Imaging device comprising current mirror circuit
A semiconductor device including pixels arranged in a matrix of n rows and m columns, in which the pixels in the m-th column are shielded from light, is provided.
1. An imaging device comprising:
a first pixel;
a second pixel; and
a current mirror circuit,
wherein a first current corresponding to a current flowing through the first pixel flows to an input transistor of the current mirror circuit,
wherein a second current flows to an output transistor of the current mirror circuit, and
wherein a difference between the second current and a third current corresponding to a current flowing through the second pixel is calculated.
2. The imaging device according to claim 1 , wherein current value of the second current is the same as current value of the first current.
3. The imaging device according to claim 1 , wherein the current flowing through the first pixel is a current corresponding to a state in which a charge retention portion included in the first pixel is initialized.
4. An imaging device comprising:
a first pixel;
a second pixel; and
a current mirror circuit,
wherein a first current corresponding to a current flowing through the first pixel flows to an input transistor of the current mirror circuit,
wherein a second current flows to an output transistor of the current mirror circuit,
wherein a difference between the second current and a third current corresponding to a current flowing through the second pixel is calculated,
wherein each the input transistor and the output transistor is a p-channel transistor, and
wherein each of the first pixel and the second pixel includes an n-channel transistor.
5. The imaging device according to claim 4 , wherein current value of the second current is the same as current value of the first current.
6. The imaging device according to claim 4 , wherein the current flowing through the first pixel is a current corresponding to a state in which a charge retention portion included in the first pixel is initialized.
7. An imaging device comprising:
a first pixel;
a second pixel; and
a current mirror circuit,
wherein a first current corresponding to a current flowing through the first pixel flows to an input transistor of the current mirror circuit,
wherein a light-blocking layer is arranged at a side where light enters a photoelectric conversion element included in the first pixel,
wherein a second current flows to an output transistor of the current mirror circuit, and
wherein a difference between the second current and a third current corresponding to a current flowing through the second pixel is calculated.
8. The imaging device according to claim 7 , wherein current value of the second current is the same as current value of the first current.
9. The imaging device according to claim 7 , wherein the current flowing through the first pixel is a current corresponding to a state in which a charge retention portion included in the first pixel is initialized.
10. The imaging device according to claim 7 ,
wherein each the input transistor and the output transistor is a p-channel transistor,
wherein each of the first pixel and the second pixel includes an n-channel transistor.