Specifications

Lighting
LED lighting
www.digikey.com/maxim-industrial 133
than 0.9 power-factor correction
and require a very limited number
of external components. No elec-
trolytic capacitors are required,
which considerably extends the
lifetime of the driver circuit working
in a hot environment. Both the
120VAC/230VAC and 12VAC solutions
employ the MAX16834 IC, and are
available for evaluation and use in
mass production. They are both
proprietary to Maxim, which is the
only supplier to provide this combi-
nation of advantages.
Remote-controlled
applications in street,
parking, and indoor lights
As stated above, LEDs offer more
design flexibility for dimming
and changing the light color. This
versatility makes them ideal for
applications like architectural
lighting, indoor ambient lighting,
and dimmable, energy-efficient
street and outdoor lighting. All these
applications require a technology to
control the LED light remotely. For
the application to be successful in the
marketplace, the cost of upgrading
the lighting infrastructure to new LED
technology must be minimized. Not
surprising, solutions that can reuse
the present infrastructure will likely be
the first to penetrate the market.
When converting to remote-
controlled LED lighting, the most
costly infrastructure upgrade to antici-
pate is the wiring to control the LED
lights. Fortunately, two technologies
can negate the need for that costly
upgrade: LED lamps can be controlled
with a wireless link, or they can be
controlled through existing power
lines using PLC technology.
PLC technology allows communica-
tion over a long range, but this can
be problematic when breakers or
transformers on the AC line do not
allow the communication to flow
freely. While wireless communica-
tions do not have this problem, the
wireless communication range can be
limited if free bands are used. A mix
of both technologies can sometimes
be the best solution: powerline
connections for devices that are
not separated by transformers, and
wireless connections to bypass
transformers.
The main design requirements for
remote-controlled LED lighting
solutions are:
• The communication range, which
is dictated by the application. For
an indoor residential application,
something in the range of 30m is
sufficient. Street lighting can require
a range of several kilometers.
• Low power consumption. An
important selling point of LEDs
is their high energy efficiency.
It is important that an LED lamp
consume the least power possible
when the light is off and only the
communication circuit is active.
• The communication rate. Some
lighting applications require only a
low communication bit rate (i.e., a
few kbps) to control light dimming
and perhaps read possible faults.
Architectural lighting, however,
can sometimes require a high data
rate, even 100kbps. An example
can be a wall-washer application
where many lights are controlled
through a single bus and the colors
change continuously.
LEDs
WIRELESS
DOWNCONVERTER/
RECEIVER
ANTENNA
MICROCONTROLLER
BASEBAND DIGITAL
COMMUNICATION
LED DRIVER
PWM DIMMING
FAULT DETECTION
LED CURRENT CONTROL
LDO
AC-DC POWER
SUPPLY
= MAXIM SOLUTION
Block diagram of a typical wireless-controlled lighting system.
LEDs
BASEBAND CHIP/
MICRO-
CONTROLLER
LED DRIVER
PWM DIMMING
FAULT DETECTION
LED CURRENT CONTROL
AC SUPPLY
LINE
DRIVER
ANALOG
FRONT-
END
AC-DC
CONVERTER
12V/24V/48V SUPPLY
LDO
1.8V/3.3V/5V
SUPPLY
= MAXIM SOLUTION
TRANSFORMER
Block diagram of a typical PLC-controlled lighting system.
For a list of Maxim's recommended LED-lighting solutions, please go to: www.maxim-ic.com/lighting.