**The NCP1255 is a highly integrated PWM controller capable of delivering

a rugged and high performance offline power supply in a SOIC−8 package. With a supply range up to 35 V, the controller hosts a jittered 65−kHz switching circuitry operated in peak current mode control. When the power on the secondary side starts to decrease, the controller automatically folds back its switching frequency down to a minimum level of 26 kHz. As the power further goes down, the part enters skip cycle while freezing the peak current setpoint.**

To help build rugged converters, the controller features several key protective features: a brown−out, a non−dissipative Over Power Protection for a constant maximum output current regardless of the input voltage, two latched over voltage protection inputs − either through a dedicated pin or via the Vcc input − and finally, the possibility to externally adjust an auto−recovery timer duration.

Features

• 65−kHz Fixed−frequency Current−mode Control Operation with 130−kHz Excursion
• Internal and Adjustable Over Power Protection (OPP) Circuit
• Adjustable Brown−Out Protection Circuit
• Frequency Foldback down to 26 kHz and Skip−cycle in Light Load Conditions
• Adjustable Slope Compensation
• Internally Fixed 4−ms Soft−start
• Adjustable Timer−based Auto−recovery Overload/Short−circuit Protection
• 100% to 25% Timer Reduction from Overload to Short−circuit Fault
• Double Vcc Hiccup for a Reduced Average Power in Fault Mode
• Frequency Jittering in Normal and Frequency Foldback Modes
• Latched OVP Input for Improved Robustness and Latched OVP on Vcc
• Up to 35−V Vcc Maximum Rating
• Extremely Low No−load Standby Power
• This is a Pb−Free Device

Typical Applications

• Converters requiring peak−power capability such as printers power supplies, ac−dc adapters for game stations.