Demonstration of Pulse Width Modulation Function Using Single Positive Feedback Device for Neuron

A positive-feedback (PF) device and its operation scheme to implement pulse width modulation (PWM) function were demonstrated. First, the device operation mechanism for the PWM function was analyzed. By adjusting the amount of the charge stored in the ${n}^{-}$ floating body ( ${Q}_{\text {n}}$ ), the potential of the floating body changes linearly with time. When ${Q}_{\text {n}}$ reaches to a threshold value ( ${Q}_{\text {th}}$ ), the PF device turns on abruptly. From the linear time-varying property of ${Q}_{\text {n}}$ and the gate bias dependency of ${Q}_{\text {th}}$ , voltage-to-pulse width conversion for the PWM function was implemented. A rectified linear or hard-sigmoid activation function was successfully obtained from a single PF device, and it is beneficial to extremely reduce the area of a PWM neuron.