Solid-state imaging device with column amplifier
View Patent ↗It is an object to obtain a solid-state imaging device that can reduce a variation in an electric current that flows between an amplifier power supply and ground wiring in a column amplifier, which occurs in accordance with an input signal level, without degrading manufacture and operation tolerances in terms of photoelectric conversion characteristics of the solid-state imaging device. A solid-state imaging device includes: a pixel array in which imaging pixels are arranged in row and column directions; a plurality of vertical signal lines, each of which commonly outputs signals from part of the imaging pixels that is aligned in each column of the pixel array; and a plurality of column amplifiers that are provided in a one-to-one correspondence with the plurality of vertical signals lines. In the solid-state imaging device, between a column amplifier power supply and a ground in each of the plurality of column amplifiers, a current generating circuit is provided that generates a correction current in such a direction as to cancel out a variation in an operation current of each of the plurality of column amplifiers.
1. A solid-state imaging device, comprising:
a pixel array in which imaging pixels are arranged in row and column directions;
a plurality of vertical signal lines, each of which commonly outputs signals from part of the imaging pixels that is aligned in each column of the pixel array; and
a plurality of column amplifiers that are provided in a one-to-one correspondence with the plurality of vertical signals lines,
wherein between a column amplifier power supply and a ground in each of the plurality of column amplifiers, a current generating circuit is provided that generates a correction current in such a direction as to cancel out a variation in an operation current of each of the plurality of column amplifiers.
2. The solid-state imaging device according to claim 1 ,
wherein with respect to a current value that is a sum of values of the operation current and the correction current, a variation in the current value that occurs in accordance with a level of an input signal inputted to each of the plurality of column amplifiers is smaller than a variation in the operation current.
3. The solid-state imaging device according to claim 2 ,
wherein a bias potential generating circuit that applies a bias potential to the current generating circuit has a circuit configuration similar to a circuit configuration of each of the plurality of column amplifiers.
4. The solid-state imaging device according to claim 1 ,
wherein in accordance with a potential at one or a plurality of nodes in each of the plurality of column amplifiers, the current generating circuit switches between two or more levels of the correction current.
5. The solid-state imaging device according to claim 4 ,
wherein levels of the correction current are switched relative to an output of a bias potential generating circuit.
6. The solid-state imaging device according to claim 1 ,
wherein the current generating circuit is configured so that a constant electric current is passed through the current generating circuit.
7. The solid-state imaging device according to claim 1 ,
wherein a function of switching between ON/OFF states of the current generating circuit itself is provided.
8. The solid-state imaging device according to claim 7 ,
wherein the ON/OFF states of the current generating circuit itself are switched based on a level of an input signal or an output signal of each of the plurality of column amplifiers.
9. The solid-state imaging device according to claim 7 , further comprising:
an analog signal processing portion that includes a gain function; and
a control portion that controls the device as a whole,
wherein the ON/OFF states of the current generating circuit itself are switched in accordance with gain setting by the analog signal processing portion.
10. The solid-state imaging device according to claim 1 , wherein a plurality of column analog/digital converters are provided with respect to outputs of the plurality of column amplifiers, respectively.
11. A solid-state imaging device, comprising:
a pixel array in which imaging pixels are arranged in row and column directions;
a plurality of vertical signal lines, each of which commonly outputs signals from part of the imaging pixels that is aligned in each column of the pixel array; and
a plurality of column analog/digital converters that are provided in a one-to-one correspondence with the plurality of vertical signal lines,
wherein between each of the column analog/digital converters and a ground, a current generating circuit is provided that generates a correction current in such a direction as to cancel out a variation in an operation current of the each of the column analog/digital converters.