US-12627311-B2 - Analog-digital converter and method

Abstract

A method for controlling an analog-digital converter comprising first and second oscillators, and first and second elements, the method comprising a first step during which the first and second oscillators generate frequencies depending on an electrical characteristic of the first element and of the second element, respectively, and a second step during which the first and second oscillators generate frequencies depending on the electrical characteristic of the second element and of the first element, respectively.

Inventors

• François Tailliet
• Marc Battista

Assignees

• STMICROELECTRONICS INTERNATIONAL N.V.

Dates

Publication Date

20260512

Application Date

20240223

Priority Date

20230330

Claims (20)

1. 1 . A method for controlling an analog-digital converter comprising first and second oscillators and first and second elements, the method comprising: generating, in a first step by the first and second oscillators, frequencies depending on an electrical characteristic of the first element and of the second element, respectively; and generating, in a second step by the first and second oscillators, frequencies depending on the electrical characteristic of the second element and of the first element, respectively; the electrical characteristic of the first element being sensitive to variations of a physical quantity, and the electrical characteristic of the second element being insensitive or inversely sensitive to the variations of the physical quantity.
2. 2 . The method according to claim 1 , wherein the first and second oscillators are identical.
3. 3 . The method according to claim 1 , wherein the electrical characteristic of the second element is insensitive to the variations of the physical quantity.
4. 4 . The method according to claim 1 , wherein the first element is a sensor.
5. 5 . The method according to claim 1 , wherein the analog-digital converter comprises first and second counters, and the method further comprises: during the first step, counting, by the first counter, first oscillations of the first oscillator, and counting, by the second counter, first oscillations of the second oscillator; and during the second step, counting, by the first counter, second oscillations of the second oscillator, and counting, by the second counter, second oscillations of the first oscillator.
6. 6 . The method according to claim 5 , further comprising: reaching, by the second counter, a reference value; and triggering, by the second counter in response to reaching the reference value, a stopping of the oscillator associated with the first counter.
7. 7 . The method according to claim 5 , further comprising providing, by the first and second counters, counter values representative of first values of the respective electrical characteristics of the first and second elements.
8. 8 . The method according to claim 7 , further comprising: providing, by the first counter, a counter value representative of a current first value of the physical quantity.
9. 9 . The method according to claim 5 , further comprising generating, by a circuit of the analog-digital converter, a control signal of the oscillator associated with the first element depending on a state of an enabling signal of the oscillator associated with the second element and on a value of the second counter.
10. 10 . An analog-digital converter comprising: first and second elements; and first and second oscillators, wherein the first and second oscillators are configured to: generate, during a first step, frequencies depending on an electrical characteristic of the first element and of the second element, respectively; and generate, during a second step, frequencies depending on the electrical characteristic of the second element and of the first element, respectively; wherein the electrical characteristic of the first element is sensitive to variations of a physical quantity, and the electrical characteristic of the second element is insensitive or inversely sensitive to the variations of the physical quantity.
11. 11 . The analog-digital converter according to claim 10 , wherein the first and second oscillators are identical.
12. 12 . The analog-digital converter according to claim 10 , wherein the electrical characteristic of the second element is insensitive to the variations of the physical quantity.
13. 13 . The analog-digital converter according to claim 10 , wherein the first element is a sensor.
14. 14 . The analog-digital converter according to claim 10 , wherein the analog-digital converter further comprises: a first counter configured to: during the first step, count first oscillations of the first oscillator; and during the second step, count first oscillations of the second oscillator; and a second counter configured to: during the first step, count second oscillations of the second oscillator; and during the second step, count second oscillations of the first oscillator.
15. 15 . The analog-digital converter according to claim 14 , wherein the second counter is configured to: reach a reference value; and trigger, in response to reaching the reference value, a stopping of the oscillator associated with the first counter.
16. 16 . The analog-digital converter according to claim 14 , wherein the first and second counters are configured to provide counter values representative of first values of the respective electrical characteristics of the first and second elements.
17. 17 . The analog-digital converter according to claim 16 , wherein: the first counter is configured to provide a counter value representative of a current first value of the physical quantity.
18. 18 . The analog-digital converter according to claim 14 , wherein the analog-digital converter further comprises: a circuit configured to generate a control signal of the oscillator associated with the first element depending on a state of an enabling signal of the oscillator associated with the second element and on a value of the second counter.
