Patent attributes
In order to restrict variations of an output voltage of a DC—DC conversion circuit using TFTs, in a boost-type, a second n-ch TFT N2 and a second p-ch TFT P2 are newly provided. With regard to the second n-ch TFT N2, a gate thereof is connected to a second capacitor C2, a source thereof is connected to a first reference voltage source YVDD, and a drain thereof is connected to a first capacitor C1. With regard to the second p-ch TFT P2, a gate thereof is connected to the second capacitor C2, a source thereof is connected to a third capacitor C3, and a drain thereof is connected to the first capacitor C1. Thus, a voltage at the first capacitor C1 stops being influenced by the variations of a threshold voltage between a source and drain of a first diode D1.
