CPC G04B 1/10 (2013.01) [G04B 17/22 (2013.01); G04C 3/00 (2013.01); H03B 5/32 (2013.01); H03L 1/02 (2013.01)] | 9 Claims |
1. A watch comprising:
a power supply configured to be charged;
a crystal oscillation circuit including a crystal oscillator and an oscillation circuit and configured to stop oscillation when a power supply voltage falls below an oscillation stop voltage, and to start oscillation and output an oscillation signal when the power supply voltage exceeds an oscillation start voltage, which is higher than the oscillation stop voltage;
a divider circuit configured to output a reference signal by dividing the oscillation signal output from the oscillation circuit;
a temperature compensation circuit configured to perform a temperature compensation function operation that compensates for variation of the reference signal due to a temperature;
a first voltage detection circuit configured to detect that the power supply voltage exceeded a first voltage that is set higher than the oscillation start voltage; and
a control circuit configured to start the temperature compensation function operation of the temperature compensation circuit when the first voltage detection circuit detects that the power supply voltage exceeded the first voltage, and to subsequently continue the temperature compensation function operation even when the power supply voltage falls below the first voltage.
|