Double-sampled ΣΔ modulator of second order having a semi-bilinear architecture
AssigneeSTMicroelectronics S.r.l.
InventorsAngelo Nagari, Germano Nicollini
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Abstract
A second-order double-sampled ΣΔ analog/digital converter uses two fully differential switched-capacitor integrators coupled in cascade. The first integrator has a fully-floating double-sampled, bilinear switched capacitor input structure. The second integrator has a double-sampled lossless discrete integrator (LDI) switched-capacitor input structure. The converter achieves an excellent SNR with a reduced number of switches for low power consumption.
Claims24
A second-order double-sampled ΣΔ analog/digital converter comprising:
- first and second fully differential switched-capacitor integrators coupled in cascade;
- said first switched-capacitor integrator comprising a fully-floating double-sampled, bilinear switched-capacitor input structure;
- said second switched-capacitor integrator comprising a double-sampled lossless discrete integrator switched-capacitor input structure.
An analog/digital converter comprising:
- first and second fully differential switched-capacitor integrators coupled in cascade;
- said first switched-capacitor integrator comprising a first operational amplifier, a first pair of feedback capacitors connected to said first operational amplifier, and a first plurality of input capacitors and associated switches connected to said first operational amplifier to define a fully-floating double-sampled, bilinear switched-capacitor input structure;
- said second switched-capacitor integrator comprising a second operational amplifier, a second pair of feedback capacitors connected to said second operational amplifier, and a second plurality of input capacitors and associated switches connected to said second operational amplifier to define a double-sampled lossless discrete integrator switched-capacitor input structure.
A method for making an analog/digital converter comprising the steps of:
- forming a first fully differential switched-capacitor integrator comprising a fully-floating double-sampled, bilinear switched-capacitor input structure;
- and
- forming a second fully differential switched-capacitor integrator comprising a double-sampled lossless discrete integrator switched-capacitor input structure, the second switch-capacitor integrator being connected to the first switched-capacitor integrator.
Dependencies are inferred from the claim text.