Lenovo Aptiva Product Manual page 36

Aptiva S Series 1G Product Guide
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, etc.
Calculate the standby current requirements using the steps described below.
Power supplies used with this desktop board must be able to provide enough standby current to
support the standard Instantly Available (ACPI S3 sleep state) configuration. Some values are set
per specifications such as PCI 2.2. The values given in the table for Instantly Available are for a
system containing a single wake-enabled PCI (or AGP) device and five non-wake devices. Actual
measurements may vary.
To estimate the amount of stand-by current required for a particular system configuration:
1. From the PCI 2.2 row, determine the number of supported wake-enabled adapters required
(PCI and AGP) and multiply by 375 mA.
2. Determine the number of non-wake adapters and multiply by 20 mA.
3. Total the values derived from steps 1 and 2 and replace the PCI 2.2 value (currently 475 mA)
in the table with the new value.
4. Add the rows to the estimated standby current required to support Instantly Available.
5. Add the current required to support the optional features.
6. Total the estimated standby current required to support Instantly Available and the current
required to support the optional features.
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CR6F1
Figure 4. Location of Standby Power Indicator
OM08849