Sensing an external stimulus using a group of continuous-time Nyquist rate analog-to-digital converters in a round-robin manner

Patent metadata

Field	Value
Publication number	US-10608656-B2
Application number	US-201816219812-A
Country	US
Kind code	B2
Filing date	Dec 13, 2018
Priority date	Dec 14, 2017
Publication date	Mar 31, 2020
Grant date	Mar 31, 2020

Abstract

Facilitating a reduction in sensor system latency, circuit size, and current draw utilizing a group of continuous-time Nyquist rate analog-to-digital converters (ADCs) in a round-robin manner is presented herein. A sensor system can comprise a group of sensors that generate respective sensor output signals based on an external excitation of the sensor system; a multiplexer that facilitates a selection, based on a sensor selection input, of a sensor output signal of the respective sensor output signals corresponding to a sensor of the group of sensors; a sense amplifier comprising a charge or voltage sensing circuit that converts the sensor output signal to an analog output signal; and a continuous-time Nyquist rate analog-to-digital converter of the group of continuous-time Nyquist rate ADCs that converts the analog output signal to a digital output signal representing at least a portion of the external excitation of the sensor system.

First claim

What is claimed is:

1. A sensor system, comprising:
a group of sensors that generate respective sensor output signals based on an external excitation of the sensor system;
a multiplexer that selects, based on a sensor selection input, a sensor output signal of the respective sensor output signals corresponding to a sensor of the group of sensors;
a sense amplifier comprising a charge or voltage sensing circuit that converts the sensor output signal to an analog output signal; and
a continuous-time Nyquist rate analog-to-digital converter (ADC) of a group of continuous-time Nyquist rate ADCs that converts the analog output signal to a digital output signal representing at least a portion of the external excitation of the sensor system, wherein respective inputs of the continuous-time Nyquist rate ADCs are connected, in a wired-or configuration, to an output of the sense amplifier comprising the analog output signal.

2. The sensor system of claim 1 , wherein the sensor comprises an accelerometer, a gyroscope, a magnetic sensor, a pressure sensor, or a microphone.

3. The sensor system of claim 1 , wherein the charge or voltage sensing circuit comprises a charge-to-voltage (C2V) converter that converts the sensor output signal to the analog output signal.

4. The sensor system of claim 1 , wherein the continuous-time Nyquist rate ADC comprises an integrating ADC.

5. The sensor system of claim 4 , wherein the integrating ADC comprises a multi-slope ADC.

6. The sensor system of claim 5 , wherein the multi-slope ADC is a dual-slope ADC.

7. The sensor system of claim 5 , wherein the multi-slope ADC is a triple-slope ADC.

8. The sensor system of claim 1 , wherein the continuous-time Nyquist rate ADC reduces, according to an increased current consumption, a noise aliasing of the sensor system.

9. The sensor system of claim 1 , wherein the multiplexer facilitates, based on the sensor selection input, respective selections, comprising the selection, of the respective sensor output signals in a round-robin manner, and wherein the charge or voltage sensing circuit converts the respective sensor output signals to respective analog output signals comprising the analog output signal in the round-robin manner.

10. The sensor system of claim 1 , wherein the sensor output signal is a first sensor output signal, wherein the analog output signal is a first analog output signal, and wherein the continuous-time Nyquist rate ADC converts the first analog output signal to the digital output signal during a period of time in which the sense amplifier converts a second sensor output signal of the respective sensor output signals to a second analog output signal.

11. The sensor system of claim 10 , wherein the continuous-time Nyquist rate ADC is a first continuous-time Nyquist rate ADC, wherein the digital output signal is a first digital output signal, wherein the portion is a first portion, and wherein a second continuous-time Nyquist rate ADC of the group of continuous-time Nyquist rate ADCs converts the second analog output signal to a second digital output signal during a second portion of the period of time.

12. The sensor system of claim 1 , wherein the respective sensor output signals correspond to respective sensors of the group of sensors corresponding to respective axes of the sensor.

13. The sensor system of claim 1 , wherein a defined sampling period of the charge or voltage sensing circuit is equal, within a defined accuracy, to a defined drive period of the sensor.

14. A method, comprising:
in response to an external stimulus being applied to a group of sensors of a system comprising a processing component, selecting, by the system via a multiplexer of the system in a serial manner, a sensor output of a sensor of the group of sensors;
converting, by the system via a sense amplifier of the system in the serial manner, the sensor output to an analog output representing at least a portion of the external stimulus; and
converting, by the system via a continuous-time Nyquist rate analog-to-digital converter (ADC) of a group of continuous-time Nyquist rate ADCs of the system, the analog output to a digital output representing the portion of the external stimulus, wherein the continuous-time Nyquist rate ADCs are connected to an output of the sense amplifier comprising the analog output in an open collector configuration.

15. The method of claim 14 , wherein the converting the sensor output to the analog output comprises:
converting, via a charge-to-voltage converter, the sensor output to the analog output.

16. The method of claim 14 , wherein the converting the sensor output to the analog output comprises:
converting the sensor output to the analog output using a voltage sensing circuit.

17. The method of claim 14 , wherein the converting the analog output to the digital output comprises:
converting the analog output to the digital output using a multi-slope ADC.

18. The method of claim 14 , wherein the sensor is a first sensor, wherein the analog output is a first analog output, wherein the digital output is a first digital output, wherein the continuous-time Nyquist rate ADC is a first continuous-time Nyquist rate ADC, and wherein the converting the first analog output comprises:
first converting, via the first continuous-time Nyquist rate ADC, the first analog output to the first digital output during a period of time; and
second converting, via a second continuous-time Nyquist rate ADC of the group of continuous-time Nyquist rate ADCs, a second analog output corresponding to a second sensor of the group of sensors to a second digital output during a portion of the period of time.

19. The method of claim 18 , wherein the period of time is a first period of time, and wherein the second converting comprises:
initiating the second converting during a second period of time that follows the first period of time.

20. The method of claim 14 , wherein the sensor is a first sensor, wherein the sensor output is a first sensor output, wherein the analog output is a first analog output, wherein the portion is a first portion, and wherein the converting the first sensor output comprises:
first converting, by the system via the sense amplifier during a first period of time, the first sensor output of the first sensor to the first analog output; and
second converting, by the system via the sense amplifier during a second period of time that follows the first period of time, a second sensor output of a second sensor of the group of sensors to a second analog output representing at least a second portion of the external stimulus.

Assignees

• Invensense Inc

Inventors

• Tsinker Vadim

Classifications

• H03M1/14

  Conversion in steps with each step involving the same or a different conversion means and delivering more than one bit · CPC title

• H03M1/52

  Input signal integrated with linear return to datum · CPC title

• H03M1/34

  Analogue value compared with reference values (H03M1/48 takes precedence) · CPC title

• H03M1/124 Primary

  Sampling or signal conditioning arrangements specially adapted for A/D converters · CPC title

• H03M1/123 Primary

  Simultaneous, i.e. using one converter per channel but with common control or reference circuits for multiple converters · CPC title