| 摘要 |
PURPOSE:To detect an accurate voltage with a circuit having a few components by comparing input currents to the 1st and 2nd transistors (TR) to a gate of which an external input voltage is inputted so as to decide a level of an output signal. CONSTITUTION:When an input voltage Vin is smaller than a threshold voltage Vth, a collector current IC30 of a TR 28 is smaller than a collector current IC31 of a TR 29, the collector current IC30 is smaller than a collector current IC37 of a TR 37, no base current is given to a TR 19 and turned off completely and a low level output is obtained from an output terminal 22. On the other hand, when the voltage Vin is larger tha the Vth, the current IC30 is larger than the current IC31, the current IC30 of the TR 30 is smaller than a current IC37 of the TR 37, a base current is fed to the TR 19, which is turned on and a high level output is obtained from the output terminal 22. Since the output signal level is decided by the comparison of the input currents of each TR, no reference voltage generating circuit and no comparator circuit are required, the number of components is reduced and accurate voltage detection is attained.
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