Semiconductor device and control method thereof

摘要

The present invention provides a semiconductor device including a first terminal and a second terminal respectively coupled to both ends of a crystal resonator, an inverter circuit having an input coupled to the first terminal and an output coupled to the second terminal, a feedback resistor which couples between the first terminal and the second terminal, a variable capacitor coupled to at least one of the first and second terminals, and a control circuit. The control circuit performs control to increase both of the drive capability of the inverter circuit and the capacitance value of the variable capacitor in a second mode rather than a first mode.

主权项

1. A semiconductor device comprising:
first and second terminals respectively coupled to both ends of a crystal resonator; an inverter circuit having an input coupled to the first terminal and an output coupled to the second terminal; a feedback resistor which couples between the first terminal and the second terminal; a variable capacitor coupled to at least one of the first and second terminals; and a control circuit which controls a drive capability of the inverter circuit and a capacitance value of the variable capacitor, based on a mode signal which specifies each of first and second modes, wherein the control circuit performs control to increase both of the drive capability of the inverter circuit and the capacitance value of the variable capacitor in the second mode rather than the first mode, wherein upon switching from the first mode to the second mode, the control circuit increases the capacitance value of the capacitor after having increased the drive capability of the inverter circuit, and wherein upon switching from the second mode to the first mode, the control circuit decreases the drive capability of the inverter circuit after having decreased the capacitance value of the variable capacitor.