Patents by Inventor Chao-Fang Tsai

Chao-Fang Tsai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20230179889
    Abstract: A differential subrange analog-to-digital converter (ADC) converts differential analog image signals received from sample and hold circuits to a digital signal through an ADC comparator. The comparator of the differential subrange ADC is shared by a successive approximation register (SAR) ADC coupled to provide both M upper output bits (UOB) and a ramp ADC coupled to provide N lower output bits (LOB). Digital-to-analog converters (DACs) of the differential subrange SAR ADC comprises 2M buffered bit capacitor fingers connected to the comparator. Each buffered bit capacitor finger comprises a bit capacitor, a bit buffer, and a bit switch controlled by the UOB. Both DACs are initialized to preset values and finalized based on the values of the least significant bit of the UOB. The subsequent ramp ADC operation will be ensured to have its first ramp signal ramps in a monotonic direction and its second ramp signal ramp in an opposite direction.
    Type: Application
    Filed: December 2, 2021
    Publication date: June 8, 2023
    Applicant: OmniVision Technologies, Inc.
    Inventors: Chao-Fang Tsai, Zheng Yang, Chun-Hsiang Chang
  • Patent number: 11659302
    Abstract: A differential subrange analog-to-digital converter (ADC) converts differential analog image signals received from sample and hold circuits to a digital signal through an ADC comparator. The comparator of the differential subrange ADC is shared by a successive approximation register (SAR) ADC coupled to provide both M upper output bits (UOB) and a ramp ADC coupled to provide N lower output bits (LOB). Digital-to-analog converters (DACs) of the differential subrange SAR ADC comprises 2M buffered bit capacitor fingers connected to the comparator. Each buffered bit capacitor finger comprises a bit capacitor, a bit buffer, and a bit switch controlled by the UOB. Both DACs are initialized to preset values and finalized based on the values of the least significant bit of the UOB. The subsequent ramp ADC operation will be ensured to have its first ramp signal ramps in a monotonic direction and its second ramp signal ramp in an opposite direction.
    Type: Grant
    Filed: December 2, 2021
    Date of Patent: May 23, 2023
    Assignee: OmniVision Technologies, Inc.
    Inventors: Chao-Fang Tsai, Zheng Yang, Chun-Hsiang Chang
  • Patent number: 11632512
    Abstract: An arithmetic logic unit (ALU) includes a front end latch stage coupled to latch Gray code (GC) outputs of a GC generator in response to a comparator output. A signal latch stage is coupled to latch outputs of the front end latch stage. A GC to binary stage is coupled to generate a binary representation of the GC outputs latched in the signal latch stage. First inputs of an adder stage are coupled to receive outputs of the GC to binary stage. Outputs of the adder stage are generated in response to the first inputs and second inputs of the adder stage. A pre-latch stage is coupled to latch outputs of the adder stage. A feedback latch stage is coupled to latch outputs of the pre-latch stage. The second inputs of the adder stage are coupled to receive outputs of the feedback latch stage.
    Type: Grant
    Filed: February 19, 2021
    Date of Patent: April 18, 2023
    Assignee: OmniVision Technologies, Inc.
    Inventors: Lihang Fan, Min Qu, Chao-Fang Tsai, Chun-Hsiang Chang
  • Publication number: 20220269482
    Abstract: An arithmetic logic unit (ALU) includes a front end latch stage coupled to latch Gray code (GC) outputs of a GC generator in response to a comparator output. A signal latch stage is coupled to latch outputs of the front end latch stage. A GC to binary stage is coupled to generate a binary representation of the GC outputs latched in the signal latch stage. First inputs of an adder stage are coupled to receive outputs of the GC to binary stage. Outputs of the adder stage are generated in response to the first inputs and second inputs of the adder stage. A pre-latch stage is coupled to latch outputs of the adder stage. A feedback latch stage is coupled to latch outputs of the pre-latch stage. The second inputs of the adder stage are coupled to receive outputs of the feedback latch stage.
    Type: Application
    Filed: February 19, 2021
    Publication date: August 25, 2022
    Inventors: Lihang Fan, Min Qu, Chao-Fang Tsai, Chun-Hsiang Chang
  • Patent number: 11206368
    Abstract: A data transmission circuit of an image sensor. In one embodiment, the data transmission circuit includes a plurality of banks coupled in a series. A peripheral bank of the plurality of transmission banks is coupled to a function logic. Each bank includes a plurality of local buffers coupled to a local buffer control and a plurality of global buffers coupled to a global buffer control. The local buffers are settable to their enabled or disabled state by a bank enable command at the local buffer control. The enabled local buffers are configured to transfer local data to shift registers of their respective bank. The disabled local buffers are configured not to transfer the local data to the shift register of their respective bank.
