Analog bus driver and multiplexer
First Claim
1. An analog bus driver and multiplexer circuit for a detector comprising an array of pixels, the pixels being read out by columns, the circuit comprising a switched source-follower in each column connected by a bus common to the columns.
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Accused Products
Abstract
For a source-follower signal chain, the ohmic drop in the selection switch causes unacceptable voltage offset, non-linearity, and reduced small signal gain. For an op amp signal chain, the required bias current and the output noise rises rapidly with increasing the array format due to a rapid increase in the effective capacitance caused by the Miller effect boosting up the contribution of the bus capacitance. A new switched source-follower signal chain circuit overcomes limitations of existing op-amp based or source follower based circuits used in column multiplexers and data readout. This will improve performance of CMOS imagers, and focal plane read-out integrated circuits for detectors of infrared or ultraviolet light.
28 Citations
30 Claims
- 1. An analog bus driver and multiplexer circuit for a detector comprising an array of pixels, the pixels being read out by columns, the circuit comprising a switched source-follower in each column connected by a bus common to the columns.
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19. A detector of radiation, comprising:
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an array of pixels, wherein the pixels are read out by columns; and
at least one analog bus driver and multiplexer circuit for readout, the circuit comprising;
a switched source-follower in each column connected to a bus common to the columns. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. A method for readout of a detector comprising a focal plane array of pixels, wherein the pixels are read out by columns, comprising:
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providing a switched source-follower in each column followed by a switched-capacitor gain stage common to the columns;
sequentially reading out each column by switching the source-follower in each column to connect the source-follower output to a bus common to the columns;
passing the source-follower output through the bus to the switched-capacitor gain stage. - View Dependent Claims (27)
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28. An analog bus driver and multiplexer circuit for an imager, the circuit comprising:
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a plurality of columns, each column comprising a switched source-follower; and
a switched capacitor gain stage common to the plurality of columns, each source follower being connected to the switched capacitor gain stage. - View Dependent Claims (29, 30)
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Specification