| 摘要 |
A crystal oscillation circuit has a reduced circuit area and enables to stably oscillate at low consumed current. The crystal oscillation circuit includes an oscillating amplifier and a constant voltage generator. The oscillating amplifier excites a resonator composed of a resistor, a crystal oscillator and a capacitor. The constant voltage generator includes a one-stage differential circuit composed of a transistor and a capacitor for suppressing transient fluctuation of a constant voltage Vreg for generating the constant voltage Vreg served as a supply voltage for the oscillating amplifier. By generating the constant voltage Vreg through the one-stage differential circuit, the phase lag of the constant voltage Vreg reaches 90 degrees at most. This eliminates the necessity of a phase compensation capacitor, resulting in making the circuit area smaller and realizing the stable oscillation at low consumed current.
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