Patent ID: 9224757
Filing Date: 2015-12-29
Classification: H01L,H02M

Abstract:
1. A DC-DC converter comprising: an input terminal to which input voltage is applied; a voltage converter circuit that is connected to the input terminal and includes a first transistor; a control circuit that is configured to control the voltage converter circuit and includes a second transistor including a silicon film in a channel formation region; and a third transistor that is provided between the input terminal and the control circuit and configured to convert the input voltage into power supply voltage that is lower than the input voltage, wherein the first transistor and the third transistor are transistors including an oxide semiconductor film in channel formation regions, wherein the oxide semiconductor films of the first transistor and the third transistor are stacked over the silicon film of the second transistor with an insulating film provided between the oxide semiconductor films of the first and third transistors and the silicon film of the second transistor, and wherein the third transistor is configured to supply the power supply voltage to the control circuit from one of a source and a drain of the third transistor.