| 摘要 |
PURPOSE:To increase the input dynamic range by adopting a constitution so that a transistor (TR) on the current mirror side and a TR on the input side of an input differential pair go to unsaturated. CONSTITUTION:A level shifter 40 consists of a current mirror 20, a TR Q5, a diode D1 and resistors R3, R4. In giving a signal of 'L' level lower than a voltage Vref to an input terminal 1, a TR Q2 is turned on and the level of the base of the TR Q5 is decreased by a voltage R2 I more than the voltage Vcc. The collector potential of a TR Q4 is equal to a base potential with the input signal at an H level, increased by a voltage 2VBE than a voltage VEE with the input signal at an L level and the TR Q4 is not saturated in both the cases. Since the collector of the TR Q1 is connected to the voltage Vcc, even if the base potential is increased up to the voltage Vcc, the TR Q1 is not saturated while the collector and the base have only to reach the equi-potential. |
