IW3620 Datasheet, PDF (1/21 Pages) Dialog Semiconductor – Digital PWM Current-Mode Controller for AC/DC LED Driver

iW3620
Digital PWM Current-Mode Controller for AC/DC LED Driver
1.0 Features
●● Primary-side feedback eliminates opto-isolators and
simplifies design
●● Quasi-resonant operation for highest overall efficiency
●● EZ-EMI ^® design to easily meet global EMI standards
●● Up to 130 kHz switching frequency enables small
adapter size
●● Very tight LED constant current regulation
●● No external compensation components required
●● Built-in output constant-current control with primary-side
feedback for LED driver.
●● Low start-up current (10 µA typical)
●● Built-in soft start
●● Built-in short circuit protection and output overvoltage
protection
●● Current sense resistor short protection
●● Overtemperature Protection
●● Open circuit protection
●● Universal input range from 85 V_ac to 264 V_ac
●● Single-fault protection
●● Small input bulk capacitor
●● Long MTBF
2.0 Description
The iW3620 is a high performance AC/DC offline LED driver
which uses digital control technology to build peak current
mode PWM flyback power supplies. The device operates in
quasi-resonant mode at heavy load to provide high efficiency
along with a number of key built-in protection features while
minimizing the external component count, simplifying EMI
design and lowering the total bill of material cost. The
iW3620 removes the need for secondary feedback circuitry
while achieving excellent line and load regulation. It also
eliminates the need for loop compensation components while
maintaining stability over all operating conditions. Pulse-by-
pulse waveform analysis allows for a loop response that is
much faster than traditional solutions, resulting in improved
dynamic load response. The built-in current limit function
enables optimized transformer design in universal off-line
applications over a wide input voltage range.
3.0 Applications
●● LED lighting
●● High efficiency
L
+
N
V_OUT
+
+
RTN
Optional
NTC
Thermistor
1 NC
V_CC 8
2 V_SENSE OUTPUT 7
3 V_IN
I_SENSE 6
4 SD
GND 5
U1
iW3620
Figure 3.1 : Typical Application Circuit
Rev. 1.8
iW3620
February 1, 2012

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