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On Semi公司的NCP1072/NCP1075集成了700V MOSFET的固定頻率電流模式控制器,包括軟起動,頻率抖動,短路保護,最大峰值電流設定點,斜率補償,跳頻模式,動態自供電源,無負載輸入功耗小于 50 mW,主要用于輔助電源,待機電源,白色家電,智能電表.本文介紹了NCP1072/NCP1075主要特性,方框圖,12V/0.85A通用輸入電源電路圖和15W開關電源評估板電路圖,材料清單. The NCP1072/NCP1075 products integrate a fixed frequency current mode controller with a 700 V MOSFET. Available in a PDIP−7 or SOT−223 package, the NCP1072/5 offer a high level of integration, including soft−start, frequency−jittering, short−circuit protection, skip−cycle, a maximum peak current set point, ramp compensation, and a Dynamic Self−Supply (eliminating the need for an auxiliary winding). Unlike other monolithic solutions, the NCP1072/5 is quiet by nature: during nominal load operation, the part switches at one of the available frequencies (65, 100 or 130 kHz). When the output power demand diminishes, the IC automatically enters frequency foldback mode and provides excellent efficiency at light loads. When the power demand reduces further, it enters into a skip mode to reduce the standby consumption down to a no load condition. Protection features include: a timer to detect an overload or a short−circuit event, Overvoltage Protection with auto−recovery and AC input line voltage detection. For improved standby performance, the connection of an auxiliary winding stops the DSS operation and helps to reduce input power consumption below 50 mW at high line. NCP1072/NCP1075主要特性: • Built−in 700 V MOSFET with RDS(on) of 11 • Large Creepage Distance Between High−voltage Pins • Current−Mode Fixed Frequency Operation – 65 / 100 /130 kHz (130 kHz on demand only) • Peak Current: NCP1072 with 250 mA and NCP1075 with 450 mA • Fixed Ramp Compensation • Skip−Cycle Operation at Low Peak Currents Only: No Acoustic Noise! • Dynamic Self−Supply: No Need for an Auxiliary Winding • Internal 1 ms Soft−Start • Auto−Recovery Output Short Circuit Protection with Timer−Based Detection • Auto−Recovery Overvoltage Protection with Auxiliary Winding Operation • Frequency Jittering for Better EMI Signature, Including Frequency Foldback Mode • No Load Input Consumption < 50 mW • Frequency Foldback to Improve Efficiency at Light Load • Internal Temperature Shutdown • These are Pb−Free Devices NCP1072/NCP1075典型應用: • Auxiliary / Standby Isolated Power Supplies White Goods / Smart Meter / E−Meter 
圖1.NCP1072/NCP1075方框圖
圖2.NCP1075 12V/0.85A通用輸入電源電路圖 15W開關電源評估板NCP1075SOTGEVB
圖3.15W開關電源評估板NCP1075SOTGEVB外形圖
圖4.15W開關電源評估板NCP1075SOTGEVB電路圖 15W開關電源評估板NCP1075SOTGEVB材料清單(BOM):
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NCP1072-D.PDF
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