Staggered reset in CMOS digital sensor device

• US 8,300,126 B2
• Filed: 12/15/2008
• Issued: 10/30/2012
• Est. Priority Date: 12/15/2008
• Status: Expired due to Fees

• Current Assignee: AltaSens, Inc. (JVC Kenwood Corporation), Wachovia Corporation (Wells Fargo & Company)
• Original Assignee: AltaSens, Inc. (JVC Kenwood Corporation)
• Inventors: Rossi, Giuseppe, Huang, Ying
• Primary Examiner(s): Moe, Aung S
• Application Number:
  US12/335,248
• Publication Number:
  US 20100149390A1
• Time in Patent Office: 1,415 Days
• Field of Search: 348/294, 348/308, 348/301, 348/317, 348/302, 257/292, 257/293, 250/208.1, 250/339.02
• US Class Current: 348/294
• CPC Class Codes: H04N 25/62 Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels
• CPC Class Codes: H04N 25/65 applied to reset noise, e.g. KTC noise related to CMOS structures by techniques other than CDS
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors

Abstract

Systems and methods are provided that facilitate staggering resets of rows of pixels in a CMOS imaging iSoC sensor. Reset signals and select signals can be provided to pixels in a pixel array in a coordinated manner when employing full frame integration or sub-frame integration. Further, reset signals and select signals can be transferred to a first row of pixels, while reset signals can be transferred to a second row of pixels during a unique readout time interval when utilizing sub-frame integration. Within the unique readout time interval, reset signals can be transferred to the first row of pixels during a first time period, while reset signals can be transferred to the second row of pixels during a second time period, where the first and second time periods are non-overlapping. Accordingly, cross-talk between rows of pixels during reset can be mitigated, which leads to enhanced uniformity.

Claims

1. A system that staggers resets of rows of pixels in a complementary metal-oxide-semiconductor (CMOS) imaging system-on-chip (iSoC) sensor, comprising:

a reset component that sends reset signals to reset transistors of pixels included in a pixel array to reset the pixels;

a select component that transfers select signals to select transistors of the pixels included in the pixel array to readout values from the pixels; and

a signal timing component that controls timing of the reset component and the select component to coordinate transferring reset signals and select signals to the pixels, wherein when employing sub-frame integration, a first select signal is transferred at a first time period, a first reset signal is transferred at a second time period, a second select signal is transferred at a third time period, and a second reset signal is sent at a fourth time period, such that disparate rows of pixels in the pixel array are reset at different, non-intersecting time periods during a unique readout time interval, wherein the unique readout time is not longer than a time needed to integrate one frame and the first time period, the second time period, the third time period and the fourth time period are non-overlapping.

2. The system of claim 1, the reset component sends the reset signals to the reset transistors to connect floating diffusion regions of the pixels to respective reset buses, which supply reset pulses to the floating diffusion regions.

3. The system of claim 1, the signal timing component mitigates cross-talk between rows of pixels in the pixel array when employing sub-frame integration mode.

4. The system of claim 1, the signal timing component manages the reset component and the select component to send the reset signals and the select signals to pixels in a first row of the pixel array during a first unique readout time interval and a second row of the pixel array during a second unique readout time interval when employing full frame integration.

5. The system of claim 1, the signal timing component controls the reset component to transfer the reset signals to pixels in a first row of the pixel array and pixels in a second row of the pixel array during different, non-intersecting time periods within the unique readout time interval when utilizing sub-frame integration.

6. The system of claim 5, the signal timing component further controls the select component to transmit the select signals to pixels in the first row of the pixel array during the unique readout time interval.

7. The system of claim 1, further comprising a mode selection component that obtains an input related to a chosen integration mode from a set of possible integration modes and effectuates operation utilizing the chosen integration mode, outputs from each of the possible integration modes exhibit substantially similar fixed pattern noise.

8. The system of claim 1, further comprising a pointer tracking component that identifies a row corresponding to a read pointer during a unique readout time interval for full frame integration and identifies a first row corresponding to a read pointer and a second row corresponding to a reset pointer during the unique readout time interval for sub-frame integration.

