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公开(公告)号：US12250485B2
公开(公告)日：2025-03-11
申请号：US17659041
申请日：2022-04-13
Applicant: OMNIVISION TECHNOLOGIES, INC.
Inventor： Tao Sun
Abstract: A ramp generator includes an operational amplifier having an output to generate a ramp signal. An integration current source is coupled to a first input and a reference voltage is coupled to a second input of the operational amplifier. A feedback capacitor and a reset switch are coupled between the first input and the output of the operational amplifier. The reset switch is turned on to reset the ramp generator. A ramp event is configured to be generated in the ramp signal at the output of the operational amplifier in response to the reset switch being turned off. An assist current source is coupled between the output of the operational amplifier and ground. The assist current source is configured to conduct an assist current from the output of the operational amplifier to ground in response to the reset switch being turned off.
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公开(公告)号：US11722801B1
公开(公告)日：2023-08-08
申请号：US17659042
申请日：2022-04-13
Applicant: OMNIVISION TECHNOLOGIES, INC.
Inventor： Hiroaki Ebihara , Zhenfu Tian , Tao Sun , Liang Zuo , Yu-Shen Yang , Satoshi Sakurai , Rui Wang
IPC: H04N25/75 , H04N25/772
CPC classification number: H04N25/75 , H04N25/772
Abstract: A ramp buffer circuit includes an input device having an input coupled to receive a ramp signal. A bias current source is coupled to an output of the input device. The input device and the bias current source are coupled between a power line and ground. An assist current source is coupled between the output of the input device and ground. The assist current source is configured to conduct an assist current from the output of the input device to ground only during a ramp event generated in the ramp signal.
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Patent Agency Ranking
公开(公告)号：US11627273B2
公开(公告)日：2023-04-11
申请号：US17217950
申请日：2021-03-30
Applicant: OMNIVISION TECHNOLOGIES, INC.
Inventor： Tao Sun
Abstract: A ramp generator includes a plurality of switched current sources coupled in parallel between a resistor and ground. A digital ramp control signal generator includes a counter to generate a ramp control signal in response to a clock signal. Each bit of the ramp control signal is coupled to control switching of a respective one of the plurality of switched current sources to generate a ramp signal at an output of the ramp generator. The digital ramp control signal generator is coupled to receive a reset signal to zero the ramp control signal. The digital ramp control signal generator is further coupled to receive a set bits signal to initialize the ramp signal to a preset value after every reset of the ramp control signal to add a DC offset compensation current determined by the preset value to the ramp signal.
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公开(公告)号：US11770634B1
公开(公告)日：2023-09-26
申请号：US17719602
申请日：2022-04-13
Applicant: OMNIVISION TECHNOLOGIES, INC.
Inventor： Zhenfu Tian , Hiroaki Ebihara , Tao Sun , Yi Liu , Shan Chen
Abstract: A ramp generator includes an operational amplifier having an output to generate a ramp signal. An integration current source is coupled to a first input and a reference voltage is coupled to a second input of the operational amplifier. A feedback capacitor is coupled between the first input and the output of the operational amplifier. A monitor circuit is coupled to the first and second inputs of the operational amplifier to generate an output flag in response to a comparison of the first and second inputs. A trimming control circuit is configured to generate a trimming signal in response to the output flag. An assist current source is configured to conduct an assist current from the output of the operational amplifier to ground in response the trimming signal generated by the trimming control circuit.
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公开(公告)号：US20230336889A1
公开(公告)日：2023-10-19
申请号：US17719602
申请日：2022-04-13
Applicant: OMNIVISION TECHNOLOGIES, INC.
Inventor： Zhenfu Tian , Hiroaki Ebihara , Tao Sun , Yi Liu , Shan Chen
CPC classification number: H04N5/378 , H03K4/08 , H04N5/3765
Abstract: A ramp generator includes an operational amplifier having an output to generate a ramp signal. An integration current source is coupled to a first input and a reference voltage is coupled to a second input of the operational amplifier. A feedback capacitor is coupled between the first input and the output of the operational amplifier. A monitor circuit is coupled to the first and second inputs of the operational amplifier to generate an output flag in response to a comparison of the first and second inputs. A trimming control circuit is configured to generate a trimming signal in response to the output flag. An assist current source is configured to conduct an assist current from the output of the operational amplifier to ground in response the trimming signal generated by the trimming control circuit.
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公开(公告)号：US20230336165A1
公开(公告)日：2023-10-19
申请号：US17659041
申请日：2022-04-13
Applicant: OMNIVISION TECHNOLOGIES, INC.
Inventor： Tao Sun
Abstract: A ramp generator includes an operational amplifier having an output to generate a ramp signal. An integration current source is coupled to a first input and a reference voltage is coupled to a second input of the operational amplifier. A feedback capacitor and a reset switch are coupled between the first input and the output of the operational amplifier. The reset switch is turned on to reset the ramp generator. A ramp event is configured to be generated in the ramp signal at the output of the operational amplifier in response to the reset switch being turned off. An assist current source is coupled between the output of the operational amplifier and ground. The assist current source is configured to conduct an assist current from the output of the operational amplifier to ground in response to the reset switch being turned off.
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公开(公告)号：US20220321815A1
公开(公告)日：2022-10-06
申请号：US17217950
申请日：2021-03-30
Applicant: OMNIVISION TECHNOLOGIES, INC.
Inventor： Tao Sun
Abstract: A ramp generator includes a plurality of switched current sources coupled in parallel between a resistor and ground. A digital ramp control signal generator includes a counter to generate a ramp control signal in response to a clock signal. Each bit of the ramp control signal is coupled to control switching of a respective one of the plurality of switched current sources to generate a ramp signal at an output of the ramp generator. The digital ramp control signal generator is coupled to receive a reset signal to zero the ramp control signal. The digital ramp control signal generator is further coupled to receive a set bits signal to initialize the ramp signal to a preset value after every reset of the ramp control signal to add a DC offset compensation current determined by the preset value to the ramp signal.
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