Power-efficient analog systems to perform signal-processing using floating-gate MOS device for portable applications

Abstract

Digital Signal Processors (DSPs) have been an important component of all signal processing systems for over two decades now. Some of the obvious advantages of digital signal processing are the flexibility to make specific changes in the processing functions through hardware or software programming, faster processing speeds of the DSPs, cheaper storage, and retrieval of digital information and lower sensitivity to electrical noise.

The explosive growth of wireless and signal processing applications has resulted in an increasing demand for such systems with low cost, low power consumption, and small form factors. With high--level of integration to single--chip systems, power consumption becomes a very important concern to be addressed. Intermediate--Frequency (IF) band signal processing requires the use of an array of DSPs, operating in parallel, to meet the speed requirements. This is a power intensive approach and makes use of certain communication schemes impractical in applications where power budget is limited. The front--end ADC and back--end DAC converters required in these systems become expensive when the signal is of wideband nature and a greater resolution is required.

We present techniques to use floating--gate devices to implement signal processing systems in the analog domain in a power efficient and cost effective manner. Use of floating--gate devices mitigates key limitations in analog signal processing such as the lack of flexibility to specific changes in processing functions and the lack of programmability. This will impact the way a variety of signal processing systems are designed currently. It also enables array signal processing to be done in an area efficient manner. As will be shown through sample applications, this methodology promises to replace expensive wideband ADC and DAC converters with relatively easy to implement baseband data converters and an array of power intensive high speed DSPs with baseband DSPs. This approach is especially beneficial for portable systems where a lot of applications are running from a single battery.