1 Features

• Critical Conduction Mode
• Peak-Current Mode Control
• Skip-Cycle Mode for Low-Standby Power
• Hiccup Mode for Continuous Overload Protection
• Cycle-by-Cycle Overcurrent Protection Maintains Accuracy Over the Universal AC Line
• Line-Voltage Feedforward
• OVP Protection by Sensing the Auxiliary Winding
• Integrated 0.7-A Peak Gate Driver
• Direct Opto-Coupler Interface
• Leading Edge Blanking of Current Sense Signal
• Maximum Frequency Clamp 130 kHz
• Programmable Soft-Start
• Thermal Shutdown
• 8-Pin VSSOP Package
• Create a Custom Design using the LM5023 with the WEBENCH Power Designer

2 Applications

• Universal Input AC-to-DC Notebook Adapters from 10 W to 65 W
• High-Efficiency Housekeeping and Auxiliary Power Supplies
• Battery Chargers
• Consumer Electronics (DVD Players, Set-Top Boxes, DTV, Gaming, Printers)

3 Description

The LM5023 is a quasi-resonant pulse width modulated (PWM) controller which contains all of the features needed to implement a highly efficient off-line power supply. The LM5023 uses the transformer auxiliary winding for demagnetization detection to ensure critical conduction mode (CrCM) operation. The LM5023 features a hiccup mode for overcurrent protection with an auto restart to reduce the stress on the power components during an overload. A skip-cycle mode reduces power consumption at light loads for energy conservation applications (ENERGY STAR®, CEPCP, and so forth). The LM5023 also uses the transformer auxiliary winding for output overvoltage protection (OVP); if an OVP fault is detected the LM5023 latches off the controller.

1. For all available packages, see the orderable addendum at the end of the data sheet.

Simplified Schematic