NCP1244 Fixed Frequency Current Mode Controller for Flyback Converters The NCP1244 is a new fixed frequency currentmode controller featuring the Dynamic SelfSupply. This function greatly simplifies www.onsemi.com the design of the auxiliary supply and the V capacitor by activating CC the internal startup current source to supply the controller during MARKING startup, transients, latch, standby etc. This device contains a special DIAGRAM HV detector which detect the application unplug from the AC input 8 line and triggers the X2 discharge current. 44Xfff It features a timerbased fault detection that ensures the detection of ALYWX SOIC7 overload and an adjustable compensation to help keep the maximum CASE 751U 1 power independent of the input voltage. Due to frequency foldback, the controller exhibits excellent 44Xfff = Specific Device Code efficiency in light load condition while still achieving very low X = A or B fff = 065 or 100 standby power consumption. Internal frequency jittering, ramp A = Assembly Location compensation, and a versatile latch input make this controller an L = Wafer Lot excellent candidate for the robust power supply designs. Y = Year A dedicated Off mode allows to reach the extremely low no load W = Work Week input power consumption via sleeping whole device and thus = PbFree Package minimize the power consumption of the control circuitry. PIN CONNECTIONS Features FixedFrequency CurrentMode Operation (65 kHz and 100 kHz Latch18 HV frequency options) FB 2 Frequency Foldback then Skip Mode for Maximized Performance in CS 3 6 V CC Light Load and Standby Conditions GND 4 5 DRV TimerBased Overload Protection with Latched (Option A) or (Top View) AutoRecovery (Option B) Operation Highvoltage Current Source with Dynamic SelfSupply, Simplifying the Design of the V Circuitry ORDERING INFORMATION CC See detailed ordering and shipping information in the package Frequency Modulation for Softened EMI Signature dimensions section on page 39 of this data sheet. Adjustable Overpower Protection Dependant on the Bulk Voltage Latchoff Input Combined with the Overpower Protection Sensing Input V Operation up to 28 V, With Overvoltage Detection CC Typical Applications 500/800 mA Source/Sink Drive Peak Current ACDC Adapters for Notebooks, LCD, and Printers Capability Offline Battery Chargers 10 ms SoftStart Consumer Electronic Power Supplies Internal Thermal Shutdown Auxiliary/Housekeeping Power Supplies NoLoad Standby Power < 30 mW Offline Adapters for Notebooks X2 Capacitor in EMI Filter Discharging Feature These Devices are PbFree and Halogen Free/BFR Free Semiconductor Components Industries, LLC, 2014 1 Publication Order Number: December, 2018 Rev. 2 NCP1244/DNCP1244 TYPICAL APPLICATION EXAMPLE Figure 1. Flyback Converter Application Using the NCP1244 PIN FUNCTION DESCRIPTION Pin No Pin Name Function Pin Description 1 LATCH LatchOff Input Pull the pin up or down to latchoff the controller. An internal current source allows the direct connection of an NTC for over temperature detection. 2 FB Feedback + Shutdown pin An optocoupler collector to ground controls the output regulation. The part goes to the low consumption Off mode if the FB input pin is pulled to GND. 3 CS Current Sense This Input senses the Primary Current for currentmode operation, and offers an overpower compensation adjustment. 4 GND The controller ground 5 DRV Drive output Drives external MOSFET 6 VCC VCC input This supply pin accepts up to 28 Vdc, with overvoltage detection. The pin is connected to an external auxiliary voltage. It is not allowed to connect another circuit to this pin to keep low input power consumption. 8 HV Highvoltage pin Connects to the rectified AC line to perform the functions of Startup Current Source, SelfSupply and X2 capacitor discharge function and the HV sensing for the overpower protection purposes. It is not allowed to connect this pin to DC voltage. www.onsemi.com 2