| 摘要 |
A Schmitt trigger circuit 10 includes a pair of transmission gates 20, 22 connected, respectively, between a pair of threshold voltages VtH, VtL and the threshold input port 16 of a comparator 12. The control lead of one transmission gate 20 is connected to the output 18 of the comparator 12 through an inverter 24. The control lead of the other transmission gate 22 is connected directly to the output 18 of the comparator 12. The other input port 14 of the comparator 12 receives the signal input. Also disclosed is a circuit 26 for generating the reference voltages VtH, VtL. The circuit 26 includes an operational amplifier 28 driving a complementary pair of current mirrors (M1, M3, M5; M4, M6) which force current through a pair of resistors (RH, RL) to ground potential. The resistors (RH, RL) provide stable reference potentials.
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