    Type: Grant
    Filed: May 22, 2020
    Date of Patent: December 21, 2021
    Assignee: OMNIVISION TECHNOLOGIES, INC.
    Inventors: Chun-Hsiang Chang, Zejian Wang, Chao-Fang Tsai, Jingwei Lai
  • Patent number: 11196949
    Abstract: A subrange analog-to-digital converter (ADC) converts analog image signal received from a bitline to a digital signal through an ADC comparator. The comparator is shared by a successive approximation register (SAR) ADC coupled to provide M upper output bits (UOB) of the subrange ADC and a ramp ADC coupled to provide N lower output bits (LOB). The digital-to-analog converter (DAC) of the SAR ADC comprises M buffered bit capacitors connected to the comparator. Each buffered bit capacitor comprises a bit capacitor, a bit buffer, and a bit switch controlled by one of the UOB of the SAR ADC. A ramp buffer is coupled between a ramp generator and a ramp capacitor. The ramp capacitor is further coupled to the same comparator. The implementation of ramp buffer and the bit buffers as well as their sharing of the same kind of buffer reduces differential nonlinear (DNL) error of the subrange ADC.
    Type: Grant
    Filed: October 2, 2019
    Date of Patent: December 7, 2021
    Assignee: OmniVision Technologies, Inc.
    Inventors: Chao-Fang Tsai, Zheng Yang
  • Publication number: 20210368116
    Abstract: A data transmission circuit of an image sensor. In one embodiment, the data transmission circuit includes a plurality of banks coupled in a series. A peripheral bank of the plurality of transmission banks is coupled to a function logic. Each bank includes a plurality of local buffers coupled to a local buffer control and a plurality of global buffers coupled to a global buffer control. The local buffers are settable to their enabled or disabled state by a bank enable command at the local buffer control. The enabled local buffers are configured to transfer local data to shift registers of their respective bank. The disabled local buffers are configured not to transfer the local data to the shift register of their respective bank.
    Type: Application
    Filed: May 22, 2020
    Publication date: November 25, 2021
    Inventors: Chun-Hsiang Chang, Zejian Wang, Chao-Fang Tsai, Jingwei Lai
  • Publication number: 20210105422
    Abstract: A subrange analog-to-digital converter (ADC) converts analog image signal received from a bitline to a digital signal through an ADC comparator. The comparator is shared by a successive approximation register (SAR) ADC coupled to provide M upper output bits (UOB) of the subrange ADC and a ramp ADC coupled to provide N lower output bits (LOB). The digital-to-analog converter (DAC) of the SAR ADC comprises M buffered bit capacitors connected to the comparator. Each buffered bit capacitor comprises a bit capacitor, a bit buffer, and a bit switch controlled by one of the UOB of the SAR ADC. A ramp buffer is coupled between a ramp generator and a ramp capacitor. The ramp capacitor is further coupled to the same comparator. The implementation of ramp buffer and the bit buffers as well as their sharing of the same kind of buffer reduces differential nonlinear (DNL) error of the subrange ADC.
    Type: Application
    Filed: October 2, 2019
    Publication date: April 8, 2021
    Applicant: OmniVision Technologies, Inc.
    Inventors: Chao-Fang Tsai, Zheng Yang
  • Patent number: 10841525
    Abstract: Apparatuses and methods for data transmission in an image sensor are disclosed herein. An example data transmission circuit may include a plurality of transmission banks coupled in series with a first one of the plurality of transmission banks coupled to function logic, where each of the plurality of transmission banks are coupled to provide image data to a subsequent transmission bank in a direction toward the function logic in response to a clock signal, a plurality of delays coupled in series, wherein each of the plurality of delays is associated with and coupled to a respective transmission bank of the plurality of transmission banks, and wherein the clock signal is received by each of the plurality of transmission banks after being delayed by a respective number of delays of the plurality of delays in relation to the function logic.
    Type: Grant
    Filed: August 23, 2019
    Date of Patent: November 17, 2020
    Assignee: OmniVision Technologies, Inc.
    Inventors: Chao-Fang Tsai, Chun-Hsiang Chang, Zejian Wang
  • Patent number: 10375338
    Abstract: A hybrid bonded image sensor has a photodiode die with macrocells having at least one photodiode and a bond contact; a supporting circuitry die with multiple supercells, each supercell having at least one macrocell unit having a bond contact coupled to the bond contact of a macrocell of the photodiode die. Each macrocell unit lies within a supercell and has a reset transistor adapted to reset photodiodes of the macrocell of the photodiode die. Each supercell has at least one common source amplifier adapted to receive signal from the bond contact of a selected macrocell unit of the supercell, the common source amplifier coupled to drive a column line through a selectable source follower. In embodiments, the common source amplifiers of several supercells drive the selectable source follower through a distributed differential amplifier.
