| 摘要 |
Structures and methods for CMOS voltage controlled phase shift oscillators are provided. The CMOS voltage controlled phase shift oscillators, or phase shift circuit, includes any odd number of stages coupled in series. Each stage includes a CMOS amplifier. A phase shift network is coupled to the CMOS amplifier. The CMOS amplifier provides a gain and allows a small phase shift in each stage to eventually provide a signal which is 180 degrees out of phase with the input signal. In the CMOS amplifier, the PMOS transistor is a diode connected PMOS transistor which acts as a low valued load resistance. In the phase shift network, an NMOS transistor is used as a voltage variable resistor for providing a resistance value in the circuit. |
