Hi Pat:
You ask about re-shaping the current waveform to move from Class D to Class A. You ask: "Do we really have that much latitude with our product design?" Yes. An active PFC does this. I don't know of any simple AND PRACTICAL circuit re-designs that will also do this. You can do things such as add a 100-watt light bulb in parallel with your 200-watt load. This will probably move the waveshape outside the Class D envelope. You can also reduce the size of the filter capacitor, which will move the waveshape outside the Class D envelope. In essence, IEC 1000-3-2 outlaws the conventional rectifier-storage capacitor circuit. For power exceeding 75 watts, for all practical purposes, you MUST go to a PFC circuit. In some cases, you can meet the Class D limits through use of a series inductor. Good luck, and let us know your results. Best regards, Rich ------------------------------------------------------------- Richard Nute Quality Department Hewlett-Packard Company Product Regulations Group San Diego Division (SDD) Tel : 619 655 3329 16399 West Bernardo Drive FAX : 619 655 4979 San Diego, California 92127 e-mail: [email protected] -------------------------------------------------------------
