Power Integrations always seems to be at the forefront of power-related issues. So it’s no surprise that its HiperPFS-3 family of power-factor-correction ICs offer high power factor and high efficiency across the entire load range. Targeting applications with continuous power demands up to 405 W for universal input and 900 W for high-line, the ICs feature efficiency levels of better than 95 percent from 10 percent load to full load and consume less than 60 mW under no-load conditions. A power factor of above 0.92 is easily achievable at 20 percent load.
The devices include a variable frequency CCM controller, a high-voltage power MOSFET, and the company’s Qspeed low QRR boost diode. They also employ an innovative means to control EMI without adversely affecting power factor at light loads. Poor system power factor at light load is caused by capacitors that reduce differential-mode EMI that’s fed back to the AC line.
The 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, minimizing the phase angle difference between the input voltage and the current. Consequently, designers can increase the size of the capacitors while minimizing or eliminating differential-mode chokes, thereby reducing EMI without degrading light load power factor performance. The result is a smaller, lower cost, EMI filter stage.
The power-factor-correction ICs are available in thermally efficient eSIP-16 packages that simplify heat-sink mounting. They cost $1.27 in 10,000 piece quantities.