Failsafe pulsed laser driver
A failsafe pulsed laser driver and method for using the same are disclosed. In one embodiment, an apparatus comprises a laser array having a plurality of lasers; and a laser driver coupled to the laser array, wherein the laser driver comprises a current limiter to provide a maximum current at or below a threshold current of lasers in the laser array or at a current level to meet laser safety requirements under circuit failure conditions; one or more capacitors coupled to current limiter and the laser array, the one or more capacitors to be charged in response to current from the current limiter; and a switch coupled to the one or more capacitors operable to cause current from the one or more capacitors to flow through the laser array.
1. A laser driver, comprising:
a capacitor to limit current delivered to a vertical cavity surface emitting laser (VCSEL) according an amount of voltage used to charge the capacitor;
a current limited circuit to charge the capacitor via a maximum current at or below a threshold current of the VCSEL; and
a timing circuit to enable a discharge of the capacitor, wherein the timing circuit is programmed based on the amount of voltage used to charge the capacitor.
2. The laser driver of claim 1 , wherein the VCSEL comprises a plurality of lasers.
3. The laser driver of claim 1 , wherein the timing circuit is programmed based on a size of the capacitor.
4. The laser driver of claim 1 , wherein the timing circuit is programmed based on a duration of illumination desired.
5. The laser driver of claim 1 , comprising a switch coupled to the timing circuit coupled to control the switch.
6. The laser driver of claim 1 , wherein the timing circuit is operable to control a pulse width and pulse period of a current pulse discharged by one or more capacitors into a laser array.
7. The laser driver of claim 1 , wherein the current limiter comprises a current limited load switch.
8. The laser driver of claim 1 , wherein the current limiter comprises one or more resistors.
9. The laser driver of claim 1 , wherein the VCSEL comprises a plurality of VCSELs.
10. An apparatus comprising:
a projector configured to project a dot pattern on an object, wherein the projector comprises:
a laser array comprising a plurality of lasers;
a laser driver that comprises:
a capacitor to limit current delivered to the laser array according to an amount of voltage used to charge the capacitor;
a current limited circuit to charge the capacitor via a maximum current at or below a combined-threshold current of the laser array; and
a timing circuit to enable a discharge of the capacitor, wherein the timing circuit is programmed based on the amount of voltage used to charge the capacitor;
a switch coupled to the capacitor operable to cause current from the capacitor to flow through the laser array;
first and second cameras configured to simultaneously capture a pair of images of the object illuminated with the dot pattern; and
a processing unit to receive the captured pair of images and reconstruct depth information using the captured pair of images.
11. The apparatus of claim 10 , wherein the timing circuit is to control the switch.
12. The apparatus of claim 10 , wherein the timing circuit is operable to control a pulse width and pulse period of a current pulse discharged by the capacitor into the laser array.
13. The apparatus of claim 10 , wherein the current limited circuit comprises a current limited load switch.
14. The apparatus of claim 10 , wherein the current limited circuit comprises one or more resistors.
15. The apparatus of claim 10 , wherein the timing circuit is coupled with a switch that comprises a transistor.
16. The apparatus of claim 10 , wherein the timing circuit is programmed based on a size of the capacitor.
17. The apparatus of claim 10 , wherein the timing circuit is programmed based on a duration of illumination desired.
18. A method comprising:
limiting a current delivered to a vertical cavity surface emitting laser (VCSEL) according to an amount of voltage used to charge the capacitor;
charge the capacitor via a current limited circuit with a maximum current at or below a combined threshold current of the VCSEL; and
discharging the capacitor via a timing circuit to illuminate the VCSEL, wherein the timing circuit is programmed based on the amount of voltage used to charge the capacitor.
19. The method of claim 18 , wherein the timing circuit is programmed based on a size of the capacitor.