The NCP1028 offers a new solution targeting output power levels from a few watts up to 15 W in a universal mains flyback application. Our proprietary high-voltage technology lets us include a power MOSFET together with a startup current source, all directly connected to the bulk capacitor. To prevent lethal runaway in low input voltage conditions, an adjustable brown-out circuitry blocks the activity until sufficient input level is reached. Current-mode operation together with an adjustable ramp compensation offers superior performance in universal mains applications. Furthermore, an Over Power Protection pin brings the ability to precisely compensate all internal delays in high input voltage conditions and optimize the maximum output current capability. Protection wise, a timer detects an overload or a short-circuit and stops all operations, ensuring a safe auto-recovery, low duty cycle burst operation. Finally, a great RDS(on) figure makes the circuit an excellent choice for standby/auxiliary offline power supplies or applications requiring higher output power levels.
Features •Built-in 700 V MOSFET with Typical RDS(on) of 5.8 , TJ = 25°C •Current-Mode Fixed Frequency Operation: 65 kHz and 100 kHz •Fixed Peak Current of 800 mA •Skip-Cycle Operation at Low Peak Currents •Internal Current Source for Clean and Lossless Startup Sequence •Auto-Recovery Output Short Circuit Protection with Timer-Based Detection •Programmable Brown-Out Input for Low Input Voltage Detection •Programmable Over Power Protection •Input to Permanently Latchoff the Part •Internal Frequency Jittering for Improved EMI Signature •Extended Duty Cycle Operation to 80% Typical •No-Load Input Standby Power of 85 mW @ 265 Vac •500 mW Loaded, Input Power of 715 mW @ 230 Vac •These are Pb-Free Devices**
Typical Applications •Medium Power AC-DC Adapters for Chargers •Auxiliary/Standby Power Supplies for ATX and TVS Power Supplies
