LD7750B
9/19/2011
High Voltage Green-Mode PWM Controller with
Over Temperature Protection
Rev. 00
General Description
The LD7750B integrates several functions of protections,
and EMI-improved solution in a tiny package to minimize
the component counts and the circuit space.
The device provides functions of low startup current,
green-mode
compensation.
Voltage
power-saving
operation,
leading-edge
blanking of the current sensing and internal slope
Also, the LD7750B features more
and
OTP
(Over
Temperature
protections like OLP (Over Load Protection), OVP (Over
Protection),
Protection) to prevent the circuit being damaged under
abnormal conditions.
Furthermore, the LD7750B features frequency swapping
to depress radiation noise, providing an excellent solution
for EMI filter design.
Features
High-Voltage (500V) Startup Circuit
Current Mode Control
Green Mode Control
UVLO (Under Voltage Lockout)
LEB (Leading-Edge Blanking) on CS Pin
Internal Frequency swapping
Internal Slope Compensation
Internal Over Current Protection
OVP (Over Voltage Protection) on Vcc
OLP (Over Load Protection)
External OTP through a NTC
500mA Driving Capability
Applications
Switching AC/DC Adaptor and Battery Charger
Open Frame Switching Power Supply
LCD Monitor/TV Power
Typical Application
AC
input
EMI
Filter
*
HV VCC OUT
OTP
LD7750B
CS
GND
COMP
*
photocoupler
1
Leadtrend Technology Corporation
LD7750B-DS-00
September 2011
www.leadtrend.com.tw
LD7750B
Pin Configuration
SOP-7 (TOP VIEW)
VCC
OUT
HV
SOP-8/ DIP-8 (TOP VIEW)
OUT
5
8
6
5
8
7
VCC
6
NC
HV
TOP MARK
YYWWPP
1
2
3
4
1
TOP MARK
YYWWPP
2
3
4
YY:
WW:
PP:
Year code
Week code
Production code
OTP
COMP
GND
CS
CS
Ordering Information
Part number
LD7750B GS
LD7750B GR
LD7750B GN
SOP-8
SOP-7
DIP-8
Package
Green package
Green package
Green package
Top Mark
LD7750BGS
LD7750BGR
LD7750BGN
Shipping
2500 /tape & reel
2500 /tape & reel
3600 /tube /Carton
The LD7750B is ROHS compliant and Halogen Free.
Protection Mode
Part number
LD7750B
Switching Freq.
100kHz
VCC OVP
Latch
OLP
Auto recovery
OTP Pin
Latch
Pin Descriptions
SOP-8, DIP-8
SOP-7
NAME
FUNCTION
Pulling this pin below 0.95V will shutdown the controller to enter latch
1
1
OTP
mode until the AC power-on recycles. Connecting a NTC between this
pin and ground will achieve OTP protection function. Let this pin float to
disable the latch protection.
2
3
4
5
6
7
2
3
4
5
6
COMP
CS
GND
OUT
VCC
NC
Voltage feedback pin. Connecting a photo-coupler with it can close
control loop and achieve regulation.
Current sense pin, for sensing the MOSFET current.
Ground.
Gate drive output to drive the external MOSFET.
Supply voltage pin.
Unconnected Pin.
Connect this pin to a positive terminal of bulk capacitor to provide the
8
8
HV
startup current for the controller. When Vcc voltage trips the UVLO(on),
this HV loop will be turned off to reduce the power loss on the startup
circuit.
COMP
2
Leadtrend Technology Corporation
LD7750B-DS-00
September 2011
www.leadtrend.com.tw
GND
OTP
LD7750B
Block Diagram
3
Leadtrend Technology Corporation
LD7750B-DS-00
September 2011
www.leadtrend.com.tw
LD7750B
Absolute Maximum Ratings
Supply Voltage VCC
High-Voltage Pin, HV
COMP,OTP, CS
OUT
Maximum Junction Temperature
Operating Ambient Temperature
Operating Junction Temperature
Storage Temperature Range
Package Thermal Resistance (SOP-7, SOP-8)
Package Thermal Resistance (DIP-8)
Power Dissipation (SOP-7, SOP-8)
Power Dissipation (DIP-8)
Lead temperature (Soldering, 10sec)
ESD Voltage Protection, Human Body Model (except HV Pin)
ESD Voltage Protection, Machine Model
-0.3V 30V
-0.3V~500V
-0.3 ~7V
-0.3 ~Vcc+0.3
150°C
-40°C to 85°C
-40°C to 125°C
-65°C to 150°C
160°C/W
100°C/W
400mW
650mW
260°C
2.5KV
250V
Caution:
Stresses beyond the ratings specified in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only
rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification
is not implied.
Recommended Operating Conditions
Item
Supply Voltage Vcc
Comp Pin Capacitor
Min.
10
4.7
Max.
24
100
Unit
V
nF
4
Leadtrend Technology Corporation
LD7750B-DS-00
September 2011
www.leadtrend.com.tw
LD7750B
Electrical Characteristics
(T
A
= +25°C unless otherwise stated, V
CC
=15.0V)
PARAMETER
High-Voltage Supply (HV Pin)
High-Voltage Current Source
Off-State Leakage Current
Supply Voltage (Vcc Pin)
Startup Current
V
COMP
=0V
Operating Current
(with 1nF load on OUT pin)
V
COMP
=3V,
OLP tripped
OVP tripped, VCC=OVP
UVLO (off)
UVLO (on)
OVP Level
Voltage Feedback (COMP Pin)
Short Circuit Current
Open Loop Voltage
Green Mode Threshold VCOMP
Zero Duty
Current Sensing (CS Pin)
Maximum Input Voltage,Vcs_off
Leading Edge Blanking Time
Input impedance
Delay to Output
1
100
0.39
0.425
250
0.46
V
ns
MΩ
ns
V
COMP
=0V
COMP pin open
0.2
5.5
0.26
6.0
2.75
1.6
0.32
mA
V
V
V
8.0
15.0
25.0
200
320
1.1
3.3
0.61
0.70
9.0
16.0
26.0
10.0
17.0
27.0
400
μA
mA
mA
mA
mA
V
V
V
V
CC
< UVLO(on), HV=500V
V
CC
> UVLO(off), HV=500V
0.5
1.0
1.5
35
mA
μA
CONDITIONS
MIN
TYP
MAX
UNITS
5
Leadtrend Technology Corporation
LD7750B-DS-00
September 2011
www.leadtrend.com.tw
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