Voltage controlled oscillator using low voltage high frequency semiconductors

摘要

The voltage-controlled oscillator has a ring oscillator (20) which is controlled by an input voltage. The ring structure consists of several CMOS inverter amplifiers. The output of a first CMOS inverter amplifier is fed into the input of the next CMOS inverter amplifier. The output of the ring oscillator is fed to an inverter unit (21). Each CMOS inverter amplifier contains a PMOS transistor and a first NMOS transistor connected in series between a supply voltage and earth, and with their gates connected in parallel. There is a second NMOS transistor with its gate connected to the ring oscillator input, its source connected to the PMOS gate and first NMOS transistors gate, and its drain connected to a ring oscillator output.