9. The system of claim 8, the read pointer indicates pixels to be read out and reset during the unique readout time interval and the reset pointer indicates pixels to be reset during the unique readout time interval.

10. The system of claim 1, the signal timing component coordinates sending a first reset signal to pixels in a first row corresponding to a read pointer during a first time period within a unique readout time interval and sending a second reset signal to pixels in a second row corresponding to a reset pointer during a second time period within the unique readout time interval while operating in sub-frame integration mode, the first time period and the second time period are non-overlapping to stagger the first reset signal and the second reset signal.

11. The system of claim 1, the signal timing component staggers resetting pixels in a first row corresponding to a read pointer and pixels in a second row corresponding to a reset pointer.

12. A system that staggers resets of rows of pixels in a CMOS imaging system-on-chip (iSoC) sensor, comprising:

a reset component that sends reset signals to reset transistors of pixels included in a pixel array to reset the pixels;

a select component that transfers select signals to select transistors of the pixels included in the pixel array to readout values from the pixels; and

a signal timing component that controls timing of the reset component and the select component to coordinate transferring reset signals and select signals to the pixels, wherein the signal timing component coordinates;

transmitting a first select signal to pixels in the first row during a time period prior to sending a first reset signal to pixels in a first row corresponding to a read pointer during a first time period within a unique readout time interval;

transmitting a second select signal to pixels in the first row during a time period subsequent to sending the first reset signal; and

sending a second reset signal to pixels in a second row corresponding to a reset pointer during a second time period within the unique readout time interval while operating in sub-frame integration mode, wherein the first time period and the second time period are non-overlapping to stagger the first reset signal and the second reset signal and the first select signal initiates reading values from pixels in the first row and the second select signal causes reading of reset values from pixels in the first row.

13. A method that facilitates staggering resets for sub-frame integration in a CMOS sensor imager, comprising:

sending a first select signal to a first set of pixels in a first row corresponding to a read pointer during a first time period within a unique readout time interval to read respective values from pixels in the first set, wherein the unique readout time interval is not longer than a time need to integrate one frame;

transferring a first reset signal to the first set of pixels in the first row during a second time period within the unique readout time interval to reset pixels in the first set;

transmitting a second reset signal to a second set of pixels in a second row corresponding to a reset pointer during a third time period within the unique readout time interval to reset pixels in the second set; and

conveying a second select signal to the first set of pixels in the first row during a fourth time period within the unique readout time interval to readout respective reset values from pixels in the first set,

wherein the first time period, the second time period, the third time period, and the fourth time period are non-overlapping.

14. The method of claim 13, further comprising ordering transmission of signals within the unique readout time interval to cause the first select signal to be sent first, the first reset signal transferred second, the second reset signal transmitted third, and the second select signal conveyed fourth.

15. The method of claim 13, further comprising ordering transmission of signals within the unique readout time interval to cause the second reset signal to be transmitted first, the first select signal sent second, the first reset signal transferred third, and the second select signal conveyed fourth.

16. A method that facilitates staggering resets for sub-frame integration in a CMOS sensor imager, comprising:

sending a first select signal to a first set of pixels in a first row corresponding to a read pointer during a first time period within a unique readout time interval to read respective values from pixels in the first set, wherein the unique readout time interval is not longer than a time need to integrate one frame;

transferring a first reset signal to the first set of pixels in the first row during a second time period within the unique readout time interval to reset pixels in the first set;

transmitting a second reset signal to a second set of pixels in a second row corresponding to a reset pointer during a third time period within the unique readout time interval to reset pixels in the second set; and

conveying a second select signal to the first set of pixels in the first row during a fourth time period within the unique readout time interval to readout respective reset values from pixels in the first set;

ordering transmission of signals within the unique readout time interval to cause the first select signal to be sent first, the first reset signal transferred second, the second reset signal transmitted third, and the second select signal conveyed fourth.