</a>PWM" title="PWM">PWM" title="PWM">PWM控制器,適用于離線開關電源如LCD TV,CRT TV和筆記本電腦適配器.采用突發模式操作,待機時具有超低功耗.器件采用BiCMOS技術,高達26V工作電壓.本文介紹了ICE2QS03G亮點,主要特性,方框圖和典型應用電路,以及36W評估板主要指標,電路圖,材料清單和PCB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

采用準諧振PWM控制器ICE2QS03G的36W評估板

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. 36W評估板EVALQRS-36W-ICE2QS03G外形圖

36W評估板主要指標:


圖4. 36W評估板電路圖
36W評估板材料清單:



圖5. 36W評估板變壓器架構圖

圖6. 36W評估板PCB布局圖(頂層)

圖7. 36W評估板PCB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