Patent ID: 8228131
Filing Date: 2012-07-24
Classification: H03L

Abstract:
1. A crystal-oscillator circuit, comprising: a quartz crystal unit; a first variable-capacitance element, connected to the quartz crystal unit so as to form an oscillation loop, and whose capacitance value changes depending on a first control signal; a temperature compensation circuit configured to provide the first control signal for the first variable-capacitance element to compensate for a temperature characteristic of the quartz crystal unit; a variable-capacitance element group, connected to the quartz crystal unit, and whose capacitance value changes depending on a second control signal; and a time constant circuit configured to generate a time constant signal which changes with a predetermined time constant, and to provide the time constant signal for the variable-capacitance element group as the second control signal, wherein the time constant circuit uses reverse saturation current of a P-N junction and a capacitive element.