Readout of array-based analog data in semiconductor-based devices

• US 20040095490A1
• Filed: 11/12/2003
• Published: 05/20/2004
• Est. Priority Date: 03/30/2001
• Status: Active Grant

• Current Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Original Assignee: Micron Technology, Inc.
• Inventors: Huang, Steve, Ang, Lin Ping
• Granted Patent: US 6,819,280 B2
• Time in Patent Office: Days
• US Class Current: 348/294
• CPC Class Codes: H04N 25/67 applied to fixed-pattern noise, e.g. non-uniformity of response
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array

Abstract

Systems and techniques to readout array-based analog data with reduced power requirements and reduced fixed pattern noise. An image sensor on an integrated circuit may include a sensor array to provide array-based analog data, a parallel sampling circuitry to receive the array-based analog data in parallel, a pipelined amplification circuitry to serially amplify the received array-based analog data, and an analog-to-digital converter to convert the amplified array-based analog data into digital data.

Claims

1. An integrated circuit comprising:

a parallel sampling circuitry to receive array-based analog data in parallel;

a pipelined amplification circuitry to serially amplify the received array-based analog data; and

an analog-to-digital converter to convert the amplified array-based analog data into digital data.

2. The integrated circuit of claim 1, wherein the pipelined amplification circuitry comprises programmable pipelined amplification circuitry.

3. The integrated circuit of claim 2, wherein the analog-to-digital converter comprises a pipelined analog-to-digital converter.

4. The integrated circuit of claim 3, further comprising a sensor array to provide the array-based analog data.

5. The integrated circuit of claim 4, wherein the sensor array comprises an image sensor array.

6. The integrated circuit of claim 5, wherein the image sensor array comprises an active pixel sensor array.

7. The integrated circuit of claim 6, wherein the parallel sampling circuitry comprises parallel sample and hold and charge mode readout circuitry without amplification circuitry.

8. The integrated circuit of claim 7, wherein the programmable pipelined amplification circuitry comprises a differential switched capacitor circuitry including at least two programmable capacitors.

9. The integrated circuit of claim 8, wherein the pipelined analog-to-digital converter comprises a differential error-correcting analog-to-digital converter.

10. The integrated circuit of claim 9, wherein the programmable pipelined amplification circuitry comprises a first gain stage and a second gain stage, wherein the first gain stage provides a gain of less than four.

11. The integrated circuit of claim 9, wherein the programmable pipelined amplification circuitry comprises two gain stages including offset storing capacitors.

12. The integrated circuit of claim 11, wherein the programmable pipelined amplification circuitry comprises three gain stages.

13. The integrated circuit of claim 9, further comprising a control circuitry to perform digital processing operations on the digital data.

14. The integrated circuit of claim 13, wherein the digital processing operations comprise black level calibration and correction.

15. The integrated circuit of claim 14, wherein the digital processing operations further comprise outlier detection and filtering.

16. The integrated circuit of claim 9, further comprising a micro-lens layer.

17. A method comprising:

forming an image sensor array on a substrate including a semiconductor material;

forming a sampling circuitry on the substrate to receive analog data from the image sensor array in parallel;

forming a pipelined gain stage on the substrate to serially amplify the received analog data; and

forming a pipelined analog-to-digital converter on the substrate to convert the amplified analog data into digital data.

18. The method of claim 17, further comprising forming a control circuitry on the substrate.

19. The method of claim 18, wherein forming a control circuitry comprises forming a timing circuitry to provide two non-overlapping clock signals to the pipelined gain stage.

20. The method of claim 19, wherein forming a control circuitry comprises forming a sequential selecting circuitry to selectively pass the analog data from the sampling circuitry to the pipelined gain stage in coordination with one of said two non-overlapping clock signals.

21. The method of claim 20, wherein forming a sampling circuitry comprises forming a correlated double sampling circuitry without amplification circuitry.

22. The method of claim 21, wherein forming a pipelined gain stage comprises forming a fully differential, programmable pipelined gain stage.

