Patents by Inventor Ian D. Crawford
Ian D. Crawford has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11837848Abstract: A fly-back or boost stage transfers its stored energy to the energy storage capacitor of the fast driver discharge stage in a single event pulse. The charging voltage of a single flyback pulse on the capacitor is measured in real time and, if necessary, the charging current is diverted via a shunt active device or transistor, to ground, thus preventing the storage capacitor from overcharging with the risk of component damage. A series sense resistor is used to determine the presence and amount of the wasted shunt current in order that this current may be minimized by turning down the flyback energy, thus maximizing the overall efficiency.Type: GrantFiled: September 30, 2020Date of Patent: December 5, 2023Assignee: Analog Modules, Inc.Inventors: Ian D Crawford, Jeff Richter
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Publication number: 20210098965Abstract: A fly-back or boost stage transfers its stored energy to the energy storage capacitor of the fast driver discharge stage in a single event pulse. The charging voltage of a single flyback pulse on the capacitor is measured in real time and, if necessary, the charging current is diverted via a shunt active device or transistor, to ground, thus preventing the storage capacitor from overcharging with the risk of component damage. A series sense resistor is used to determine the presence and amount of the wasted shunt current in order that this current may be minimized by turning down the flyback energy, thus maximizing the overall efficiency.Type: ApplicationFiled: September 30, 2020Publication date: April 1, 2021Inventors: Ian D. Crawford, Jeff Richter
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Patent number: 10777967Abstract: A current driver is disclosed which allows very short pulses at high currents to be generated for high power laser diodes. The parasitic inductance of the laser diode limits the speed at which the laser diode may be turned on and off. A high voltage is used to charge this inductance rapidly and maximize the rise time. The fall time is shortened by allowing a similar high voltage to be generated at turnoff without damage to the laser diode or switching components. A portion of the energy stored in the parasitic inductance may recovered to reduce drain on the power source, and to improve overall efficiency. The anode of the laser may be switched to ground at the end of a pulse.Type: GrantFiled: December 16, 2019Date of Patent: September 15, 2020Assignee: Analog Modules, Inc.Inventors: Ian D Crawford, Dwight E Wildon
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Publication number: 20200119518Abstract: A current driver is disclosed which allows very short pulses at high currents to be generated for high power laser diodes. The parasitic inductance of the laser diode limits the speed at which the laser diode may be turned on and off. A high voltage is used to charge this inductance rapidly and maximize the rise time. The fall time is shortened by allowing a similar high voltage to be generated at turnoff without damage to the laser diode or switching components. A portion of the energy stored in the parasitic inductance may recovered to reduce drain on the power source, and to improve overall efficiency. The anode of the laser may be switched to ground at the end of a pulse.Type: ApplicationFiled: December 16, 2019Publication date: April 16, 2020Inventors: Ian D Crawford, Dwight E Wildon
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Patent number: 10511142Abstract: A current driver is disclosed which allows very short pulses at high currents to be generated for high power laser diodes. The parasitic inductance of the laser diode limits the speed at which the laser diode may be turned on and off. A high voltage is used to charge this inductance rapidly and maximize the rise time. The fall time is shortened by allowing a similar high voltage to be generated at turnoff without damage to the laser diode or switching components. A portion of the energy stored in the parasitic inductance may recovered to reduce drain on the power source, and to improve overall efficiency. The anode of the laser may be switched to ground at the end of a pulse.Type: GrantFiled: April 17, 2018Date of Patent: December 17, 2019Assignee: Analog Modules, Inc.Inventors: Ian D Crawford, Dwight E Wildon
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Publication number: 20180323576Abstract: A current driver is disclosed which allows very short pulses at high currents to be generated for high power laser diodes. The parasitic inductance of the laser diode limits the speed at which the laser diode may be turned on and off. A high voltage is used to charge this inductance rapidly and maximize the rise time. The fall time is shortened by allowing a similar high voltage to be generated at turnoff without damage to the laser diode or switching components. A portion of the energy stored in the parasitic inductance may recovered to reduce drain on the power source, and to improve overall efficiency. The anode of the laser may be switched to ground at the end of a pulse.Type: ApplicationFiled: April 17, 2018Publication date: November 8, 2018Inventors: Ian D. Crawford, Dwight E. Wildon
