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 low peak current, no acoustic noise takes place.

Finally, the IC is self−supplied from the DC rail, eliminating the

need of an auxiliary winding. This feature ensures operation in

presence of low output voltage or shorts.

Features

• No Auxiliary Winding Operation

• Internal Output Short−Circuit Protection

• Extremely Low No−Load Standby Power

• Current−Mode with Skip−Cycle Capability

• Internal Leading Edge Blanking

• 250 mA Peak Current Source/Sink Capability

• Internally Fixed Frequency at 40 kHz, 60 kHz and 100 kHz

• Direct Optocoupler Connection

• Built−in Frequency Jittering for Lower EMI

• SPICE Models Available for TRANsient and AC Analysis

• Internal Temperature Shutdown

• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant

Typical Applications

• AC−DC Adapters

• Offline Battery Chargers

• Auxiliary/Ancillary Power Supplies (USB, Appliances, TVs, etc.)