19. 19 . An analog-digital converter comprising: first and second sensors; first and second oscillators, wherein the first and second oscillators are configured to: generate, during a first step, frequencies depending on an electrical characteristic of the first sensor and of the second sensor, respectively; and generate, during a second step, frequencies depending on the electrical characteristic of the second sensor and of the first sensor, respectively; and a first counter configured to: during the first step, count first oscillations of the first oscillator; and during the second step, count first oscillations of the second oscillator; and a second counter configured to: during the first step, count second oscillations of the second oscillator; and during the second step, count second oscillations of the first oscillator; wherein the electrical characteristic of the first sensor is sensitive to variations of a physical quantity, and the electrical characteristic of the second sensor is insensitive or inversely sensitive to the variations of the physical quantity.
20. 20 . The analog-digital converter according to claim 19 , wherein: the first and second oscillators are identical; and the electrical characteristic of the second sensor is insensitive to the variations of the physical quantity.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the priority benefit of French patent application number FR2303071, filed on Mar. 30, 2023, entitled “Convertisseur analogique-numérique,” which is hereby incorporated herein by reference to the maximum extent allowable by law. TECHNICAL FIELD The present description relates generally to electronic devices and methods, and more particularly to analog-digital converters and methods. The embodiments described relate more particularly to methods and converters based on oscillators. BACKGROUND An analog-digital converter is an electronic device the function of which is to translate an analog quantity into a digital value encoded on a plurality of bits. The converted signal is generally an electrical voltage. Some converters use variations of a frequency of an oscillator, which are generated by variations of a physical characteristic (or quantity) measured by a sensor, e.g., temperature, pressure, relative humidity, light, etc. The electrical properties of the sensor vary the frequency, and a measurement of an information representative of the frequency provides a conversion into a digital value representative of the physical quantity measured. However, such converters are sensitive to variations of an operating characteristic of the circuit, e.g., the supply voltage, to the aging thereof, or to variations in the manufacturing process. SUMMARY One embodiment addresses all or some of the drawbacks of known analog-digital converters. One embodiment provides a method for controlling an analog-digital converter comprising first and second oscillators, and first and second elements, the method comprises a first step during which the first and second oscillators generate frequencies depending on an electrical characteristic of the first element and of the second element, respectively, and a second step during which the first and second oscillators generate frequencies depending on the electrical characteristic of the second element and of the first element, respectively. Another embodiment provides an analog-digital converter comprising first and second oscillators, and first and second elements, wherein the first and second oscillators are configured for generating, during a first step, frequencies depending on an electrical characteristic of the first element and of the second element, respectively, and during a second step, frequencies depending on the electrical characteristic of the second element and of the first element, respectively. According to one embodiment, the first and second oscillators are identical. According to one embodiment, the electrical characteristic of the first element is sensitive to variations of a physical quantity, the electrical characteristic of the second element being insensitive to variations of the physical quantity. According to one embodiment, the first element is a sensor. According to one embodiment, the converter comprises first and second counters configured so that during the first step, the first counter counts the oscillations of the first oscillator and the second counter counts the oscillations of the second oscillator; and during the second step, the first counter counts the oscillations of the second oscillator and the second counter counts the oscillations of the first oscillator. According to one embodiment, the second counter triggers, when same reaches a reference value, the stopping of the oscillator associated with the first counter. According to one embodiment, the first and second counters provide values representative of the values of the respective electrical characteristics of the first and second elements. According to one embodiment, the first counter supplies a value representative of a current value of the physical quantity. In one embodiment, the converter includes a circuit configured for generating an oscillator control signal associated with the first element according to the state of an enabling signal of the oscillator associated with the second element and to the value of the second counter. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing features and advantages, as well as others, will be described in detail in the following description of specific embodiments given by way of illustration and not limitation with reference to the accompanying drawings, wherein: FIG. 1 schematically illustrates an embodiment of an analog-digital converter; FIG. 2A schematically illustrates a step of an embodiment of the analog-digital converter shown in FIG. 1; FIG. 2B schematically illustrates another step of an embodiment of the analog-digital converter of FIG. 1; FIG. 3 illustrates an example of embodiment of a part of the embodiment shown in FIG. 1; and FIG. 4 illustrates an example of embodiment of another part of the embodiment shown in FIG. 1. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS Like features have been designated by like references in the various figures. In particular, the structur