Flyback Controller. R7731A Datasheet

R7731A Controller. Datasheet pdf. Equivalent

R7731A Datasheet
Recommendation R7731A Datasheet
Part R7731A
Description Burst Triple Mode PWM Flyback Controller
Feature R7731A; R7731A Burst Triple Mode PWM Flyback Controller General Description The R7731A is a high-performan.
Manufacture Richtek Technology
Datasheet
Download R7731A Datasheet




Richtek Technology R7731A
R7731A
Burst Triple Mode PWM Flyback Controller
General Description
The R7731A is a high-performance, low cost, low start-up
current and current mode PWM controller with burst triple
mode to support green mode power saving operation. The
R7731A integrates functions of soft start, Under Voltage
LockOut (UVLO), Leading Edge Blanking (LEB), Over
Temperature Protection (OTP) and internal slope
compensation. It provides the users a superior AC/DC
power application of higher efficiency, low external
component counts and lower cost solution.
To protect the external power MOSFET from being
damaged by supply over voltage, the R7731A output driver
is clamped at 12V. Furthermore, R7731A features fruitful
protections like Over Load Protection (OLP) and Over
Voltage Protection (OVP) to eliminate the external
protection circuits and provide reliable operation. R7731A
is available in SOT-23-6 and DIP-8 packages.
Ordering Information
R7731A
Package Type
E : SOT-23-6
N : DIP-8
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
Features
z Very Low Start-up Current (<30μA)
z 10/14V UVLO
z Soft Start Function
z Current Mode Control
z Jittering Switching Frequency
z Internal Leading Edge Blanking
z Built-in Slope Compensation
z Burst Triple Mode PWM for Green-Mode
z Cycle-by-Cycle Current Limit
z Feedback Open Protection
z Over Voltage Protection
z Over Temperature Protection
z Over Load Protection
z Soft Driving for Reducing EMI
z Driver Capability ±200mA
z High Noise Immunity
z Opto-Coupler Short Protection
z RoHS Compliant and Halogen Free
Applications
z Adaptor and Battery Charger
z ATX Standby Power
z Set-Top Box (STB)
z DVD and CD(R)
z TV/Monitor Standby Power
z PC Peripherals
Marking Information
R7731AGE
IDP=W
IDP= : Product Code
W : Date Code
R7731AGE
RichTek
R7731A
GNYMDNN
R7731AGN : Product Number
YMDNN : Date Code
R7731A-10 August 2011
www.richtek.com
1



Richtek Technology R7731A
R7731A
Pin Configurations
GATE VDD CS
654
23
GND COMP RT
SOT-23-6
Typical Application Circuit
AC Mains
(90V to 265V)
(TOP VIEW)
RT VDD
R7731A
COMP
GATE
GND
CS
GND COMP NC RT
87
65
2 34
GATE VDD NC CS
DIP-8
VO+
VO-
*
* : See Application Information
Functional Pin Description
Pin No.
SOT-23-6 DIP8
Pin Name
Pin Function
1
8
GND
Ground.
Comparator Input. By connecting an opto-coupler to this pin, the peak
2 7 COMP
current set point is adjusted accordingly to the output power requirement.
3
5 RT
Set the switching frequency by connecting a resistor to GND.
4
4 CS
Primary Current Sense.
5 2 VDD IC Power Supply.
6 1 GATE Gate Driver Output to drive the external MOSFET.
--
3, 6 NC
No Internal Connection.
www.richtek.com
2
R7731A-10 August 2011



Richtek Technology R7731A
Function Block Diagram
R7731A
COMP
CS
Brown out
sensing
COMP open
sensing
OLP
Constant
Power
LEB X3
Shutdown
Logic
OTP
POR
OVP
+
-
27V
+
UVLO -
14V/10V
Counter
Bias &
Bandgap
SS
Slope
Ramp
Jittering Oscillator
Dmax
-
-
+
PWM
comparator
S
Q
R
Soft
Driver
Burst
Triple Mode
COMP
VBURL
VBURH
VDD
VDD
RT
GATE
GND
R7731A-10 August 2011
www.richtek.com
3







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