TNY278PN is a switch-mode power supply (SMPS) controller IC manufactured by Power Integrations. It belongs to the TinySwitch‑III family, designed for low- to medium-power AC‑DC converters such as adapters, chargers, and standby power supplies. (alldatasheet.com)

It integrates a high-voltage 700 V MOSFET, oscillator, current-limit, and protection circuits in a single package, enabling simple flyback SMPS designs with minimal external components.

Main Specifications

• Series: TinySwitch‑III

• Input voltage: 85 – 265 VAC

• Internal MOSFET breakdown voltage: 700 V

• Maximum output power: ~22 W (depending on design)

• Switching frequency: ≈132 kHz

• Duty cycle: ~65 %

• Package: DIP‑8 (7 pins used)

• Operating temperature: −40 °C to +150 °C (alldatasheet.com)

Key Features

• Integrated 700 V high-voltage MOSFET

• Auto-restart protection during short-circuit or overload

• Thermal shutdown protection

• Current-limit protection

• Frequency jitter to reduce EMI noise

• Low standby power consumption

Typical Applications

• Phone and USB chargers

• TV standby power supplies

• Small AC‑DC adapters

• DVD / set-top box power boards

• Home appliance control boards

✅ Simple explanation:
TNY278PN is a compact SMPS switching IC that converts 110–220 V AC into low-voltage DC (like 5 V or 12 V) for low- to medium-power electronics.

I can also make a complete TinySwitch comparison table (TNY263PN → TNY290PG) showing:

• Maximum output power

• Package type

• Series family (TinySwitch‑II, III, IV)

• Replacement compatibility

This is extremely useful if you are repairing or designing power supplies.

Do you want me to make that table?