HP MAY21J8412 7.2.2 SFF/MT/CMT Power Distribution

Power and Signal Distribution

7.2.2 SFF/MT/CMT Power Distribution

The SFF, MT, and CMT systems use a common power source power supply unit contained within the system chassis. Figure 7-2 shows the block diagram for power distribution for SFF/MT/CMT form factors.

Front Bezel

System Board

Power Button

Power Control Logic, DC/DC Converter

Power On

& Voltage Regulators

P1

P2

P3

+12 Vmain

+12 Vsb

-12 V

PS

Fan

Fan

Pwr

+12 Vcpu

On

Cmd

Spd

Good

90 - 264 VAC Power Supply Unit

NOTE: Return (RTN or ground) not shown.

Conn	Pin 1	Pin 2	Pin 3	Pin 4	Pin 5	Pin 6
P1	RTN	RTN	–12 V	+12 Vmain	+12 Vmain	+12 Vsb
P2	FANcmd	Fan Speed	PS On	Pwr Good	Rsvd	Rsvd
P3	RTN	RTN	+12 Vcpu	+12 Vcpu

NOTES:

Connectors not shown to scale.

All + and – values are VDC.

Rsvd= Reserved

RTN = Return (signal ground)

P3

3 4

1 2

P2

6 5 4 3 2 1

P1

46

1 3

Figure 7-2. SFF/MT/CMT Power Distribution and Cabling, Block Diagram

The +12Vsb (auxilary) voltage is always produced by the power supply unit as long as the system is connected to a live AC source. When the PS On signal is asserted, the power supply unit produces the +12 Vmain, +12 Vcpu, and -12 V outputs.

The standard 240-watt and 320-watt power supplies have a 70% minimum efficiency rating at 100% of the rated load, measured while operating from 100 VAC @60 Hz and 230 VAC @ 50 Hz.

The optional 80Plus Gold-rated high-efficiency 240-watt and 320-watt power supplies operate at the following efficiencies while operating from 100 VAC @60 Hz and 230 VAC @ 50 Hz :

100% of rated load: 87% efficient

50% of rated load: 90% efficient

20% of rated load: 87% efficient

Technical Reference Guide www.hp.com 7-3