Laser drive and control systems useful for laser diode protection
AssigneePSC Inc.
InventorScott R. Grodevant
Life of this patent
Estimating the term…
Abstract
A laser drive and control system which provides protection for a laser diode by preventing excess current from a power source, that normally supplies power to the laser diode, from destroying the laser diode when the voltage supplied by the power source to the laser diode decreases below a certain voltage which causes excess current. The system is implemented in CMOS circuitry for miniaturization into an integrated circuit chip.
Claims20
A system for driving and controlling a laser diode, the system preventing excess current from a power source, which provides an operating voltage for the laser diode, from causing damage to the laser diode when the voltage supplied by the power source to the laser diode decreases below a certain voltage which causes the excess current, said system comprising:
- means for comparing said certain voltage with a voltage corresponding to the voltage across the laser diode and for outputting a comparison signal as a result thereof;
- and
- means responsive to the comparison signal from said comparing means for regulating the voltage across the laser diode for increasing voltages across the laser diode when the voltage corresponding to the voltage across the laser diode drops below said certain voltage thereby preventing damaging the laser diode.
A system for controlling an input voltage to a laser diode so that the input voltage does not drop below a predetermined value, comprising:
- a comparator configured to receive the input voltage on a first port and a threshold voltage on a second port, the comparator outputting a comparison signal having one of a first and a second level based on whether the input voltage does or does not exceed the threshold voltage;
- and
- voltage increasing means coupled to the comparator and configured to increase the input voltage as an increased voltage when the comparison signal indicates that the input voltage does not exceed the threshold voltage,
- wherein one of the increased voltage and the input voltage are sent to an input of the laser diode based on the result of the comparison made by the comparator, and
- wherein the voltage increasing means passes the input voltage to the input of the laser diode unamplified when the comparison signal indicates that the input voltage does exceed the threshold voltage.
Dependencies are inferred from the claim text.