Semiconductor device, physical information acquiring apparatus, and signal reading-out method
A semiconductor device includes: an element array portion in which unit elements are disposed in a matrix; and a signal processing portion including a signal processing circuit executing predetermined signal processing based on unit signals outputted from the circuit elements, respectively, every column, in which a function of the signal processing circuit is controlled in such a way that power consumption of the signal processing circuit concerned corresponding to the unit elements each not required becomes lower in a phase of an element selection mode in which only information on a part of the unit pixels for one row in the element array portion is required than in a phase of a normal operation mode.
1. A semiconductor device, comprising:
a pixel array portion in which unit pixels are disposed in a matrix of columns and rows and vertical signal lines are connected to the unit pixels configured to provide readout signals from the unit pixels;
an analog to digital conversion portion including a comparing processing portion and a counting processing portion;
the comparison processing portion configured to compare the unit pixels with a reference signal whose level is gradually changed,
the counting processing portion configured to carry out a counting operation to convert an analog unit signal into digital data based on a comparison result in the comparison processing portion by using a counting clock for analog-to-digital conversion;
the analog to digital conversion portion being configured to perform analog to digital conversion processing for acquiring digital data of the readout signals on the basis of output data of the counting processing portion; and
an operating current supplying portion, including transistors, at least one of the transistors having a gate terminal, a first current terminal and a second current terminal, the first current terminal being connected to at least one of the vertical signal lines at a node between the pixel array portion and the AD conversion portion, the second current terminal being connected to a reference current source, and the gate terminal being connected to a control signal line, wherein
power consumption is configured to be lower in a first operation mode than a second operation mode, where during the first operation mode only the readout signals from the unit pixels that are required are readout and during a second operation mode the readout signals from all of the unit pixels are readout.
2. The semiconductor device, according to claim 1 , wherein the first operation mode is an element selection mode and the second operation mode is a normal mode, and wherein a non-selected part of the readout signals are not readout in the first operation mode.
3. The semiconductor device according to the claim 2 , wherein during the first operation mode the control signal line provides a stop signal to electrically disconnect the analog to digital conversion portion from the pixel array portion.
4. The semiconductor device, according to claim 2 , wherein:
the element selection mode is one of a thinning out mode and a cutting out mode, and wherein
the thinning out mode comprises horizontal skipping processing and the cutting out mode comprises horizontal cutting out processing.
5. The semiconductor device, according to claim 4 , wherein in the thinning out mode, unit pixel signals are read out at every predetermined interval column, and in the cutting out mode unit pixels are read out in a partitioned area.
6. The semiconductor device, according to claim 4 , further comprising:
a transferring portion configured to hold the readout signals corresponding to the unit pixels outputted from the pixel array portion in memory portions and successively transfer the readout signals held in the memory portions to a subsequent stage, the memory portions being cascade-connected to one another, wherein
during the thinning out mode, only readout signals on a part of the unit pixels in the pixel array portion that are required are readout, the readout signals corresponding to the unit pixels each not required are inhibited from being readout.
7. The semiconductor device, according to claim 4 , further comprising:
a transferring portion configured to successively transfer the readout signals when only readout signals on a part of the unit pixels for one row in the pixel array portion are required, wherein
during the cutting out mode, only readout signals on a part of the unit pixels in the pixel array portion that are required are readout, the readout signals corresponding to the unit pixels each not required are inhibited from being readout.
8. The semiconductor device, according to claim 7 , wherein
the transferring portion comprises:
a shift register configured to successively shift the readout signal during horizontal skipping processing, when a horizontal transfer clock is inputted to horizontally transfer pixel data.
9. The semiconductor device, according to claim 8 , thither comprising:
an output selector positioned on an outputting side of the shift register during the horizontal skipping processing.
10. The semiconductor device, according to claim 8 , wherein the pixel data non-selection column on an outputting side of the shift register is not horizontally transferred.
11. The semiconductor device, according to claim 7 , wherein when a horizontal transfer of the pixel data is performed, a horizontal read control pulse is outputted with one pixel as a unit, which controls the reading out timing of the pixel data.
12. The semiconductor device, according to claim 2 , wherein
the first operation mode is controlled such that only signals of the it pixels for one row in the pixel array portion are required.
13. An electronic apparatus, comprising:
a pixel array portion in which unit pixels are disposed in a matrix of columns and rows and vertical signal lines are connected to the unit pixels configured to provide readout signals from the unit pixels;
an analog to digital conversion portion including a comparing processing portion and a counting processing portion;
the comparison processing portion configured to compare the unit pixels with a reference signal whose level is gradually changed,
the counting processing portion configured to carry out a counting operation to convert an analog unit signal into digital data based on a comparison result in the comparison processing portion by using a counting clock for analog-to-digital conversion;
the analog to digital conversion portion being configured to perform analog to digital conversion processing for acquiring digital data of the readout signals on the basis of output data of the counting processing portion; and
an operating current supplying portion, including transistors, at least one of the transistors having a gate terminal, a first current terminal and a second current terminal, the first current terminal being connected to at least one of the vertical signal lines at a node between the pixel array portion and the AD conversion portion, the second current terminal being connected to a reference current source, and the gate terminal being connected to a control signal line, wherein
power consumption is configured to be lower in a first operation mode than a second operation mode, where during the first operation mode only the readout signals from the unit pixels that are required are readout and during a second operation mode the readout signals from all of the unit pixels are readout.
14. The electronic apparatus, according to claim 13 , wherein the first operation mode is an element selection mode and the second operation mode is a normal mode, and wherein a non-selected part of the readout signals are not readout in the first operation mode.
15. The electronic apparatus, according to claim 14 , wherein during the first operation mode the control signal line provides a stop signal to electrically disconnect the analog to digital conversion portion from the pixel array portion.
16. The electronic apparatus, according to claim 14 , wherein:
the element selection mode is one of a thinning out mode and a cutting out mode, and wherein
the thinning out mode comprises horizontal skipping processing and the cutting out mode comprises horizontal cutting out processing.
17. The electronic apparatus, according to claim 16 , wherein in the thinning out mode, unit pixel signals are read out at every predetermined interval column, and in the cutting out mode unit pixels are read out in a partitioned area.
18. The electronic apparatus, according to claim 16 , further comprising:
a transferring portion configured to hold the readout signals corresponding to the unit pixels outputted from the pixel array portion in memory portions and successively transfer the readout signals held in the memory portions to a subsequent stage, the memory portions being cascade-connected to one another, wherein
during the thinning out mode, only readout signals on a part of the unit pixels in the pixel array portion that are required are readout, the readout signals corresponding to the unit pixels each not required are inhibited from being readout.
19. The electronic apparatus, according to claim 16 , further comprising:
a transferring portion configured to successively.
20. The electronic apparatus, according to claim 14 , wherein
the first operation mode is controlled such that only signals of the unit pixels for one row in the pixel array portion are required.