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All   >>  Energy Efficiency   >>   Power Supplies   >>   Questions
 

I'm currently part of a project involving DC-to-DC conversion and opted to use your MC34063 chip. I would like to ask if this could provide multiple output voltages (say -24V, -56V, -5V) from an input voltage of 5V; or do I have to use other chips like the uA78S40 or several of them.

The MC33063A can produce a -5 volt output along with a -24, and -56 provided the current demands are low on the -24 and -56 volt supplies. You would regulate the -5 volt unit and have two additional windings on a single powered iron core. The additional windings would be at the proper volts/turn to provide the -24 and -56 volt supplies. These additional windings must be operated during the flyback or return time. You are dependent upon this period to provide a regulated volts/turn of the single core assembly. This is used in many designs. The uA78S40 is the main IC that the MC33063 was developed from. In the very beginning the first MC33063's were uA78S40 IC's placed in a 8 pin package and only part of the IC was wired bonded out. You can use any invert circuit approach to achieve of multiple outputs. Another IC that may have promise is the MC33163. It has higher current capability. Be sure to read application note AN920 or AN920A. These were written by Jade Alberkrack who is one of the best linear and switching power supply application engineers I know. Answered by:
ON Semiconductor
2011-06-15 18:00:46.0