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In
most modern embedded systems there is more than one supply voltage
necessary. Therefore an advanced power supply and management
system is required. This newsletter will show you some examples.
Enjoy!
Wolfgang
Patelay
Technical Editor, EPN
5V/30mA
boost converter (Fairchild)
Aimed
at use in space-constrained mobile and ultra-portable devices,
the FAN5665 is a high-efficiency 30mA adaptive charge pump boost
converter in a compact 1.21x1.21mm WL-CSP package. For USB-enabled
devices needing a 5V I/O rail, this converter chip provides
an optimal quick-fix solution.
Click
here
AC/DC
power supplies (Micro Power Direct)
The
MPA150x series of power-factor-corrected AC/DC power supplies
provides up to 150W of output power in a very compact 1U height
U-Chassis. Six standard models operate from auto-ranging inputs
of 90 to 132VAC or 180 to 264VAC, providing tightly regulated
single outputs.
Click
here
600W
1/2-brick DC/DC unit (SynQor)
The
PQ60120HZA50 DC/DC converter measures only 61x58.4x10.5mm in
an open-frame format, delivering a regulated output of 12V up
to a maximum rating of 50A from the full telecom input-voltage
range of 35 to 75V. Targeting IBAs (intermediate bus architectures),
the device makes use of the latest high-performance components
to delivers the maximum 50A rating at up to 95% efficiency.
Click
here
Rugged
Li-Ion cell (Saft)
The
VL 25500-125 Li-ion (lithium-ion) cell is capable of operating
at temperatures of up to +125°C, which extends its use into
the design of MWD (measurement while drilling) tools. The lithium
cells are integrated into ruggedised cylindrical MWD battery
systems, known as "Staves", which are then incorporated into
MWD tools.
Click
here
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Generating
multiple supply voltages in a system
Most
systems require more than just one single supply voltage. The
requirements change greatly depending on the application, the
type of loads involved and the level of voltages and power needed.
The questions one hears almost daily show that there is a need
to detail the very basic thoughts behind generating and controlling
multiple supply voltages. This article by Jürgen Kühnel from
National Semiconductor will discuss different scenarios.
Click
here
A
green alternative to batteries
For
many applications, fuel cells are an increasingly attractive
source of power. To improve the overall power system, they can
usefully be combined with ultracapacitors, which help provide
peak power to meet short-term burst power demands. Ultracapacitors'
high power density, excellent efficiency and long operating
life make them a good match to fuel cells. This article by Adrian
Schneuwly from Maxwell Technologies examines how fuel cells
and ultracapacitors can work together, using the example of
electric fork-lift trucks to demonstrate the potential benefits.
Click
here
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Depletion-mode
MOSFET kick-starts power supply
Many
switch-mode power supplies use “kick-start” circuits to initialize
their offline operation. These circuits may be simple resistors,
such as International Rectifier’s IRIS4015, or more complicated
arrangements built with bipolar transistors or MOSFETs. This
Design Idea by Gregory
Mirsky, Milavia International, Buffalo Grove, Illinois, shows
a conventional PFC circuit whose IC initially receives power
from the output through a depletion- mode MOSFET, a DN2470 from
Supertex.
Click
here
Battery
monitor also enables constant-power-boost converter
Some
microcontrollers permit operation below a supply voltage of
3V. This feature allows powering directly from a 3V alkaline
or lithium battery without the voltage drop and leakage current
of a regulator. It is important to monitor the battery voltage
to ensure system integrity, and you can also use this information
for system purposes. The circuit in this Design Idea by Rex
Niven, Forty Trout Electronics, Eltham, Victoria, Australia,
maintains constant power to a white-LED-display backlight by
adjusting the duty cycle of a boost-power converter.
Click
here
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4|
Market Research |
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IP
continues outpacing traditional PBXs
IP
telephony has crossed over from an emerging technology to the
mainstream choice for business voice, reports In-Stat. User
acceptance of IP telephony is high, with sales of IP lines in
the first half of 2007 continuing to solidly outpace those of
traditional lines as the move to IP telephony among businesses
continues, the high-tech market research firm says.
Click
here
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5|
Book of the Month |
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Power
sources and supplies, by Marty Brown
Newnes has worked with Marty Brown, a leader in the field
of power design to select the very best design-specific material
from the Newnes portfolio. Marty selected material for its timelessness,
its relevance to current power supply design needs, and its
real-world approach to design issues. Special attention is given
to switching power supplies and their design issues, including
component selection, minimization of EMI, toroid selection,
and bread-boarding of designs. Emphasis is also placed on design
strategies for power supplies, including case histories and
design examples.
Click
here
Copyright 2008, Reed
Business Information.
EPN and EDN Europe are members of the Reed Electronics Group
Reed Business France - 2 rue Maurice Hartmann, 92133 Issy-les-Moulineaux,
France
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