| 摘要 |
PURPOSE:To stabilize the oscillation by applying constant current control to the operating current of an oscillator based on the voltage corresponding to a clamp voltage by providing one diode in series with an oscillation circuit so as to detect the equivalent clamp voltage of the oscillator. CONSTITUTION:In causing a minute current to flow through a start resistor between a control input terminal 230 and ground, the current flows to an input transistor 214 through TRs 211, 212 of the current mirror stage to supply an operation current of the oscillator to TRs 105, 106 constituting a constant current circuit. The operating current of the oscillator flows to a diode 201 to generate a forward voltage drop VD. A differential amplifier 202 amplifies a difference voltage between a diode voltage VD and a terminal voltage of a resistor 210 to increase the current flowing through a resistor 210 via TRs 203, 204 thereby making the difference zero. The current is fed back to a diode 201 via a current mirror stage of a bias control circuit 20 and a current mirror stage of the oscillator 10 and the currents reach equilibrium finally.
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