Power supply system and management device

A management device that manages a plurality of series cell groups connected in series, the plurality of series cell groups each including a plurality of cells connected in series, the management device comprising:

• a plurality of voltage detection circuits connected respectively to the plurality of series cell groups, the plurality of voltage detection circuits each detecting a voltage of each of the plurality of cells included in a subject series cell group;
• a plurality of first power supply circuits connected respectively to the plurality of series cell groups, each of the plurality of first power supply circuits reducing a voltage across both ends of the subject series cell group and supplying power to a subject voltage detection circuit;
• a plurality of active cell balancing circuits connected respectively to the plurality of series cell groups, the plurality of active cell balancing circuits each being configured to selectively charge any one of the plurality of cells included in the subject series cell group, using a voltage across both ends of the subject series cell group;
• a plurality of second power supply circuits connected respectively to the plurality of series cell groups, each of the plurality of second power supply circuits reducing a voltage across both ends of the subject series cell group and supplying power to a subject active cell balancing circuit;
• and
• a control circuit that acquires each of voltage values of the cells from the plurality of voltage detection circuits, the control circuit performing active balancing between the plurality of cells included in each of the plurality of series cell groups, using the plurality of active cell balancing circuits, and performing passive balancing between the plurality of series cell groups,
• wherein
• the plurality of second power supply circuits are power supply circuits higher in efficiency than the plurality of first power supply circuits and are configured to supply power also to each of the plurality of voltage detection circuits,
• a voltage detection circuit among the plurality of voltage detection circuits, connected to a respective one of the plurality of series cell groups being undergoing the passive balancing and consuming power is supplied with power from a respective one of the plurality of first power supply circuits, and
• a voltage detection circuit among the plurality of voltage detection circuits, connected to a respective one of the plurality of series cell groups being undergoing active cell balancing by a respective one of the plurality of active cell balancing circuits is supplied with power from a respective one of plurality of the second power supply circuits.