Fairchild’s PFC Controller Reduces Losses and Eliminates Components
Fairchild Semiconductor has introduced a power factor correction (PFC) controller IC that reduces standby power as much as 320mW in switch-mode power supply (SMPS) designs under 250 Watts, such as notebook adaptors. In addition to increasing energy efficiency, the highly integrated FAN7528 saves board space by reducing component count.
The FAN7528 is an active PFC controller that operates in critical conduction mode (CRM). Unlike conventional current-mode CRM PFC controllers, the FAN7528 integrates a dual-output control function to increase efficiency with a universal ac input. This integrated feature renders the sensing of the rectified ac line voltage for power factor correction unnecessary, leading to a pronounced drop in standby power in certain adaptor applications, as compared to similar devices.
"Engineers designing power supply adaptors must adhere to a number of energy-efficiency standards such as Energy2000, Blue Angel and the EU Code of Conduct," said CJ Kim, Fairchild's Power Supply Product Line Manager. "Fairchild designed the FAN7528 to automatically sense ac line voltage by integrating dual-output control. In addition to offering a dramatic efficiency improvement, this integration helps designers eliminate discrete components."
With its ability to eliminate an input voltage-sensing network, the FAN7528 cuts system power loss to 80mW compared to alternative controllers that need to sense input voltage. In addition to low power consumption, the FAN7528 integrates an open-feedback disable function (65µA) for system protection against damaging power surges. To further increase power efficiency, Fairchild's controller utilizes a patent-pending variable on-time control method utilized to reduce total harmonic distortion.
The FAN7528 is a lead (Pb)-free product that meets or exceeds the requirements of the joint IPC/JEDEC standard J-STD-020C and is compliant with the European Union requirements now in effect. In lots of 1,000, these controllers cost $1.00 each and are available 8 weeks ARO.
