Provided are a method and circuit for controlling heat generation of a power transistor, in which the power transistor can be protected by preventing heat generation of the power transistor by using a metal-insulator transition device that can function as a fuse and can be semi-permanently used. Also, a yeast extract or yeast-derived bioactive peptide having activities as an anti-stress agent, an anti-fatigue agent, premenstrual syndrome and menstrual pain relaxants, and a brain-neurotrophic factor, and a method for preparing the bioactive peptide is provided. The charge accumulation region is adjacent to at least one pixel cell of a pixel array.