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CN-122029761-A - Dynamic biasing of photodetectors in LiDAR applications

CN122029761ACN 122029761 ACN122029761 ACN 122029761ACN-122029761-A

Abstract

The present invention discloses a system for the control of a system, the system includes one or more photodetector circuits. The system also includes a global bias circuit configured to generate a first bias voltage and coupled to each of the one or more photodetector circuits such that a respective bias voltage corresponding to each photodetector circuit is based on the first bias voltage. In addition, the system includes one or more local bias circuits, each local bias circuit corresponding to a respective photodetector circuit. Each local bias circuit is configured to generate a respective second bias voltage and is coupled to its respective photodetector circuit such that its respective bias voltage of its respective photodetector circuit is also based on the respective second bias voltage.

Inventors

  • LI YIMIN
  • GU CHEN

Assignees

  • 图达通智能美国有限公司

Dates

Publication Date
20260512
Application Date
20240927
Priority Date
20230928

Claims (20)

  1. 1. A system, the system comprising: one or more photodetector circuits; a global bias circuit configured to generate a first bias voltage and coupled to each of the one or more photodetector circuits such that a respective bias voltage corresponding to each photodetector circuit is based on the first bias voltage, and One or more local bias circuits, each local bias circuit corresponding to a respective photodetector circuit, each local bias circuit configured to generate a respective second bias voltage and coupled to its respective photodetector circuit such that the respective bias voltage of its respective photodetector circuit is also based on the respective second bias voltage.
  2. 2. The system of claim 1, wherein: The global bias circuits include global voltage sources configured to generate the first bias voltages, and each local bias circuit includes a respective local voltage source configured to generate its respective second bias voltage.
  3. 3. The system of any one of claim 1 or claim 2, wherein: Each photodetector circuit includes a respective photodetector having a respective first node and a respective second node; The global bias circuit is coupled to each photodetector circuit such that a first node voltage at its respective first node is based on the first bias voltage; each local bias circuit is coupled to its corresponding photodetector circuit such that a second node voltage at its respective second node is based on the second bias voltage, and The respective bias voltage of each photodetector circuit is a voltage across the respective first node and the respective second node of its respective photodetector.
  4. 4. The system of claim 3, wherein the respective first nodes are cathodes of their respective photodetectors and the second nodes are anodes of their respective photodetectors.
  5. 5. The system of any of claims 3 or 4, wherein each local bias circuit includes a respective amplifier coupled to the respective second node of the respective photodetector of its corresponding photodetector circuit such that the respective second node voltage at the respective second node is based on a respective common mode voltage of the respective amplifier.
  6. 6. The system of claim 5, wherein the respective second nodes are coupled to respective first inputs of their corresponding amplifiers.
  7. 7. The system of any of claims 5 or 6, wherein the respective local voltage source of each local bias circuit is coupled between ground and a respective second input of the respective amplifier of its respective local bias circuit.
  8. 8. The system of any of claims 5 to 7, wherein each local bias circuit comprises a respective resistor coupled between the respective first input and the respective output of its corresponding amplifier.
  9. 9. The system of any of claims 3 to 8, wherein at least one respective photodetector circuit of the one or more photodetector circuits comprises a respective current limiting circuit coupled between the global bias circuit and the respective first node of its corresponding photodetector.
  10. 10. The system of any of claims 3 to 9, wherein at least one respective photodetector circuit of the one or more photodetector circuits comprises a respective reset circuit coupled to the respective second node of its corresponding photodetector and configured to reset the corresponding photodetector after activation of the corresponding photodetector.
  11. 11. The system of claim 10, wherein the respective reset circuits comprise a fast charge circuit coupled between the global bias circuit and the respective second node of its corresponding photodetector.
  12. 12. The system of any one of claim 10 or claim 11, wherein the respective reset circuits comprise current quenching circuits coupled between ground and the respective second nodes of their corresponding photodetectors.
  13. 13. The system of any one of claims 1 to 12, wherein the first bias voltage is adjustable such that the respective bias voltage of each photodetector circuit is adjustable via adjustment of the first bias voltage.
  14. 14. The system of claim 13, wherein the first bias voltage is adjusted based on an ambient temperature in a vicinity of at least one of the one or more photodetector circuits.
  15. 15. The system of any of claims 1 to 14, wherein the respective second bias voltage of each respective local bias circuit is adjustable such that the respective bias voltage of its corresponding photodetector circuit is individually adjustable via adjustment of its corresponding second bias voltage.
  16. 16. The system of claim 15, wherein the respective second bias voltages are adjusted based on one or more characteristics of the corresponding photodetectors.
  17. 17. The system of claim 16, wherein the one or more characteristics of the corresponding photodetectors comprise one or more of: Voltage characteristics; Current characteristics or Temperature.
  18. 18. The system of any one of claims 15 to 17, wherein: the one or more photodetector circuits include a plurality of photodetector circuits, and At least one respective second bias voltage is adjusted such that one or more performance characteristics of the two or more photodetector circuits match.
  19. 19. A system, the system comprising: a photodetector; A first voltage source configured to generate a first bias voltage and coupled to the photodetector such that a first node voltage at a first node of the photodetector is based on the first bias voltage; an amplifier coupled to the photodetector such that a second node voltage at a second node of the photodetector is based on a common mode voltage of the amplifier, a bias voltage across the photodetector is based on the first node voltage and the second node voltage, and A second voltage source configured to generate a second bias voltage and coupled to the amplifier such that the common mode voltage is based on the respective second bias voltage.
  20. 20. The system of claim 19, wherein the first node of the photodetector is a cathode and the second node of the photodetector is an anode.

