| 摘要 |
PROBLEM TO BE SOLVED: To remove a sense of incongruity for users by preventing malfunction due to the power failure in the event of a large load current in a control device of an air conditioner. SOLUTION: A commercial source of a.c. voltage 1 is transformed into the d.c. voltage by a rectifier 2, and this d.c. voltage is smoothed by a smoothing capacitor 3. This smoothed voltage is transformed into a predetermined voltage by a switching power circuit such as a switching transformer circuit 4, diodes Da and Db, and capacitors Ca and Cb so as to be outputted. An air conditioner uses the voltage V1 for the power source of a microcomputer 13 of a control means, and the V2 for the power source of a load 5. In the operation of the air conditioner, the microcomputer 13 inputs a detection signal (a current proportional to the input current : the output current of the switching power source) by a resistor 11 and a current detection circuit 12 for detection. Meanwhile, when detecting a hit of the commercial source of a.c. voltage 1 by the detection signal of a hit detection circuit 10, the microcomputer 13 controls at least the current of a load 5 according to the detected input current, or stops the operation of the load 5 and informs of the hit. |
