Low Voltage Distribution; Figure 7-3. Low Voltage Supply - Compaq Deskpro 4000 Technical Reference Manual

7.3.2

LOW VOLTAGE DISTRIBUTION

Voltages less than 3.5 VDC are produced through regulator circuitry on the system board.
Power Supply
From
Pentium II
Microprocessor
Figure 7–3. Low Voltage Supply, Block Diagram
The VccP regulator produces the VccP (Pentium Pro processor core) voltage according to the
state of the VID4..0 signals from the Pentium II microprocessor. This allows automatic selection
of the proper core voltage depending on the installed microprocessor component. The possible
voltages available are listed as follows:
VID4..0 VccP
10000 3.5 VDC
10001 3.4 VDC
10010 3.3 VDC
10011 3.2 VDC
10100 3.1 VDC
10101 3.0 VDC
10110 2.9 VDC
10111 2.8 VDC
2SK2248S
+3.3 VDC
+12 VDC Regulator
Circuit
+5 VDC
2SK1388
1.5 VDC
+5 VDC
+12 VDC
Regulator
VID0
Circuit
VID1
VID2
VID3
VID4
VID4..0 VccP
11000 2.7 VDC
11001 2.6 VDC
11010 2.5 VDC
11011 2.4 VDC
11100 2.3 VDC
11101 2.2 VDC
11110 2.1 VDC
11111 CPU not installed
Compaq Deskpro 4000 and 6000 Personal Computers
First Edition - October 1997
Technical Reference Guide
VTT (+1.5 VDC)
VccP
VID4..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
00110-01111 Reserved
featuring the Pentium II Processor
Microprocessor
To
Pentium II
Processor
7-5