Phihong Intros 150W PFC SwitchersAugust 16, 1999 by Jeff Shepard
Phihong USA (Fremont, CA) has introduced a new generation of 150W open-frame switching power supplies that incorporate active input power factor correction (PFC). The new PSF-151 triple output switcher incorporates second-generation PFC circuitry claimed to yield fewer parts, better airflow and greater reliability.According to Phihong, the printed circuit board of the PSF-151 has been laid out to optimize cooling, with components arranged to facilitate longitudinal airflow. Provided the same amount of airflow, the PSF-151 components will be cooler and therefore more reliable than equivalent 150W models, Phihong claims. The power supply's single-IC dual-purpose PWM and PFC controller reduces the number of components needed, further improving airflow, and also synchronizes the PWM and PFC operating frequencies for lower electrical noise. Measuring 203mm x 107mm x 38mm, the PSF-151 is intended for applications such as networking, telecommunications and industrial process control. The unit operates from a 90-264Vac universal input. The input PFC circuit improves power factor to >0.95 and meets European IEC1000-3-2 line harmonic requirements. The power supply provides one or two high current main outputs, as well as a +12V at 1A fan output. All outputs will remain in regulation for typically 16mS after loss of ac power (120Vac, full output load). An optional power fail signal provides TTL-level warning before the main dc output falls out of regulation.The PSF-151 features protection against output short circuits, forced output overvoltage and excessive internal temperature. Each of these faults causes the supply to enter a self-protection mode. When the fault is cleared, the supply automatically recovers. The new power supply is available in 11 dual- and triple-output models with voltages ranging from 3.3V to 48V. Pricing for the dual output models starts at $119 in quantities of 100.