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Patent number: 8729870Abstract: A current-driven load such as LEDs or laser diodes is driven by a current driver having a two stages (or phases), the outputs of which have ripple which is forced to be out-of-phase with one another. In analog embodiments, an output (ripple or switching) of a master stage hysteresis controller is phase-shifted and scaled, and modulates the input of a slave stage hysteresis controller so that the slave stage pulls into a ripple-canceling phase. In digital embodiments, a faster of the two phases is designated “master”, maximum and minimum thresholds are set, and the slave phase's on time is based on a previous cycle's slave phase ON time, the master stage OFF time and an offset. The slave controller may “lock” to the anti-phase of the master stage (or phase). The ripple currents at the summed output of the master and slave stages substantially cancel.Type: GrantFiled: June 25, 2012Date of Patent: May 20, 2014Assignee: Analog Modules, Inc.Inventors: Ian D. Crawford, Jeffrey T. Richter, Steven L. Pickles, John A. Harwick, Noal Chandler
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Patent number: 8619239Abstract: A technique for providing range correction values in a laser rangefinder range processor uses return pulse width (rather than return pulse amplitude) for correcting amplitude (range walk) and speed of light problems. A plurality of range correction values may be generated in a test setup (by simulating return pulse delays) and stored in a lookup table based on return pulse width, nominal range (time of return), and other factors such as temperature and pressure. The technique is also capable of correcting other problems such as receiver delay. The technique allows for the use of a saturating preamplifier with the increased sensitivity that it offers, and is relatively simple to implement, as it may be embedded within a digital processor (DSP) or gate array that is normally present for a basic range counter implementation.Type: GrantFiled: January 28, 2011Date of Patent: December 31, 2013Assignee: Analog Modules Inc.Inventors: Ian D. Crawford, Noal T. Chandler
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Patent number: 8451432Abstract: A laser spot tracker comprising a quadrant detector. A portion of a spot of laser light reflected from an object being illuminated (OBI) may be defocused to occupy a significant portion such as one-third of the field of view, while another portion remains focused, therefore allowing for quick calculation of the spot centroid. With such a “composite spot”, multiple target (OBI) positions may simultaneously be defined in elevation and azimuth with respect to null by analyzing the energy in each quadrant. The X and Y angle information (off null) for multiple targets (OBIs), and their codes may be displayed. For a large, defocused spot, two segmented multi-element detectors may be used, one in front of and the other behind the focal plane to reduce the effects of hot spots in a spot of laser light collected from an object being illuminated.Type: GrantFiled: July 13, 2010Date of Patent: May 28, 2013Assignee: Analog-Modules, Inc.Inventors: Ian D. Crawford, Noal Chandler, John Harwick, Dwight Wildon, Charles G. Smith
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Publication number: 20130070239Abstract: A laser spot tracker comprising a quadrant detector. A portion of a spot of laser light reflected from an object being illuminated (OBI) may be defocused to occupy a significant portion such as one-third of the field of view, while another portion remains focused, therefore allowing for quick calculation of the spot centroid. With such a “composite spot”, multiple target (OBI) positions may simultaneously be defined in elevation and azimuth with respect to null by analyzing the energy in each quadrant. The X and Y angle information (off null) for multiple targets (OBIs), and their codes may be displayed. For a large, defocused spot, two segmented multi-element detectors may be used, one in front of and the other behind the focal plane to reduce the effects of hot spots in a spot of laser light collected from an object being illuminated.Type: ApplicationFiled: July 13, 2010Publication date: March 21, 2013Applicant: ANALOG MODULES INC.Inventors: Ian D. Crawford, Noal Chandler, John Harwick, Dwight Wildon, Charles G. Smith
