Overview: NCP1200A PWM Current−Mode Controller for Universal Off−Line Supplies Featuring Low Standby Power
Housed in SOIC−8 or PDIP−8 package, the NCP1200A enhances the previous NCP1200 series by offering a reduced optocoupler current together with an increased drive capability. Due to its novel concept, the circuit allows the implementation of complete off−line AC−DC adapters, battery charger or a SMPS where standby power is a www.DataSheet4U.com key parameter. With an internal structure operating at a fixed 40 kHz, 60 kHz or 100 kHz, the controller supplies itself from the high−voltage rail, avoiding the need of an auxiliary winding. This feature naturally eases the designer task in battery charger applications. Finally, current−mode control provides an excellent audio−susceptibility and inherent pulse−by−pulse control. When the current setpoint falls below a given value, e.g. the output power demand diminishes, the IC automatically enters the so−called skip cycle mode and provides excellent efficiency at light loads. Because this occurs at a user adjustable low peak current, no acoustic noise takes place.
