NCP1937_15 Datasheet, PDF (1/38 Pages) ON Semiconductor – Combination Power Factor Correction and Quasi-Resonant Flyback Controllers for Adapters

NCP1937
Combination Power Factor
Correction and Quasi-
Resonant Flyback
Controllers for Adapters
This combination IC integrates power factor correction (PFC) and
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quasi−resonant flyback functionality necessary to implement a
compact and highly efficient Switched Mode Power Supply for an
adapter application.
MARKING DIAGRAM
1
HV/X2
20
PFBHV
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 4^th valley and toggles to a frequency
foldback mode with a minimum frequency clamp beyond the 4^th
valley to eliminate audible noise. Skip mode operation allows
excellent efficiency in light load conditions while consuming very low
standby power consumption.
Common General Features
BO/X2
SOIC−20
PControl
PONOFF
Narrow Body _QCT
CASE 751BS Fault
PSTimer
QFB
PFBLV
GND
PCS/PZCD
PDRV
QDRV
QCS
VCC
QZCD
NCP1937 = Specific Device Code
xx
= A1, A2, A3, B1, B2, B3, C1, C4 or C61
A
= Assembly Location
WL = Wafer Lot
YY
= Year
WW = Work Week
G
= Pb−Free Package
• Wide V_CC Range from 9 V to 30 V with Built−in Overvoltage
Protection
• High−Voltage Startup Circuit and Active Input Filter Capacitor
Discharge Circuitry for Reduced Standby Power
ORDERING INFORMATION
See detailed ordering and shipping information on page 5 of
this data sheet.
• Integrated High−Voltage Brown−Out Detector
• Integrated High−Voltage Switch Disconnects PFC Feedback Resistor
Divider to Reduce Standby Power
• Fault Input for Severe Fault Conditions, NTC
• Feed−Forward for Improved Operation across Line and
Compatible (Latch and Auto−Recovery Options)
Load
• 0.5 A / 0.8 A Source / Sink Gate Drivers
• Adjustable PFC Disable Threshold Based on Output
• Internal Temperature Shutdown
Power
• Power Savings Mode Reduces Supply Current
Consumption to 70 mA Enabling Very Low Input Power
Applications
QR Flyback Controller Features
• Valley Switching Operation with Valley−Lockout for
Noise−Free Operation
PFC Controller Features
• Frequency Foldback with Minimum Frequency Clamp
• Critical Conduction Mode with Constant On Time
Control (Voltage Mode) and Maximum Frequency
for Highest Performance in Standby Mode
• Minimum Frequency Clamp Eliminates Audible Noise
Clamp
• Accurate Overvoltage Protection
• Timer−Based Overload Protection (Latched or
Auto−Recovery options)
• Bi−Level Line−Dependent Output Voltage
• Adjustable Overpower Protection
• Fast Line / Load Transient Compensation
• Winding and Output Diode Short−Circuit Protection
• Boost Diode Short−Circuit Protection
• 4 ms Soft−Start Timer
© Semiconductor Components Industries, LLC, 2015
1
June, 2015 − Rev. 4
Publication Order Number:
NCP1937/D