Infineon Technologies ICE5QR4770AG | Demoboard AN-DEMO_5QR4770AG_15W1

Description

This application note is an engineering report of 15 W 12 V and 5 V demo board designed in a quasiresonantflyback converter topology using the 5th generation Quasi-Resonant CoolSET™,ICE5QR4770AG. The target applications of ICE5QR4770AG are either auxiliary power supply of white goods, PC, server and TV or enclosed adapter, Blu-Ray player, set-top box, game console, etc. With the CoolMOS™ integrated in this IC, it greatly simplifies the design and layout of the PCB. The improved novel digital frequency reduction with proprietary Quasi-Resonant operation offers lower EMI and higher efficiency for wide AC range by reducing the switching frequency difference between low and high line.The enhanced Active Burst Mode power enables flexibility in standby power operation range selectionand Quasi-Resonant operation during Active Burst Mode. As a result, the system efficiency, over theentire load range, is significantly improved compared to conventional free running Quasi-Resonantconverter implemented with only maximum switching frequency limitation at light load. In addition,numerous adjustable protection functions have been implemented in ICE5QR4770AG to protect thesystem and customize the IC for the chosen application. In case of failure modes, like brownout or line over voltage, VCC over/under voltage, open control-loop or over load, output overvoltage, overtemperature, VCC short to ground and CS short to ground, the device enters to protection mode. Bymeans of the cycle-by-cycle peak current limitation, the dimension of the transformer and current ratingof the secondary diode can both be optimized. Thus, a cost effective solution can be easily achieved.

Features

• Novel quasi-resonant switching scheme
• Rapid and adjustable start-up with cascode configuration
• 2 level selectable active burst mode level
• Built-in digital soft-start
• Cycle by cycle peak current limitation
• Digital frequency reduction with decreasing load for higher efficiency
• Adjustable line input over-voltage and brown IN/OUT protection
• VCC and CS pin short to ground protection
• OLP, output short, output over-voltage, OTP with hysteresis and VCC over/under voltage protection
• Auto-restart for all protection features

Typical applications

• Offline aux SMPS for server, PC power, aircon, refrigerator and audio/ Offline main SMPS for adapter, set-top-box, water purifier, TV, industrial SMPS and POE

More information

• Datasheet
• IC product information