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LD7523
6/16/2009
Smart Green-Mode PWM Controller with Multiple Protections
REV: 00
General Description Features
The LD7523 is a low startup current, current mode PWM High-Voltage CMOS Process with Excellent ESD
controller with green-mode power-saving operation. The protection
SOP-8/DIP-8 package integrated functions such as the Very Low Startup Current (< 35A)
leading- edge blanking of the current sensing, internal Current Mode Control
Non-audible-noise Green Mode Control
slope compensation, line compensation, and several
UVLO (Under Voltage Lockout)
protection features. The protection functions include
LEB (Leading-Edge Blanking) on CS Pin
cycle-by-cycle current limit, OVP, OLP, and brownout
Internal Slope Compensation
protection. It provides the users a high efficiency, low
Programmable Line Compensation
external component counts solution for AC/DC power OVP (Over Voltage Protection)
applications. OLP (Over Load Protection)
Furthermore, to satisfy various protection requirements, Brownout Protection
Built in OLP De-Latch Timer
both latch-mode protection and auto-recoverable
500mA Driving Capability
protection can be easily achieved by configuring LD7523
on different operation modes. Applications
The special green-mode control is not only to achieve the Switching AC/DC Adaptor and Battery Charger
low power consumption but also to offer a Open Frame Switching Power Supply
non-audible-noise operation when the LD7523 is LCD Monitor/TV Power
operating under light load or no load condition.
Typical Application
AC EMI
input Filter
VCC
OVP
OUT
LD7523
CS
BNO
GND COMP
photocoupler
TL431
1
Leadtrend Technology Corporation www.leadtrend.com.tw
LD7523-DS-00 June 2009
LD7523
Pin Configuration
SOP-8 & DIP-8(TOP VIEW)
GND
OVP
VCC
OUT
8 7 6 5
YY : Year code (D: 2004, E: 2005.....)
TOP MARK WW : Week code
YYWWPP ## : Production code
1 2 3 4
COMP
BNO
CS
NC
Ordering Information
Part number Package TOP MARK Shipping
LD7523 GS SOP-8 Green Package LD7523GS 2500 /tape & reel
LD7523 GN DIP-8 Green Package LD7523GN 3600/tube /carton
The LD7523 is ROHS Complaint/ Green Package.
Pin Descriptions
PIN NAME FUNCTION
Brownout Protection Pin. Connect a resistor divider between this pin and bulk
1 BNO capacitor voltage to set the brownout level and line compensation. When the
voltage of this pin fall below threshold voltage, the PWM output will be shut off.
Voltage feedback pin (same as the COMP pin in UC384X). Connect it with a
2 COMP
photo-coupler to close the control loop and achieve the regulation.
3 NC NC
4 CS Current sense pin, connect to sense the MOSFET current
5 GND Ground
6 OUT Gate drive output to drive the external MOSFET
7 VCC Supply voltage pin
This pin is active-high to provide the OVP function. Connecting a zener or a
resistor voltage divider to Vcc will set the OVP level. Once the voltage rise
8 OVP
above 2.5V, the OVP will be tripped and the gate drive off. Short this pin to
ground to disable the OVP function.
2
Leadtrend Technology Corporation www.leadtrend.com.tw
LD7523-DS-00 June 2009
LD7523
Block Diagram
VCC
Gain
BNO = 0.04
Line
Vref OK
Compensation internal bias
12.75V & Vref PG
/9.75V
1.25V UVLO
/1.10V Brownout Comparator VCC OK
Comparator
OVP 1 = OVP
1 = ACUV
S Q
2.5V 1 = OLP
OVP
Comparator
PG R
OLP
Delay
5.0V De-Latch
OLP Counter
Comparator
Auto Recoverable Protections
65KHz
PG
OSC
Driver
PG
Stage
OUT
Green- Mode
Control
Vbias
S Q
PWM
COMP Comparator
2R R
R
+ Slope
Compensation
Leading +
CS Edge
Blanking +
+ Line
Compensation
0.85V
OCP
Comparator
GND
3
Leadtrend Technology Corporation www.leadtrend.com.tw
LD7523-DS-00 June 2009
LD7523
Absolute Maximum Ratings
Supply Voltage VCC -0.3V~30V
COMP, BNO, CS -0.3V ~7V
OUT -0.3V ~Vcc+0.3V
Maximum Junction Temperature 150