Power Electronics

PWM Controller Enables Ultra-Low Standby Power

FAIRCHILD SEMICONDUCTOR has developed the FAN302HL PWM controller for low standby power charger applications. Incorporating mWSaver™technology, the device features patented technologies that allow the FAN302HL to minimize standby input power consumption to <[email protected], exceeding ENERGY STAR® Program Requirements for Computers Version 5.0 efficiency standards.

This highly integrated PWM controller provides several features to enhance the performance of general flyback converters. Integrating a 500V JFET, the FAN302HL allows the device to cut off the current path after the device is turned on, reducing start-up losses. The patented constant current control topology enables simplified circuit design without secondary constant current feedback circuitry, especially important in battery charger applications.

The FAN302HL also provides several protection features. These include cycle-to-cycle current limiting to ensure a fixed peak current limit level, even if a short circuit occurs. Additionally, the gate output is also clamped at 15V to protect the power MOSFET from high gate-source voltage damages.

The FAN302HL does not require an external secondary-side over-voltage protection (OVP) circuit. If either VS pin OVP or internal over-temperature protection is triggered, the device enters latch mode until AC power is removed, saving second side OVP components and tightening VO protection (<6V).

The controller's design reduces losses in both the power MOSFET and the PWM IC. Primary side regulation control and no second side current sensing provides lower losses and improved efficiency. Proprietary burst mode operation, with lower operation current, minimizes the standby power consumption.

Fairchild Semiconductor
South Portland, ME


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