Description
The TOPSwitch family implements, with only three pins, all functions necessary for an off-line switched mode control system: high voltage N-channel power MOSFET with controlled turn-on gate driver, voltage mode PWM controller with integrated 100 kHz oscillator, high voltage start-up bias circuit, bandgap derived reference, bias shunt regulator/error amplifier for loop compensation and fault protection circuitry. Compared to discrete MOSFET and controller or self oscillating (RCC) switching converter solutions, a TOPSwitch integrated circuit can reduce total cost, component count, size, weight and at the same time increase efficiency and system reliability. These devices are intended for 100/110/230 VAC off-line Power Supply applications in the 0 to 100 W (0 to 50 W universal) range and 230/277 VAC off-line power factor correction (PFC) applications in the 0 to 150 W range.

Product Highlights
Low Cost Replacement for Discrete Switchers
• 20 to 50 fewer components - cuts cost, increases reliability
• Source-connected tab and Controlled MOSFET turn-on
   reduce EMI and EMI filter costs
• Allows for a 50% smaller and lighter solution
• Cost competitive with linears above 5 W

Up to 90% Efficiency in Flyback Topology
• Built-in start-up and current limit reduce DC losses
• Low capacitance 700 V MOSFET cuts AC losses
• CMOS controller/gate driver consumes only 6 mW
• 70% maximum duty cycle minimizes conduction losses

Simplifies Design - Reduces Time to Market
• Supported by many reference design boards
• Integrated PWM Controller and 700 V MOSFET in a
   industry standard three pin TO-220 package
• Only one external capacitor needed for compensation,
   bypass and start-up/auto-restart functions

System Level Fault Protection Features
• Auto-restart and cycle by cycle current limiting functions
   handle both primary and secondary faults
• On-chip latching thermal shutdown protects the entire
   system against overload
  
Highly Versatile
• Implements Buck, Boost, Flyback or Forward topology
• Easily interfaces with both opto and primary feedback
• Supports continuous or discontinuous mode of operation