Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Amplitude control
Reexamination Certificate
2005-12-29
2009-06-02
Le, Dinh T. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Amplitude control
C327S030000
Reexamination Certificate
active
07541857
ABSTRACT:
An impedance compensation circuit for inputs of a programmable device includes programmable impedance circuits connected with input nodes. The programmable impedance circuits can be configured to apply a compensating voltages to input nodes to reduce or eliminate unwanted offset voltages. An impedance compensation circuit may include resistors in series or current sources in parallel. A set of bypass switches selectively apply each resistor or current source to an input node, thereby changing the offset voltage of the node and compensating for impedance mismatches. Control logic provides signals to control the bypass switches. The control logic may be implemented using programmable device resources, enabling the control logic to be updated and improved after the manufacturing of the device is complete. The control logic can automatically evaluate offset voltages at any time and change compensating impedances accordingly. This reduces manufacturing costs and takes into account temperature and aging effects.
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Lai Tin H.
Patel Rakesh H.
Shumarayev Sergey
Wong Wilson
Altera Corporation
Le Dinh T.
Townsend and Townsend / and Crew LLP
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