Methods and devices for peak signal detection

Patent metadata

Field	Value
Publication number	US-11971505-B2
Application number	US-202017107313-A
Country	US
Kind code	B2
Filing date	Nov 30, 2020
Priority date	Nov 30, 2020
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

A method includes counting a first set of photons having times of flight that falls within a first time range and being detected during a first time period, determining a second time range based on the first set of photons, the second time range being smaller than the first time range, counting a second set of photons having times of flight that fall within the second time range and being detected during a second time period, and determining a third time range based on the second set of photons, the third time range being smaller than the second time range.

First claim

What is claimed is:

1. A device to detect a peak time interval, the device comprising:
a first counter configured to increment a first count each time a first-counter increment command is received, the first counter being configured to decrement the first count each time a first-counter decrement command is received;
a gate circuit configured to receive a photon-detection alert from a radiation-sensitive pixel each time a photon is detected by the radiation-sensitive pixel, the gate circuit comprising a first state wherein the gate circuit transmits the first-counter increment command to the first counter each time the photon-detection alert is received and the gate circuit comprising a second state wherein the gate circuit transmits the first-counter decrement command to the first counter each time the photon-detection alert is received; and
a decoder circuit configured to receive the first count from the first counter and configured to receive a timing signal that communicates an optical-emission time by an optical emitter wherein the decoder circuit is configured to deliver a control signal to the gate circuit that:
sets the gate circuit to the first state after passage of a first-state delay that is determined based on the first count and measured from the optical-emission time; and
sets the gate circuit to the second state after passage of a second-state delay that is determined based on the first count and measured from the optical-emission time.

2. The device of claim 1 , further comprising:
a second counter configured to increment a second count each time a second-counter increment command is received, the second counter being configured to decrement the second count each time a second-counter decrement command is received;
the gate circuit comprises a third state wherein the gate circuit transmits the second-counter increment command to the second counter each time the photon-detection alert is received and the gate circuit comprising a fourth state wherein the gate circuit transmits the second-counter decrement command to the second counter each time the photon-detection alert is received; and
wherein the control signal sets the gate circuit to the third state after passage of a third-state delay that is determined based on the second count and the first count, the third-state delay being measured from the time of the optical-emission time; and
wherein the control signal sets the gate circuit to the fourth state after passage of a fourth-state delay that is determined based on the second count and the first count, the fourth-state delay being measured from the time of the optical-emission time.

3. The device of claim 2 , wherein the first-state delay is further determined by the second count and the second-state delay is further determined by the second count.

4. The device of claim 3 , wherein the decoder circuit is configured to receive a global-step signal that determines:
a duration of a first-state period wherein the gate circuit is set to the first state;
a duration of a second-state period wherein the gate circuit is set to the second state;
a duration of a third-state period wherein the gate circuit is set to the third state; and
a duration of a fourth-state period wherein the gate circuit is set to the fourth state.

5. The device of claim 1 , wherein the radiation-sensitive pixel comprises a Single Photon Avalanche Diode.

6. The device of claim 1 , wherein the radiation-sensitive pixel comprises a Single Photon Avalanche Diode (SPAD) coupled to an OR tree.

7. The device of claim 1 , further comprising a processor configured to perform the time-of-flight operation.

8. A method for detecting a peak time interval in a time-of-flight system, the method comprising:
incrementing, by a first counter, a first count in response to receiving a first-counter increment command;
decrementing, by the first counter, the first count in response to receiving a first-counter decrement command;
receiving, by a gate circuit, a photon-detection alert from a radiation-sensitive pixel in response to detecting a photon by the radiation-sensitive pixel, the gate circuit having a first state wherein the gate circuit transmits the first-counter increment command to the first counter in response to receiving the photon-detection alert, and the gate circuit having a second state wherein the gate circuit transmits the first-counter decrement command to the first counter in response to receiving the photon-detection alert;
receiving, by a decoder circuit, the first count from the first counter;
receiving, by the decoder circuit, a timing signal that communicates an optical-emission time by an optical emitter;
transmitting, by the decoder circuit, a control signal to the gate circuit;
setting the gate circuit to the first state after a passage of a first-state delay determined in accordance with the first count and measured from the optical-emission time; and
setting the gate circuit to the second state after a passage of a second-state delay determined in accordance with the first count and measured from the optical-emission time.

9. The method of claim 8 , further comprising:
incrementing, by a second counter, a second count in response to receiving a second-counter increment command;
decrementing, by the second counter, the second count in response to receiving a second-counter decrement command;
transmitting, by the gate circuit in a third state, the second-counter increment command to the second counter in response to receiving the photon-detection alert;
transmitting, by the gate circuit in a fourth state, the second-counter decrement command to the second counter in response to receiving the photon-detection alert;
setting the gate circuit to the third state by the control signal after a passage of a third-state delay determined in accordance with the second count and the first count, the third-state delay measured from the time of the optical-emission time; and
setting the gate circuit to the fourth state by the control signal after a passage of a fourth-state delay determined in accordance with the second count and the first count, the fourth-state delay measured from the time of the optical-emission time.

10. The method of claim 9 , wherein the first-state delay is further determined by the second count, and wherein the second-state delay is determined by the second count.

11. The method of claim 10 , further comprising receiving, by the decoder circuit, a global-step signal, the global-step signal determining a duration of a first-state period wherein the gate circuit is set to the first state, a duration of a second-state period wherein the gate circuit is set to the second state, a duration of a third-state period wherein the gate circuit is set to the third state, and a duration of a fourth- state period wherein the gate circuit is set to the fourth state.

12. The method of claim 8 , wherein the radiation-sensitive pixel comprises a Single Photon Avalanche Diode.

13. The method of claim 8 , wherein the radiation-sensitive pixel comprises a Single Photon Avalanche Diode (SPAD) coupled to an OR tree.

14. The method of claim 8 , further comprising detecting a distance from an object based on time-of-flight.

15. A time-of-flight system, comprising:
an optical emitter configured to emit photons;
an optical receiver comprising a radiation-sensitive pixel;
a first counter configured to increment a first count in response to receiving a first-counter increment command, the first counter configured to decrement the first count in response to receiving a first-counter decrement command;
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Assignees

• St Microelectronics Grenoble 2

Inventors

• Mellot Pascal

Classifications

• G01S7/4865 Primary

  Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487) · CPC title

• G01S7/487

  Extracting wanted echo signals {, e.g. pulse detection} · CPC title

• G01S17/10

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) · CPC title

• G01S7/484

  Transmitters · CPC title

• G01S7/4815

  using multiple transmitters · CPC title