| 摘要 |
PROBLEM TO BE SOLVED: To reduce a power consumption of an oscillation circuit, without impairing the oscillation starting properties. SOLUTION: An oscillation signal turns into a predetermined amplitude value by a detection circuit OPC, a transfer of oscillation operation has shifted from initial state to a steady state is detected and turns on a P-channel MOS transistor P1, and hence a capacitor CA is connected between an input terminal IN of a CMOS inverter IV0 and a power source terminal VDD. In the initial state, the load capacity is reduced to cancel the dropped part of a conductance gm of the CMOS inverter IV0, corresponding to a reduction in a power consumption. Thus, a negative resistance necessary for maintaining proper oscillation starting properties is obtained, and in normal state, load capacity is increased to suppress unevenness of an oscillation frequency.
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