    Type: Grant
    Filed: February 1, 2017
    Date of Patent: August 6, 2019
    Assignee: OmniVision Technologies, Inc.
    Inventors: Zheng Yang, Hiroaki Ebihara, Chun-Ming Tang, Chao-Fang Tsai, Rui Wang, Tiejun Dai
  • Patent number: 10263031
    Abstract: A hybrid-bonded image sensor has a photodiode die with multiple macrocells; each macrocell has at least one photodiode and a coupling region. The coupling regions couple to a coupling region of a macrocell unit of a supporting circuitry die where they feed an input of an amplifier and a feedback capacitor. The feedback capacitor also couples to output of the amplifier, and the amplifier inverts between the input and the output. The method includes resetting a photodiode of the photodiode die; coupling signal from photodiode through the bond point to the supporting circuitry die to a feedback capacitor and to an input of the amplifier, the feedback capacitor also coupled to an inverting output of the amplifier; and amplifying the signal with the amplifier, where a capacitance of the feedback capacitor determines a gain of the amplifier.
    Type: Grant
    Filed: February 1, 2017
    Date of Patent: April 16, 2019
    Assignee: OmniVision Technologies, Inc.
    Inventors: Rui Wang, Hiroaki Ebihara, Zheng Yang, Chun-Ming Tang, Chao-Fang Tsai, Tiejun Dai
  • Publication number: 20180220094
    Abstract: A hybrid bonded image sensor has a photodiode die with macrocells having at least one photodiode and a bond contact; a supporting circuitry die with multiple supercells, each supercell having at least one macrocell unit having a bond contact coupled to the bond contact of a macrocell of the photodiode die. Each macrocell unit lies within a supercell and has a reset transistor adapted to reset photodiodes of the macrocell of the photodiode die. Each supercell has at least one common source amplifier adapted to receive signal from the bond contact of a selected macrocell unit of the supercell, the common source amplifier coupled to drive a column line through a selectable source follower. In embodiments, the common source amplifiers of several supercells drive the selectable source follower through a distributed differential amplifier.
    Type: Application
    Filed: February 1, 2017
    Publication date: August 2, 2018
    Inventors: Zheng YANG, Hiroaki EBIHARA, Chun-Ming TANG, Chao-Fang TSAI, Rui WANG, Tiejun DAI
  • Publication number: 20180220095
    Abstract: A hybrid-bonded image sensor has a photodiode die with multiple macrocells; each macrocell has at least one photodiode and a coupling region. The coupling regions couple to a coupling region of a macrocell unit of a supporting circuitry die where they feed an input of an amplifier and a feedback capacitor. The feedback capacitor also couples to output of the amplifier, and the amplifier inverts between the input and the output. The method includes resetting a photodiode of the photodiode die; coupling signal from photodiode through the bond point to the supporting circuitry die to a feedback capacitor and to an input of the amplifier, the feedback capacitor also coupled to an inverting output of the amplifier; and amplifying the signal with the amplifier, where a capacitance of the feedback capacitor determines a gain of the amplifier.
    Type: Application
    Filed: February 1, 2017
    Publication date: August 2, 2018
    Inventors: Rui WANG, Hiroaki EBIHARA, Zheng YANG, Chun-Ming TANG, Chao-Fang TSAI, Tiejun DAI
  • Patent number: 9859312
    Abstract: An image sensor includes a photodiode disposed in a first semiconductor material, and the photodiode is positioned to absorb image light through the backside of the first semiconductor material. A first floating diffusion is disposed proximate to the photodiode and coupled to receive image charge from the photodiode in response to a transfer signal applied to a transfer gate disposed between the photodiode and the first floating diffusion. A second semiconductor material, including a second floating diffusion, is disposed proximate to the frontside of the first semiconductor material. A dielectric material is disposed between the first semiconductor material and the second semiconductor material, and includes a first bonding via extending from the first floating diffusion to the second floating diffusion, a second bonding via disposed laterally proximate to the first bonding via, and a third bonding via disposed laterally proximate to the first bonding via.
    Type: Grant
    Filed: February 8, 2017
    Date of Patent: January 2, 2018
    Assignee: OmniVision Technologies, Inc.
    Inventors: Rui Wang, Hiroaki Ebihara, Zheng Yang, Chun-Ming Tang, Chao-Fang Tsai, Tiejun Dai