Abstract: A method for stabilize single-stage sigma-delta modulators is disclosed. The method of the present invention employs stability detectors to detect whether the modulator enters the unstable region or not. And internal signal paths that already exist in stable operation are used to recover a unstable modulator to stable region. In the first kind of embodiment, stabilization effect is supported by reduction of effective order. And in the second kind of embodiment, individual instability recovery in each stage in the modulator provide the necessary stabilization mechanism. The present invention can be applied to various configurations, such as multiple feedback and feedforward, and various application, like low-pass and band-pass system.

Abstract: The invention relates to a technique called "Internal Linear Feedback (ILF)" for the stabilization of high-order sigma-delta modulators. The ILF technique involves an overload detector and a selector. Once "overloaded" is detected by the overload detector, the selector is activated to make the modulator entering the ILF mode, in which additional internal linear feedback paths are employed to stabilize the modulator. Otherwise, the modulator operates in normal mode as a general high-order modulator.