PURPOSE: To exactly control a cut-off operation corresponding to the operating condition of a main body equipment by turning on a power source corresponding to a power source control signal from an external equipment and turning off the power source by the control of the control means of the main body equipment.
CONSTITUTION: When any factor to turn on a main power source 31 is generated at an external equipment 34, the external equipment 34 activates a power source control signal 34a. Therefore, the output of an OR circuit 38a is made active, and the main power source 31 is turned on. Then, a control means 32 of a main body equipment 30 starts operating, first of all, a power source control signal 32a is kept active just after the power source is turned on, and the main power source is kept in the ON state. Next, the control means 32 transmits a reset signal 32b to the external equipment 34. Then, the external equipment 34 makes the power source control signal output inactive. With this processing, a control terminal A of the main power source 31 is turned to a state to be controlled only by the control means 32. Thus, the main power source 31 can be turned off only by the judgement of the control means 32 itself.
KISHI HARUHIKO
WADA KEIKO
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