Back to results
US 8,299,513 B2Granted
High conversion gain image sensor
AssigneeOmniVision Technologies, Inc.
InventorTiejun Dai
Life of this patent
Estimating the term…
Abstract
An image sensor includes a photosensitive element, a reset circuit, an amplifier transistor, and a current source. The photosensitive element is coupled to generate an image charge in response to incident light and transfer the image charge to a circuit node. The reset circuit is coupled to selectively reset a voltage at the circuit node. The amplifier transistor includes a gate terminal responsive to the voltage at the circuit node. A current source is coupled between a high level power rail and a second terminal of the amplifier transistor.
Claims9
Image sensor circuitry, comprising:
- pixel cell circuitry for acquiring an image charge in response to incident light and generating an image signal indicative of the image charge;
- sample and hold circuitry to sample and hold the image signal;
- a bit line coupled between the pixel cell circuitry and the sample and hold circuitry;
- and
- a current source coupled between a high voltage power rail and the bit line,
- wherein the pixel cell circuitry includes:
- a photosensitive element coupled to a first circuit node, the photosensitive element for generating the image charge in response to the incident light and transferring the image charge to the first circuit node;
- and
- an amplifier transistor having a gate terminal coupled to the first circuit node and a second terminal coupled to the current source and the bit line, wherein the bit line couples the sample and hold circuitry to a second circuit node between the current source and the second terminal of the amplifier transistor,
- wherein the image sensor circuitry further includes boost circuitry coupled to selectively boost a voltage potential of a third terminal of the amplifier transistor and wherein the boost circuitry is coupled to the third terminal which is opposite the second terminal to which the current source and the bit line are coupled.
7 more elements
An image sensor, comprising:
- pixel cell circuitry for acquiring an image charge in response to incident light and generating an image signal indicative of the image charge;
- sample and hold circuitry to sample and hold the image signal;
- a bit line coupled to the pixel cell circuitry;
- a first current source selectively coupled between a high voltage power rail and the bit line to drive a first current onto the bit line between the pixel cell circuitry and the sample and hold circuitry;
- a second current source selectively coupled between the pixel cell circuitry and a low voltage power rail;
- a switched ring interconnection including switches to selectively couple the pixel cell circuitry, the sample and hold circuitry, and the first and second current sources to each other via selective enablement of the switches of the switched ring interconnect, wherein the switched ring interconnection includes:
- a first group of switches coupled to be responsive to a first control signal, the first group of switches to selectively couple the bit line to the high voltage rail, the second current source to the pixel cell circuitry, and the sample and hold circuitry to a node between the pixel cell circuitry and the second current source when the first control signal is asserted to configure the pixel cell circuitry into a standard conversion gain configuration;
- and
- a second group of switches coupled to be responsive to a second control signal, the second group of switches to selectively couple the bit line to the sample and hold circuitry, the first current source to the bit line between the sample and hold circuitry and the pixel cell circuitry, and the low voltage rail to the pixel cell circuitry when the second control signal is asserted to configure the pixel cell circuitry into a high conversion gain configuration.
6 more elements
Dependencies are inferred from the claim text.