Method and apparatus for separating the reference current from the input signal in sigma-delta converter

摘要

An integrator system may have a pair of sampling circuits each having a sampling capacitor to sample a respective component of a differential input signal, and an integrator having inputs coupled to outputs of the sampling circuits. The system may have a shorting switch coupled between input terminals of the sampling capacitors. The shorting switch may be engaged during an interstitial phase between sampling and output phases of the sampling circuits. By shorting input terminals of the sampling capacitors together, the design reduces current drawn by the system and, in some designs, severs relationships between current draw and information content sampled by the system. The integrator system may receive analog and digital input signals.

主权项

1. An integrator system, comprising:
an integrator having a pair of inputs, a pair of sampling circuits, each having a sampling capacitor, to sample respective components of a differential input signal on the sampling capacitor in a first phase of operation and to drive a representation of the sampled input signal to the integrator inputs in a second phase of operation, and a shorting switch to connect input terminals of the sampling capacitors together during third and fourth phases of operation that occur between successions of the first phase and the second phase, wherein the differential input signal is decoupled from the sampling capacitors during the third and fourth phases.