| 摘要 |
PURPOSE:To minimize the power consumption of a DC constant voltage regulated power supply circuit by increasing the resistance value of a base bias resistance of a control transistor as the load current is decreased. CONSTITUTION:A current Ir is prescribed by a main base bias resistance R only in case a load current Id is small and the both-terminal voltage Vbe of a resistance Rs is less than the level of an active area of a transistor TR Q1. While the current Ir is controlled by the parallel resistance value obtained by adding together the resistance R, a secondary base bias resistance Rc and the equivalent resistance of the TR Q1 if the current Id increases and the voltage Vbe rises up to the level of the active area of the TR Q1. Thus, the current Ir is increased. When the current Id increases, the TR Q1 is turned on and the current Ir is prescribed by the parallel resistance value of both resistances R and Rc and then maximized. In such a way, the current consumption of a power supply circuit is reduced.
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