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Dear Sir/Madam
Power over Ethernet (PoE) and bringing the power close to its
load (PoL) are two trends in power electronics and power supply.
This newsletter contains some more information for you – Enjoy!
Wolfgang Patelay
Technical Editor, EPN
DC/DC Stepdown Converters (ON Semiconductor)
The NCP1521 and NCP1522 600mA DC/DC stepdown converters are
optimised for portable applications powered from one-cell Li-Ion
or three-cell Alkaline/NiCd/NiMH batteries. The devices include
integrated soft-start, cycle-by-cycle current limiting, and
thermal-shutdown protection.
Click here
Voltage-Supervisor Chips (Intersil)
The ISL88011-ISL88015-family offers both fixed and/or
adjustable voltage-monitoring with all the functions for critical
monitoring, including power-on reset control, customisable
supply-voltage supervision, watchdog-timer capability and manual
reset. By integrating all of these features into a 5-pin SOT23
package and requiring only 5.5µA of supply current, the family can
help reduce system cost and board space.
Click here
High-Voltage Capacitors (AVX)
AVX has expanded its Flexiterm series of capacitors
with a high-voltage MLC chip in case sizes from 1,206 to 2,220 for
applications requiring 600 to 3,000V. The capacitor provides high
value, low leakage and small size in a rugged package that will not
crack under extreme board flexure or temperature-damage cycle
conditions.
Click here
PoL
Management Devices (Freescale)
In the race for high-performance applications,
today's systems put more and more challenges on power supplies.
New requirements comprise accurate operating-voltage regulation,
low operating voltage, high current, fast transient response,
and multiple voltages. Putting the power supply close to its
load (i.e. PoL) can address the new challenges. Freescale has
developed a family of PoL power-management devices to address
this market, namely MC34701, MC34702 and MC34703.
Click here
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Fluorescent-Lamp Ballast Controller for T4/T5 Lamps
The new generation of fluorescent lamps of the T4 and T5 type is
optimised for high efficiency. In order to function over a
lifetime, they require a specific, more complex start-up
procedure and intensive monitoring of the operating behaviour
compared to the older lamp T8 and T12 types. The controller IC
described by Michael Herfurth
from Infineon in his article offers optimised functionality for
this new generation of lamps,.
Click
here
Designing PoE-Powered Devices: Ensure Compliance Today
The IEEE 802.3af standard for Power-over-Ethernet (PoE)
describes how to distribute up to 12.95W today over Ethernet's CAT-5
cable so network devices can operate without an AC power cord. To
help designers meet the requirements of their application as well as
requirements of 802.3af compliance and interoperability, this
article by Todd Nelson, Dave Dwelley and Jacob Herbold from Linear
Technology presents many of the challenges facing a PD design and
uses an example circuit to illustrate possible solutions.
Click here
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Tapped inductor, boost regulator deliver high voltage
When you face the task of generating a regulated voltage that's
higher than the available power-supply voltage, you may consider
a boost regulator. Although a boost converter can in theory
generate almost any voltage that's higher than its input,
practical considerations limit the output to approximately eight
times its applied voltage. To generate an even higher voltage,
consider using a tapped-inductor boost topology. This Design
Idea by
David Ng and Adam Huff
from,
Linear Technology
shows an implementation of a converter that boosts a 3V input to
100V dc.
Click here
Low-dropout regulator, SMPS cascade suppress ripple, maintain
efficiency
A
step-down SMPS (switched-mode power supply) efficiently converts
unregulated power to a regulated output voltage. However, unwanted
switching-induced ripple and input transients may appear on the
output. Applying noisy power to an RF power amplifier can inject
spurious signals or modulated noise into the broadcast spectrum. A
low-dropout linear regulator's low output noise and high PSRR
(power-supply rejection ratio) ensure clean power that imposes no
interference on a power amplifier's output.
This Design Idea by Scot Lester, Texas
Instruments, explains why two regulators work better than one
in noise-sensitive applications.
Click here
Sponsor TEXAS INSTRUMENTS
This issue sponsored
by: Texas Instruments
New DC/DC Controller from Texas Instruments Boosts Efficiency:
TI’s TPS40140 dual or two-phase stackable controller turns power
supplies in data center and telecommunication equipment into
fully scalable, stackable power systems with greater load
handling/maximum efficiency. Free samples, more info available.
Click here for more information.
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4| Book of The Month |
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Digital Power Electronics and Applications, by Fang Lin Luo,
Hong Ye and Muhammad Rashid
The purpose of this book is to describe the theory of Digital
Power Electronics and its applications. The authors apply
digital control theory to power electronics in a manner
thoroughly different from the traditional, analog control
scheme.
Click here
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5| Competition |
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Sampling Thermal and Shielding Products
Get your hands on two of Chomerics' sample kits packed with
dozens of different types of thermally conductive compounds and
EMI shielding tapes and gaskets. Delivered in rugged plastic
boxes, the shielding kit and thermal kit, worth 290 and 180
euros respectively, highlight the company's solutions in these
fields. Three pairs of such kits are on offer.
Click here
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EPN and EDN Europe are members of the Reed Electronics Group
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France
Tel- +33 (0) 1 46 29 23 60
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