IW1696 Datasheet, PDF (1/11 Pages) Dialog Semiconductor – Low-Power Off-line Digital Green-Mode PWM Controller

iW1696
Low-Power Off-line Digital Green-Mode PWM Controller
1.0 Features
●● Primary-side feedback eliminates opto-isolators and
simplifies design
●● 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
●● Able to meet < 30 mW no load power consumption
●● Low start-up current (10 μA typical)
●● Built-in soft start
●● Built-in short circuit protection and output overvoltage
protection
●● Built-in current sense resistor short protection
●● No audible noise over entire operation range
2.0 Description
The iW1696 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 iW1696 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 overall
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.
The ultra-low start-up power and operating current at light
load ensure that the iW1696 is ideal for applications targeting
the newest regulatory standards for average efficiency.
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
iW1696
1 V_CC
OUTPUT 5
2 GND
3 V_SENSE
I_SENSE 4
Figure 3.1: iW1696 Typical Application Circuit
Rev. 2.0
iW1696
February 13, 2012

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