SUPPLY VOLTAGE DRIFT INSENSITIVE DIGITALLY CONTROLLED OSCILLATOR AND PHASE LOCKED LOOP CIRCUIT

摘要

A digitally controlled oscillator includes a ring oscillator and a first supplementary circuit. The ring oscillator is coupled to a supply voltage and generates a signal oscillated at an oscillating frequency. The oscillating frequency is controlled by a digital code and further varies with a supply voltage drift in a first direction. The first supplementary circuit is coupled to the ring oscillator and facilitates the oscillating frequency to vary with the supply voltage drift in a second direction reverse to the first direction.

主权项

1. A digitally controlled oscillator, comprising:
a ring oscillator, coupled to a supply voltage and generating a signal oscillated at an oscillating frequency, wherein the oscillating frequency is controlled by a digital code and further varies with a supply voltage drift in a first direction; and a first supplementary circuit, coupled to the ring oscillator and facilitating the oscillating frequency to vary with the supply voltage drift in a second direction reverse to the first direction.