Vr Power-State Transitions - Intel Xeon Processor E5-1600 Datasheet

Product families

page of 258

/ 258
Contents
Table of Contents
Bookmarks

Table of Contents

7.1.9.3.5

SVID Power State Functions: SetPS

The processor has three power state functions and these will be set seamlessly via the

SVID bus using the SetPS command. Based on the power state command, the SetPS

commands sends information to VR controller to configure the VR to improve efficiency,

especially at light loads. For example, typical power states are:

• PS0(00h): Represents full power or active mode

• PS1(01h): Represents a light load 5 A to 20 A

• PS2(02h): Represents a very light load <5 A

The VR may change its configuration to meet the processor's power needs with greater

efficiency. For example, it may reduce the number of active phases, transition from

CCM (Continuous Conduction Mode) to DCM (Discontinuous Conduction Mode) mode,

reduce the switching frequency or pulse skip, or change to asynchronous regulation.

For example, typical power states are 00h = run in normal mode; a command of 01h=

shed phases mode, and an 02h=pulse skip.

The VR may reduce the number of active phases from PS0 to PS1 or PS0 to PS2 for

example. There are multiple VR design schemes that can be used to maintain a greater

efficiency in these different power states, please work with your VR controller suppliers

for optimizations.

The SetPS command sends a byte that is encoded as to what power state the VR

should transition to.

If a power state is not supported by the controller, the slave should acknowledge with

command rejected (11b)

Note the mapping of power states 0-n will be detailed in the VR12/IMVP7 Pulse Width

Modulation Specification .

If the VR is in a low power state and receives a SetVID command moving the VID up

then the VR exits the low power state to normal mode (PS0) to move the voltage up as

fast as possible. The processor must re-issue low power state (PS1 or PS2) command if

it is in a low current condition at the new higher voltage. See

state transitions.

Figure 7-2.