17-05-2013, 03:24 PM
Power Management System
Power Management.pptx (Size: 400.51 KB / Downloads: 29)
INTRODUCTION
Power management is a feature in which that turns off the power or switches the system to a low-power state when inactive.
In computing this is known as PC power management and is built around a standard called ACPI (Advanced Configuration and Power Interface).
All recent (consumer) computers have ACPI support.
Examples:
Electrical Appliances such as:
copiers, computers and computer peripherals (like monitors and printers)
How ?
At Processor Level :
By reducing CPU’s Core-voltage and Clock rate.
Example: Intel, IBM , AMD processors….
At Operating system Level:
Hibernation:
When a computer system hibernates it saves the contents of the RAM to disk and powers down the machine.
On startup it reloads the data. This allows the system to be completely powered off while in hibernate mode.
Hibernate mode is enabled by default in some versions of Windows and can be disabled in order to recover this disk space.
Sleep( or standby) mode
Sleep mode refers to a low power mode for electronic devices such as computers, televisions, and remote controlled devices.
It saves significantly on electrical consumption compared to leaving a device fully on and, upon resume, allow the user to avoid having to reissue instructions or to wait for a machine to reboot.
Many devices signify this power mode with a pulsed or red colored LED power light.
Apples’ Fusion Drive Technology
Hard Disk are big, cheap and relatively slow.
While Semiconductor memories are small, expensive and extremely fast.
Apple’s new Fusion Drive gives advantage of both.
Fusion Drive is basically two drives in one but looks one.
Use of Super Capacitors in Alkaline batteries
High-data rate GPRS and cameras with electronic flash auto-focus drives require significant pulses of power.
This power is taken from alkaline batteries.
Alkaline batteries has many distinct features such as easy availability, reasonable cost, high energy density, longer life and easy to design.
Without Super Capacitor
1. In a typical case, a digital still camera driven by two AA batteries might draw a peak power of 3W and current of 1.5A during the auto focus phase of its operation.
2. Such a drive function might last around 0.4s, during which time the battery voltage would drop around 300mV for a new battery.
3.But the voltage drop will increase to as much as 600mV when the battery reaches approximately 50% charge level.