Low−Standby Power High Performance PWM Controller

The NCP1231 represents a major leap towards achieving low standby power in medium−to−high power Switched−Mode Power Supplies such as notebook adapters, off−line battery chargers and consumer electronics equipment. Housed in SOIC−8 or PDIP−8, the NCP1231 contains all needed control functionality to build a rugged and efficient power supply. Among the unique features offered by the NCP1231 is an event management scheme that can disable the front−end PFC circuit during standby, thus reducing the no load power consumption. The NCP1231 itself goes into cycle skipping at light loads while limiting peak current (to 25% of nominal peak) so that no acoustic noise is generated and while in the skip cycle mode.

FEATUREs
• Current−Mode Operation with Internal Ramp Compensation
• Extremely Low Startup Current of 30 A Typical
• Skip−Cycle Capability at Low Peak Currents
• Adjustable Soft−Start
• Overvoltage and Brown−Out Protection
• Short−Circuit Protection Independent of Auxiliary Level
• Internal Frequency Dithering for Improved EMI Signature
• Go−To−Standby Signal for PFC Front Stage
• Extremely Low No−Load, Noiseless, Standby Power
• Internal Leading Edge Blanking
• +500 mA/−800 mA Peak Current Drive Capability
• Available in Three Frequency Options: 65 kHz, 100 kHz, and 133 kHz
• Direct Optocoupler Connection
• SPICE Models Available for TRANsient and AC Analysis
• Pb−Free Packages are Available

Typical Applications
• High Power AC−DC Adapters for Notebooks, etc.
• Offline Battery Chargers
• Set−Top Boxes Power Supplies, TV, Monitors, etc.