programming circuit for analog memory using pulsewidth modulation (PWM) signals and the circuit performance obtained from measurements using a floating-gate EEPROM device. This programming circuit attains both high programming speed and high precision. We fabricated the programming circuit using standard 0.6-μm CMOS technology and constructed an analog memory using the programming circuit and a floating-gate MOSFET. The measurement results indicate that the analog memory attains a programming time of 75 μs, an updating resolution of 11 bit, and a memory setting precision of 6.5 bit. This programming circuit can be used for intelligent information processing hardware such as self-learning VLSI neural networks as well as multilevel flash memory