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Publication number: 20120268026Abstract: A current-driven load such as LEDs or laser diodes is driven by a current driver having a two stages (or phases), the outputs of which have ripple which is forced to be out-of-phase with one another. In analog embodiments, an output (ripple or switching) of a master stage hysteresis controller is phase-shifted and scaled, and modulates the input of a slave stage hysteresis controller so that the slave stage pulls into a ripple-canceling phase. In digital embodiments, a faster of the two phases is designated “master”, maximum and minimum thresholds are set, and the slave phase's on time is based on a previous cycle's slave phase ON time, the master stage OFF time and an offset. The slave controller may “lock” to the anti-phase of the master stage (or phase). The ripple currents at the summed output of the master and slave stages substantially cancel.Type: ApplicationFiled: June 25, 2012Publication date: October 25, 2012Applicant: ANALOG MODULES INC.Inventors: Ian D. Crawford, Jeffrey T. Richter, Steven L. Pickles, John A. Harwick, Noal Chandler
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Publication number: 20120194798Abstract: A technique for providing range correction values in a laser rangefinder range processor uses return pulse width (rather than return pulse amplitude) for correcting amplitude (range walk) and speed of light problems. A plurality of range correction values may be generated in a test setup (by simulating return pulse delays) and stored in a lookup table based on return pulse width, nominal range (time of return), and other factors such as temperature and pressure. The technique is also capable of correcting other problems such as receiver delay. The technique allows for the use of a saturating preamplifier with the increased sensitivity that it offers, and is relatively simple to implement, as it may be embedded within a digital processor (DSP) or gate array that is normally present for a basic range counter implementation.Type: ApplicationFiled: January 28, 2011Publication date: August 2, 2012Applicant: ANALOG MODULES INC.Inventors: Ian D. Crawford, Noal T. Chandler
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Patent number: 8207711Abstract: A current-driven load such as LEDs or laser diodes is driven by a current driver having a two stages (or phases), the summed outputs of which have ripple which is forced to be out-of-phase with one another. In analog embodiments, an output (ripple or switching) of a master stage hysteresis controller is phase-shifted and scaled, and modulates the input of a slave stage hysteresis controller so that the slave stage pulls into a ripple-canceling phase. In a digital embodiment, a faster of the two phases is designated “master”, maximum and minimum thresholds are set, and the slave phase's on time is based on a previous cycle's slave phase ON time, the master stage OFF time and an offset. The slave controller preferentially “locks” to the anti-phase of the master stage (or phase) and the ripple current at the summed output substantially cancels.Type: GrantFiled: August 15, 2009Date of Patent: June 26, 2012Assignee: Analog Modules, Inc.Inventors: Ian D. Crawford, Jeffrey T. Richter, Steven L. Pickles, John A. Harwick
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Patent number: 8184670Abstract: In a pulsed laser diode driver an energy storage capacitor is continuously being charged to a supply voltage Vr. When a pulse is initiated, energy stored in the capacitor is delivered to the laser diode load. The capacitor voltage Vd at the end of a pulse is used to control Vr to ensure that Vd is maintained above a minimum voltage Vm required to ensure operation of a current control device (such as FET) just above saturation. Test pulses (such as with attenuated currents or reduced pulsewidth) may be fired to determine an initial optimum value for Vr. After a test pulse, a slightly high estimate for Vr may be used and may be iterated (incremented) down to an optimum value Vm during a firing burst. A digital processor may be used to calculate and store data to optimize the performance. Various embodiments are disclosed.Type: GrantFiled: October 7, 2010Date of Patent: May 22, 2012Assignee: Analog Modules, Inc.Inventors: Ian D. Crawford, John A. Harwick, Timothy M Ayres
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Publication number: 20110085576Abstract: In a pulsed laser diode driver an energy storage capacitor is continuously being charged to a supply voltage Vr. When a pulse is initiated, energy stored in the capacitor is delivered to the laser diode load. The capacitor voltage Vd at the end of a pulse is used to control Vr to ensure that Vd is maintained above a minimum voltage Vm required to ensure operation of a current control device (such as FET) just above saturation. Test pulses (such as with attenuated currents or reduced pulsewidth) may be fired to determine an initial optimum value for Vr. After a test pulse, a slightly high estimate for Vr may be used and may be iterated (incremented) down to an optimum value Vm during a firing burst. A digital processor may be used to calculate and store data to optimize the performance. Various embodiments are disclosed.Type: ApplicationFiled: October 7, 2010Publication date: April 14, 2011Applicant: ANALOG MODULES INC.Inventors: Ian D. Crawford, John A. Harwick, Timothy M. Ayres
