ISL1903 Datasheet, PDF (1/19 Pages) Intersil Corporation – Dimmable Buck LED Driver - AC Mains or DC Input LED Driver

Dimmable Buck LED Driver - AC Mains or DC Input LED
Driver
ISL1903
The ISL1903 is a high-performance, critical conduction mode
(CrCM), single-ended buck LED driver controller. It may be used
with DC input converters, but also supports single-stage
conversion of the AC mains to a constant current source with
power factor correction (PFC). The ISL1903 supports buck
converter topologies, such as isolated forward converters or
non-isolated source return buck converters. Operation in CrCM
allows near zero-voltage switching (ZVS) for improved
efficiency while maximizing magnetic core utilization.
The ISL1903 is compatible with both leading and trailing edge
modulated AC mains dimmers. It provides all of the features
required for high-performance dimmable LED ballast designs.
Applications
• Industrial and commercial LED lighting
• Retrofit LED lamps with triac dimming
• Universal AC mains input LED retrofit lamps
• AC or DC input LED ballasts
Features
• Excellent LED current regulation over line, load, and
temperature
• 0 - 100% dimming with leading-edge (triac) and
trailing-edge dimmers
• Power factor correction for up to 0.995 power factor and
less than 20% harmonic content
• Critical conduction mode (CrCM) operation for
quasi-resonant high efficiency performance
• Supports Universal AC Mains Input
• Configurable for PWM or DC current dimming control of
LEDs
• Monitors FET switching current for load regulation
• Supports isolated and non-isolated buck topologies
• Closed loop soft-start for no overshoot
• OFFREF feature to set dimming off-point to improve fixture
performance matching
• -40°C to +125°C operation
• Pb-free (RoHS compliant)
EMI Filter
AC Mains
1
VDD
14 DHC
5
CS+
AC 12
OUT 16
ISL1903
8 DELADJ
OC 6
13 GND
VERR 9
3 VREF
RAMP
10
FB 7
IOUT
4
100
90
80
70
60
50
40
30
20
10
0
100 90 80 70 60 50 40 30 20 10 0
CONDUCTION ANGLE (%)
FIGURE 1A. BOOST-RETURN (BUCK) TOPOLOGY
FIGURE 1B. CURRENT vs AC CONDUCTION ANGLE
FIGURE 1. ISL1903 APPLICATION PERFORMANCE
September 20, 2012
1
FN8285.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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