Description

The NCP1027 (marked Q0265R on the package) is a High-Voltage Switcher IC manufactured by onsemi, designed for medium-power offline switch-mode power supplies (SMPS) featuring low standby power. It targets output power levels from a few watts up to 15W in universal mains flyback applications, making it a popular choice for compact AC-DC adapters and auxiliary/standby power supplies.

Using onsemi's proprietary high-voltage technology, the NCP1027 integrates a power MOSFET together with a startup current source, both directly connected to the bulk capacitor — significantly reducing external component count compared to discrete flyback controller designs. To prevent lethal runaway under low input voltage conditions, it includes adjustable brown-out circuitry that blocks operation until a sufficient input level is reached. Current-mode operation combined with adjustable ramp compensation delivers strong performance across universal mains voltage ranges.

For protection, an internal timer detects overload or short-circuit conditions and stops operation, ensuring safe auto-recovery via low duty-cycle burst mode. An integrated, auto-recovery Overvoltage Protection (OVP) continuously monitors the VCC level and temporarily shuts down driving pulses if the feedback loop runs away — giving the design robust self-protection against common failure modes.

Key Specifications

• Function: High-voltage switching regulator (integrated power MOSFET) for offline SMPS
• Manufacturer: onsemi
• Package Marking: Q0265R
• Package: DIP-7 (through-hole)
• Target Output Power: Up to 15W (universal mains flyback)
• VCC Operating Range: ~7.9V–8.9V
• Output Voltage (internal MOSFET rating): 700V
• Integrated startup current source
• Brown-out protection, over-power protection, auto-recovery OVP and short-circuit protection

Common Applications

• Universal mains offline flyback power supplies
• Auxiliary/standby power supplies (e.g., ATX and TV power supplies)
• Low-power AC-DC adapters
• General offline SMPS designs requiring low standby power consumption

Package Includes

• 1 x NCP1027 IC