Active 102 W flyback switch with integrated 650 V MOSFET
The Infineon ICE3B2065P-2 is an offline flyback switch IC rated for 102 W output power, integrating a 650 V avalanche-rated CoolMOS MOSFET and a PWM controller in a single TO-220-6 Formed Leads package. The internal switch eliminates the external MOSFET and its gate-drive loop, reducing BOM count and PCB area in isolated AC-DC supplies. The 67 kHz switching frequency is a practical midpoint for flyback designs — high enough to shrink the transformer core, low enough to keep switching losses manageable in a through-hole package without an external heatsink at the 102 W ceiling.
Fault protection and control features for robust offline supplies
The ICE3B2065P-2 packs five protection modes: current limiting, open-loop detection, overload, over-temperature, and over-voltage. In a flyback supply, the most commonly triggered is overload — the controller enters auto-restart hiccup mode, reducing average power delivery and preventing transformer saturation until the fault clears. Soft start ramps the duty cycle from zero at power-up, limiting the inrush current into the output capacitor bank and the magnetizing current surge through the transformer. Without it, the first few cycles would stress the output rectifier and the bulk capacitor beyond their surge ratings. The Vcc supply range of 8.5 V to 21 V accommodates both the startup charge from the bulk capacitor through a startup resistor and the steady-state supply from an auxiliary winding. The 15 V startup threshold is typical for this class — the controller remains off until the Vcc rail crosses 15 V, ensuring the gate drive has enough headroom to fully enhance the internal MOSFET.
Package and mounting: TO-220-6 Formed Leads
The PG-TO220-6-47 package is a through-hole outline with formed leads that stand off from the PCB, allowing flux cleaning underneath the body. The centre tab is the drain of the internal MOSFET and provides the primary thermal path — a copper pad on the PCB or a clip-on heatsink is needed to keep the junction below 130 °C at full load. Bulk packaging means the parts ship in tubes or trays, not tape-and-reel. For a rework lab or a low-volume production line that hand-loads through-hole components, bulk is the expected format. For automated wave-solder lines, the tube feed works with most through-hole insertion machines.