PURPOSE: To stably carry out load operation even at the time of low output by installing a load switching circuit to decrease the number of driven loads when output of an inverter circuit determined according to signal supplied from outside becomes less than or equal to a prescribed value.
CONSTITUTION: Under normal operational conditions, an output of an inverter circuit 1 is controlled by a controlling circuit 3 according to a signal S supplied from outside, and a plurality of loads 2 are simultaneously driven. Meanwhile, when the output of the inverter circuit 1 determined according to the signal S becomes lower than or equal to a prescribed value, the number of driven loads 2 decreases by a load selection switching circuit 4. Consequently, in the case of relatively high output of the inverter circuit 1, a plurality of loads 2 are driven simultaneously and their output are controlled to change simultaneously and is contrast with it, in the case of relatively low output of the inverter 1, the number of the loads 2 decreases along with output decrease. As a result, even if load 2 which is difficult for driving at low output is used, output in decreased stably by decreasing the number of driven loads 2.
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YAMANAKA YUKIO
OKAMOTO FUTOSHI
