Abstract: A power control circuit for a device such as a personal computer, including a laptop or notebook computer, which can conserve battery use, prevent power surges to promote longer battery charges and longer battery life, and can assure that circuitry is correctly biased. The power control circuitry of the present invention achieves these objectives by appropriately staggering the powering on of circuit components of the computer. A circuit for achieving these objectives may feature at least one memory for storing power control state data and a multiplexer for receiving the power control state data stored in the at least one memory. Further, a plurality of serially connected power control output circuits connected to the multiplexer output power control signals based on the power control state data stored in the at least one memory.

Abstract: The time a microprocessor CPU must wait for memory access is controlled to be one of two values by stretching the CPU clock signal either a first time duration or a second time duration, depending on the expected delay caused by the memory access. The clock stretching is in increments of one quarter of the CPU clock period and is done with both the leading and trailing edges of the clock pulse.

Abstract: Power dissipation of a CMOS circuit such as a microprocessor is reduced by dynamically slowing down the microprocessor clock during selected system operations such as hold, wait, or AT peripheral bus access cycles. The microprocessor clock is slowed to its minimum allowable frequency with precise synchronous control to maintain the accuracy of high frequency clock edges and to prevent glitches or substandard pulse widths.