Efficient Saturation Control for Fully Differential Integrator in Continuous-Time Sigma-Delta Modulators

This paper presents an alternative approach to saturation control in an integrator, that occurs in Sigma-Delta modulators (ΣΔMs). This solution simplifies the design process with a 1.2- V power supply and consumes significantly less power than conventional saturation control methods. Additionally, this solution provides a good phase margin, that guarantees the stability, without requiring additional compensation techniques, and it has the added benefit of reducing the gain of the integrator as the system enters saturation, while also maintaining integrator inputs fixed at the proper common-mode voltage. This innovative approach offers a promising solution for efficient and stable saturation control in ΣΔM integrators, preventing distortion in the output signal, with potential applications in a wide range of electronic systems, such as audio systems. The circuit has been designed in a 90-nm CMOS technology.