Charge pump having two sub charge pumps which include a common charge/discharge terminal

摘要

A charge pump according to the invention has first and second sub charge pumps which include a common charging/discharging terminal and perform charging/discharging operations. When the first sub charge pump is operated, and electricity to be offset is charged or discharged due to a junction capacitor located at a PN junction which exists between transistors included in the first sub charge pump, the second sub charge pump performs a discharging operation if the electricity is charged, and a charging operation if it is discharged, in order to offset the electricity. Moreover, while the first sub charge pump performs a charging operation, the second sub charge pump performs a charging operation for a time period shorter by a predetermined time period than the charging period of the first sub charge pump. On the other hand, while the first sub charge pump performs a discharging operation, the second sub charge pump performs a discharging operation for a time period shorter by a predetermined time period than the discharging period of the first sub charge pump.