Specifications

APPLICATION SPOTLIGHT
16
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LED controller with hysteretic-mode control enhances transient
response, simplifies design
Driver boosts CFL performance for next-generation energy-saving
lighting
Micrel
Semiconductor
The Micrel Semiconductor MIC3203
LED-driver controller targets lighting
applications characterised by load and
line variations that demand fast transient
response and a wide input-voltage range.
The driver accepts input voltages from 4.5V
to 42V and generates the gate-drive signal for
The NXP Semiconductors UBA2028 is a
highly integrated driver for dimmable
Compact Fluorescent Lamps (CFLs),
enabling lamp producers to
deliver more consumer-friendly
CFLs offering improved light
quality, faster warm-up,
improved dimming
and longer product
lifetimes.
The UBA2028 enables designers to
respond to market demands for better quality,
functionality and performance from CFL lamps.
By delivering an integrated chip solution to
replace standard discrete implementations
in electronic ballasts, it supports more
compact designs offering highly efficient
power conversion and extended CFL lifetimes
beyond 15,000 hours. On-chip features include
an external power MOSFET, allowing use in a
wide range of applications from low-voltage
lighting to line-powered incandescent-bulb
replacement.
The hysteretic-mode control scheme
employed uses an error comparator,
instead of an error amplifier, to
maintain the inductor current within
a desired window. This eliminates
the need for an oscillator and loop
compensation, thereby allowing
fast response to transients, reducing
component count, and simplifying
design. The MIC3203 also eliminates
any potential for instability since loop
compensation is not required.
The MIC3203 is able to regulate the
LED-driving current within ±5% of the target
value throughout variations in input voltage
and load conditions. The drive current is set by
connecting a high-side current-sensing resistor
to the current-sense input.
A dedicated pin is provided for PWM dimming,
allowing brightness control from 1% to 99%.
FEATURES:
 Peak eciency over 90%
 1μAshutdowncurrent
 8-pin SOIC package
 Operating temperature range:
-40°C to 125°C
 Over-temperature shutdown protection
 Adjustable constant LED current
FEATURES:
 Peak eciency over 90%
 1μAshutdowncurrent
 8-pin SOIC package
 Operating temperature range:
-40°C to 125°C
 Over-temperature shutdown protection
 Adjustable constant LED current
APPLICATIONS:
 Architectural and industrial lighting
 MR16 bulb replacement
 Automotive exterior and interior lighting
 Indicators and emergency lights
 12V lighting systems
APPLICATIONS:
 280mA maximum steady-state current
 1.5A maximum ignition current
 Adjustable preheat time and preheat current
 Single ignition attempt
 Adaptive non-overlap time control
NXP
Semiconductors
a 600V Metal-Oxide- Semiconductor Transistor
(MOST) half-bridge power circuit, a dimming
function, a high-voltage level-shift circuit, an
oscillator function, lamp-voltage monitoring,
current-control circuitry, a timer function and
protection features.
In addition, the UBA2028 provides
true dimming capabilities.
This results in a smoother
dimming experience with no
flickering or noise, and allows
an unprecedented dimming
range down to 10% of full light
intensity. A power-down function is
also available.
Overall, the advanced features of the
UBA2028 will enable CFL lamps to deliver
performance indistinguishable from that of
incandescent bulbs, allowing consumers to
take advantage of the energy savings offered
by CFLs without sacrificing quality of light.
A separate Enable pin gives the flexibility to
enable or disable the output independently.
The device switches at up to 1.5MHz, allowing
the use of small external components, and
features frequency dither to minimise EMI. A
dither-disabled version, the MIC3203-1, is also
available in the same package style.
FAX
[phone]
EMAIL
ftm.asia
@
futureelectronics.com
Reader Response No.
22
FAX
[phone]
EMAIL
ftm.asia
@
futureelectronics.com
Reader Response No.
23