| 摘要 |
PURPOSE:To keep the level of a signal constant even if a power supply voltage is fluctuated by connecting a constant current source in series with an emitter follower so as to change level shift amount in response to fluctuation in power supply voltage. CONSTITUTION:A transistor (TR) Q6 and a resistor R6 forming the constant current source 1 are connected between an emitter follower EF comprising a TRQ4 and a resistor R4 and a ground point. A node n3 of a resistor split circuit as a reference voltage circuit comprising resistors R7, R8 connected in series between a power supply voltage Vcc and ground point is connected to a base of the Q6 and a voltage dividing the power supply voltage Vcc by the resistor ratio of the resistors R7, R8 is applied thereto. Thus, a current flowing to the constant current source 1 is changed in following to flucturation of the power supply voltage and the level shift amount is changed, and then even if the power supply voltage is changed, the signal level is kept constant. |
