Dual Voltage and Current Control Feedback Loop For an Optical Sensor System
AssigneeOsram Sylvania Inc.
InventorsVipin C. Madhani, Alan Adamsky
Life of this patent
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Abstract
A dual voltage and current control feedback control loop for an optical sensor system. A power supply provides a regulated DC voltage. A current source receives the regulated DC voltage and provides switched current to a light source. A current feedback representative of the current to the light source is provided to the power supply on a feedback path when the current source is driving the light source. A voltage feedback representative of the DC voltage is provided to the power supply on the feedback path when the current source is not driving the light source.
Claims18
A light source circuit for an optical sensor system, the circuit comprising:
- a power supply to provide a regulated direct current (DC) voltage output;
- a voltage feedback circuit to provide a voltage feedback representative of the DC voltage output on a feedback path to the power supply;
- a current source coupled to the power supply to receive the regulated DC voltage output and to provide a current output to a light source, the current source being configured to provide a current feedback representative of the current output on the feedback path to the power supply;
- and
- a switch, whereby the current source is configured to provide the current output to the light source and the power supply is configured to adjust the DC voltage output in response to the current feedback when the switch is closed and the power supply is configured to adjust the DC voltage output in response to the voltage feedback when the switch is open.
An optical sensor system comprising:
- a controller;
- a light source circuit coupled to the controller to drive a light source in response to control signals from the controller, the light source circuit comprising:
- a power supply to provide a regulated direct current (DC) voltage output;
- a voltage feedback circuit to provide a voltage feedback representative of the DC voltage output on a feedback path to the power supply,
- a current source coupled to the power supply to receive the regulated DC voltage output and to provide a current output to the light source, the current source being configured to provide a current feedback representative of the current output on the feedback path to the power supply, and
- a switch, whereby the current source is configured to provide the current output to the light source and the power supply is configured to adjust the DC voltage output in response to the current feedback when the switch is closed and the power supply is configured to adjust the DC voltage output in response to the voltage feedback when the switch is open;
- transmission optics to direct light from the light source toward an object;
- receiver optics to receive light reflected from the object;
- and
- detector circuits to convert the reflected light to one or more electrical signals, the controller being configured to provide a data signal output representative of a distance to at least one point on the object in response to the one or more electrical signals.
A method of providing current to a light source under the control of a switch in an optical sensor system, the method comprising:
- providing the current through a current source to the light source when the switch is closed;
- adjusting a DC input voltage to the current source in response to a current feedback signal provided on a feedback path when the switch is closed, the current feedback signal being representative of current provided to the light source;
- and
- adjusting the DC input voltage to the current source in response to a voltage feedback signal provided on the feedback path when the switch is open, the voltage feedback signal being representative of the DC input voltage.
Dependencies are inferred from the claim text.