IW1706 Datasheet, PDF (1/11 Pages) Dialog Semiconductor – Low-Power Off-Line Digital Green-Mode PWM Controller

iW1706
Low-Power Off-Line Digital Green-Mode PWM Controller
1.0 Features
2.0 Description
●● Primary-side feedback eliminates opto-isolators and
simplifies design
●● Adaptively controlled soft start-up enables fast and
smooth start-up for a wide range of capacitive loads
(from 330 μF to 6000 μF)
●● Very tight constant voltage regulation
●● EZ-EMI ^® design enhances manufacturability
●● Intrinsically low common mode noise
●● Optimized 72 kHz maximum PWM switching frequency
achieves best size and efficiency
●● Adaptive multi-mode PWM/PFM control improves
efficiency
●● Quasi-resonant operation for highest overall efficiency
●● Direct drive of low-cost BJT switch
●● Dynamic base current control
●● No external compensation components required
●● Complies with EPA 2.0 energy-efficiency specifications
with ample margin
●● Built-in short circuit protection and output overvoltage
protection
The iW1706 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 iW1706 features a distinctive
soft-start scheme, which allows for fast and yet smooth
start-up with both small and large capacitive loads. The
iW1706 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 the iW1706 can achieve both
highest average efficiency and fast yet smooth start-up with
a wide range of capacitive loads, and are ideal for network
power adapter applications.
●● Built-in current sense resistor short circuit protection
●● Constant current control enables output current limit and
overload protection
●● No audible noise over entire operating range
3.0 Applications
●● Network power adapters for ADSL, wireless access
points, routers.
L
+
N
+
V_OUT
GND
U1
iW1706
1 V_CC
OUTPUT 5
2 GND
3 ^VSENSE
I_SENSE 4
Figure 3.1: iW1706 Typical Application Circuit
Rev. 1.1
iW1706
February 1, 2012

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