  Positive-feedback (PF) device and its operation scheme to implement pulse
width modulation (PWM) function was proposed and demonstrated, and the device
operation mechanism for implementing PWM function was analyzed. By adjusting
the amount of the charge stored in the n- floating body (Qn), the potential of
the floating body linearly changes with time. When Qn reaches to a threshold
value (Qth), the PF device turns on abruptly. From the linear time-varying
property of Qn and the gate bias dependency of Qth, fully functionable PWM
neuron properties including voltage to pulse width conversion and hard-sigmoid
activation function were successfully obtained from a single PF device. A PWM
neuron can be implemented by using a single PF device, thus it is beneficial to
extremely reduce the area of a PWM neuron circuit than the previously reported
one.
