Optical sensor for range finding and wind sensing measurements
View Patent ↗Techniques are disclosed for providing an optical sensor that can be used for wind sensing and an optical scope. The optical sensor can include a photodiode, an electrical switch, a trans-impedance amplifier (TIA), and a capacitive trans-impedance amplifier (CTIA), enabling the optical sensor to perform both wind-sensing and range-finding functions. Some embodiments may include some or all of these components in an application-specific integrated circuit (ASIC), depending on desired functionality.
1. An optical sensor comprising:
a photodiode configured to receive detect light shone on the optical sensor;
an electrical switch configured to toggle an output of the photodiode between a first electrical node and a second electrical node;
a trans-impedance amplifier (TIA) comprising:
an input connected with the first electrical node; and
an output connected with a first output of the optical sensor; and
a capacitive trans-impedance amplifier (CTIA) comprising:
an input connected with the second electrical node; and
an output connected with a second output of the optical sensor.
2. The optical sensor of claim 1 , wherein the CTIA further comprises an integration reset input connected with a third output of the optical sensor, the integration reset input enabling an integration performed by the CTIA to be reset.
3. The optical sensor of claim 1 , wherein the photodiode comprises a PIN diode.
4. The optical sensor of claim 3 , wherein the photodiode comprises an InGaS PIN diode.
5. The optical sensor of claim 1 , wherein the photodiode comprises a flip-chip diode.
6. The optical sensor of claim 1 , wherein the electrical switch, the TIA, and the CTIA compose at least part of an application-specific integrated circuit (ASIC).
7. An optical sensor package comprising:
a body having electrical pins coupled thereto and housing a photodiode and electrical circuitry, wherein:
the body further comprises a window and the photodiode is positioned within the body such that at least a portion of light passing through the window will shine on the photodiode;
the electrical circuitry comprises:
an electrical switch configured to toggle an output of the photodiode between a first electrical node and a second electrical node;
a trans-impedance amplifier (TIA) comprising:
an input connected with the first electrical node; and
an output connected with a first output of the optical sensor; and
a capacitive trans-impedance amplifier (CTIA) comprising:
an input connected with the second electrical node; and
an output connected with a second output of the optical sensor.
8. The optical sensor package of claim 7 , wherein the CTIA further comprises an integration reset input connected with a third output of the optical sensor, the integration reset input enabling an integration performed by the CTIA to be reset.
9. The optical sensor package claim 7 , wherein the photodiode comprises a PIN diode.
10. The optical sensor package of claim 7 , wherein the body is hermetically sealed.
11. The optical sensor package of claim 7 , wherein the photodiode is disposed on a pedestal mounted on a circuit board within the body.
12. The optical sensor package of claim 7 , wherein the electrical switch, the TIA, and the CTIA compose at least part of an application-specific integrated circuit (ASIC), disposed within the body.
13. A method of operating an optical sensor, the method comprising:
using a switch within electrical circuitry of the optical sensor to cause the optical sensor to operate in a first mode, wherein, in the first mode:
an output of a photodiode of the optical sensor is provided to a trans-impedance amplifier (TIA) via the switch, and
an output of the TIA is connected with a first output of the optical sensor; and
using the switch to cause the optical sensor to operate in a second mode, wherein, in the second mode:
the output of the photodiode of the optical sensor is provided to a capacitive trans-impedance amplifier (CTIA) via the switch, and
an output of the CTIA is connected with a second output of the optical sensor.
14. The method of operating a dual-mode optical sensor of claim 13 , further comprising causing an integration performed by the CTIA to be reset based on an input received at the optical sensor.
15. The method of operating a dual-mode optical sensor of claim 13 , further comprising providing output signals of the TIA and output signals of the CTIA to a first analog-to-digital converter (ADC) and a second ADC, respectively.
16. The method of operating a dual-mode optical sensor of claim 15 , further comprising determining a range measurement based on output signals of the first ADC.
17. The method of operating a dual-mode optical sensor of claim 16 , further comprising causing determining a ballistic solution based on the range measurement.
18. The method of operating a dual-mode optical sensor of claim 15 , further comprising causing determining a crosswind measurement based on output signals of the second ADC.
19. The method of operating a dual-mode optical sensor of claim 18 , further comprising causing determining a ballistic solution based on the crosswind measurement.