| 摘要 |
PURPOSE:To attain the satisfactory comparison for lower power supply voltage by inserting a DC level shift circuit between the base of an amplifying transistor of the first stage and an input terminal. CONSTITUTION:The collector current of a transistor (TR)42 is foled by a current mirror circuit CM4 and compared with the collector current of a Tr41. This differential current is used as the base current of an output Tr46, and the output of a voltage comparator is obtained from the collector of the Tr46 through a terminal 10. In such a way, the collector currents of both Trs 36 and 38 are supplied as the reference current to give the DC level shifts to input terminals 1 and 2. Thus it is enough to supply the power supply voltage larger than the sum of the base-emitter voltage VBE of npn type Trs 41 and 42 of a differential amplifier DA4 and the saturated collector-emitter voltage of pnp type Trs 44 and 45 of the circuit CM4. Therefore the comparison is possible for lowe power supply voltage of 1V with supply of DC voltage less than the voltage VBE.
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