Integrated LIDAR illumination power control
Methods and systems for performing three dimensional LIDAR measurements with an integrated LIDAR measurement device are described herein. In one aspect, a Gallium Nitride (GaN) based illumination driver integrated circuit (IC), an illumination source, and a return signal receiver IC are mounted to a common substrate. The illumination driver IC provides a pulse of electrical power to the illumination source in response to a pulse trigger signal received from the return signal receiver IC. In another aspect, the GaN based illumination driver IC controls the amplitude, ramp rate, and duration of the pulse of electrical power based on command signals communicated from the return signal receiver IC to the illumination driver IC. In a further aspect, illumination driver IC reduces the amount of electrical power consumed by the illumination driver IC during periods of time when the illumination driver IC is not providing electrical power to the illumination source.
1. An integrated LIDAR measurement device, comprising:
an illumination source mounted to a printed circuit board; and
a Gallium Nitride (GaN) based illumination driver integrated circuit (IC) mounted to the printed circuit board, the illumination driver IC electrically coupled to the illumination source and a first electrical power source, wherein the illumination driver IC is configured to selectively electrically couple the illumination source to the first electrical power source in response to a pulse trigger signal, causing the illumination source to emit a measurement pulse of illumination light.
2. The integrated LIDAR measurement device of claim 1 , wherein the first electrical power source provides a first voltage across a first node and a second node of the first electrical power source, wherein a first node of the illumination source is electrically coupled to the first node of the electrical power source, wherein the illumination driver IC is electrically coupled to a second node of the illumination source and the second node of the first electrical power source, and wherein the illumination driver IC is configured to selectively electrically couple the second node of the illumination source to the second node of the first electrical power source in response to the pulse trigger signal.
3. The integrated LIDAR measurement device of claim 2 , wherein the GaN based illumination driver IC comprises:
a first field effect transistor (FET) having a source, a drain coupled to a first node of a second electrical power source, and a gate configured to receive a gate charge control signal;
a second FET having a drain coupled to the source of the first FET, a source coupled to a second node of the second electrical power source, and a gate configured to receive a gate discharge control signal; and
a third FET having a gate coupled to the source of the first FET and the drain of the second FET, a drain coupled to the second node of the illumination source, and a source coupled to the second node of the first electrical power source, wherein the gate charge control signal causes the gate of the third FET to be selectively coupled to the first node of the second electrical power source, and wherein the gate discharge control signal causes the gate of the third FET to be selectively coupled to the second node of the second electrical power source.
4. The integrated LIDAR measurement device of claim 2 , further comprising:
a first field effect transistor (FET) having a source, a drain coupled to a first node of a second electrical power source, and a gate configured to receive a gate charge control signal;
a second FET having a drain coupled to the source of the first FET, a source coupled to a second node of the second electrical power source, and a gate configured to receive a gate discharge control signal; and
a first plurality of FETS each having a drain coupled to the second node of the illumination source, a source coupled to the second node of the first electrical power source, and a gate selectively coupled to the source of the first FET and the drain of the second FET.
5. The integrated LIDAR measurement device of claim 4 , wherein a FET selection signal determines whether the gate of each of the first plurality of FETS is electrically coupled to the source of the first FET and the drain of the second FET.
6. The integrated LIDAR measurement device of claim 5 , wherein the gate of each of the first plurality of FETS is selectively coupled to the source of the first FET and the drain of the second FET based on a first bit of the FET selection signal, and further comprising:
a second plurality of FETS each having a drain coupled to the second node of the illumination source, a source coupled to the second node of the first electrical power source, and a gate selectively coupled to the source of the first FET and the drain of the second FET based on a second bit of the FET selection signal.
7. The integrated LIDAR measurement device of claim 6 , wherein the first plurality of FETS is a different number of FETS than the second plurality of FETS.
8. The integrated LIDAR measurement device of claim 1 , wherein the GaN based illumination driver IC includes a power save control module that supplies a controlled amount of electrical power to a portion of the GaN based illumination driver IC based on the pulse trigger signal.
