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Switched-mode dimmable LED
drivers are known for their efficiency
and precise control of LED current.
They can also provide dimming
functionality which allows the end
user to create fantastic lighting
effects while reducing their power
consumption.An8-bitmicrocontroller
(MCU) implementation can provide
the necessary building blocks
to create solutions that enable
communications,
customizations
and intelligent control. Additionally,
core
independent
peripheral
integration provides significant
flexibility versus that of pure analog
or ASIC implementation and enables
innovation that expands lighting
product capabilities and provides
product differentiation. Features
such as predictive failure and
maintenance, energy monitoring,
color and temperature maintenance
and remote communications and
control, are just some of the
advanced capabilities that can make
intelligent lighting solutions even
more attractive.
Although LED drivers offer many
advantages over previous lighting
solutions, there are also challenges
in their implementation. But fear
not, by the end of this article you’ll
learn how an 8-bit MCU can be used
to alleviate design challenges and
create high-performance switched-
mode LED driving solutions with
capabilities beyond that of traditional
solutions.
An 8-bit microcontroller can be used
to independently control up to four
LED channels which is something
most off-the-shelf LED driver
controllers cannot provide. In Figure
1, the LED dimming engines can
be created out of the peripherals
available in the microcontroller. Each
of these engines has an independent
closed channel that can control the
switched-mode power converter
with minimal to no central processing
unit (CPU) intervention. This leaves
the CPU free to perform other
important tasks such as supervisory
functions, communications or added
intelligence in the system.
LED DIMMING ENGINE
In Figure 2, the LED driver, which
is based on the Current-Mode
Boost converter, is controlled by
the LED dimming engine. The
engine is mainly composed of core
independent peripherals (CIP) such
as complementary output generator
(COG), digital signal modulator
LED Dimming Engine: An 8-bit MCU-based solution
for a Switched-Mode Dimmable LED driver
Mark Pallones, Microchip Technology Inc.
Automotive
Special Edition
36 l New-Tech Magazine Europe