23. The method of claim 22, wherein forming a pipelined gain stage comprises forming a first gain stage including two programmable capacitors optimized to provide, in conjunction with capacitors in the sampling circuitry, a gain of less than three.

24. The method of claim 22, wherein forming a pipelined analog-to-digital converter comprises forming a fully differential one and a half bit error-correcting analog-to-digital converter.

25. The method of claim 22, wherein forming an image sensor array comprises forming an active pixel sensor array.

26. The method of claim 22, wherein all of said forming comprises using a complementary metal oxide semiconductor manufacturing process.

27. An image sensor comprising:

an image sensor array;

parallel sampling circuitry coupled with the image sensor array; and

a serial readout circuitry coupled with the parallel sampling circuitry, the serial readout circuitry including a gain stage and an analog-to-digital converter.

28. The image sensor of claim 27, wherein the parallel sampling circuitry comprises parallel sample and hold and charge mode readout circuitry not including an amplifier and configured to sample the image sensor array using correlated double sampling.

29. The image sensor of claim 27, wherein the gain stage comprises a differential switched capacitor circuitry including at least two programmable capacitors to amplify signal and reset values passed from sequential portions of the parallel sampling circuitry.

30. The image sensor of claim 27, wherein the analog-to-digital converter comprises a differential error-correcting analog-to-digital converter.

31. The image sensor of claim 27, wherein the image sensor array comprises an active pixel sensor array including at least one photodiode.

32. The image sensor of claim 27, wherein the gain stage comprises a pipelined gain stage.

33. The image sensor of claim 32, wherein the pipelined gain stage comprises three gain stages.

34. The image sensor of claim 27, further comprising a control circuitry to perform digital processing operations on digital data received from the analog-to-digital converter.

35. The image sensor of claim 34, wherein the digital processing operations comprise black level calibration and correction.

36. An image sensor comprising:

array means for converting received photons into electrical signals;

low fixed-pattern-noise means for sampling the electrical signals; and

serial means for amplifying the sampled electrical signals separate from said parallel means.

37. The image sensor of claim 36, wherein said array means comprises an active pixel sensor array.

38. The image sensor of claim 36, wherein said low fixed-pattern-noise means comprises column parallel correlated double sampling means for sampling signal and reset values from the array means without amplification.

39. The image sensor of claim 36, wherein said serial means comprises gain-stage means for low-power amplification of the electrical signals and means for converting amplified electrical signals into digital data.

40. An active pixel sensor camera system comprising:

an active pixel sensor array comprising rows and columns of elements configured to receive photons and form an electrical representation of the received photons;

a parallel sampling circuitry coupled with the active pixel sensor array and configured to sequentially sample groups of the elements to obtain analog voltages corresponding to the electrical representations;

a pipelined gain stage coupled with the parallel sampling circuitry and configured to serially amplify the obtained analog voltages;

a pipelined analog-to-digital converter coupled with the pipelined gain stage and configured to convert the amplified analog voltages into digital pixel data and to transfer the digital pixel data to an output port; and

an image display device coupled with the output port and having a display screen, the image display device configured to transfer pixel data from the output port, such that the device arranges the pixel data in sequential order of rows to display a visual image, corresponding to the received photons, on the display screen.

41. The camera system of claim 40, wherein the pipelined gain stage comprises a programmable fully differential switched capacitor circuitry.

42. The camera system of claim 41, wherein the pipelined gain stage comprises a first gain stage and a second gain stage, wherein the first gain stage provides a gain of less than two.

43. The camera system of claim 41, wherein the pipelined gain stage comprises three gain stages.

44. The camera system of claim 41, wherein the pipelined analog-to-digital converter comprises a fully differential error-correcting analog-to-digital converter.

45. The camera system of claim 44, wherein the parallel sampling circuitry comprises parallel sample and hold and charge mode readout circuitry without amplification circuitry.

46. The camera system of claim 40, further comprising a control circuitry to perform digital processing operations on the digital pixel data before the digital pixel data is transferred to the output port.

47. The camera system of claim 46, wherein the digital processing operations comprise black level calibration and correction.

48. The camera system of claim 47, further comprising a micro-lens layer.