Chapter 6 Power and Signal Distribution

6.3.2 LOW VOLTAGE PRODUCTION/DISTRIBUTION

Voltages less than 3.3 VDC including processor core (VccP) voltage are produced through regulator circuitry (Figure 6-4) on the system board.

+5 AUX

+5 VDC

+3.3 VDC

+12 VDC

Power Supply

+3.3 VDC

+3 AUX

+5 VDC

+12 VDC

+12.8 Vcpu

VID0

VID1

VID2

Processor VID3

VID4

3.3

DIMM Circuit

AGP

PWR

DDR

Power

Circuitry

Regulator

Circuit

3.3VDC

DIMMs

VDDQ (1.5 VDC)

AGP Bus

 

2.5 S3 VDC

+1.8 VDC DDR DIMMs

+1.4 Ref

VccP (see text)

Processor

Figure 6–4.Low Voltage Supply and Distribution Diagram

The VccP regulator produces the VccP (processor core) voltage according to the strapping of signals VID4..0 by the processor. The possible voltages available are listed as follows:

VID 4..0

VccP

00000

2.05 VDC

00001

2.00 VDC

00010

1.95 VDC

00011

1.90 VDC

00100

1.85 VDC

00101

1.80 VDC

00110

1.75 VDC

00111

1.70 VDC

01000

1.65 VDC

01001

1.60 VDC

01010

1.55 VDC

VID 4..0

VccP

01011

1.50 VDC

01100

1.45 VDC

01101

1.40 VDC

01110

1.35 VDC

01111

1.30 VDC

10000

3.50 VDC

10001

3.40 VDC

10010

3.30 VDC

10011

3.20 VDC

10100

3.10 VDC

10101

3.00 VDC

VID 4..0

VccP

10110

2.90 VDC

10111

2.80 VDC

11000

2.70 VDC

11001

2.60 VDC

11010

2.50 VDC

11011

2.40 VDC

11100

2.30 VDC

11101

2.20 VDC

11110

2.10 VDC

11111

No CPU

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6-8Compaq Evo and Workstation Personal Computers

Featuring the Intel Pentium 4 Processor

Second Edition- January 2003

Page 133
Image 133
Compaq W4000 manual LOW Voltage PRODUCTION/DISTRIBUTION, VID0 VID1 VID2, VID4, Agp Pwr Ddr, Vid