9. The integrated LIDAR measurement device of claim 8 , wherein the portion of the GaN based illumination driver IC includes any of a pulse amplitude control circuit, a pulse termination generator; and a FET selection circuit.
10. The integrated LIDAR measurement device of claim 8 , wherein the power save control module includes:
a resistor having a first node and a second node, wherein the pulse trigger signal is supplied at the first node of the resistor;
a capacitor having a first node coupled to the first node of the resistor and a second node coupled to a second node of a second electrical power source;
a first FET having a source coupled to the second node of the capacitor, a gate coupled to the second node of the resistor, and a drain; and
a second FET having a gate coupled to the drain of the first FET, a drain coupled to a first node of a second electrical power source, wherein the controlled amount of electrical power is provided at a source of the second FET.
11. The integrated LIDAR measurement device of claim 1 , wherein the GaN based illumination driver IC includes a pulse initiation signal generator that generates a pulse initiation signal to a portion of the GaN based illumination driver IC based on the pulse trigger signal.
12. The integrated LIDAR measurement device of claim 11 , wherein the pulse initiation signal generator includes:
a resistor having a first node and a second node, wherein the first node is coupled to a first node of a second electrical power source;
a FET having a source coupled to a second node of the second electrical power source, a drain coupled to the second node of the resistor, and a gate, wherein the pulse trigger signal is provided at the gate of the FET, and wherein the pulse initiation signal is provided at the drain of the FET.
13. The integrated LIDAR measurement device of claim 11 , wherein the GaN based illumination driver IC includes a pulse termination signal generator that generates a pulse termination signal to a portion of the GaN based illumination driver IC based on the pulse trigger signal, wherein a delay between the pulse initiation signal and the pulse termination signal is based on a pulse width control signal provided to the GaN based illumination driver IC.
14. The integrated LIDAR measurement device of claim 1 , wherein the GaN based illumination driver IC includes a pulse amplitude control circuit that controls an amplitude of the measurement pulse of illumination light based on an amplitude control signal provided to the GaN based illumination driver IC.
15. The integrated LIDAR measurement device of claim 14 , wherein the pulse amplitude control circuit includes:
a first resistor having a first node and a second node, wherein the pulse amplitude control signal is provided on the first node of the first resistor;
a FET having a source, a gate coupled to the second node of the first resistor, and a drain coupled to a node of a second electrical power source;
a second resistor having a first node coupled to the source of the FET and a second node coupled to a gate of a charge control FET; and
a capacitor having a first node coupled to the second node of the first resistor and a second node coupled to the second node of the second resistor.
16. The integrated LIDAR measurement device of claim 1 , further comprising:
a photodetector mounted to the printed circuit board, the photodetector configured to detect a return pulse of light and generate an output signal indicative of the detected return pulse, wherein the return pulse is an amount of the measurement pulse reflected from a location in a surrounding environment illuminated by the corresponding measurement pulse;
a return pulse receiver IC mounted to the printed circuit board, the return pulse receiver configured to determine a time of flight of the measurement pulse from the LIDAR device to the measured location in the three dimensional environment and back to the LIDAR device based on the output signal, wherein the return pulse receiver IC generates the pulse trigger signal and communicates the pulse trigger signal to the GaN based illumination driver IC.
17. A LIDAR measurement system, comprising:
a plurality of integrated LIDAR measurement devices, each comprising:
an illumination source mounted to a printed circuit board;
a Gallium Nitride (GaN) based illumination driver integrated circuit (IC) mounted to the printed circuit board, the illumination driver IC electrically coupled to the illumination source and a first electrical power source, wherein the illumination driver IC is configured to selectively couple the illumination source and the electrical power source in response to a pulse trigger signal, causing the illumination source to emit a measurement pulse of illumination light; and
a return pulse receiver IC mounted to the printed circuit board, the return pulse receiver configured to determine a time of flight of the measurement pulse from the LIDAR device to a measured location in the three dimensional environment and back to the LIDAR device, wherein the return pulse receiver IC generates and communicates the pulse trigger signal to the GaN based illumination driver IC; and
a master controller configured to generate a plurality of pulse command signals, each communicated to a different integrated LIDAR measurement device of the plurality of integrated LIDAR measurement devices, wherein each return pulse receiver IC generates the corresponding pulse trigger signal based on the received pulse command signal.
