To reduce the change of power current when a power pin of a package connector is connected to the terminal of a mother board connector and when a hot-line loading/unloading mode is switched to a normal operation mode.

When the power voltage of an electronic circuit 14 is reduced less than a set level, a mode setting part 12 outputs a loading/unloading mode signal to a mode setting signal line 13, and the part 12 outputs a normal operation mode signal to the line 13 when the power voltage of the circuit 14 is higher than the set level. A switch 11 is opened when the loading/unloading signal is outputted to the line 13 from the part 12, and the switch 11 is short- circuited when the normal operation mode signal is outputted to the line 13 from the part 12 respectively. A power consumption reduction control circuit 15 reduces the power consumption of the circuit 14 when the loading/unloading mode signal is outputted to the line 13 from the part 12.