| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a power circuit that is suitable for 24 V-system electronic control systems for automobiles. SOLUTION: The power circuit, which is for use in electronic control systems for automobiles mounted with a rated 24 V battery in order to drop the battery voltage VB down to a set voltage VC of 5 V before feeding it to a processing circuit 12, comprises an NPN transistor Tr1 and a PNP transistor Tr2 series- connected along the power feed line extended from the battery voltage VB to the processing circuit 12, a power source IC 10 for controlling the base current of the trailing transistor Tr2 to bring the voltage output thereof to the processing circuit 12 to the set voltage VC, and two resistors Ra and Rb of the same resistance series-connected between the battery voltage VB and the set voltage VC. The base of the leading transistor Tr1 is connected to the interconnection between the resistors Ra and Rb. The power consumption is thus uniformly dispersed between both transistors Tr1 and Tr2 to reduce their power.</p> |
