Power efficient laser diode driver circuit and method
First Claim
1. A depth camera system, comprising:
- a power supply including a voltage output;
a laser diode including an anode terminal and a cathode terminal;
a laser diode driver including an output stage, the output stage including first and second transistors, the laser diode driver configured to;
selectively turn the first and second transistors on and off to selectively pull a voltage level at an output node of the output stage down toward ground to cause current to flow from the voltage output of the power supply through the laser diode, which causes the laser diode to turn on and emit light, andselectively turn the first and second transistors on and off to selectively pull the voltage level at the output node of the output stage up toward a voltage level at the voltage output of the power supply to cause substantially no current to flow from the voltage output of the power supply through the laser diode, which causes the laser diode to turn off and not emit light;
an image pixel detector configured to detect light originating from the laser diode that has reflected off an object and is incident of the image pixel detector; and
one or more processors configured to produce depth images in dependence on outputs of the image pixel detector, and configured to update an application based on the depth images.
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Accused Products
Abstract
A voltage mode laser diode driver selectively turns on and off a laser diode. An output stage has an output node configured to be connected to one of the terminals of the laser diode. Depending upon implementation, an active swing controller drives the output stage in a manner that substantially prevents inductive kickback from causing the output node voltage to swinging above the voltage level at the voltage output of the power supply, or swing below ground. The output stage provides a discharge path around the laser diode to shunt current associated with the inductive kickback, and substantially eliminates ringing on the output node of the output stage while the laser diode is off. A power supply controller adjusts the voltage level of the voltage output of the power supply so that current through the laser diode when on and emitting light is substantially equal to a predetermined desired current.
186 Citations
20 Claims
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1. A depth camera system, comprising:
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a power supply including a voltage output; a laser diode including an anode terminal and a cathode terminal; a laser diode driver including an output stage, the output stage including first and second transistors, the laser diode driver configured to; selectively turn the first and second transistors on and off to selectively pull a voltage level at an output node of the output stage down toward ground to cause current to flow from the voltage output of the power supply through the laser diode, which causes the laser diode to turn on and emit light, and selectively turn the first and second transistors on and off to selectively pull the voltage level at the output node of the output stage up toward a voltage level at the voltage output of the power supply to cause substantially no current to flow from the voltage output of the power supply through the laser diode, which causes the laser diode to turn off and not emit light; an image pixel detector configured to detect light originating from the laser diode that has reflected off an object and is incident of the image pixel detector; and one or more processors configured to produce depth images in dependence on outputs of the image pixel detector, and configured to update an application based on the depth images. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for use with depth camera system, the method comprising:
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producing a voltage output having a voltage level; selectively turning first and second transistors on and off to selectively pull a voltage level at one of two terminals of a laser diode down toward ground, causing a current to flow from the voltage output through the laser diode, which causes the laser diode to turn on and emit light; selectively turning the first and second transistors on and off to selectively pull the voltage level at the one of two terminals of the laser diode up to a power supply voltage, causing substantially no current to flow from the voltage output through the laser diode, which causes the laser diode to turn off and not emit light; detecting light originating from the laser diode that has reflected off an object and is incident of an image pixel detector; producing depth images in dependence on the light that is incident on the image pixel detector; and updating an application based on the depth images. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A depth camera system, comprising:
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a power supply including a voltage output; a power supply controller configured to produce a feedback signal that is provided to the power supply and used by the power supply to adjust a voltage level of the voltage output of the power supply; a laser diode including an anode terminal and a cathode terminal; a laser diode driver including an output stage, the output stage including first and second transistors, the laser diode driver configured to; selectively turn the first and second transistors on and off to selectively pull a voltage level at an output node of the output stage down toward ground to cause current to flow from the voltage output of the power supply through the laser diode, which causes the laser diode to turn on and emit light, and selectively turn the first and second transistors on and off to selectively pull the voltage level at the output node of the output stage up toward a voltage level at the voltage output of the power supply to cause substantially no current to flow from the voltage output of the power supply through the laser diode, which causes the laser diode to turn off and not emit light; an image pixel detector configured to detect light originating from the laser diode that has reflected off an object and is incident of the image pixel detector; and one or more processors configured to produce depth images in dependence on outputs of the image pixel detector, and configured to update an application based on the depth images. - View Dependent Claims (19, 20)
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Specification