Patent ID: 8134355

Claim:
A semiconductor device that monitors a voltage between a reference potential and an input potential and obtains a constant output potential regardless of a value of the voltage after the voltage exceeds a predetermined threshold voltage, comprising: a first to sixth transistors and a resistor, in which: a gate of the first transistor is electrically connected to a gate of the second transistor, either a source or a drain of the first transistor is electrically connected to a first wiring and the other of the source and the drain of the first transistor is electrically connected to either a source or a drain of the third transistor, either a source or a drain of the second transistor is electrically connected to the first wiring and the other of the source and the drain of the second transistor is electrically connected to either a source or a drain of the fourth transistor, a gate of the second transistor is electrically connected to the other of the source and the drain of the second transistor, a gate of the third transistor is electrically connected to the other of the source and the drain of the fourth transistor, the other of the source and the drain of the third transistor is electrically connected to a second wiring, a gate of the fourth transistor is electrically connected to either the source or the drain of the third transistor, one terminal of the resistor is electrically connected to the other of the source and the drain of the fourth transistor and the other terminal of the resistor is electrically connected to the second wiring, a gate of the fifth transistor is electrically connected to the other of the source and the drain of the second transistor, either a source or a drain of the fifth transistor is electrically connected to the first wiring and the other of the source and the drain of the fifth transistor is electrically connected to either a source or a drain of the sixth transistor, a gate of the sixth transistor is electrically connected to either the source or the drain of the sixth transistor and the other of the source and the drain of the sixth transistor is electrically connected to the second wiring.