Document
LD7750A
06/25/2010
High Voltage Green-Mode PWM Controller with
Over Temperature Protection
Rev. 00
General Description
The LD7750A 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 power-saving operation, leading-edge blanking of the current sensing and internal slope compensation. Also, the LD7750A features more protections like OLP (Over Load Protection), OVP (Over Voltage Protection), and OTP (Over Temperature Protection) to prevent the circuit being damaged under abnormal conditions. The LD7750A features built-in auto-recovery function for OVP on Vcc pin and OLP.
Furthermore, the LD7750A features frequency swapping to depress radiation noise, providing an excellent solution for EMI filter design.
Features
z High-Voltage (500V) Startup Circuit z Current Mode Control z Green Mode Control z UVLO (Under Voltage Lockout) z LEB (Leading-Edge Blanking) on CS Pin z Internal Frequency swapping z Internal Slope Compensation z Internal Over Current Protection z OVP (Over Voltage Protection) on Vcc z OLP (Over Load Protection) z External OTP through a NTC z 500mA Driving Capability
Applications
z Switching AC/DC Adaptor and Battery Charger z Open Frame Switching Power Supply z LCD Monitor/TV Power
Typical Application
Leadtrend Technology Corporation
LD7750A-DS-00 June 2010
1
www.leadtrend.com.tw
Pin Configuration
SOP-7 (TOP VIEW)
SOP-8/DIP-8 (TOP VIEW)
LD7750A
HV VCC OUT HV NC VCC OUT
8 65
TOP MARK YYWWPP
1 234
8765
TOP MAR K YYWWPP
1 23 4
YY: WW: PP:
Year code Week code Production code
OTP COM P
CS GND OTP COMP
CS GND
Ordering Information
Part number LD7750A GS
Package
SOP-8
Green package
LD7750A GR
SOP-7
Green package
LD7750A GN
DIP-8
Green package
The LD7750A is ROHS compliant.
Top Mark LD7750AGS LD7750AGR LD7750AGN
Protection Mode
Part number LD7750A
Switching Freq. 65kHz
VCC OVP Latch
OLP Auto recovery
Shipping 2500 /tape & reel 2500 /tape & reel 3600 /tube /Carton
OTP Pin Latch
Pin Descriptions
SOP-8
SOP-7
11
22
33 44 55 66 7
88
NAME
OTP
COMP CS GND OUT VCC NC
HV
FUNCTION Pulling this pin below 0.95V will shutdown the controller to enter latch 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. 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 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.
Leadtrend Technology Corporation
LD7750A-DS-00 June 2010
2
www.leadtrend.com.tw
Block Diagram
LD7750A
Leadtrend Technology Corporation
LD7750A-DS-00 June 2010
3
www.leadtrend.com.tw
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, at Ambient Temperature = 85°C) Power Dissipation (DIP-8, at Ambient Temperature = 85°C) Lead temperature (Soldering, 10sec) ESD Voltage Protection, Human Body Model (except HV Pin) ESD Voltage Protection, Machine Model Gate Output Current
LD7750A
-0.3V 30V -0.3V~500V -0.3 ~7V -0.3 ~Vcc+0.3 150°C -20°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 500mA
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.
Leadtrend Technology Corporation
LD7750A-DS-00 June 2010
4
www.leadtrend.com.tw
Electrical Characteristics
(TA = +25°C unless otherwise stated, VCC=15.0V)
PARAMETER
CONDITIONS
High-Voltage Supply (HV Pin) High-Voltage Current Source Off-State Leakage Current Supply Voltage (Vcc Pin) Startup Current
VCC< UVLO(on), HV=500V VCC> UVLO(off), HV=500V
Operating Current (with 1nF load on OUT pin)
VCOMP=0V VCOMP=3V, OLP tripped
OVP tripped, VCC=OVP
UVLO (off)
UVLO (on)
OVP Level
Voltage Feedback (COMP Pin) Short Circuit Current Open Loop Voltage
VCOMP=0V COMP pin open
Green Mode Threshold VCOMP
Zero Duty
Current Sensing (CS Pin) Maximum Input Voltage,Vcs_off
Leading Edge Blanking Time
Input impedance
Delay to Output
LD7750A
MIN TYP MAX UNITS
0.5 1.0 1.5 mA 35 μA
200 320 400 1.2 2.3 0.61 0.70
9.0 10.0 11.0 15.0 16.0 17.0 25.0 26.0 27.0
μA mA mA mA mA V V V
.