NCP1248AD100R2G ON Semiconductor

NCP1248 Fixed Frequency Current Mode Controller for Flyback Converters The NCP1248 is a new fixed-frequency current-mode controller NCP1248 TYPICAL APPLICATION EXAMPLE CCLAMP TR 1 D9 D1 dc output RHV 3 GND L2 L1 1 2 1 2 2 COUT D8 D3 ac input CX2 CX1 IC1 5 D10 C1 4 1 8 3 4 LATCH HV 3 4 C4 2 FB 6 Q1 GND 3 6 GND CS VCC NTC GND 4 5 GND DRV GND GND NCP1248 GND GND ROPP GND OK1 4 1 C3 3 2 C2 IC2 PC817 NCP431 GND GND GND GND Figure 1. Flyback Converter Application Using the NCP1248 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.