Patent ID: 7609756

Claim:
A system for converting an analog signal to a digital signal, the system comprising: a multiphase oscillator having a period of oscillation and providing a plurality of phase signals, each oscillating at the period of the multiphase oscillator; a sample and hold circuit for capturing during a sampling interval an analog signal in response to a phase signal of the multiphase oscillator and for holding the sampled analog signal at the end of the sampling interval; a ramp generator connected to the output of the sample and hold circuit at a ramp node, the ramp generator operative to generate a ramp signal that starts at the voltage of the held analog signal; a comparator that provides a transition in an output signal when the ramp signal exceeds the reference voltage during a conversion interval that follows the sampling interval; and a time-to-digital converter connected to the output of the comparator, the time-to-digital converter operative, during the conversion interval, to sample, using phase signals of the multiphase oscillator, the comparator output signal and convert the comparator output signal to a multibit digital signal.