To provide a charger wherein produced heat and power loss are reduced and the fully charged state of a secondary battery can be detected with accuracy.
A current detection circuit 230 of a charge control IC chip 200 includes the following: a current detection transistor 231 whose terminals are connected in common with the current inflow terminal and the control terminal of a control transistor 220 and which forms a current mirror with respect to the control transistor 220; a voltage clamp circuit 233 that controls the current outflow terminal voltage of the current detection transistor 231 and the current outflow terminal voltage of the control transistor 220 to an identical potential; and a current-voltage conversion circuit 232 that detects the charging current passed through the control transistor 220 by the current of the current detection transistor 231.
TAKADA KAZUHISA
YOSHIDA MASAHITO
ARAI SHIGENORI
