Q17
|
What' forward converter ?
|
A DC to DC converter topology. First-tier PC makers required
superior circuit design. Outperforms traditional half-bridge
design in terms of reliability and efficiency.
Q18
|
The difference between Forward converter and half bridge circuit design.
|
|
Forward
Converter Design
|
Traditional
Half-Bridge Design
|
Converter type
|
A DC to DC converter topology,
similar to flyback converter but the forward converter
stores energy in the output inductor instead of
the transformer.
|
A DC to DC converter topology
(configuration) employing four active switching
components in a bridge configuration across a power
transformer. |
Key component
|
Power MOS |
Bipolar transistor, a transistor
which operates by the action of minority carriers
across a P/N junction; and is a current controlled
device as opposed to a voltage controlled device. |
Control mode
|
Current mode, a control method
for switch-mode converters where the converter adjusts
its regulating pulsewidth in response to measured
output current and output voltage, using a dual
loop control circuit. Since output current is measured,
current mode control allows accurate sharing between
power supplies. |
Voltage mode, a method of closed
loop control of a switching converter where the
pulse width is varied in response to changes in
the output voltage to regulate the output. |
Switching frequence (The rate
at which the DC voltage is switched on and off during
the pulse width modulation process in a switching
power supply.)
|
100KHz |
32KHz |
Operating temperature
|
Power MOS with good stability
in high temperature |
Bipolar transistor doesn't with
good stability in high temperature |
Reliability
|
Better MTBF (Mean Time Between
Failures, may be calculated or demonstrated. The
usual calculation is per Mil-Std 217 rev E. Demonstrated
reliability is usually determined by temperature
accelerated life testing. Demonstrated MTBF is almost
always greater than calculated MTBF., due to the
compact design, reduced components count, and application
of high reliability components ( power MOS and IC)
|
Normal |
Power Factor
|
The ratio of true power to apparent
power in an AC circuit. In power conversion technology,
power factor is used in conjunction with describing
the AC input current to the power supply. |
Q19
|
What's Seasonic Dr. Cable?
|
It's a cable management kit that applies to power supplies.
Customers could get it free in Seasonic V8-300 retail
package. Dr. cable includes split tube / cable tie to
make your PC clean & neat , trim trouble wires quickly,
clean layout for locating connectors easily, and smooth
air flow to reduce thermal problems.
Magic bracket is an all-in one magic bracket designed
by Seasonic. Customers get it free from Seasonic Super
Versatile retail package. Super Versatile series is developed
as a total solution to the Micro ATX requirements. Mounting
a customized adapter bracket, the Super Versatile can
be converted a PS/2 or PS/3 form factor. The magic bracket
can applied to even more OEM systems to allow your OEM
PC upgrading simpler than ever.
Q21
|
The heavier the PSU the better?
|
Many users ever heard that the heavier the power supply
the better. Is this theory correct or not? Let us discuss
this topic from both theoretical and practical viewpoints.
Theoretical speaking, it’s true
under following conditions:
|
1.
|
all with the same
DC output wattage |
|
2.
|
all apply the same circuit design |
|
3.
|
all adopt the same
raw materials |
|
4.
|
all with the same product characteristics
and functions |
Once users known all above conditions, they don’t need
to judge a power supply by its weight. That’s right, and
that’s why we say it theoretically works.
How these conditions affect the
weight of a power supply?
|
1.
|
Output wattage:
Power supplies with different total output wattage
need different level of components. So we could
never compare the weight of a 400W power supply
with a 300W one. |
|
2.
|
Circuit design:
As all other electronic products, to achieve the
same feature the simpler the circuit design, the
better. It’s the same logic that the compact the
better program because it can reduce the possibility
of bugs and speed up calculation. Because a compact
circuit design is with relatively lighter weight,
the standpoint of ''heavier is better'' could not
work. |
|
3.
|
Raw materials: It’s
the major factor of the weight of a power supply.
Due to limitation of the space of the power supply,
the circuit design can’t influence the weight too
much. On the other hand, the raw materials in power
supply play a critical role. Let’s take following
major components for example: |
| |
A.
|
Power supply case: it is made by different
steel and most of them is heavy. The job of a case
is to protect your power supply, so it couldn’t
be too thin. However, an overweight case could cause
power supply crush during transportation. |
| |
B.
|
Heat sink: Due to its size, heat sink
is the first thing that comes to your eyes after
opening the power supply. The duty of a heat sink
is to release heat. Actually it’s the surface of
a heat sink matter, not the size. You can image
the larger size of the heat sink, the less room
left for other components, and less functions are
able to apply on the power supply. However, a power
supply with high efficiency runs efficiently, releases
less heat, and need no such large heat sink to solve
thermal problem. Yes, then you may understand how
complicated the question is. |
| |
C.
|
Heavyweight components: some components
are much heavier than others. But is it means better
performance? Not really. For example, comparing
a power supply with passive PFC to the one active
PFC, you may find the Active PFC solution is much
lighter than the passive one. Because the Active
PFC is composed by small ICs while the passive PFC
is made by huge and heavy chock whose size and weight
should increase as the power goes up. |
|
4.
|
Product characteristics
and functions: Different characteristics and functions
are made by different circuit designs and raw materials,
which will result in different weights. |
In conclusion, to judge the performance of a power supply
by weight is not a good choice. Previously experts suggested
this simple method because at that time most power supplies
were designed under similar circuit design and applied
similar raw materials. Nowadays, however, due to technology
progresses, this method becomes out-of-day and not that
feasible.
