Patent ID: 8593858

Claim:
A driving method of a semiconductor device, the semiconductor device comprising: a memory element comprising a first transistor, a capacitor, and a second transistor; a first word line electrically connected to a gate terminal of the first transistor; a first bit line electrically connected to a source terminal of the first transistor; a source line electrically connected to a drain terminal of the first transistor; a second word line electrically connected to a gate terminal of the second transistor; and a second bit line electrically connected to a source terminal of the second transistor, wherein the gate terminal of the first transistor is electrically connected to a drain terminal of the second transistor, and wherein the capacitor is electrically connected to the gate terminal of the first transistor and the first word line, the driving method comprising the steps of: supplying a potential to the second word line to turn on the second transistor; supplying a potential to the first bit line step-by-step to supply an electrical charge to the gate terminal of the first transistor, while reading a current which flows into the first transistor; and stopping supplying the potential step-by-step to the first bit line when the current which flows into the first transistor reaches a given value, so that data writing is performed.