R7731
Burst Triple Mode PWM Flyback Controller
General Description
Features
Very Low Start-Up Current (<30μA)
10/14V UVLO
The R7731 is a high performance, low cost, low start-up
current, current mode PWM controller with burst triple
mode to support green mode power saving operation. The
R7731 integrates functions of Soft-Start, Under Voltage
Lockout (UVLO), Leading Edge Blanking (LEB), Over
Temperature Protection (OTP), internal slope
compensation. It provides the users a superior AC/DC
power application of higher efficiency, low external
component counts and lower cost solution.
Soft-Start Function
Current Mode Control
Jittering Switching Frequency
Internal Leading Edge Blanking
Built-in Slope Compensation
Burst Triple Mode PWM for Green-Mode
Cycle-by-Cycle Current Limiting
Feedback Open Protection
Output Over Voltage Protection
Over Temperature Protection
Over Load Protection
To protect the external power MOSFET from being
damaged by supply over voltage, the R7731 output driver
is clamped at 12V. Furthermore, R7731 features fruitful
protections like OLP (Over Load Protection) ,OVP (Over
Voltage Protection) to eliminate the external protection
circuits and provide reliable operation. R7731 is available
in SOT-23-6 andDIP-8 packages.
Soft Driving for Reducing EMI
High Noise Immunity
Opto Coupler Short Protection
RoHS Compliant and Halogen Free
Applications
Adaptor and Battery Charger
ATX Standby Power
Set Top Boxes (STB)
DVDand CD(R)
TV/Monitor Standby Power
PC Peripherals
Typical Application Circuit
VO+
AC Mains
(90V to 265V)
VO-
RT
VDD
R7731
COMP
GATE
CS
GND
DS7731-03 March 2011
www.richtek.com
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