Power supply for an electronic device

An electronic device composed of a plurality of logic units comprising:

• a first AC power supply stabilizing AC supplied by commercial AC network to output it and a second AC power supply disposed in parallel with respect to said first AC power supply and similarly stabilizing AC supplied by the same commercial AC network to output an AC having a frequency, which is asynchronous to the frequency of the AC outputted by said first AC power supply;
• a plurality of DC power supplies connected with said first AC power supply and converting the AC supplied by said first AC power supply into DC to output it;
• a plurality of DC power supplies connected with said second AC power supply and converting the AC supplied by said second AC power supply into DC to output it;
• a first reference potential bus bar applying a reference potential to said logic units, one end of which is connected at a connecting part with said plurality of DC power supplies connected with said first AC power supply in common, and another end of which is sufficiently far from said connecting part and connected with said logic units at another connecting part;
• a second reference potential bus bar applying a reference potential to said logic units, one end of which is connected at a connecting part with said plurality of DC power supplies connected with said second AC power supply in common, and another end of which is sufficiently far from said connecting part and connected with said logic units a another connecting part, a part of a path thereof between the two connecting parts being located away from said first reference potential bus bar;
• a plurality of connecting bus bars applying voltages necessary for driving LSIs within said logic units thereto, one end of each of which is connected with a voltage output terminal of each of said plurality of DC power supplies, and another end of each of which is connected with said logic unit;
• and
• a board disposed on said logic unit, whose potential itself serves as a reference potential, the other ends of said first and said second reference potential bus bar, which ends are different from said connecting parts connected with the reference potentials of said DC power supplies, being connected with said board so as to make the reference voltage applied to said logic unit from said plurality of DC power supplies uniform.

An electronic device, comprising:

• at least two AC power supplies, respectively providing different alternating currents;
• a plurality of DC power supplies respectively connected to input the alternating current from said AC power supplies and respectively output DC currents, so that the DC currents have ripples correlated to the alternating currents, which ripples tend to differ from each other in phase and frequency corresponding to differences in phase and frequency of the AC currents so that when combined the ripples will tend to beat;
• a plurality of reference bus bars respectively connected to said plurality of DC power supplies for separately transmitting a reference voltage of said DC currents respectively and for providing inductance damping the ripples;
• an electronic unit having a reference volt node connected to said reference bus bars at a location remote from a connection of said reference bus bars to said DC power supplies with a spacing being sufficient to provide inductance damping that will reduce a magnitude of the ripples by at least a factor of 2, and said electronic unit having a plurality of separate electronic circuits, each having a reference input connected to said reference voltage node and a power input;
• and
• a plurality of conductors respectively connecting the power inputs of said electronic circuits with said DC power supplies.

Apparatus, comprising:

• a plurality of independently DC powered electric devices mounted together as an electronic unit;
• an input;
• a first AC power supply stabilizing AC supplied at said input by a commercial AC network to output a first alternating current at a frequency difference from the commercial AC network;
• a second AC power supply in parallel with said first AC power supply and stabilizing the AC supplies at said input by the commercial AC network to output a second alternating current at a frequency asynchronous to the frequency of the first alternating current;
• a first DC power supply connected with said first AC power supply and converting the first alternating current into DC and outputting a first direct current with a first ripple, at a first voltage having a first reference level and a first voltage level;
• a second DC power supply connected with said second AC power supply and converting the second alternating current into DC and outputting a second direct current with a second ripple, at a second voltage with a second reference level and a second voltage level;
• a first reference potential bus bar for applying a reference potential to the electronic devices, and having one end connected to said first DC power supply and another end connected with said electronic devices for transmitting the first reference level of the first direct current separately from the second reference level of the second direct current;
• a second reference potential bus bar for applying a reference potential to the electronic devices, and having one end connected to said second DC power supply and another end connected with said electronic devices for transmitting the second reference level of the second direct current along a path located away from said first reference potential bus bar;
• first and second connecting bars for respectively applying the first and second voltage levels independently to difference ones of said electronic devices, and each having one end connected with a respective one of said first and second DC power supplies and another end connected with a respective one of said electronic devices;
• said electronic devices having a common reference voltage node connected to the another ends of said first and said second reference potential bus bars;
• and
• the one and another ends being sufficiently far apart to provide a current path length that together with a reference potential bus bar cross-section between the one and another ends provides inductance that reduces the ripple in the respective first and second direct currents so that a beat formed at the common reference voltage node by the first and second ripples will be reduced at least about 20% as compared to a beat that would be formed when the one ends of said first and second reference potential bus bars are electrically connected.