Patent ID: 7515005

Claim:
A variable frequency multi-phase oscillator for generating multi-phase signals, comprising: a correlator for receiving a control signal from an external source and generating a threshold voltage; a plurality of delay cells coupled in series with each other, each delay cell having an output port, each delay cell receiving the control signal from the external source and the threshold voltage from the correlator and generating one multi-phase signal; and a NOR circuit for receiving a plurality of multi-phase signals from the plurality of delay cells and generating an output signal to one of the plurality of delay cells, the NOR circuit being coupled to the output port of each delay cell, wherein each delay cell further comprising a current supply for providing a charging current, a capacitor coupled to the current supply, a comparator coupled to the current supply and the capacitor, the comparator generating a digital signal, a switch coupled in parallel with the capacitor, and a logic unit having a first input terminal, a second input terminal, a first output terminal and a second output terminal, the first input terminal receiving the digital signal from the comparator, the second input terminal acting an input terminal of the delay cell, the first output terminal providing one of multi-phase signals, and the second output terminal providing a control signal to the switch.