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
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