Circuit Device And Real-Time Clock Device

A circuit device includes a main power supply terminal, a backup power supply terminal, a voltage detection circuit, a register section, a processing circuit, and a power supply control circuit. A main power supply voltage is supplied through the main power supply terminal. A backup power supply voltage from a backup element is supplied through the backup power supply terminal. The voltage detection circuit detects the backup power supply voltage and outputs backup voltage data corresponding to the backup power supply voltage. Threshold voltage data is stored in the register section. The processing circuit compares the backup voltage data with the threshold voltage data. The power supply control circuit performs charging control on the backup element for charging with the main power supply voltage on the basis of the result of a comparison made by the processing circuit.