METHODS, ELECTRICAL POWER CONTROL SYSTEM, AND POWER CONTROL CIRCUIT FOR MAINTAINING OR PROVIDING CONSTANT OR SUBSTANTIALLY CONSTANT POWER, FOR REDUCING AND/OR MINIMIZING POWER DECAY, AND FOR IMPROVING AN INFRARED SOURCE DRIVER, AND METHODS OF USING SAME

A power system, power circuit, and methods for maintaining or providing a constant or substantially constant power source and for reducing and/or minimizing power decay of a predetermined component are provided. Such improvement of power delivery and minimization of power loss is important for precision instrumentation applications. One such application is the infrared (“IR”) source driver for a Fourier Transform Infrared Spectrometer (“FTIR”). The power system and/or circuit may include two integrated circuits in a novel way to make an efficient constant power IR source driver. The method may include having a switching regulator comparing a sample of output voltage with a reference voltage, a second element computing, calculating and/or creating a voltage that is a product of another voltage and a current to obtain a signal proportional to delivered power, and operating a closed loop regulator to provide a constant delivered power to the source.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

A power control circuit or apparatus, a power control system, a Fourier Spectrometer for use with the power control circuit or apparatus, power control system and method(s) of using same are disclosed herein. The power control circuit or apparatus operates as a predetermined component driver or a source driver to provide a constant, stable or substantially constant or stable supply of power to a predetermined component, such as a radiation source.

Turning now to the details of the figures,FIG. 1shows the general principles of a standard Michelson interferometer. The Michelson interferometer has a radiation source10which sends a single radiation beam20towards beamsplitter30which is situated at an angle to two mirrors, a fixed mirror40and a movable mirror50. Radiation beam20is partially reflected toward fixed mirror40in the form of radiation beam22, and is partially transmitted through beamsplitter30towards movable mirror50as radiation beam24. Beam22is then reflected off of fixed mirror40, back towards beamsplitter30, where it is once again partially split, sending some radiation25back towards source10, and some radiation26toward detector60. Similarly, beam24reflects off of movable mirror50and is reflected back toward beamsplitter30. Here also, beam24is again split, sending some radiation back to source10and other radiation26toward detector60.

Detector60measures the interference between the two radiation beams emanating from the single radiation source. These beams have, by design, traveled different distances (optical path lengths), which creates a fringe effect which is measurable by detector60.

FIG. 2shows the lay out and component structure of a Michelson interferometer of the prior art, e.g., U.S. Pat. No. 6,141,101 to Bleier, herein incorporated by reference.FIG. 2shows interferometer100, and includes a radiation source110, a beamsplitter130, a movable reflecting assembly150, a fixed reflecting assembly140and a detector142. Radiation source110is mounted in a secure position by mounting assembly112. With radiation source110in mounting assembly112, radiation beam120is alignable along a path which will fix the direction of the beam at the appropriate angle to beamsplitter130.

Radiation source110can be collimated white light for general interferometry applications, such as optical surface profiling, collimated infrared light for an infrared Spectrometer, a single collimated radiation intensity laser light source, etc., for accurate distance measurements or any now known, or which become known in the future, light/radiation source used in spectroscopy. Additionally or alternatively, For operation as a Fourier Transform Spectrometer, radiation source110may be a broadband light source (i.e., a light source that radiates in a broad band of wavelengths; also referred to herein as (and used interchangeably with) “light”, “light source”, “radiation”, “light source/beam”, “radiation source”, “radiation beam”, “radiation/light source”, “thermal source” and “radiation/light beam”).

Movable reflecting assembly150may utilize a hollow corner-cube retroreflector152. The hollow corner-cube retroreflector152could be made in accordance with the disclosure of U.S. Pat. No. 3,663,084 to Lipkins, herein incorporated by reference.

Retroreflector152is mounted to a movable base assembly144, which assembly allows for adjustment of the location of retroreflector152in a line along the path of beam120. The displacement of assembly144is adjustable; e.g., through use of adjusting knob146. Other means of moving assembly144are also anticipated by the invention, including such means that might allow for continuous, uniform movement of assembly144. For example, means of movement of assembly144might be accomplished in accordance with the structure described in U.S. Pat. No. 5,335,111 to Bleier, herein incorporated by reference, or by co-pending application Ser. No. 12/505,279 filed on Jul. 17, 2009.

The use of retroreflector152as the movable reflecting assembly150allows for any angular orientation of retroreflector152as long as edge portions of the retroreflector mirrors do not clip a portion of beam120.

