| 摘要 |
A comparator circuit (10) for sensing whether an input voltage (Vi) is greater than a reference voltage Vr of predetermined amplitude comprises first and second high-speed FETs (12 and 14), each having its drain-to-source portion coupled in series with a resistor between a voltage source and a current source (20). The FETs are supplied at their respective gates with the input voltage Vi and the reference voltage Vr. When the voltage at the gate of each of the FETs exceeds the voltage at the gate of the other, then the FET having the higher gate voltage conducts and produces a smaller voltage at its drain. The voltage at the drain of one of the FETs is compensated by a compensating network (26) for changes caused by temperature variations. The compensated drain voltage is input to a voltage-sensitive switch (44) which is supplied with a separate one of a pair of indicating voltages having different amplitudes. The switch outputs a separate one of the indicating voltages when the compensated gate voltage exceeds or falls below a predetermined threshold, which occurs when Vi>Vr and Vr>Vi, respectively.
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