Standby current requirements – Intel D845WN User Manual
Page 19
Desktop Board Features
19
CAUTION
If the standby current necessary to support multiple wake events from the PCI and/or USB buses
exceeds power supply capacity, the desktop board may lose register settings stored in memory.
Power supplies used with this board must be able to provide enough standby current to support the
standard Instantly Available (ACPI S3 sleep state) configuration as outlined in Table 4. Values are
determined by specifications such as PCI 2.2. Actual measurements may vary.
To estimate the total amount of standby current required for a particular system configuration,
standby current requirements of all installed components must be added. Refer to the descriptions
in and follow the steps outlined below:
1.
Note the total D845HV or D845WN board standby current requirement.
2.
Add to that the total PS/2 port standby current requirement if a wake-enabled device is
connected.
3.
Add, from the PCI 2.2 slots (wake-enabled) row, the total of the number of wake-enabled
devices installed (PCI and AGP) multiplied by the standby current requirement.
4.
Add, from the PCI 2.2 slots (nonwake-enabled) row, the total of the number of wake-enabled
devices installed (PCI and AGP) multiplied by the standby current requirement.
5.
Add all additional wake-enabled devices’ and nonwake-enabled devices’ standby current
requirements as applicable.
6.
Add all the required current totals from steps 1 through 5 to determine the total estimated
standby current power supply requirement.
Table 4.
Standby Current Requirements
Instantly Available Current
Support
Description
Standby Current
Requirements (mA)
Estimate for integrated board
components
Total for the D845HV/D845WN
board
770*
PS/2 ports
**
345
PCI 2.2 slots (wake-enabled)
375
PCI 2.2 slots (nonwake-enabled)
100
CNR** (wake enabled)
875
CNR** (non-wake enabled)
40
Estimate for add-on components
(Add to integrated board
components shown above)
USB ports
**
700
* Refer to the Intel Desktop Board D845HV/D845WN Technical Product Specification for the exact standby current
requirements
** Dependent upon system configuration