The NCP1254 is a highly integrated PWM controller capable of delivering a rugged and high performance offline power supply in a TSOP−6 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 partenters skip cycle while freezing the peak current setpoint.
To help building rugged converters, the controller features several key protective features: 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 a dual−level auto−recovery/latched overload/ short−circuit timer.

FEATUREs
• 65−kHz Fixed−frequency Current−mode Control Operation with 130−kHz Excursion
• Internal and Adjustable Over Power Protection (OPP) Circuit
• Frequency Foldback down to 26 kHz and Skip−cycle in Light Load Conditions
• Adjustable Slope Compensation
• Internally Fixed 4−ms Soft−start
• Fixed 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.