Fault tolerant active current sharing

A parallel power supply, comprising:

• a plurality of parallel power supply modules, wherein each of said plurality of parallel power supply modules contributes an output current level to a common electrical load;
• a master reference voltage circuit that provides a master reference voltage level to said plurality of power supply modules at a common load adjustment reference node;
• a load adjustment amplifier within each of said plurality of parallel power supply modules, wherein each of said load adjustment amplifiers compares an output voltage from its corresponding parallel power supply module with said master reference voltage level and adjusts an output current from its corresponding parallel power supply module in response thereto;
• and
• an internal reference circuit within each of said plurality of power supply modules, said internal reference circuit comprising:
• a first voltage source;
• and
• an amplifier that compares said master reference voltage level at said common load adjustment reference node with a voltage level from said first voltage source to generate an internal reference voltage level applicable to said common load adjustment reference node, wherein said internal reference voltage level is maintained lower than said master reference voltage level.

A current sharing method for maintaining a balanced current level among a plurality of power supply modules that are connected in parallel to form a parallel power supply that supplies a single load, said current sharing method comprising:

• detecting an output voltage level from each of said plurality of power supply modules;
• comparing each of said output voltage levels with a master reference voltage level;
• detecting a voltage differential between an output voltage level of a given one of said plurality of power supply modules and said master reference voltage level;
• in response to detecting a voltage differential between an output voltage level of a given one of said plurality of power supply modules and said master reference voltage level, adjusting an output current from said given one of said power supply modules such that current sharing is provided among said plurality of power supply modules;
• and
• within each of said power supply modules:
• providing an alternate voltage source;
• and
• comparing said master reference voltage level with a voltage level at said alternate voltage source to generate an internal reference voltage level applicable to said common voltage adjustment node, wherein said internal reference voltage level is maintained lower than said master reference voltage level.