< /a> PWM" title="PWM">PWM" title="PWM">PWM控制器,适用于离线 开关电源如LCD TV,CRT TV和笔记本电脑适配器.采用突发模式操作,待机时具有超低功耗.器件采用BiCMOS技术,高达26V工作电压.本文介绍了ICE2QS03G亮点,主要特性,方框图和典型应用电路,以及36W评估板主要指标,电路图,材料清单和PCB布局图.

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亮点:

• 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

图1.ICE2QS03G方框图

图2.ICE2QS03G典型应用电路图

采用准谐振PWM控制器ICE2QS03G的36W评估板

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.

图3. 36W评估板EVALQRS-36W-ICE2QS03G外形图

36W评估板主要指标:


图4. 36W评估板电路图
36W评估板材料清单:



图5. 36W评估板变压器架构图

图6. 36W评估板PCB布局图(顶层)

图7. 36W评估板PCB布局图(底层)
详情请见:
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