POWER SUPPLY CIRCUIT OF AIR CONDITIONER FOR AUTOMOBILE

摘要

PURPOSE:To provide an air conditioner whereby an air-conditioning control can be performed even if a voltage change caused by other loads on the side of the vehicle mounted with it is generated and thereby the voltage of the second power supply of the vehicle is reduced. CONSTITUTION:A first power supply 4 is used as the primary side input of a switching regulator circuit 5, and a secondary side output 9 of the switching regulator circuit 5 is connected with a second power supply 1 via a diode 10. When the voltage of the second power supply 1 is made lower than the voltage of the secondary side output 9 of the switching regulator circuit 5, a power is supplied from the secondary side output 9 of the switching regulator circuit 5 to a control part 3 via the diode 10.