Variable capacitance switched capacitor input system and method
First Claim
1. A variable capacitance switched capacitor input system comprising:
- a differential integrator circuit having first and second input summing nodes;
a variable sensing capacitor;
a switching system for connecting one terminal of said variable sensing capacitor to one of said nodes in a first phase and to the other of said nodes in a second phase; and
a second terminal of said variable sensing capacitor for receiving a first voltage level in said first phase and a second voltage level in said second phase for transferring the charge on said variable sensing capacitor to said first summing node in said first phase and to said second summing node in said second phase and canceling errors in the differential integrator circuit output caused by leakage current.
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Abstract
A variable capacitance switched capacitor input system and method includes a differential integrator circuit having first and second input summing nodes and a variable sensing capacitor; one terminal of the variable sensing capacitor is connected to one of the nodes in the first phase and to the other of the nodes in the second phase; an input terminal connected to a second terminal of the variable sensing capacitor receives a first voltage level in the first phase and a second voltage level in the second phase for delivering the charge on the variable sensing capacitor to the first summing node in the first phase and to the second summing node in the second phase and canceling errors in a differential integrator circuit output caused by leakage current.
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Citations
19 Claims
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1. A variable capacitance switched capacitor input system comprising:
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a differential integrator circuit having first and second input summing nodes; a variable sensing capacitor; a switching system for connecting one terminal of said variable sensing capacitor to one of said nodes in a first phase and to the other of said nodes in a second phase; and a second terminal of said variable sensing capacitor for receiving a first voltage level in said first phase and a second voltage level in said second phase for transferring the charge on said variable sensing capacitor to said first summing node in said first phase and to said second summing node in said second phase and canceling errors in the differential integrator circuit output caused by leakage current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A variable capacitance switched capacitor input system comprising:
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a differential integrator circuit having first and second input summing nodes; first and second variable sensing capacitors; first and second switching systems associated with said first and second variable sensing capacitors, respectively, each said switching system connecting one terminal of its associated variable sensing capacitor to one of said nodes in a first phase and to the other of said nodes in a second phase; and each said variable sensing capacitor having a second terminal for receiving a first voltage level in said a first phase and a second voltage level in said second phase for transferring the charge on the associated said variable sensing capacitor to said one summing node in said first phase and to the other summing node in said second phase and canceling errors in each phase in the differential circuit output caused by leakage current. - View Dependent Claims (11, 12)
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13. A variable capacitance switched capacitor input system comprising:
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a differential integrator circuit having first and second input summing nodes; first and second variable sensing capacitors; first and second switching systems associated with said first and second variable sensing capacitors, respectively, each said switching system connecting one terminal of its associated variable sensing capacitor to one of said nodes in a first phase and to the other of said nodes in a second phase; and each of said variable sensing capacitors having a shared second terminal for receiving a first voltage level in said first phase and a second voltage level in said second phase for transferring the charge on the associated said variable sensing capacitor to said one summing node in said first phase and to the other summing node in said second phase and canceling errors in each phase in the differential circuit output caused by leakage current.
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14. A variable capacitance switched capacitor sigma delta modulator system comprising:
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a differential integration circuit having first and second input summing nodes; a variable sensing capacitor; a switching system for connecting one terminal of said variable sensing capacitor to one of said nodes in a first phase and to the other of said nodes in a second phase; and a second terminal of said variable sensing capacitor for receiving a first voltage level in said first phase and a second voltage level in said second phase for transferring the charge on said variable sensing capacitor to said first summing node in said first phase and to said second summing node in said second phase and canceling errors in the differential integrator circuit output caused by leakage current.
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15. A variable capacitance switched capacitor sigma delta modulator system comprising:
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a differential integrator circuit having first and second input summing nodes; first and second variable sensing capacitors; first and second switching systems associated with said first and second variable sensing capacitors, respectively, each said switching system connecting one terminal of its associated variable sensing capacitor to one of said nodes in a first phase and to the other of said nodes in a second phase; and each said variable sensing capacitor having a second terminal for receiving a first voltage level in said first phase and a second voltage level in said second phase for transferring the charge on the associated said variable sensing capacitor to said one summing node in said first phase and to the other summing node in said second phase and canceling errors in each phase in the differential circuit output caused by leakage current. - View Dependent Claims (16, 17)
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18. A variable capacitance switched capacitor sigma delta modulator system comprising:
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a differential integrator circuit having first and second input summing nodes; first and second variable sensing capacitors; first and second switching systems associated with said first and second variable sensing capacitors, respectively, each said switching system connecting one terminal of its associated variable sensing capacitor to one of said nodes in a first phase and to the other of said nodes in a second phase; and each of said variable sensing capacitors having a shared second terminal for receiving a first voltage level in said first phase and a second voltage level in said second phase for transferring the charge on the associated said variable sensing capacitor to said one summing node in said first phase and to the other summing node in said second phase and canceling in each phase in the differential circuit output caused by leakage current.
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19. A switching method for a variable capacitance switched capacitor input system having a differential integrator circuit having first and second input summing nodes, a variable sensing capacitor and second terminal of said variable sensing capacitor comprising:
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connecting one terminal of said variable sensing capacitor to one of said summing nodes in a first phase and to the other of said summing nodes in a second phase; and applying to said second terminal of said variable capacitor a first voltage level in said first phase and a second voltage level in said second phase for transferring the charge on said variable sensing capacitor to said first summing node in said first phase and to said second summing node in said second phase and canceling errors in the differential integrator circuit output caused by leakage current.
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Specification