Abstract: A battery protection circuit with a novel configuration and a power storage device including the battery protection circuit are provided. The battery protection circuit includes a switch circuit for controlling charge and discharge of a battery cell; the switch circuit includes a mechanical relay, a first transistor, and a second transistor; the switch circuit has a function of controlling electrical connection between a first terminal and a second terminal; the mechanical relay has a function of breaking electrical connection between the first terminal and the second terminal; the first transistor has a function of supplying first current between the first terminal and the second terminal; the second transistor has a function of supplying second current between the first terminal and the second terminal; and the first current is higher than the second current.

Abstract: The data processing system includes I/O units for transmitting and receiving data, control units for processing the data, and a common bus unit including a common bus. Function cards in each unit are daisy-chained to I/O buses having characteristics to support hot-swapping, and both ends of the I/O buses are terminated with resistors respectively. The units are daisy-chained to the common bus, and both ends of the common bus are terminated with resistors respectively. Drivers/receivers drive each bus to transmit and receive data between the common bus and the I/O buses.