Scully, Scott, Murphy & Presser
Window comparator
 A window comparator includes a differential circuit stage and a load circuit stage. The differential circuit stage produces a pair of differential currents from an input voltage, the differential currents varying depending on the input voltage with having a maximum and a minimum when the input voltage is a reference voltage. The load circuit stage produces an output voltage from a reference current and a current corresponding to a selected on of the differential currents. The reference current and the current are produced such that a voltage range is determined around the predetermined voltage depending on whether the second current is greater than the reference current. Since a window of the window comparator is formed based on the current and the reference current, the output voltage changes in level depending on whether the input voltage falls into the voltage range. 
NEC Corporation
H G
H03K G01R
inventional inventional
Tomohiro
Fujii