Voltage reduction techniques for portable systems

Supply voltage scaling to 1 V and below is the key to low-power system design. Threshold voltage reduction enables aggressive supply scaling but increases leakage power. Emerging technologies such as MTCMOS and variable threshold bulk/SOI will be essential in controlling leakage while achieving high performance levels at low supply voltages. Power can also be reduced by adaptively varying the supply voltage in applications where the computational workload varies with time. Aggressive voltage and power level scaling requires efficient DC-DC conversion circuitry and in some cases, it is necessary to embed this function in the processor.