Onsemi NCP1351

Description

The NCP1351 is a current mode controller targeting low power off line flyback Switched Mode Power Supplies (SMPS) where cost is of utmost importance. Based on a fixed peak current technique (quasi fixed TON), the controller decreases its switching frequency as the load becomes lighter. As a result, a power supply using the NCP1351 naturally offers excellent no load power consumption, while optimizing the efficiency in other loading conditions. When the frequency decreases, the peak current is gradually reduced down to approximately 30% of the maximum peak current to prevent transformer mechanical resonance. The risk of acoustic noise is thus greatly diminished while keeping good standby power performance.An externally adjustable timer permanently monitors the feedback activity and protects the supply in presence of a short circuit or an overload. Once the timer elapses, NCP1351 stops switching and stays latched for version A, and tries to restart for Version B.

Features

• Quasi-fixed TON, Variable TOFF Current Mode Control
• xtremely Low Current Consumption at Startup
• Peak Current Compression Reduces Transformer Noise
• Primary or Secondary Side Regulation
• Dedicated Latch Input for OTP, OVP
• Programmable Current Sense Resistor Peak Voltage
• Natural Frequency Dithering for Improved EMI Signature
• Easy External Over Power Protection (OPP)
• Undervoltage Lockout
• Very Low Standby Power via Off-time Expansion
• SOIC-8 Package
• Standard Overcurrent Protection, Latched or Auto-Recovery, A & B Versions
• Dual Trip Point Overcurrent Protection, Latched orAuto-Recovery, C & D Versions
• These are Pb-Free Devices

Typical applications

• Auxiliary Power Supply
• Off-line Battery Charger
• Printer, Game Stations, Low-Cost Adapters

More information

• Datasheet
• IC product information