Back to results
US 7,397,410 B2Granted
Input tracking high-level multibit quantizer for delta-sigma ADC
AssigneeTexas Instruments Incorporated
InventorYuQing Yang
Life of this patent
Estimating the term…
Abstract
A quantization circuit includes a plurality of resistors, a plurality of tap points, and a plurality of coarse comparators. Each coarse comparator has a first input coupled to an input voltage and a second input coupled to a corresponding coarse tap point voltage. Each coarse comparator operates during a first phase to produce a “1” only if the input voltage exceeds the corresponding coarse tap point voltage. A plurality of fine comparators each have a first input coupled to the input voltage, and each fine comparator operates during a second phase to produce a fine output level indicative of whether the input voltage exceeds a corresponding tap point voltage of a group of tap points located immediately below the tap point connected to the highest coarse comparator producing a “1”.
Claims17
A conversion circuit comprising:
- (a) a coarse-resolution quantization circuit including
- i. a resistor string including a plurality of resistors and a plurality of tap points between the various resistors, and
- ii. a plurality of coarse-resolution comparators, each coarse-resolution comparator having a first input coupled to receive an input voltage and a second input coupled to a corresponding coarse-resolution tap point, each coarse-resolution comparator being operable during a first phase to produce a first logic level only if the input voltage exceeds a voltage of the coarse-resolution tap point coupled to the second input of that coarse-resolution comparator;
- and
- (b) a fine-resolution quantization circuit including
- i. a plurality of fine-resolution comparators each having a first input coupled to receive the input voltage, each fine-resolution comparator being operable during a second phase to produce a fine-resolution output logic level indicative of whether the input voltage exceeds a voltage of a tap point coupled to a second input of that fine-resolution comparator, and
- ii. a control circuit operative to selectively couple the second input of each fine-resolution comparator to a corresponding tap point of a group of tap points located immediately below a coarse-resolution tap point coupled to a highest coarse-resolution comparator producing the first logic level, the output logic levels of the fine-resolution comparators and the coarse-resolution comparators up to and including the highest coarse-resolution comparator producing the first logic level representing a thermometer code representation of a quantized value of the input voltage.
4 more elements
A method of quantizing an analog input signal, comprising:
- (a) during a first phase time, coupling a first input of each of a plurality of coarse-resolution comparators to the input voltage, wherein a second input of each coarse-resolution comparator is coupled to a plurality of corresponding coarse tap points, respectively, of a resistor string which also includes a plurality of intermediate tap points to cause each coarse-resolution comparator to produce a first logic level only if the input voltage exceeds a voltage of the coarse-resolution tap point coupled to the first input of that course-resolution comparator;
- and
- (b) during a second phase time which follows the first phase time,
- i. coupling a first input of each of a plurality of fine-resolution comparators to the input voltage, and
- ii. selectively coupling a second input of each fine-resolution comparator to a corresponding tap point of a group of tap points located immediately below a coarse-resolution tap point coupled to a highest coarse-resolution comparator producing the first logic level to cause each fine-resolution comparator to produce a second logic level indicative of whether the input voltage exceeds a voltage of the tap point coupled to the second input of that fine-resolution comparator,
- wherein output logic levels of the fine-resolution comparators and the coarse-resolution comparators up to and including the highest coarse-resolution comparator producing the first logic level together represent a thermometer code representation of the input voltage.
3 more elements
A circuit for quantizing an analog input signal, comprising:
- (a) means for coupling a first input of each of a plurality of coarse-resolution comparators to the input voltage during a first phase time, wherein a second input of each coarse-resolution comparator is coupled to a plurality of corresponding coarse tap points, respectively, of a resistor string which also includes a plurality of intermediate tap points to cause each coarse-resolution comparator to produce a first logic level only if the input voltage exceeds a voltage of the coarse-resolution tap point coupled to the first input of that course-resolution comparator;
- (b) a plurality of fine-resolution comparators each having a first input coupled to the input voltage;
- and
- (c) means for selectively coupling a second input of each fine-resolution comparator to a corresponding tap point of a group of tap points located immediately below a coarse-resolution tap point coupled to a highest coarse-resolution comparator producing the first logic level to cause each fine-resolution comparator to produce a second logic level indicative of whether the input voltage exceeds a voltage of the tap point coupled to the second input of that fine-resolution comparator during a second phase time which follows the first phase time,
- wherein output logic levels of the fine-resolution comparators and the coarse-resolution comparators up to and including the highest coarse-resolution comparator producing the first logic level together represent a thermometer code representation of the input voltage.
2 more elements
Dependencies are inferred from the claim text.