Patent ID: 6690245
Filing Date: 2004-02-10
Classification: H03B,H03K

Abstract:
An oscillation control circuit comprising:a pair of power lines; an oscillator circuit having a first CMOS inverter and a piezoelectric oscillator connected between output and input terminals of said first CMOS inverter; a second CMOS inverter connected to said first CMOS inverter in series for receiving an oscillation signal produced from said first CMOS inverter; a control MOS transistor connected between a source of at least one of N- and P-channel transistors forming said second CMOS inverter and at least one of said power lines; an operation control circuit for maintaining said control MOS transistor in cutoff until an oscillation amplitude of the oscillation signal exceeds a given value; and said operation control circuit having a capacitor and a Schmitt trigger having input/output characteristics having a given hysteresis, said capacitor being charged and discharged according to said oscillation signal, said Schmitt trigger controlling said control MOS transistor according to a charging voltage for said capacitor.