Narrowband TIA and signaling for optical distance measurement systems

Patent metadata

Field	Value
Publication number	US-11428790-B2
Application number	US-201715613835-A
Country	US
Kind code	B2
Filing date	Jun 5, 2017
Priority date	Jun 5, 2017
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

An optical distance measurement system includes a transmission circuit and a receive circuit. The transmission circuit is configured to generate narrowband intensity modulated light transmission signals over a first band of frequencies and direct the narrowband light transmission signal toward a target object. The receive circuit is configured to receive reflected light off the target object, convert the reflected light into a current signal proportional to the intensity of the reflected light, filter frequencies outside a second band of frequencies from the current signal to create a filtered current signal, and convert the filtered current signal into a voltage signal. The second band of frequencies corresponds with the first band of frequencies.

First claim

What is claimed is:

1. An optical distance measurement receiver comprising:
a photodiode having an anode and a cathode, and configured to receive light reflected off an object over a first band of frequencies, and convert the received light into a photodiode current signal, the photodiode current signal proportional to an intensity of the received light;
an inductor coupled between the anode and a ground terminal, the inductor configured to filter frequencies that are outside a second band of frequencies from the photodiode current signal, providing a filtered current signal;
a transimpedance amplifier (TIA) having a first TIA input, a second TIA input and a TIA output, the first TIA input coupled to the inductor, the second TIA input coupled to the ground terminal, and the TIA output configured to provide a voltage signal proportional to the filtered current signal;
a resistor having first and second resistor terminals, the first resistor terminal connected to the inductor, and the second resistor terminal connected to the TIA output and
a capacitor having first and second capacitor terminals, the first capacitor terminal connected to the first resistor terminal, and the second capacitor terminal connected to the second resistor terminal.

2. The optical distance measurement receiver of claim 1 , wherein a capacitance of the capacitor is tunable such that the receiver has a resonant frequency corresponding to a frequency of the received light.

3. The optical distance measurement receiver of claim 1 , wherein:
the photodiode is further configured to receive light reflected off the object over a third band of frequencies, the third band of frequencies being exclusive of the first band of frequencies;
the further configured to filter frequencies outside a fourth band of frequencies from the photodiode current signal to create a second filtered current signal; and
the TIA is further configured to receive the second filtered current signal from the tuning network and convert the second filtered current signal into a second voltage signal corresponding to the second filtered current signal.

4. The optical distance measurement receiver of claim 1 , wherein the inductor is coupled between the first TIA input and the ground terminal.

5. The optical distance measurement receiver of claim 1 , wherein an inductance of the inductor is determined by the first band of frequencies and a fundamental capacitance of the photodetector.

6. The optical distance measurement receiver of claim 1 , further comprising a processing circuit configured to determine a distance from the optical distance measurement receiver to the object responsive to the voltage signal.

Assignees

• Texas Instruments Inc

Inventors

• Haroun Baher S
• Warke Nirmal C
• Magee David P

Classifications

• G01S17/26

  wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals · CPC title

• G01S7/4865

  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

• G01S7/4861 Primary

  Circuits for detection, sampling, integration or read-out · CPC title