Imaging device and camera system including sense circuits to make binary decision
An imaging device includes: a pixel array section having an array of pixels, each of which has a photoelectric converting device and outputs an electric signal according to an input photon; a sense circuit section having a plurality of sensor circuits each of which makes binary decision on whether there is a photon input to a pixel in a predetermined period upon reception of the electric signal therefrom; and a decision result IC section which integrates decision results from the sense circuits, pixel by pixel or for each group of pixels, multiple times to generate imaged data with a gradation, the decision result IC section including a count circuit which performs a count process to integrate the decision results from the sense circuits, and a memory for storing a counting result for each pixel from the count circuit, the sense circuits sharing the count circuit for integrating the decision results.
1. An imaging device comprising:
a first substrate including
a plurality of pixels (DPX) arranged in rows and columns, and
a plurality of signal lines coupled to the plurality of pixels (DPX) respectively; and
a second substrate including
a plurality of sense amplifiers coupled to the plurality of signal lines respectively, the plurality of sense amplifiers including a first sense amplifier,
a counter circuit coupled to the plurality of sense amplifiers, and
a memory coupled to the counter,
wherein the first sense amplifier includes a first inverter and a second inverter serially coupled to the first inverter.
2. The imaging device according to claim 1 , wherein the first sense amplifier includes a first capacitor coupled to an input node of the first inverter.
3. The imaging device according to claim 2 , wherein the first sense amplifier includes a first switch circuit coupled between the second inverter and the first capacitor.
4. The imaging device according to claim 3 , wherein the first sense amplifier includes a second switch configured to couple the first capacitor to an output node of the second inverter.
5. The imaging device according to claim 4 , wherein the first sense amplifier includes a third switch circuit coupled between a signal line of the plurality of signal lines and the first capacitor.
6. The imaging device according to claim 5 , wherein the first sense amplifier includes a second capacitor coupled to a node disposed between the first capacitor and the third switch circuit.
7. The imaging device according to claim wherein the first substrate further includes
a digital pixel having a photodiode, and
an output signal line coupled to the digital pixel to output signals generated by the photodiode.
8. The imaging device according to claim 7 , wherein the first substrate further includes a transfer transistor coupled to the digital pixel and the output signal line.
9. The imaging device according to claim 7 , further comprising:
a first capacitor coupled to the output signal line, the first capacitor having a dielectric film diposed between its electrodes.
10. The imaging device according to claim 9 , wherein the first capacitor is disposed at a bonding surface of the first and second substrates.
11. The imaging device according to claim 9 , wherein the second substrate further includes
an input signal line coupled to the first capacitor to receive the signals from the output signal line via the first capacitor, and
a second sense amplifier coupled to the input signal line to receive the signals from the input signal line.
12. The imaging device according to claim 11 , wherein the second sense amplifier includes a first inverter and a second inverter serially coupled to the first inverter.
13. The imaging device according to claim 12 , wherein the second sense amplifier includes a first switch circuit coupled between the first capacitor and the second inverter.
14. The imaging device according to claim 13 , wherein the second sense amplifier includes a second switch configured to couple the first capacitor to an output node of the second inverter.
15. The imaging device according to claim 14 , wherein the second sense amplifier further includes a second capacitor coupled to the first capacitor.
16. The imaging device according to claim 15 , wherein the second capacitor is coupled to a node shared by at least one of the first capacitor, the first switch, the second switch and the first inverter.
17. The imaging device according to claim 15 , wherein the second capacitor is coupled to a node shared by at least two of the first capacitor, the first switch, the second switch and the first inverter.
18. The imaging device according to claim 15 , wherein the second capacitor is coupled to a node shared by at least three of the first capacitor, the first switch, the second switch and the first inverter.
19. The imaging device according to claim 15 , wherein the second capacitor is coupled to a node shared by the first capacitor, the first switch, the second switch and the first inverter.