Multi-phase oscillator and method therefor

摘要

The invention relates to a multi-phase inverter ring oscillator generating multiple output signals arranged in groups of four. In an example embodiment, an even number of inverters are coupled together in a cascaded series, each inverter has an input and an output, the output of one inverter is coupled to the input of a next sequential one of the inverters. There are a corresponding number of cross-coupled transistors. Each cross-coupled transistor couples the input of one inverter to the output of the next sequential one of the inverters. In a particular example embodiment, a four-phase inverter ring oscillator generates four output signals that are shifted 90° in phase and may be used to generate 50% duty cycle clocks.