| 摘要 |
PURPOSE:To eliminate an output current change caused by power supply fluctuation and the fluctuation of DELTAVBE by providing a power supply fluctuation removing circuit and a starter circuit. CONSTITUTION:When a voltage is generated at a power source 2, a constant current circuit is turned to an active state by a starter circuit 4. When the base potential of a transistor Q6 is higher than that of a transistor Q7, for the starter circuit 4, the transistor Q7 is cut off and automatically stops the function. When the constant current source is turned to the active state, an output current value is decided by a resistor R1. This current is supplied to a transistor Q5 by transistors Q4 and Q3 and defined as the driving current of a constant current source 1. By designing this constant current source so as to make current density equal for the transistors Q5 and Q6 and for the transistors Q3 and Q4, these two pairs of VBE are turned to OV and there is no influence of the DELTAVBE. On the other hand, even when the voltage of a power source 2 is fluctuated, the current value decided by the resistor R1 is fixed, and the influence of the power supply fluctuation can be eliminated as well.
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