| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of the conventional crystal oscillation circuit wherein the circuit cannot obtain stable oscillation characteristics due to delays in the oscillation start and a deviation in an operating point at steady-state oscillation, since a DC bias is automatically set to a reference level, in the conventional crystal oscillation circuits including a resonance section and an amplifier section, wherein a reference current source applies constant current bias to a first MOSFET configuring the amplifier section, a second MOSFET is self-biased, and an oscillation amplitude is given to both the MOSFETs in terms of AC. SOLUTION: The DC bias of the crystal oscillation circuit disclosed herein can be optimally set by controlling the base level of the second MOSFET to an optional level by a base level control means. Thus, the oscillation start-up performance of the crystal oscillation circuit is improved and the stability and the reliability at the steady-state oscillation are improved. COPYRIGHT: (C)2005,JPO&NCIPI
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