ABSTRACT
This chapter explores various circuit technologies for low-power systems grouped by the controllable parameters. Low-power complementary metal oxide semiconductor circuit design is required to extend the battery lifetime of portable electronics such as cellular phones or personal digital assistants. The supply voltage, the threshold voltage and the clock frequency are parameters that can be dynamically controlled to reduce power dissipation. Conditional clocking also reduces the dynamic-power consumption since the clock signals are only distributed to operating modules. The propagation delay and the power consumption are correlated in the circuit. The multiple supply system provides a high-voltage supply for high-performance circuits and a low-voltage supply for low-performance circuits. A supply switch is one of the most effective means to cut off power in the idle state. The operating power is also reduced with the conditional clocks, which deliver clock signals only to active modules.
