| 摘要 |
PURPOSE:To enable an integration of circuits with suppressed loss of a constant- current source transistor, by providing a maximum voltage detection means which detects the maximum voltage and a power source voltage control means which controls a power source voltage of a constant-current circuit according to the voltage detected. CONSTITUTION:Due to variation in equivalent resistances 21 a comparison between the highest voltage of an electrode 24 and the voltages at the both ends of a resistor 4 is made by a transistor 2, and by controlling a transistor 1 in order to make the both of the above values to be equal (a forward voltage of a diode 5 and a base emitter voltage of the transistor 2 are disregarded) an impedance of the transistor 1 is controlled, and the voltage of a terminal 7 is set. The voltage between the emitter and collector of a transistor 35 may, therefore, be maintained constantly low, if the voltage of a constant-voltage diode 3 is selected to be sufficiently low. In other words, the loss of the transistor 35 may be kept minimum. |
