Charge detection is essential for a large number of commercial and scientific applications. A charge amplifier is one of the most fundamental building blocks for a detector system. This thesis describes the design, circuit implementation, and post-silicon testing of two different charge amplifier designs, analog and digital, that address some commonly seen fundamental challenges in the charge detection application. In particular, the proposed designs can be integrated with an image charge detector (ICD) to study the characteristics of dust on Mars. The proposed charge amplifier design utilizes a small 10 fF feedback capacitor to achieve a high gain. The fully integrated custom differential charge amplifier design improves the accuracy and robustness of its charge gain, and provides a compact method to extract detector capacitance for gain calibration. Conventional charge amplifiers' charge-to-voltage gain is a function of the detector parasitic capacitance. Therefore, a high precision photo-current calibration method is proposed here to enable an accurate gain calibration. In addition, a novel "digital amplifier" with close to rail-to-rail output swing is proposed to realize an infinite equivalent open-loop gain. Consisting of an ADC and charge pump as the amplifier core, this proposed design maintains a consistent closed-loop gain independent of the input parasitic capacitance. The ADC is realized as a single comparator, i.e. a 1-bit ADC, which, together with an SR latch and a differential charge pump, replaces the conventional analog amplifier core.
College and Department
Ira A. Fulton College of Engineering and Technology; Electrical and Computer Engineering
BYU ScholarsArchive Citation
Song, Yixin, "CMOS Charge Amplifier for Scientific Instruments" (2021). Theses and Dissertations. 9690.
charge amplifier, charge detection, ASIC, ion detection, charge calibration