Patent ID: 8164933

Claim:
A semiconductor device comprising: a rectifier circuit comprising a first transistor and a first capacitor, a comparing circuit, and a voltage generation circuit, wherein: a first input terminal of the rectifier circuit is electrically connected to a first input terminal of the voltage generation circuit, a second input terminal of the rectifier circuit is electrically connected to an output terminal of the voltage generation circuit, an output terminal of the rectifier circuit is electrically connected to a first input terminal of the comparing circuit, an output terminal of the comparing circuit is electrically connected to a second input terminal of the voltage generation circuit, the first input terminal of the rectifier circuit is electrically connected to a first terminal of the first capacitor, the second input terminal of the rectifier circuit is electrically connected to a second gate of the first transistor, the output terminal of the rectifier circuit is electrically connected to a second terminal of the first transistor, a second terminal of the first capacitor is electrically connected to a first terminal of the first transistor and a first gate of the first transistor, the comparing circuit is configured to output a first signal to the output terminal of the comparing circuit determined by comparing a first voltage of the first input terminal of the comparing circuit with a reference voltage of a second input terminal of the comparing circuit, the voltage generation circuit is configured to output a second voltage to the output terminal of the voltage generation circuit in accordance with the first signal, and a threshold voltage of the first transistor is controllable by the second voltage.