NCP1937A1DR2G

结合功率因数校正和准谐振的反激式电流模式控制器

This combination IC integrates power factor correction PFC and quasi-resonant flyback functionality necessary to implement a compact and highly efficient Switched Mode Power Supply for an adapter application.The PFC stage exhibits near-unity power factor while operating in a Critical Conduction Mode CrM with a maximum frequency clamp. The circuit incorporates all the features necessary for building a robust and compact PFC stage while minimizing the number of external components.The quasi-resonant current-mode flyback stage features a proprietary valley-lockout circuitry, ensuring stable valley switching. This system works down to the 4th valley and toggles to a frequency foldback mode with a minimum frequency clamp beyond the 4th valley to eliminate audible noise. Skip mode operation allows excellent efficiency in light load conditions while consuming very low standby power consumption.

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<10mW No Load Standby Performance

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Lowest no load performance

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High Voltage Startup Circuit and Active Input Filter Capacitor Discharge Circuitry

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Eliminates the need for an external HV startup circuit and X2 resistors.

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High Voltage Line Voltage Detector

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Optimize performance based on 110 v or 220 V ac mains

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Integrated High Voltage Switch Disconnects PFC Feedback Resistor Divider

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Reduces no load standby power

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Fault Input for Severe Fault Conditions

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Enhanced protection capability

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Bi-Level Line-Dependent Output Voltage

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Optimized system with different input voltages

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Boost Diode Short-Circuit Protection

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Enhanced protection features

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Adjustable PFC Disable Threshold Based on Output Power

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Optimized system to improve efficiency

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Frequency Foldback with Minimum Frequency Clamp

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Enhanced efficiency at light and no load

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Minimum Frequency Clamp

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Eliminates audible noise

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Valley Switching Operation with Valley-Lockout

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Noise free operation

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**PFC******

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**QR Flyback Controller******

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