LD7575 - DS-04b - Green-Mode PWM Controller with High-Voltage Start-Up Circuit

Oct 12, 2026

LD7575 is a current-mode PWM controller designed for efficient AC/DC power applications, combining a high-voltage startup current source with a lossless startup circuit. It integrates leading-edge blanking on the CS pin, internal slope compensation, programmable switching frequency, and green-mode control for non-audible noise operation. The device provides UVLO, OVP on Vcc, and OLP protection, and supports SOP-8 and DIP-8 packages with 500 mA gate driving capability.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages18

Reading Time45 min

AccessFree to download

General Description

Features

Applications

Pin Configuration and Descriptions

Typical Application

Block Diagram

Absolute Maximum Ratings

Recommended Operating Conditions

Electrical Characteristics

LD7575 11/29/2007 | Green-Mode PWM Controller with High-Voltage
Start-Up Circuit | | | --- | --- | | REV: 04b
General Description
The LD7575 is a current-mode PWM controller with excellent power-saving operation. It features a highvoltage current source to directly supply the startup current from bulk capacitor and further to provide a lossless startup circuit. The integrated functions such as the leading-edge blanking of the current sensing, internal slope compensation, and the small package provide the users a high efficiency, minimum external component counts, and low cost solution for AC/DC power applications.
Furthermore, the embedded over voltage protection, overload protection and the special green-mode control provide the solution for users to design a high performance power circuit easily. The LD7575 is offered in both SOP-8 and DIP-8 package. | Features
z High-Voltage (500V) Startup Circuit
z Current Mode Control
z Non-Audible-Noise Green Mode Control
z UVLO (Under Voltage Lockout)
z LEB (Leading-Edge Blanking) on CS Pin
z Programmable Switching Frequency
z Internal Slope Compensation
z OVP (Over Voltage Protection) on Vcc
z OLP (Over Load Protection)
z 500mA Driving Capability
Applications
z Switching AC/DC Adapter and Battery Charger
z Open Frame Switching Power Supply
z LCD Monitor/TV Power | | Typical Application
| | 1 Leadtrend Technology Corporation [www.leadtrend.com.tw](www.leadtrend.com.tw) LD7575-DS-04b November 2007 LD7575 | Pin Configuration
SOP-8 & DIP-8 (TOP VIEW)

YY: Year code
WW: Week code
PP: Production code
HV
NC
VCC
OUT
RT
COMP
CS
GND | | --- | | Ordering Information
Part number Package Top Mark Shipping LD7575 PS SOP-8 PB Free LD7575PS 2500 /tape & reel LD7575 GS SOP-8 Green Package LD7575GS 2500 /tape & reel LD7575 PN DIP-8 PB Free LD7575PN 3600 /tube /Carton
The LD7575 is ROHS compliant/ Green Package.
Pin Descriptions
PIN NAME FUNCTION 1 RT This pin will program the switching frequency, to connect a resistor with ground to set the switching frequency. 2 COMP Voltage feedback pin (same as the COMP pin in UC384X), By connecting a photo-coupler to close the control loop and achieve the regulation. 3 CS Current sense pin, connect to sense the MOSFET current 4 GND Ground 5 OUT Gate drive output to drive the external MOSFET 6 VCC Supply voltage pin 7 NC Unconnected Pin 8 HV Connect this pin to 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 off to save the power loss on the startup circuit. | 2 Leadtrend Technology Corporation [www.leadtrend.com.tw](www.leadtrend.com.tw) LD7575-DS-04b November 2007 LD7575 | Block Diagram | | | | --- | --- | --- | | RT
COMP
CS | HV

Green-Mode Control

5.0V

GND | VCC
OUT | 3 Leadtrend Technology Corporation [www.leadtrend.com.tw](www.leadtrend.com.tw) LD7575-DS-04b November 2007 LD7575 Absolute Maximum Ratings Supply Voltage VCC 30V High-Voltage Pin, HV -0.3V~500V COMP, RT, CS -0.3 ~7V Junction Temperature 150°C Operating Ambient Temperature -40°C to 85°C Storage Temperature Range -65°C to 150°C Package Thermal Resistance (SOP-8) 160°C/W Package Thermal Resistance (DIP-8) 100°C/W Power Dissipation (SOP-8, at Ambient Temperature = 85°C) 400mW Power Dissipation (DIP-8, at Ambient Temperature = 85°C) 650mW Lead temperature (Soldering, 10sec) 260°CESD Voltage Protection, Human Body Model (except HV Pin) 3KVESD Voltage Protection, Machine Model 200V Gate Output Current 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 specifi

FAQs

What is LD7575’s primary function and operating approach?

LD7575 is a current-mode PWM controller with a high-voltage startup circuit and integrated protections. It uses green-mode control to support efficient power conversion with non-audible noise operation.

How does the startup circuit work in LD7575?

The HV pin connects to the positive terminal of the bulk capacitor to supply startup current. When Vcc reaches the UVLO(on) threshold, the HV startup loop turns off to reduce power loss.

Which protection features are included in LD7575?

LD7575 includes UVLO (under-voltage lockout), OVP (over-voltage protection) on Vcc, and OLP (over-load protection). It also uses leading-edge blanking on the CS pin and internal slope compensation for stable current-mode control.

Oct 12, 2026

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