NCP1937 Series

Combo Power Factor Correction + QR Flyback Controller

Catalog

Combo Power Factor Correction + QR Flyback Controller

Part	Outputs and Type	Outputs and Type	Current - Output	Utilized IC / Part	Main Purpose	Voltage - Input [Min]	Voltage - Input [Max]	Voltage - Output	Supplied Contents	Regulator Topology	Board Type	Power - Output	Supplier Device Package	Operating Temperature [Max]	Operating Temperature [Min]	Mounting Type	Voltage - Supply [Max]	Voltage - Supply [Min]	Package / Case [y]	Package / Case [x]	Package / Case	Package / Case	Mode	Current - Startup
ON Semiconductor NCP1937BADAPGEVB	Isolated	1	4.25 A	NCP1937	DC/DC Step Down	90 VAC	265 VAC	20 V	Board(s)	Flyback	Fully Populated	90 W
ON Semiconductor NCP1937C1DR2G													20-SOIC	125 °C	-40 °C	Surface Mount	30 VDC	9 V	3.9 mm	0.154 in	17 Leads	20-LSOP	Critical Conduction (CRM)	20 mA
ON Semiconductor NCP1937C4DR2G													20-SOIC	125 °C	-40 °C	Surface Mount	30 VDC	9 V	3.9 mm	0.154 in	17 Leads	20-LSOP	Critical Conduction (CRM)	20 mA
ON Semiconductor NCP1937B3DR2G													20-SOIC	125 °C	-40 °C	Surface Mount	30 VDC	9 V	3.9 mm	0.154 in	17 Leads	20-LSOP	Critical Conduction (CRM)	20 mA

Catalog

Combo Power Factor Correction + QR Flyback Controller

Key Features

• <10mW No Load Standby Performance

• High Voltage Startup Circuit and Active Input Filter Capacitor Discharge Circuitry

• High Voltage Line Voltage Detector

• Integrated High Voltage Switch Disconnects PFC Feedback Resistor Divider

• Fault Input for Severe Fault Conditions

• Bi-Level Line-Dependent Output Voltage

• Boost Diode Short-Circuit Protection

• Adjustable PFC Disable Threshold Based on Output Power

• Frequency Foldback with Minimum Frequency Clamp

• Minimum Frequency Clamp

• Valley Switching Operation with Valley-Lockout

• PFC

• QR Flyback Controller

Description

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.