Power factor correction ICs target light-load performance
For applications with continuous power demands up to 405W for universal input and 900W for high-line, the ICs feature efficiency levels of better than 95% from 10% load to full load and consume less than 60 mW under no-load conditions. A power factor of above 0.92 is achievable at 20% load.
The highly integrated HiperPFS-3 devices include the variable frequency CCM controller, high-voltage power MOSFET and a Qspeed low QRR boost diode. The new devices also employ an innovative means of controlling EMI without adversely affecting power factor at light loads. Poor system power factor at light load is caused by X capacitors that are used to reduce differential mode EMI being fed back to the AC line. HiperPFS-3 ICs incorporate a digital power factor-enhancing circuit that activates during light load conditions; this increases the compensation to overcome the reactance of X capacitors in the EMI filter, minimising the phase angle difference between the input voltage and the current. Consequently, designers may increase the size of the X capacitors while minimising or eliminating differential-mode chokes, thereby reducing EMI without degrading light load power factor performance. This results in a smaller, lower cost, EMI filter stage.
Power Integrations observes, “Standby energy-use standards such as ErP Lot 6 have previously forced designers of PCs and other systems to include both a main PSU and standby power supply. The light load efficiency of our new HiperPFS-3 ICs enables them to eliminate the standby power supply, saving components, design time, space and cost.”
Available for both high and low-line applications, HiperPFS-3 ICs cover a continuous output power up to 900W. Thermally efficient eSIP-16 packaging simplifies heat sink mounting. Devices cost $1.27 (10,000).
Power Integrations; www.power.com/products/hiperpfs-3