2 3 are turned on and all of the operating current modes of regulator 120 i are changed into the low current consumption mode consequently it is possible to decrease the power consumption of power supply system 100 moreover link control section 130 switches the operating current mode of dcdc 110 into the normal mode when one of the operating current modes of regulator 120 i i 1 2 3 is changed into the normal mode if the operating current mode of dcdc 110 is set into the low current consumption mode consequently a source voltage having an excellent transient response characteristic is supplied to the regulator which is brought into the normal mode furthermore link control section 130 receives as input control signal ddpsm_link indicating whether or not the operating current mode of dcdc 110 is to be switched depending on the on off state of at least one of regulators 120 i i 1 2 3 or the operating current mode of the regulator and switches the operating current mode of dcdc 110 depending on the on off state of the regulator or the operating current mode of the regulator if control signal ddpsm_link indicates a switching command in addition link control section 130 receives as input a specifying signal for specifying the regulator to be used for switching the operating current mode of dcdc 110 and switches the operating current mode of dcdc 110 depending on the on off state of the regulator specified by the specifying signal or the operating current mode of the regulator consequently it is possible to enhance a general purpose when the number of the regulators is increased in embodiment 1 the description has.