Row driver circuit for a sensor including a shared row-reset bus and a charge pump boosting circuit
First Claim
1. A method comprising:
- selecting a row from a plurality of rows in a pixel array;
opening a path between a first line having a first voltage and a bus through one or more row select transistors;
selecting the row for reset;
opening a path between a second line having a second voltage and the bus through one or more reset enable transistors, said second voltage being higher than said first voltage; and
providing the second voltage to the one or more row select transistors.
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Accused Products
Abstract
A row driver according to an embodiment drives a shared row-reset bus to one of a select voltage and a boosted voltage to select a row for readout and to reset the pixels in the row, respectively. The boosted voltage is higher than the select voltage. A row select circuit includes PMOS transistors through which a path may be opened between a supply line carrying the select voltage and the bus. A reset enable circuit includes PMOS transistors through which a path may be opened between a supply line carrying the boosted voltage and the bus. In order to prevent a parasitic diode leakage between the two supply lines during reset, the n-wells of the PMOS transistors in the row select circuit may be coupled to the supply line carrying the boost voltage.
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Citations
26 Claims
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1. A method comprising:
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selecting a row from a plurality of rows in a pixel array;
opening a path between a first line having a first voltage and a bus through one or more row select transistors;
selecting the row for reset;
opening a path between a second line having a second voltage and the bus through one or more reset enable transistors, said second voltage being higher than said first voltage; and
providing the second voltage to the one or more row select transistors. - View Dependent Claims (2, 3, 4)
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5. A row driver comprising:
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a bus;
a first line operative to carry a select voltage;
a second line operative to be driven to a boosted voltage, said boosted voltage being higher than the select voltage; and
a first circuit operative to couple the bus to the first line in response to a row select signal, said first circuit including a transistor coupled to the second line, wherein the boosted voltage comprises a reset enable signal. - View Dependent Claims (8, 9, 10)
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6. A row driver comprising:
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a bus;
a first line operative to carry a select voltage;
a second line operative to be driven to a boosted voltage, said boosted voltage being higher than the select voltage;
a first circuit operative to couple the bus to the first line in response to a row select signal, said first circuit including a transistor coupled to the second line; and
a second circuit operative to couple the bus to the second line in response to a row reset signal. - View Dependent Claims (11, 12, 13)
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7. A row driver comprising:
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a bus;
a first line operative to carry a select voltage;
a second line operative to be driven to a boosted voltage, said boosted voltage being higher than the select voltage; and
a first circuit operative to couple the bus to the first line in response to a row select signal, said first circuit including a transistor coupled to the second line, wherein the transistor is coupled to the second line such that there is no parasitic diode leakage between the first line and the second line through the transistor in response to the second line being driven to the boosted voltage.
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14. A row driver comprising:
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a bus;
a first line operative to carry a select voltage;
a second line operative to be driven to a boosted voltage, said boosted voltage being higher than the select voltage; and
a first circuit operative to couple the bus to the first line in response to a row select signal, said first circuit including a transistor coupled to the second line, wherein the bus comprises a shared row-reset bus.
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15. A sensor comprising:
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a pixel array including a plurality of pixels arranged in rows and columns a plurality of buses, each bus coupled to pixels in one row of the pixel array;
a first line operative to carry a select voltage;
a second line operative to carry a row enable voltage;
a charge pump boost circuit operative to drive the second line to a boosted voltage, said boosted voltage being higher than the select voltage;
a plurality of row drivers, each row driver coupled to an associated one of the buses and including a first circuit operative to couple said bus to the first line in response to a row select signal, said first circuit including a transistor coupled to the second line, wherein the bus comprises a shared row-reset bus. - View Dependent Claims (19, 20, 21, 25)
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16. A sensor comprising:
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a pixel array including a plurality of pixels arranged in rows and columns a plurality of buses, each bus coupled to pixels in one row of the pixel array;
a first line operative to carry a select voltage;
a second line operative to carry a row enable voltage;
a charge pump boost circuit operative to drive the second line to a boosted voltage, said boosted voltage being higher than the select voltage;
a plurality of row drivers, each row driver coupled to an associated one of the buses and including a first circuit operative to couple said bus to the first line in response to a row select signal, said first circuit including a transistor coupled to the second line; and
a second circuit operative to couple the bus to the second line in response to a row reset signal. - View Dependent Claims (22, 23, 24)
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17. A sensor comprising:
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a pixel array including a plurality of pixels arranged in rows and columns a plurality of buses, each bus coupled to pixels in one row of the pixel array;
a first line operative to carry a select voltage;
a second line operative to carry a row enable voltage;
a charge pump boost circuit operative to drive the second line to a boosted voltage, said boosted voltage being higher than the select voltage; and
a plurality of row drivers, each row driver coupled to an associated one of the buses and including a first circuit operative to couple said bus to the first line in response to a row select signal, said first circuit including a transistor coupled to the second line, wherein the transistor is coupled to the second line such that there is no parasitic diode leakage between the first line and the second line through the transistor in response to the second line being driven to the boosted voltage.
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18. A sensor comprising:
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a pixel array including a plurality of pixels arranged in rows and columns a plurality of buses, each bus coupled to pixels in one row of the pixel array;
a first line operative to carry a select voltage;
a second line operative to carry a row enable voltage;
a charge pump boost circuit operative to drive the second line to a boosted voltage, said boosted voltage being higher than the select voltage; and
a plurality of row drivers, each row driver coupled to an associated one of the buses and including a first circuit operative to couple said bus to the first line in response to a row select signal, said first circuit including a transistor coupled to the second line. wherein the boosted voltage comprises a reset enable signal.
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26. A method of operating an image sensor comprising:
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selecting a row from a plurality of rows in a pixel array;
connecting a first line having a first voltage to a bus through one or more row select transistors;
selecting the row for reset;
connecting a second line having a second voltage to the bus through one or more reset enable transistors, said second voltage being higher than said first voltage; and
providing the second voltage to the one or more row select transistors.
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Specification