NCP1236 Fixed Frequency Current Mode Controller for Flyback Converters The NCP1236 is a new fixedfrequency currentmode controller featuring Dynamic SelfSupply (DSS). This device is pintopin www.onsemi.com compatible with the previous NCP12xx families. The DSS function greatly simplifies the design of the auxiliary MARKING supply and the V capacitor by activating the internal startup current CC DIAGRAM source to supply the controller during transients. 8 Due to frequency foldback, the controller exhibits excellent 36Xff efficiency in light load condition while still achieving very low ALYW standby power consumption. Internal frequency jittering, ramp SOIC7 compensation, and a versatile latch input make this controller an CASE 751U 1 excellent candidate for converters where components cost is the key 36Xff = Specific Device Code constraints. X = A, B, C or D In addition, the controller includes a new high voltage circuitry that ff = 65 or 100 combines a startup current source and a brownout detector able to A = Assembly Location L = Wafer Lot sense the input voltage either from the rectified ac line or the dc Y = Year filtered bulk voltage. The high voltage sensing circuitry is used for the W = Work Week overpower protection purposes as well. Overpower protection, = PbFree Package overload protection, and next protective features increases safety level of the final application. PIN CONNECTIONS Finally, due to a careful design, the precision of critical parameters is well controlled over the entire temperature range (40C to Latch18 HV +125C). FB 2 Features CS 3 6 V CC FixedFrequency CurrentMode Operation with BuiltIn Ramp GND 4 5 DRV Compensation (Top View) 65 kHz or 100 kHz Oscillator Frequency Frequency Foldback then Skip Mode for Maximized Performance in ORDERING INFORMATION Light Load and Standby Conditions See detailed ordering and shipping information in the package TimerBased Overload Protection with Latched (option A) or dimensions section on page 33 of this data sheet. AutoRecovery (option B) Operation, Shortened Overload Timer for Increased Safety (options C and D), (see all options on page 2) Highvoltage Current Source with BrownOut Internal Thermal Shutdown detection and Dynamic SelfSupply, Simplifying the PintoPin Compatible with the Existing NCP12xx Design of the V Capacitor CC Series Frequency Modulation for Softened EMI Signature, These Devices are PbFree, Halogen Free/BFR Free including during Frequency Foldback mode and are RoHS Compliant Adjustable Overpower Compensation Typical Applications Latchoff Input for Severe Fault Conditions, Allowing ACDC Adapters for Notebooks, LCD, and Printers Direct Connection of an NTC for Overtemperature Offline Battery Chargers Protection (OTP) Consumer Electronic Power Supplies V Operation up to 28 V, with Overvoltage Detection CC Auxiliary/Housekeeping Power Supplies 500 mA Peak Source / Sink Current Drive Capability 4.0 ms SoftStart Semiconductor Components Industries, LLC, 2016 1 Publication Order Number: January, 2016 Rev. 5 NCP1236/DNCP1236 TYPICAL APPLICATION EXAMPLE VOUT VIN (dc) LATCH HV FB NCP1236 CS VCC GND DRV Figure 1. Flyback Converter Application Using the NCP1236 OPTIONS Autorecovery Timer Part Option Frequency OCP Fault Fault Timer A 65 kHz Latched 128 ms 1 s A 100 kHz Latched 128 ms 1 s B 65 kHz Autorecovery 128 ms 1 s B 100 kHz Autorecovery 128 ms 1 s NCP1236 C 65 kHz Latched 32 ms 1.5 s C 100 kHz Latched 32 ms 1.5 s D 65 kHz Autorecovery 32 ms 1.5 s D 100 kHz Autorecovery 32 ms 1.5 s 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 An optocoupler collector to ground controls the output regulation. 3 CS Current Sense This Input senses the Primary Current for currentmode operation, and Offers an overpower compensation adjustment. 4 GND IC Ground 5 DRV Drive output Drives external MOSFET 6 V V input This supply pin accepts up to 28 Vdc, with overvoltage detection CC CC 8 HV Highvoltage pin Connects to the bulk capacitor or the rectified AC line to perform the functions of Startup Current Source, Dynamic SelfSupply and brownout detection www.onsemi.com 2