Analogue-to-digital converter
AssigneeNordic Semiconductor ASA
InventorsCarsten Wulff, Ola Bruset, Werner Luzi
Life of this patent
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Abstract
An integrated-circuit, continuous-time, sigma-delta analog-to-digital converter has a single-ended analog input, a converter reference input, and a ground connection. The converter has a resistor-capacitor integrator arranged to receive the single-ended analog input. The integrator comprises a differential amplifier. The converter also has a clocked comparator connected to an output from the integrator, and circuitry arranged so that reference inputs to the amplifier and to the comparator can be maintained at a common voltage derived from the converter reference input.
Claims18
An integrated-circuit, continuous-time, sigma-delta analogue-to-digital converter having a single-ended analogue input, a converter reference input, and a ground connection, wherein the converter comprises:
- a resistor-capacitor integrator arranged to receive the single-ended analogue input, wherein the integrator comprises a differential amplifier having an amplifier reference input;
- a clocked comparator arranged to receive an output from the integrator and having a comparator reference input;
- circuitry arranged so that the amplifier reference input and the comparator reference input can be maintained at a common voltage derived from the converter reference input;
- and
- an arrangement of resistors comprising:
- (a) first and second resistors, wherein a first end of the first resistor is connected to the single-ended analogue input, a first end of the second resistor is connected to ground, and the second ends of the first and second resistors are connected to a second input of the amplifier;
- and
- (b) (i) a third resistor, wherein a first end of the third resistor is switchably connectable to the converter reference input or to ground, and a second end of the third resistor is connected to the second input of the amplifier, or (ii) third and fourth resistors, wherein a first end of the third resistor is connected to ground and a first end of the fourth resistor is connected to the converter reference input, and wherein the second ends of the third and fourth resistors are switchably connectable to the second input to the amplifier such that either one or other of the second ends is connected at a time.
Dependencies are inferred from the claim text.