iW1760 Product Brief
Off-Line Digital Green-Mode Quasi-Resonant PWM Controller
1.0 Features 2.0 Description
No-load power consumption < 50mW at 230V along The iW1760 is a high performance AC/DC power supply
AC
with fast dynamic load response and short turn-on delay controller which uses digital control technology to build peak
in typical 20W and above adapter applications current mode PWM flyback power supplies. The device
operates in quasi-resonant mode to provide high efficiency
Primary-side feedback eliminates opto-isolators and
along with a number of key built-in protection features
simplifies design
while minimizing the external component count, simplifying
Adaptively controlled soft-start enables fast and smooth EMI design and lowering the total bill of material cost. The
start-up for a wide range of capacitive loads (from iW1760 removes the need for secondary feedback circuit
330F to 6,000F) with output voltage up to 12V while achieving excellent line and load regulation. It also
eliminates the need for loop compensation components
Tight constant-voltage regulation across line and load
while maintaining stability over all operating conditions.
range
Pulse-by-pulse waveform analysis allows for a loop response
Proprietary optimized 79kHz maximum PWM switching that is much faster than traditional solutions, resulting in
frequency with quasi-resonant operation achieves best improved dynamic load response. The built-in power limit
size, efficiency and common mode noise function enables optimized transformer design in universal
off-line applications and allows for a wide input voltage
User-configurable 5-level cable drop compensation
range.
provides design flexibility
iWatts innovative proprietary technology ensures that
EZ-EMI design enhances manufacturability
power supplies built with the iW1760 can achieve both
Adaptive multi-mode PWM/PFM control improves
highest average active efficiency and less than 50mW no-
efficiency
load power consumption in 20W output power range, and
have fast yet smooth start-up with a wide range of capacitive
No external loop compensation components required
loads with output voltage up to 12V, and are ideal for network
Built-in single-point fault protections against output
and monitor adapter applications.
short-circuit, output over-voltage, output over-current,
and current-sense-resistor-short fault
3.0 Applications
Dedicated pins for external over-temperature protection
Power adapters for network devices and monitors
and over-voltage protection, with latch function available
AC/DC power supplies in home appliances
Tight constant current control enables output current
limit and over-load protection
Universal input AC/DC adapters (15W - 40W)
No audible noise over entire operating range
L
N
V
OUT
+
+
RTN
U1
iW1760
1 V V 8
SENSE CC
+
2 SD GND 7
CFG OUTPUT
3 6
4 5
ASU I
SENSE
R
NTC
CDC
Figure 3.1: iW1760 Typical Application Circuit (Using Depletion Mode N-FET as Active Start-up Device)
(Achieving < 50mW No-load Power Consumption in 20W Adapter Designs)
Rev . 0.3 iW1760 Pgea 1
May 3, 2012iW1760 Product Brief
Off-Line Digital Green-Mode Quasi-Resonant PWM Controller
L
N
V
OUT
+
+
RTN
U1
iW1760
1 8
V V
SENSE CC
+
2 7
SD GND
3 CFG OUTPUT 6
4 5
ASU I
SENSE
R
NTC
CDC
Figure 3.2: iW1760 Typical Application Circuit (Alternative Circuit without Using Active Start-up Device)
Note: Pin 4 (ASU) can be left unconnected if an active start-up device is not needed in the application circuit.
4.0 Pinout Description
iW1760
1 8
V V
SENSE CC
2 7
SD GND
CFG OUTPUT
3 6
4 5
ASU I
SENSE
Figure 4.1: 8 Lead SO-8 Package
Pin # Name Type Pin Description
1 V Analog Input Auxiliary voltage sense (used for primary regulation).
SENSE
External shutdown control. Used for external over-temperature protection (OTP)
2 SD Analog Input
by connecting an NTC resistor from this pin to Ground.
Used for external cable drop compensation (CDC) configuration and
3 CFG Analog Input
supplemental over-voltage protection (OVP).
4 ASU Output Control signal for active start-up device (BJT or depletion mode N-FET).
5 I Analog Input Primary current sense. Used for cycle-by-cycle peak current control and limit.
SENSE
6 OUTPUT Output Gate drive for external MOSFET switch.
7 GND Ground Ground.
8 V Power Input Power supply for control logic.
CC
Rev . 0.3 iW1760 Pgea 2
May 3, 2012