IW1690 Datasheet, PDF (1/13 Pages) Dialog Semiconductor – Low-Power Off-line Digital PWM Controller

iW1690
Low-Power Off-line Digital PWM Controller
1.0 Features
2.0 Description
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Primary-side feedback eliminates opto-isolators and
simplifies design
Direct drive of BJT switching device
Multi-mode operation for highest overall efficiency
Built-in cable drop compensation
Very tight output voltage regulation
No external compensation components required
Complies with CEC/EPA no load power consumption
The iW1690 is a high performance AC/DC power supply
controller which uses digital control technology to build peak
s _{current mode PWM flyback power supplies. The device}
directly drives a BJT switching device and provides high
n _{efficiency along with a number of key built-in protection}
ig ^{features while minimizing the external component count,}
simplifying EMI design and lowering the total bill of material
s cost. The iW1690 removes the need for secondary
feedback circuitry while achieving excellent line and load
e _{regulation. It also eliminates the need for loop compensation}
D ^{components while maintaining stability over all operating}
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and average efficiency regulations
Built-in output constant-current control with primary-side
w _feedback
e Low start-up current (10 µA typical)
Built-in soft start
N _{Built-in short circuit protection and output overvoltage}
r _protection
o _{Optional AC line under/overvoltage protection}
F _{Fixed switching frequency: 45 kHz, 65 kHz or 75 kHz}
Dynamic base current control
d _{PFM operation at light load}
de ^{Built-in current sense resistor short protection}
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 iW1690 is ideal for applications targeting
the newest regulatory standards for average efficiency and
standby power.
3.0 Applications
• Low power AC/DC adapter/chargers for cell phones,
PDAs, digital still cameras
• Low power AC/DC adapter/chargers to replace RCC
implementations
en ^L
N
m⁺
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V_OUT
Not
Recom
1 V_SENSE
V_CC 8
2 V_IN
OUTPUT 7
3 R_IN
4 I_BC
I_SENSE 6
GND 5
U1
GND
iW1690
Figure 2.0.1 iW1690 Typical Application Circuit
Rev. 1.8
iW1690
February 3, 2012

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