Offset error compensation of input signals in analog-to-digital converter
First Claim
1. An analog-to-digital converter receiving an analog input signal including an offset component, the analog-to-digital converter comprising:
- (a) a switched capacitor input circuit configured to sample the analog input signal to produce and store a signal representative of the sampled input signal between a first conductor and a second conductor;
(b) a conversion circuit coupled to the first conductor and the switched capacitor input circuit and configured to produce a digital output signal representative of the analog input signal;
(c) an offset correction circuit having an output coupled to the second conductor and an input receiving a digital offset correction signal, the offset correction circuit including a switched capacitor correction circuit operative in response to the offset correction control signal to transfer charge to/from the second conductor;
(d) the conversion circuit being operative in response to adjustment by the offset correction circuit of a signal conducted by the first conductor to produce the digital output signal compensated for the offset component.
1 Assignment
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Accused Products
Abstract
An analog-to-digital converter receiving an analog input signal (VIN) including an offset component, and includes a switched capacitor input circuit (101) configured to sample the analog input signal (VIN) to produce and store a signal representative of the sampled input signal between a first conductor (17) and a second conductor (27). A conversion circuit (1) is coupled to the first conductor (27) and the switched capacitor input circuit (101) to produce a digital output signal (DATA OUT). An offset correction circuit (4) includes an output coupled to the second conductor (27) and an input receiving a digital offset correction signal (DATA IN), the offset correction circuit (4) including a switched capacitor correction circuit (4A) operative in response to the offset correction control signal (DATA IN) to transfer charge to/from the second conductor (27). The conversion circuit (1) operates in response to adjustment by the offset correction circuit (4) of a signal conducted by the second conductor (27) to produce the digital output signal (DATA OUT) compensated for the offset component.
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Citations
25 Claims
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1. An analog-to-digital converter receiving an analog input signal including an offset component, the analog-to-digital converter comprising:
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(a) a switched capacitor input circuit configured to sample the analog input signal to produce and store a signal representative of the sampled input signal between a first conductor and a second conductor;
(b) a conversion circuit coupled to the first conductor and the switched capacitor input circuit and configured to produce a digital output signal representative of the analog input signal;
(c) an offset correction circuit having an output coupled to the second conductor and an input receiving a digital offset correction signal, the offset correction circuit including a switched capacitor correction circuit operative in response to the offset correction control signal to transfer charge to/from the second conductor;
(d) the conversion circuit being operative in response to adjustment by the offset correction circuit of a signal conducted by the first conductor to produce the digital output signal compensated for the offset component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of avoiding loss of resolution in conversion of an analog input signal having an offset component to a digital signal, the method comprising:
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(a) determining a magnitude of the offset component;
(b) producing an offset compensation control signal representative of the magnitude of the offset component; and
(c) controlling a transfer of offset compensation charge into or out of a conductor in a switched capacitor input circuit of an analog-to-digital converter to adjust a signal representative of the analog input voltage being conducted by the first conductor so as to cause a conversion circuit of the analog-to-digital converter to produce a digital output signal having a full-scale value equal to the magnitude of the analog input signal plus or minus the magnitude of the offset component. - View Dependent Claims (17, 18, 19, 20)
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21. An analog-to-digital conversion system for avoiding loss of resolution in conversion of an analog input signal having an offset component to a digital signal, comprising:
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(a) means for determining a magnitude of the offset component;
(b) means for producing an offset compensation control signal representative of the magnitude of the offset component; and
(c) means for controlling a transfer of offset compensation charge into or out of a conductor in a switched capacitor input circuit of an analog-to-digital converter to adjust a signal representative of the analog input voltage being conducted by the first conductor so as to cause a conversion circuit of the analog-to-digital converter to produce a digital output signal having a full-scale value equal to the magnitude of the analog input signal plus or minus the magnitude of the offset component. - View Dependent Claims (22, 23, 24, 25)
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Specification