Self Auto-Calibration of Analog Circuits in a Mixed Signal Integrated Circuit Device
First Claim
1. An integrated circuit having at least one analog input device and an auto-calibration circuit to minimize input offset voltage in at least one analog input device, comprising:
- at least one analog input device having a digitally controlled input offset voltage compensation circuit; and
an auto-calibration circuit, said auto-calibration circuit being coupled to said at least one analog input device and to the input offset voltage compensation circuit, wherein input offset voltage is minimized in said at least one analog input device during an auto-calibration cycle that is initiated by an event.
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Accused Products
Abstract
Auto-calibration of the analog circuits occurs when requested by a user and/or the occurrence of an event(s). The user may invoke an auto-calibration on demand through an auto-calibration (ACAL) input to the mixed-signal integrated circuit. An external voltage calibration (VCAL) input may be used for auto-calibration of the mixed-signal integrated circuit to a user-supplied common-mode voltage reference. Auto-calibration of the mixed-signal integrated circuit may also be initiated upon the occurrence of any one or more of the following events: 1) detection of auto-calibration data corruption, e.g., parity checking of auto-calibration data values digitally stored in the mixed-signal integrated circuit; 2) an internal timer that causes a calibration request after a programmable timeout period, 3) change in the internal integrated circuit die temperature as determined by a temperature sensor, and 4) a change in the power supply and/or internal supply voltage(s).
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Citations
29 Claims
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1. An integrated circuit having at least one analog input device and an auto-calibration circuit to minimize input offset voltage in at least one analog input device, comprising:
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at least one analog input device having a digitally controlled input offset voltage compensation circuit; and an auto-calibration circuit, said auto-calibration circuit being coupled to said at least one analog input device and to the input offset voltage compensation circuit, wherein input offset voltage is minimized in said at least one analog input device during an auto-calibration cycle that is initiated by an event. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for minimizing an input offset voltage in an analog input device upon an occurrence of an event, said method comprising the steps of:
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(a) detecting an occurrence of an event; (b) switching from a normal mode to an auto-calibration mode upon detection of the occurrence of the event an analog input device having an input offset voltage compensation circuit; (c) applying a reference voltage to the analog input device; (d) minimizing an input offset voltage of the analog input device by; (i) measuring an output voltage of the analog input device; and (ii) applying input offset compensation values to the input offset voltage compensation circuit until the output voltage from the analog input device is at a desired value and then storing the input offset compensation value that minimizes the input offset voltage of the analog input device; and (e) switching the analog input device from the calibration mode to the normal mode. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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Specification