| 摘要 |
PURPOSE:To stabilize the operations of respective circuits by providing an input decision circuit which decides one of voltages at input terminals, a switching means which switches an input and a load circuit at the same time according to its indication, and a main stabilized voltage circuit and a subordinate stabilized voltage CONSTITUTION:When a voltage is supplied from a subordinate input terminal 2 first, changeover switches 4 and 7 turn ON to their A sides according to the indication of the input decision circuit 2. Consequently, the voltage is supplied from the terminal 2 to the main stabilized voltage circuit 5 to supply constant voltages to load circuits 8 and 9. Then when a voltage is supplied from a main input terminal 1, the switches 4 and 7 turn ON to their B sides according to the indication of the circuit 3. Consequently, the voltage is supplied from the terminal 1 to the circuit 5, which supplies a constant voltage to the circuit 8; and the voltage is supplied from the terminal 1 to the subordinate stabilized voltage circuit 6, which supplies a constant voltage to the circuit 9. Consequently, the load of the circuit 5 is reduced to suppress heat generation from one place. Therefore, a small-sized power circuit becomes free from abnormal operations, etc., due to magnetic saturation of a coil, a transformer, etc., and temperature rises of respective components and respective circuits. |
