VOLTAGE COMPARATORS WITH LARGE COMMON MODE INPUT VOLTAGE RANGE

摘要

A voltage comparator circuit with a wide common mode input voltage range which extends beyond supply voltage parameter values. The comparator circuit utilizes an input stage having two input transistors, the emitter electrodes of which are connected to receive input signals and the collector electrodes of which are connected to two current sources. A current fixing circuit is coupled to the collector electrodes of said two input transistors and acts to fix the direct current in the collector circuits at a first value IO and the currents supplied by the current sources at a second value k IO, where k is greater than 2. An output stage is provided with two input circuits respectively connected to the collector electrodes of the two input transistors and with a logic circuit arrangement set to either one of two logic levels in accordance with the sign of the difference in the voltages applied to the pair of emitter electrodes of the two input transistors.