NEC breakthrough paves way for powerless standy-by modes

Flip-flop fiddling

NEC has announced the development of a memory circuit element that, it claims, will allow chips to consume no power when they're put in stand-by mode.

The circuit component is a non-volatile magnetic flip-flop (MFF) - not a reference to cheap footwear but to a transistor-based circuit of the type assembled by schoolboys to make two lightbulbs flash alternately.

In processors, the circuit is used as the basis of a 1-bit memory cell, storing a bit in its two possible states, within the register storage space.

Existing flip-flops require power to maintain their state and a clock circuit to control them. NEC's MFF uses magnetism to eliminate the need for juice.

So, says NEC, use MFFs instead of traditional memory flip-flops and non-volatile MRam cells instead of SRam, and you have the basis for a system-on-a-chip part that can be completely powered down yet still retain data - something traditional SoCs can't do.

Using MRam, the company added, also gets over the limited write life of Flash chips - MRams have "unlimited write endurance", NEC said.

NEC said it has made a working MFF that can operate at 1.2V or less - the same voltage range as standard SoC flip-flops - and at clock speeds of up to 3.5GHz. By working to these parameters, NEC said, it should be easy to integrate the new flip-flop structure into existing chip circuit designs. ®