| 摘要 |
PURPOSE:To obtain a differential level shift circuit which is steady to the fluctuation of the power voltage having good frequency characteristics, by connecting the current source to the emitter of transistor TR having the differential working and then selecting the rotational frequency properly. CONSTITUTION:Power source +VCC is connected to the collector of TR21 and TR22 each having the differential working; and current source 25 is connected in common to the emitter via resistances 23 and 24. And here the current of source 25 is referred to as I, the value of resistances 23 and 24 are R, the base-emitter voltage of TR21 and TR22 are VBE, and the logic amplitude value of the output voltage is Vl respectively. In that case, the value of I and R are set so as to satisfy equation Vl<IR<VCC+VBE. And in case VCC varies, the minimum VCC is referred to as VCCmin. Then the value of I and R are set so as to satisfy IR<VCCmin<VBE. |
