Semiconductor integrated circuit and operation method of the same

A semiconductor integrated circuit comprising:

• an input terminal;
• a DC-DC converter;
• a charge output terminal;
• a voltage detecting circuit;
• and
• a charge timer,
• wherein a DC input voltage generated by rectifying and smoothing reception signals repetitively supplied as an RF signal by NFC and an RF signal by wireless power supply can be supplied to the input terminal,
• wherein the DC-DC converter can generate a DC output voltage having a desired voltage level from the DC input voltage supplied to the input terminal,
• wherein the charge output terminal can charge an external battery by using the DC output voltage generated by the DC-DC converter,
• wherein the voltage detecting circuit can detect that battery voltage of the charge output terminal reaches a predetermined voltage level by charging the battery and can generate a control signal in response to the battery voltage and the predetermined voltage level,
• wherein the charge timer can count charge time of the battery on the basis of control by the control signal generated from the voltage detecting circuit,
• wherein the voltage detecting circuit can generate a level determination signal discriminating a communication period of the NFC and a power supply period of the wireless power supply by detecting the level of the DC input voltage supplied to the input terminal, and
• wherein during execution of operation of counting the charge time of the battery by the charge timer, the voltage detecting circuit controls the charge timer by the control signal in the communication period of the NFC so that the charge timer holds a count value of the counting operation.