The invention provides: a charging and discharging control circuit which includes
a charging and discharging control terminal having a test function as well and
which is capable of conducting switch over among a normal application state, a
charging and discharging prohibition state, and a test state; and a charging type
power supply unit. Any one of a level "L", "H", or "M" of a voltage inputted to
a charging and discharging control terminal is selected using the charging and
discharging control terminal and a test fuse to allow switch over to the normal
application state, the charging and discharging prohibition state, or the test
state. In the test state, two modes for shortening a test delay time are realized
depending on whether or not the test fuse is cut.