NCP1240 Fixed Frequency Current Mode Controller for Flyback Converters The NCP1240 is a new fixedfrequency 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. This HV structure allows 40Xfff the brownout detection as well. ALYWX SOIC7 It features a timerbased fault detection that ensures the detection of CASE 751U 1 overload and an adjustable compensation to help keep the maximum power independent of the input voltage. 40Xfff = Specific Device Code Due to frequency foldback, the controller exhibits excellent X = A, B, E or F fff = 065 or 100 efficiency in light load condition while still achieving very low A = Assembly Location standby power consumption. Internal frequency jittering, ramp L = Wafer Lot compensation, and a versatile latch input make this controller an Y = Year excellent candidate for the robust power supply designs. W = Work Week A dedicated Off mode allows to reach the extremely low no load = PbFree Package input power consumption via sleeping whole device and thus minimize the power consumption of the control circuitry. PIN CONNECTIONS Features Latch18 HV FixedFrequency CurrentMode Operation (65 kHz and 100 kHz FB 2 frequency options) CS 3 6 V CC Frequency Foldback then Skip Mode for Maximized Performance in GND 4 5 DRV Light Load and Standby Conditions TimerBased Overload Protection with Latched (Options A and E) or (Top View) AutoRecovery (Options B and F) Operation Highvoltage Current Source with BrownOut Detection and ORDERING INFORMATION See detailed ordering and shipping information on page 44 of Dynamic SelfSupply, Simplifying the Design of the V Circuitry CC this data sheet. Frequency Modulation for Softened EMI Signature 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, 2015 1 Publication Order Number: July, 2015 Rev. 1 NCP1240/DNCP1240 TYPICAL APPLICATION EXAMPLE TR 1 GND dc output RHV D9 D1 3 L2 L1 12 12 COUT D3 2 D8 D10 5 CX1 ac input CX2 IC1 34 34 C1 1 8 4 LATCH HV C4 2 FB GND 6 GND Q1 3 6 NTC CS VCC GND 4 5 GND DRV GND GND NCP1240 GND GND ROPP GND OK1 4 1 C3 C2 3 2 IC2 PC817 NCP431 GND GND GND GND Figure 1. Flyback Converter Application Using the NCP1240 OPTIONS Part Option Frequency OCP Fault A 65 kHz Latched A 100 kHz Latched B 65 kHz Autorecovery NCP1240 B 100 kHz Autorecovery E 65 kHz Latched F 65 kHz Autorecovery 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, brownout detection 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 D4 D6 D5 D7 CBULK + RCLAMP CCLAMP D2 RSENSE W3 W1 W2 R3 R4 + R2 R1 RLOAD