Housed in SOIC−8 or PDIP−8 package, the NCP1200 represents a major leap toward ultra−compact Switchmode Power Supplies. Due to a novel concept, the circuit allows the implementation of a complete offline battery charger or a standby SMPS with few external components. Furthermore, an integrated output short−circuit protection lets the designer build an extremely low−cost AC−DC wall adapter associated with a simplified feedback scheme. With an internal structure operating at a fixed 40 kHz, 60 kHz, or 100 kHz, the controller drives low gate−charge switching devices like an IGBT or a MOSFET thus requiring a very small operating power. Due to current−mode control, the NCP1200 drastically simplifies the design of reliable and cheap offline converters with extremely low acoustic generation 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 skip cycle mode and provides excellent efficiency at light loads. Because this occurs at a low peak current, no acoustic noise takes place. Finally, the IC is self−supplied from the DC rail, eliminating the need for an auxiliary winding. This feature ensures operation in the presence of low output voltage or shorts.