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Publication number: 20100207543Abstract: A current-driven load such as LEDs or laser diodes is driven by a current driver having a two stages (or phases), the summed outputs of which have ripple which is forced to be out-of-phase with one another. In analog embodiments, an output (ripple or switching) of a master stage hysteresis controller is phase-shifted and scaled, and modulates the input of a slave stage hysteresis controller so that the slave stage pulls into a ripple-canceling phase. In a digital embodiment, a faster of the two phases is designated “master”, maximum and minimum thresholds are set, and the slave phase's on time is based on a previous cycle's slave phase ON time, the master stage OFF time and an offset. The slave controller preferentially “locks” to the anti-phase of the master stage (or phase) and the ripple current at the summed output substantially cancels.Type: ApplicationFiled: August 15, 2009Publication date: August 19, 2010Applicant: ANALOG MODULES INC.Inventors: Ian D. Crawford, Jeffrey T. Richter, Steven L. Pickles, John A. Harwick
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Patent number: 7773202Abstract: A laser spot tracker device comprising a laser tracker receiver using a quadrant detector incorporated into a pair of binoculars or optical telescope system with a crosshair or reticule. Directional information from the laser tracker receiver is displayed to an operator (JTAC) to allow the reticule to be manually steered on to the target illuminated by the laser, thus identifying the target to the spotter. The laser code may be pre-selected to track a particular designator, or, the tracker may read out the code or codes of laser spots within its field of view.Type: GrantFiled: June 9, 2006Date of Patent: August 10, 2010Assignee: Analog Modules, Inc.Inventors: Ian D. Crawford, Noal Chandler, John Harwick, William Hudson, Dwight Wildon
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Publication number: 20090225299Abstract: A laser spot tracker device comprising a laser tracker receiver using a quadrant detector incorporated into a pair of binoculars or optical telescope system with a crosshair or reticule. Directional information from the laser tracker receiver is displayed to an operator (JTAC) to allow the reticule to be manually steered on to the target illuminated by the laser, thus identifying the target to the spotter. The laser code may be pre-selected to track a particular designator, or, the tracker may read out the code or codes of laser spots within its field of view.Type: ApplicationFiled: June 9, 2006Publication date: September 10, 2009Applicant: Analog Modules, Inc.Inventors: IAN D. CRAWFORD, Noal Chandler, John Harwick, Willam Hudson, Dwight Wildon
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Patent number: 7348948Abstract: A driver supplying a total current to a load has a plurality (n) of driver stages (ST1 . . . STn). One stage is a master stage. Each driver stage has a switching device (Q) and an inductor (L) connected in series between the switching device and the output of the driver stage. The switching devices are turned ON in sequence with one another, during a cycle time (Tc) which is determined by sensing current through the inductor (L1) in the master stage. When the switching device is turned ON current through the inductor rises, when the inductor current reaches the value of a demanded current the switch is turned OFF, and after the switch is turned OFF the inductor continues to supply (output) current to the load with a current which ramps down. A rectifying device (D) connected between the inductor and the supply line allows current to continue to flow in the inductor and be supplied to the load after the switch is turned OFF.Type: GrantFiled: July 12, 2004Date of Patent: March 25, 2008Assignee: Analog Modules, IncInventors: Ian D. Crawford, John Harwick, Miguel Morales
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Patent number: 7262584Abstract: A capacitor is connected to the output of a multiphase power converter, and a current-driven device (e.g., LED or laser diode) is also connected to the power converter output. A solid state switch (FET or IGBT) is connected in series with the current-driven device. Means are provided for sensing current through the current-driven device. An error amplifier compares sensed current through the current-driven device with a current level demand signal and controls the output of the power converter. Means are provided for turning the switch on and off and may be (i) a fast comparator receiving a voltage reference signal at one input and the current level demand signal at another input, and outputting the switch on/off signal to the switch or (ii) an externally-generated logic signal provided directly to the switch.Type: GrantFiled: February 9, 2005Date of Patent: August 28, 2007Assignee: Analog Modules, IncInventors: Ian D. Crawford, Miguel Morales