Description

Dynamic biasing of photodetectors in LiDAR applications Cross Reference to Related Applications The present application claims priority from U.S. provisional patent application Ser. No. 63/541,273, entitled "dynamic biasing of photodetectors in LiDAR applications" (DYNAMIC BIASING PHOTODETECTORS IN LIDAR APPLICATION), filed on 9 and 28 of 2023. The contents of the present application are incorporated by reference in their entirety for all purposes. Technical Field The present disclosure relates generally to dynamically biased photodetectors in LiDAR systems. Background Light detection and ranging (LiDAR) systems use light pulses to create an image or point cloud of an external environment. The LiDAR system may be a scanning or non-scanning system. Some typical scanning LiDAR systems include a light source, a light emitter, a light turning system, and a light detector. The light source generates a beam of light that, when emitted from the LiDAR system, is directed in a particular direction by the light turning system. When the emitted light beam is scattered or reflected by an object, a portion of the scattered or reflected light returns to the LiDAR system to form a return light pulse. The light detector detects the return light pulse. Using the difference between the time that the return light pulse is detected and the time that the corresponding light pulse in the beam is emitted, the LiDAR system may determine the distance to the object based on the speed of light. This technique of determining distance is known as time of flight (ToF) technique. The light steering system may direct the light beams along different paths to allow the LiDAR system to scan the surrounding environment and produce an image or point cloud. A typical non-scanning LiDAR system illuminates the entire field of view (FOV) rather than scanning the entire FOV. One example of a non-scanning LiDAR system is flash LiDAR, which may also use ToF technology to measure distance to an object. LiDAR systems may also use techniques other than time-of-flight and scanning to measure the surrounding environment. A reasonably designed LiDAR system may need to cover a large dynamic range, up to several tens of dB. For example, a photodetector may need to have a high gain value for weak signals from far-field targets while also being able to detect bright signals while avoiding saturation or loss of sensitivity. Typical photodetectors may include APD (avalanche photodiode) based structures, PMT (photomultiplier tube) based structures, siPM (silicon photomultiplier tube) based structures, SPAD (single photon avalanche diode) based structures, and/or quantum wires. Disclosure of Invention The present invention discloses a system for the control of a system, the system includes one or more photodetector circuits. The system also includes a global bias circuit configured to generate a first bias voltage and coupled to each of the one or more photodetector circuits such that a respective bias voltage corresponding to each photodetector circuit is based on the first bias voltage. In addition, the system includes one or more local bias circuits, each local bias circuit corresponding to a respective photodetector circuit. Each local bias circuit is configured to generate a respective second bias voltage and is coupled to its respective photodetector circuit such that its respective bias voltage of its respective photodetector circuit is also based on the respective second bias voltage. Drawings The application may best be understood by reference to the following description of an embodiment taken in conjunction with the accompanying drawings, in the several figures of which like parts may be designated by like numerals. FIG. 1 illustrates one or more exemplary LiDAR systems disposed or included in a motor vehicle. FIG. 2 is a block diagram illustrating interactions between an exemplary LiDAR system and a plurality of other systems including a vehicle perception and planning system. FIG. 3 is a block diagram illustrating an exemplary LiDAR system. Fig. 4 is a block diagram illustrating an exemplary fiber-based laser source. Fig. 5A-5C illustrate an exemplary LiDAR system that uses pulsed signals to measure distance to objects disposed in a field of view (FOV). FIG. 6 is a block diagram illustrating an exemplary apparatus for implementing the systems, apparatuses, and methods in accordance with one or more embodiments. FIG. 7 is an exemplary block diagram illustrating an exemplary photodetector system in accordance with one or more embodiments. FIG. 8 is a circuit diagram illustrating an exemplary photodetector system in accordance with one or more embodiments. FIG. 9 is a flow diagram of a method for biasing a photodetector system in accordance with one or more embodiments. Detailed Description The following description sets forth numerous specific details, such as specific configurations, parameters, examples, etc., in order to provide a more thorough under