Hybrid integrators - error correction and calibration

• Applicant: Professor Dr.-Ing. Dirk Killat
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567326700

Analog continuous-time integrators are a fundamental building block in analog computers, continuous-time delta-sigma ADCs, robust analog controllers and many other analog signal processing circuits. Analog computers are particularly suitable for solving and simulating differential equations, for which integrators are usually connected in series and fed back. When integrators are connected in series, attention must be paid to scaling, which usually requires a compromise between dynamic range and signal-to-noise ratio. With zoom ADCs, even the dynamic range of the first integrator is reduced by so-called overranging. The continuous-time integrator can be extended by analog and digital components in such a way that the limitation of the dynamic range is removed. Such hybrid integrators are not only suitable for CT delta-sigma ADCs and analog computers, but could also reduce the overranging problem in zoom ADCs, which represent a cascade of SAR ADCs and CT delta-sigma ADCs. The additional components of the hybrid integrator naturally bring with them new sources of error. Therefore, the hybrid integrator only has a chance of being used advantageously if it is possible to correct these errors automatically and continuously or to carry out a calibration. The possibilities for calibration naturally depend heavily on the application of the hybrid integrator. In this project, a hybrid integrator is to be developed according to an improved method at transistor level and possibilities for error correction and calibration are to be investigated. The methods are then to be verified on two hybrid integrators on a test chip. Three test circuits can be configured with two hybrid integrators: A simple second-order delta-sigma modulator, a sine-cosine oscillator and an analog computer with a second-order differential equation. In the practical evaluation, the hybrid integrator is critically examined with the error correction and calibration procedures both individually and in the three test circuits and compared with the simulation data.

• DFG Programme: Research Grants