DC-DC CONVERTER AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A DC-DC converter and a manufacturing method thereof are provided to reduce manufacturing costs by manufacturing a power device which reduces a voltage value of input voltage and a power device of a voltage conversion circuit using the same manufacturing process. CONSTITUTION: A voltage conversion circuit(121) is connected to an input terminal(102) and includes a first transistor. A control circuit(111) controls the voltage conversion circuit and includes a second transistor which includes a silicon material in a channel formation region. A third transistor is provided between the input terminal and the control circuit for converting and reducing input voltage. The first transistor and the third transistor include an oxide semiconductor material in the channel formation regions. The first transistor and the third transistor are laminated on the second transistor by arranging an insulating film.