| 摘要 |
A comparator (10) has voltage input terminals (20, 22) connected to control current flow through paths (33, 34) of first and second matched pair transistors (16, 18), and output terminals (41, 42) of an offset current control subcircuit (43) connected to control current flow through parallel paths (44, 45) of third and fourth matched pair transistors (38, 39). Subcircuit (43) includes a first voltage follower (47) connected to cause the common mode of an offset voltage differential applied at terminals (41, 42) to track the input common mode voltage applied at terminals (20, 22), and a second voltage follower (48) connected to define the value of the offset voltage differential according to a voltage applied at a reference voltage node (62). In described embodiments, follower (47) is an operational amplifier having an input connected to a central node (60) of a series resistor coupling voltage divider (58, 59) connected across terminals (20, 22) and an output connected to control voltage at a corresponding central node (56) of another series resistor coupling voltage divider (51, 52) connected across terminals (41, 42). Follower (48) is an operational amplifier having an input connected to a reference voltage terminal (62) and an output connected to control the voltage differential across terminals (41, 42).
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