Patent ID: 7183868
Filing Date: 2007-02-27
Classification: H03K

Abstract:
1. A CMOS oscillator circuit for use with a resonator, which is connected in a feedback configuration between an input and an output of the CMOS oscillator circuit, comprising: (a) three serially-connected dc-coupled CMOS inverters, with each CMOS inverter having an input and an output, and with the output of a first CMOS inverter being connected to the input of a second CMOS inverter, and with the output of the second CMOS inverter being connected to the input of a third CMOS inverter; (b) a first feedback resistor connected between the output of the third CMOS inverter, which forms the output of the CMOS oscillator circuit, and the input of the first CMOS inverter, which forms the input of the CMOS oscillator circuit; (c) a second feedback resistor connected between the output of the second CMOS inverter and the input of the second CMOS inverter to provide a positive resistance which decreases the gain of the second CMOS inverter to prevent any parasitic oscillation in the CMOS oscillator circuit; (d) a first capacitor connected at one side thereof to the input of the CMOS oscillator circuit, and at another side thereof to a voltage supply rail; and (e) a second capacitor connected at one side thereof to the output of the CMOS oscillator circuit, and at another side thereof to the voltage supply rail.