18. The LIDAR measurement system of claim 17 , wherein the GaN based illumination driver IC includes a pulse amplitude control circuit that controls an amplitude of the measurement pulse of illumination light based on an amplitude control signal communicated from the return pulse receiver IC to the GaN based illumination driver IC.
19. The LIDAR measurement system of claim 17 , wherein the GaN based illumination driver IC generates a pulse initiation signal and a pulse termination signal in response to the pulse trigger signal, and wherein a delay between the pulse initiation signal and the pulse termination signal is based on a pulse width control signal communicated from the return pulse receiver IC to the GaN based illumination driver IC.
20. The LIDAR measurement system of claim 17 , the GaN based illumination driver IC including a plurality of field effect transistors (FETS) each configured to selectively couple the illumination source and the electrical power source, wherein a FET selection signal determines a number of the plurality of FETS that selectively couple the illumination source and the electrical power source, and wherein the FET selection signal is communicated from the return pulse receiver IC to the GaN based illumination driver IC.
21. An integrated LIDAR measurement device, comprising:
an illumination source mounted to a printed circuit board, the illumination source configured to provide a measurement pulse of illumination light;
a Gallium Nitride (GaN) based illumination driver integrated circuit (IC) mounted to the printed circuit board, the illumination driver IC electrically coupled to the illumination source, wherein the illumination driver IC is configured to cause the illumination source to provide the measurement pulse of illumination light in response to a pulse trigger signal;
a photodetector mounted to the printed circuit board, the photodetector configured to detect a first amount of the measurement pulse of illumination light due to crosstalk between the illumination source and the photodetector and a valid return pulse of light reflected from a location in a surrounding environment illuminated by a second amount of the measurement pulse; and
a return pulse receiver IC mounted to the printed circuit board, the return pulse receiver IC configured to a difference in time between a time when the first amount of the measurement pulse is detected and a time when the valid return pulse of light is detected.
22. A method comprising:
providing a pulse of electrical power from a Gallium Nitride (GaN) based illumination driver integrated circuit (IC) mounted to a printed circuit board in response to a pulse trigger signal;
emitting a measurement pulse of illumination light in response to the pulse of electrical power from an illumination source mounted to the printed circuit board;
detecting a return pulse of light, wherein the return pulse is an amount of the measurement pulse reflected from a location in a surrounding environment illuminated by the corresponding measurement pulse; and
determining a time of flight of the measurement pulse from the LIDAR device to the measured location in the three dimensional environment and back to the LIDAR device based on the detected return pulse of light, the determining performed by a return pulse receiver IC mounted to the printed circuit board.
23. The method of claim 22 , further comprising:
controlling an amount of electrical power supplied to any of a pulse amplitude control circuit, a pulse termination generator, and a FET selection circuit of the GaN based illumination driver IC based on the pulse trigger signal.
24. The method of claim 22 , wherein a duration of the pulse of electrical power is determined by a pulse initiation signal and a pulse termination signal generated by the GaN based illumination driver IC, wherein a delay between the pulse initiation signal and the pulse termination signal is based on a pulse width control signal communicated from the return pulse receiver IC to the GaN based illumination driver IC.
25. The method of claim 22 , wherein the GaN based illumination driver IC includes a pulse amplitude control circuit that controls an amplitude of the measurement pulse of illumination light based on an amplitude control signal communicated from the return pulse receiver IC to the GaN based illumination driver IC.
26. The method of claim 22 , wherein the pulse trigger signal is communicated from the return pulse receiver IC to the GaN based illumination driver IC.