Semiconductor integrated circuit, noncontact/contact electronics device using the same and mobile terminal

A semiconductor integrated circuit comprising:

• a pair of antenna terminals connectable with an antenna;
• a rectifier operable to rectify a radio frequency signal supplied through the pair of antenna terminals thereby to output a direct-current voltage to an inside source line;
• a source-voltage terminal for supply of a source voltage from outside;
• a shunt regulator including a pull-down transistor connected between the inside source line and a ground, and passing a pull-down current through the pull-down transistor in response to a rise of a voltage of the inside source line to or above a first set voltage;
• a series regulator including a pull-up transistor connected between the source-voltage terminal and inside source line, and passing a pull-up current through the pull-up transistor in response to a fall of the voltage of the inside source line to or below a second set voltage;
• and
• a control section connected with the shunt regulator and series regulator,
• wherein the control section can control a voltage level of the first set voltage into a level higher than a voltage level of the second set voltage in case that the shunt and series regulators work in parallel.