US 9,529,079 B1 · Multiplexed multichannel photodetector

Abstract

A light detection and ranging (LIDAR) system can emit light toward an environment and detect responsively reflected light to determine a distance to one or more points in the environment. The reflected light can be detected by a plurality of plurality of photodiodes that are reverse-biased using a high voltage. Signals from the plurality of reverse-biased photodiodes can be amplified by respective transistors and applied to an analog-to-digital converter (ADC). The signal from a particular photodiode can be applied to the ADC by biasing a respective transistor corresponding to the particular photodiode while not biasing transistors corresponding to other photodiodes. The gain of each photodiode/transistor pair can be controlled by adjusting the bias voltage applied to each photodiode using a digital-to-analog converter. The gain of each photodiode/transistor pair can be controlled based on the detected temperature of each photodiode.

Claims20

Dependent claims

A system comprising:

an analog-to-digital converter;
at least one photodiode biasing voltage source;
a plurality of photodetector channels, wherein each photodetector channel comprises:
a photodiode coupled to the at least one photodiode biasing voltage source, wherein the photodiode is configured to provide a photodiode signal indicative of light incident on the photodiode when the photodiode is reverse-biased by the at least one photodiode biasing voltage source;
a capacitor coupled to the photodiode;
and
a transistor, wherein the transistor has an input coupled to the photodiode via the capacitor and an output coupled to the analog-to-digital converter, and wherein the transistor is configured to amplify the photodiode signal to provide an amplified photodiode signal at the output when the transistor is operationally biased;
and
a channel selector, wherein the channel selector is configured to individually select each respective photodetector channel in the plurality of photodetector channels by operationally biasing the respective transistor in the selected photodetector channel.

6 more elements

A method comprising:

selecting, during a first period of time, a first photodetector channel of a system, wherein the system comprises:
an analog-to-digital converter;
at least one photodiode biasing voltage source;
a plurality of photodetector channels, wherein each photodetector channel comprises:
a photodiode coupled to the at least one photodiode biasing voltage source, wherein the photodiode is configured to provide a photodiode signal indicative of light incident on the photodiode when the photodiode is reverse-biased by the at least one photodiode biasing voltage source;
a capacitor coupled to the photodiode;
and
a transistor, wherein the transistor has an input coupled to the photodiode via the capacitor and an output coupled to the analog-to-digital converter, and wherein the transistor is configured to amplify the photodiode signal to provide an amplified photodiode signal at the output when the transistor is operationally biased;
and
a channel selector, wherein the channel selector is configured to individually select each respective photodetector channel in the plurality of photodetector channels by operationally biasing the respective transistor in the selected photodetector channel;
wherein selecting the first photodetector channel comprises operating the channel selector to operationally bias the respective transistor of the first photodetector channel;
detecting, during the first period of time, light received by the respective photodiode of the first photodetector channel by detecting the output of the respective transistor of the first photodetector channel using the analog-to-digital converter;
selecting, during a second period of time, a second photodetector channel of the system, wherein selecting the second photodetector channel comprises operating the channel selector to operationally bias the respective transistor of the second photodetector channel;
and
detecting, during the second period of time, light received by the respective photodiode of the second photodetector channel by detecting the output of the respective transistor of the second photodetector channel using the analog-to-digital converter.

12 more elements

Dependencies are inferred from the claim text.

Multiplexed multichannel photodetector

Life of this patent

Multiplexed multichannel photodetector

Life of this patent

Abstract

Claims20