| 摘要 |
PROBLEM TO BE SOLVED: To provide a comparator circuit capable of a high speed operation for signals in a wide frequency band without increasing circuit currents. SOLUTION: NPN transistors Q3, Q4, Q5, and Q6 with excellent frequency characteristics are used for an output stage. The increase of the circuit currents of a PNP transistor P2 can be prevented, and the rate of the currents of the PNP transistor P2 to those of a PNP transistor P3 can be set so as to be made large. Also, the increase of an emitter size or a parasitic capacity can be prevented, and the charging/discharging of the parasitic capacity C and the inversion of the base current direction of the NPN transistor Q6 can be quickly operated. The potential of the base of the NPN transistor Q6 can be set so as to be a prescribed value Va by a voltage limiter circuit 5, and voltage change can be applied to the base of the NPN transistor Q6 so that the NPN transistor Q6 can be changed from the potential Va to an ON state. Thus, the NPN transistor Q6 can be quickly inverted from the OFF state to the ON state, and a highly precise comparator operation can be operated to signals in a wide frequency band.
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