Q22
|
Connector introduction.
|
Power Supply connectors configuration
|
Photo
|
Connectors |
Description
|
|
P8/P9 |
The P8/P9 power connectors (sometimes
also called P1/P2) that connect an AT/LPX power
supply to the motherboard. |
|
20Pin |
The industry standard ATX power-supply–to–motherboard
main connector. It first used in the ATX form factor
power supply, it also is used in the SFX form factor
or any other ATX-based variations. |
|
6 Pin
(ATX Auxiliary Power Connector) |
As motherboards and processors
evolved, the need for power became greater. Eventually,
the high current demands on the +3.3v and +5v outputs
were proving too much for the number and gauge of
the wires used.Finally, Intel modified the ATX specification
to add a second power connector for ATX motherboards
and supplies. The criteria was that if the motherboard
needed more than 18A of +3.3v power, or more than
24A of +5v power, an auxiliary connector would be
defined to carry the additional load. These higher
levels of power are normally necessary in systems
using 250-watt to 300-watt or greater supplies. |
|
3 Pin Fan M connector |
The FanM signal enables the
operating system to monitor the status of the power
supply's cooling fan so that it can take appropriate
actions, such as shutting down the system if the
fan fails. |
|
Peripheral and Floppy Drive
Power Connectors (FDD&HDD) |
In addition to the motherboard
power connectors, power supplies include a variety
of peripheral power connectors for everything from
floppy and hard drives to internal case fans Early
power supplies featured only two large style drive
connectors. Later power supplies featured four or
more of the larger peripheral (drive) connectors
and one or two of the smaller 3 1/2'' floppy drive
connectors. Depending on power ratings and intended
uses, some supplies have as many as eight peripheral/drive
connectors. |
|
4 Pin(ATX12V Connector) |
To augment the supply of +12v
power to the motherboard, Intel created a new ATX12V
power supply specification. This adds a third power
connector, called the ATX12V connector, specifically
to supply additional +12v power to the board. |
|
24 Pin/8 Pin (EPS12V Connector) |
24/8Pin are Server Power Supply Connectors which
is compatible with Intel SE7500CW2, S845WD1-E,
Super Micro Server Boards or Iwill DP533...etc.
the 24 Pin function is as like ATX 20Pin to motherboard
main connector. The 8 Pin function is as like
ATX 4Pin to supply additional +12v power to the
board.
|
Q23
|
Phased-out product replacement list |
Seasonic phased out products
list
|
Type
|
Model
Name
|
Replacement
|
|
Mini Size
|
SSA-40XXY
|
No,the models are out-of-warranty
with no known replacements. |
|
AT
|
SSG-XXXG
|
SS-XXXFS + 20-pin
ATX connector to P8/P9 AT connectors (includes switch).
|
|
AT
|
SSH-200G
|
No,the models are out-of-warranty
with no known replacements. |
|
AT
|
SSH-xxxG
|
SS-XXXFS + 20-pin
ATX connector to P8/P9 AT connectors (includes switch).
|
|
Big AT
|
SSH-xxxA
|
No,the models are out-of-warranty
with no known replacements. |
|
ATX
|
SS-XXXGPX(APX)
|
SS-XXXFS |
|
ATX
|
SS-XXXGPX for UMAX
|
SS-XXXFS+20-pin ATX connector to
Umax GPX adapter |
|
ATX
|
SS-XXXGPX(APX)Rev.C
|
SS-XXXFS |
|
ATX
|
SS-XXXGTX
|
SS-XXXFS |
|
ATX
|
SS-XXXATX
|
SS-XXXFS |
|
ATX
|
SS-XXXPS
|
SS-XXXFS |
The -5V DC output is took off from Intel ATX12V design
guide since the 1.2 version. The reasons including:
|
1.
|
The -5V usage was for last generation ISA slot.
But the old ISA had been phased out since 1993~1994. |
|
2.
|
Neither P3 nor P4 systems will need -5V output.
|
Intel didn't immediately remove -5V from their design
guide in order to keep the highest compatibility among
all ATX. After more than 5 year watching and the discussion
with major PSU manufacturers since year 2000, now Intel
is confident with this change, even taking replacement
application into consideration. No wonder for newer form
factors such as SFX and flex ATX, no -5V is required since
the first version of design guide.
Q25
|
Form Factor introduction.
|
|
Modern
PS Form Factors
|
Originated
From
|
Connector
Type
|
Associated
MB Form Factors
|
LPX style*
|
IBM PS/2 Model 30
(1987) |
AT
|
Baby-AT, Mini-AT,
LPX |
ATX style
|
Intel ATX, ATX12V (1985/2000)
|
ATX
|
ATX, NLX, Micro-ATX |
SFX style
|
Intel SFX (1997)
|
ATX |
Flex-ATX, Micro-ATX |
Data refer to http://www.informit.com
|
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