Implementing low power digital circuits using flash devices

Floating gate (flash) transistors are used exclusively for memory applications today. These applications include SD cards of various form factors, USB flash drives and SSDs. This paper presents the first approach to use flash transistors to implement binary-valued digital circuits. Since the threshold voltage of flash devices can be modified at a fine granularity during programming, several advantages are obtained by our approach. For one, speed binning at the factory can be controlled with precision. Secondly, an IC can be re-programmed in the field, to negate effects such as aging, which has been a significant problem in recent times, particularly for mission-critical applications. We present the circuit topology that we use in our flash-based digital circuit approach, and, through circuit simulations, show that our approach yields significantly improved delay (0.84×), power (0.35×), energy (0.30×) and area (0.54×) characteristics compared to a traditional CMOS standard cell based approach, when averaged over 20 randomly generated designs. Note that we used the same operating voltage (1V) for both design styles. Our proposed circuit design style is not an FPGA, because it uses hardwired interconnect. Rather, our design approach is a method to design ASIC or custom/semi-custom digital circuits.