| 摘要 |
<p>A temperature sensing circuit (13) measures the temperature of an oscillation circuit (47). A tertiary term voltage generating circuit of a control voltage generating circuit (23) generates a tertiary term voltage used as a control voltage according to the output voltage of the temperature sensing circuit (13). A frequency adjusting circuit (45) varies the oscillation frequency of the oscillation circuit (47) according to the control voltage. The tertiary term voltage generating circuit has a first MOS transistor (37) the source of which is connected to a first power supply line (25), a second MOS transistor (35) the source of which is connected to a second power supply line (26), and digital control voltage dividing circuits (31, 33) for generating first and second gate voltages according to the output voltage of the temperature sensing circuit (13). The first and second gate voltages are applied to the gates of the first and second MOS transistors (37, 35), respectively. The connection node (44) to which the drains are commonly connected are made the output end of the control voltage.</p> |
