IW1698 Datasheet, PDF (1/11 Pages) Dialog Semiconductor – Low-Power Off-line Digital Green-Mode PWM Controller

iW1698
Low-Power Off-line Digital Green-Mode PWM Controller
1.0 Features
●● Primary-side feedback eliminates opto-isolators and
simplifies design
●● No-load power consumption < 30 mW at 230 V_ac with
typical application circuit (5 star rating)
●● Adaptive multi-mode PWM/PFM control improves
efficiency
●● Quasi-resonant operation for highest overall efficiency
●● EZ-EMI ^® design to easily meet global EMI standards
●● Direct drive of low-cost BJT switch
●● Dynamic base current control
●● Very tight constant voltage and constant current
regulation with primary-side-only feedback
●● No external compensation components required
●● Complies with EPA 2.0 energy-efficiency specifications
with ample margin
●● Low start-up current (8 μA typical)
●● Built-in soft start
●● Built-in short circuit protection and output overvoltage
protection
●● Built-in current sense resistor short circuit protection
●● No audible noise over entire operating range
2.0 Description
The iW1698 is a high performance AC/DC power supply
controller which uses digital control technology to build peak
current mode PWM flyback power supplies. The device
directly drives a power BJT and operates in quasi-resonant
mode 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 iW1698 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 power limit function enables optimized transformer
design in universal off-line applications and allows for a wide
input voltage range.
iWatt’s innovative proprietary technology ensures that power
supplies built with iW1698 can achieve both highest average
efficiency and less than 30 mW no-load power consumption
with typical application circuit.
3.0 Applications
●● Low power AC/DC adapter/chargers for cell phones,
PDAs, digital still cameras
●● Linear AC/DC replacement
L
+
N
+
V_OUT
GND
U1
iW1698
1 V_CC
OUTPUT 5
2 GND
3 ^VSENSE
I_SENSE 4
Rev. 1.2
Figure 3.1: iW1698 Typical Application Circuit (Achieving < 30 mW No-load Power Consumption)
iW1698
February 6, 2012
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