</a>PWM" title="PWM">PWM" title="PWM">PWM控制器,開關頻率隨負載的降低而降低,使得整個系統的效率大大提高,突發模式使待機的功耗超低,內置了數字軟起動,并具有過壓/欠壓以及開路和過載保護與自動重起模式,主要用于LCD TV,CRT TV和筆記本電腦適配器的離線開關電源.本文介紹了ICE2QS03G產品亮點和主要特性,方框圖,典型應用電路,36W評估板ICE2QS03G36W主要指標,電路圖,材料清單和PCB元件布局圖.

ICE2QS03G is a quasi-resonant PWM controller optimized for off-line switch power supply applications such as LCD TV, CRT TV and notebook adapter. The digital frequency reduction with decreasing load enables a quasi-resonant operation till very low load. As a result, the overall system efficiency is significantly improved compared to other conventional solutions. The active burst mode operation enables an ultra-low power consumption at standby mode with small and controllable output voltage ripple. Based on the BiCMOS technology, the product has a wide operation range (up to 26V) of IC power supply and lower power consumption. The numerous protection functions give a full protection of the power supply system in failure situations. All of these make the ICE2QS03G an outstanding controller for quasi-resonant flyback converter in the market.

ICE2QS03G產品亮點:

• Active burst mode for low standby power

• Digital frequency reduction for better overall system efficiency

• Integrated power cell for IC self-power supply

ICE2QS03G主要特性:

• Quasiresonant operation till very low load

• Active burst mode operation at light/no load for low standby input power (< 100mW)

• Digital frequency reduction with decreasing load

• Power cell for VCC pre-charging with constant current

• Built-in digital soft-start

• Foldback correction and cycle-by-cycle peak current limitation

• Auto restart mode for VCC Overvoltage protection

• Auto restart mode for VCC Undervoltage protection

• Auto restart mode for openloop/overload protection

• Latch-off mode for adjustable output overvoltage protection

• Latch-off mode for Short-winding protection

圖1.ICE2QS03G方框圖

圖2.ICE2QS03G典型應用電路圖

36W評估板ICE2QS03G36W

36W Evaluation Board with Quasi-Resonant PWM Controller ICE2QS03G

The demo-board described here is a 36W power supply using quasi-resonant flyback converter topology.

The PWM controller ICE2QS03G is a second generation quasi-resonant controller IC developed by Infineon Technologies. The typical applications are for TV-sets, DVD-players, Set-top boxes, netbook adapters, home audio and printer applications. In normal operation, the digital frequency reduction with decreasing load enables a quasi-resonant operation till very low load. As a result, the system efficiency over the entire load range is significantly improved compared to conventional free running quasi resonant converter implemented with only maximum switching frequency limitation. In addition, numerous protection functions have been implemented in ICE2QS03G to protect the system and customize the IC for the chosen application. In case of failure modes, like open control-loop/over load, output overvoltage, and transformer short winding, the device switches into Auto Restart Mode or Latch-off Mode. By means of the cycle-by-cycle peak current limitation plus foldback point correction, the dimension of the transformer and the secondary diode can be lower which leads to more cost effective design.

圖3.評估板ICE2QS03G36W外形圖
評估板ICE2QS03G36W指標:


圖4.評估板ICE2QS03G36W電路圖

評估板ICE2QS03G36W材料清單:



圖5.評估板ICE2QS03G36W PCB32布局圖:頂層

圖6.評估板ICE2QS03G36W PCB32布局圖:底層
詳情請見:
http://www.infineon.com/dgdl/Datasheet_ICE2QS03G_V21_20100205.pdf?folderId=db3a304412b407950112b4182a3d24f8&fileId=db3a304324fc7f9a01250689233a7046
和
http://www.infineon.com/dgdl/EVALS-ICE2QS03G-36W-V12-20111112.pdf?folderId=db3a304412b407950112b4182a3d24f8&fileId=db3a304324fc7f9a0125068d0b17704b