NCP1237AD65R2G ON Semiconductor

NCP1237 Fixed Frequency Current Mode Controller for Flyback Converters The NCP1237 is a new generation of the NCP12xx fixedfrequency currentmode controllers featuring Dynamic SelfSupply (DSS), NCP1237 1 Latch HV 8 2 FB 3 6 CS VCC 4 GND DRV 5 Figure 1. Pinout TYPICAL APPLICATION EXAMPLE VOUT VIN (dc) LATCH HV FB NCP1237 CS VCC GND DRV Figure 2. Typical Application PIN FUNCTION DESCRIPTION Pin No Pin Name Function Pin Description 1 LATCH Latch off 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 A pulldown optocoupler controls the output regulation. 3 CS Current Sense Senses the primary current for currentmode operation, and provides a mean for overpower compensation adjustment. 4 GND IC ground 5 DRV Drive Output Drives an external MOSFET 6 V V Input This supply pin accepts up to 28 Vdc CC CC 8 HV High Voltage Pin Connects to the bulk capacitor or the rectified AC line to perform the functions of Dynamic SelfSupply and brownout / line overvoltage detections