Fairchild Semiconductor's FAN302HL PWM controller is suitable for low standby power charger applications. Incorporating mWSaver technology, the PWM controller features patented technologies that allow the device to minimise standby input power consumption of less than 10mW at 230V AC. The unit integrates a 500V junction gate field-effect transistor, allowing it to cut off the current path after the device is turned on, reducing start-up losses. The constant current control topology enables simplified circuit design without the requirement for secondary constant current feedback circuitry.
The controller also provides a cycle-to-cycle current limiting feature to ensure a fixed peak current limit level. The gate output is also clamped at 15V to protect the power MOSFET from high gate-source voltage damages. The PWM controller does not require an external secondary-side OVP (over-voltage protection) circuit. If either VS pin OVP or internal over-temperature protection is triggered, the controller enters latch mode until AC power is removed, thereby saving second side OVP components. The controller's burst mode operation, with low operation current, minimises the standby power consumption. It uses secondary-side regulation for constant voltage with good dynamic response, meeting USB 2.0 specifications. The PWM controller is suitable for applications such as mobile phone chargers, smartphones, cordless phones, DVD and set-top boxes, and power over Ethernet. It comes in an 8pin, small outline package, and offers a fixed PWM frequency at 85kHz.
