Power management system distinguishing between primary and secondary system activity
US5511203A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 2, 1994 |
| Grant date | Apr 23, 1996 |
| Priority date | — |
| Expiry date | Feb 2, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D10/00
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A power management unit is provided that includes several states, each of which is associated with a different power management mode. Transitions between the states of the power management unit are dependent upon the type of activities detected. Upon reset of the computer system, the power management unit enters a ready state during which a CPU clock signal and a system clock signal are driven at their maximum frequencies. If no primary activities are detected over certain time periods, the power management unit successively transitions from the ready state to a doze state, then to a stand-by state, and then to a suspend state. During the doze state, the frequency of the CPU clock signal is slowed, and during the stand-by state, the CPU clock signal is stopped. During the suspend state, both the CPU clock signal and the system clock signal are stopped, and the power to selected circuit portions may be removed. If a secondary activity is detected when the power management unit is in the doze state or the ready state, the power management unit enters a transitory state during which both the CPU clock signal and the system clock signal are driven at maximum frequencies for a predeterm…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.