Low frequency noise canceling photodetector preamplifier useful for computerized tomography
US5084639A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 17, 1990 |
| Grant date | Jan 28, 1992 |
| Priority date | — |
| Expiry date | Sep 17, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/261
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A preamplifier interfaces low level current-mode signals, such as from a photodetector in a computerized tomography system, to a corresponding voltage-mode signals, with a dynamic range on the order of 120 dB. The preamplifier can be implemented in CMOS technology to allow for complete integration of the computerized tomography interface function, including analog-to-digital conversion, of several channels in a single integrated circuit. The CMOS circuit accepts a current signal at its input and, after integration of the signal, produces a voltage output wherein the low frequency noise that is normally encountered with MOS transistors is cancelled through the use of correlated-double sampling. The circuit limits high frequency noise through use of low-pass filtering.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.