An LSI system with locked in temperature insensitive state achieved by using body bias technique

Forward-body-bias (FBB) technology can compensate performance fluctuation in LSIs for low-voltage-operation. However, because the FBB characteristics depend on the temperature, the FBB control effect is decreased at high temperatures. A temperature insensitive state (TIS) for supply voltage improves the LSI performance as a solution of the dependence of the FBB characteristics on temperature. When an LSI is operated in a TIS, the performance fluctuation is fixed in a low temperature condition. We propose a TIS locking circuit that achieves TIS operation and reduces performance fluctuation. The circuit achieves this by detecting the threshold voltage and generating a voltage proportional to temperature. Compensating TIS decreased performance fluctuation and power consumption of an LSI to one-third of those before TIS control was applied.