Switched capacitor analog circuits using polysilicon thin film technology
US5589847A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 23, 1991 |
| Grant date | Dec 31, 1996 |
| Priority date | — |
| Expiry date | Sep 23, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D86/481
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Switched capacitor analog circuits (such as integrators, amplifiers and digital-to-analog converters) constructed from polysilicon thin film transistors and capacitors are disclosed. The circuits are commonly implemented using conventional single crystal CMOS technologies, but this is the first time they have been realized using polysilicon TFT CMOS. The performance of the circuits is inevitably worse than that of conventional single crystal CMOS devices, but is nevertheless adequate for many large area applications. The circuits can be fabricated on large area substrates and integrated with, for example, flat panel displays, pagewidth optical scan arrays, or pagewidth printheads, offering improvements in the functionality and performance of those devices. Charge redistribution amplifiers and digital-to-analog converters are shown to operate with settling times ranging from a few microseconds to a few tens of microseconds, even with large capacitive loads, despite the relatively poor performance of polysilicon TFTs in comparison to conventional MOSFETS. Better than 8-bit accuracy is also demonstrated for the digital-to-analog converters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.