From the foregoing, the length of the beam paths20,22and26are fixed and known while the length of beam path24may be varied. The variation of the length of beam path26is, of course, critical to the operation of the interferometer, as is knowing the length as precisely as possible.

A monolithic optical assembly200, as seen inFIGS. 3-4, comprises a beamsplitter130and reflecting assembly140mounted within a top plate260, a bottom plate270and at least first and second support members210and220, respectively. As an add-on for some additional structural stability, which stability is not essential, third support member230can also be used. Support member210has an edge214. A portion of edge214is bonded to a portion of edge262of top plate260, while another portion of edge214of support member210is bonded to a portion of an edge surface of bottom plate270.

As shown inFIG. 4, around the corner from support member210, is second support member220. Second support member220is bonded to top and bottom plates260and270along different portions of a surface222thereof. The portions of surface222of support member220are bonded to portions of an edge surface264of top plate260and edge surface274of bottom plate270.

Beamsplitter130may be comprised of two panels bonded to each other along a common surface. The common surface is an optically flat reflecting surface having a beamsplitter coating thereon. Beamsplitter130is bonded along portions of top edges137to portions of bottom surface267of top plate260, and along portions of bottom edges138to portions of top surface278of bottom plate270. One panel of beamsplitter130is a compensating member. The purpose of the compensating panel is to equate the material portions of the optical path difference of the two beams created by the beamsplitter. Without the compensating panel, the beam transmitted through the beamsplitter would travel through the optical material of the beamsplitter twice, while the reflected beam would travel through optical material zero times. By adding a compensating panel, ideally of the same thickness, wedge, and material as the beamsplitter, both beams travel twice through equal portions of optical material before being recombined at the beamsplitter surface, thereby equating any differences they may have experienced in that portion of their optical path length through material. The invention also anticipates a structure where the compensating panel is separated from the beamsplitter.

The support combination of first support member210, second support member220and beamsplitter130between top plate260and bottom plate270creates a monolithic structure. As earlier discussed, it is also possible to have third support member230situated between portions of third edge surfaces266and276of top and bottom plates260and270, respectively, as seen in the figures.

To complete the required reflecting elements of a Michelson interferometer, it is seen in the figures that a mirror panel140is bonded to a portion of top surface278of bottom plate270, and to a second edge surface214of support member210. Mirror panel140is slightly over hanging top surface278of bottom plate270by a portion of a bottom edge surface of mirror panel140, and is bonded between these touching surfaces. Bonding also takes effect between the side edge surface of mirror panel140that touches edge surface214of support member210. Bonding must avoid distorting the optically flat nature of the reflecting surface142of mirror panel140.

Since mirror panel140is fixedly attached to assembly200, as has just been discussed, there is no necessity for panel140to be other than a single, flat paneled mirror; for example, panel140does not need to be a retroreflector. One of the benefits of using a retroreflector (as has been discussed earlier regarding movable reflecting assembly150and as discussed further below) in a structure is that the orientation of the retroreflector is unimportant. The secured mounting of panel140to the monolithic structure assures that the orientation of panel140will not fluctuate due to vibration and shock, and therefore, a retroreflector is unnecessary (although a retroreflector alternatively could of course be utilized).

The portion of beam120that passes through beam splitter130and interacts with retroreflector152may also be returned via a second mirror panel, similar to mirror panel140. This second mirror panel may be made integral with second support member220or be a separate panel supported by one or all of the second support member220, edge264of top plate260and bottom plate270.

Assembly200can also have a fourth support member240. While the main purpose of fourth support member240is not to help stabilize the monolithic structure of assembly200, it is nevertheless called a support member herein. Instead, fourth support member240is positioned in relation to the path traveled by beam120so as to allow beam120to pass through opening242in member240, to travel between beamsplitter130and movable reflecting assembly150. One or both of elements244,246can comprise reflecting elements for returning beam120to retroreflector252.

All members210,220,230,240,260,270,130and140, of assembly200, may be made of the same material. The material preferably being fused quartz or annealed Pyrex (e.g., any type of annealed borosilicate glass and/or glasses having a low coefficient of thermal expansion). The use of identical materials allows the coefficients of expansion of the materials to be identical, so that any temperature changes experienced by assembly200is experienced equally throughout each member to allow assembly200to expand and contract uniformly, thereby substantially removing distortions in the reflecting surfaces of beamsplitter130and mirror panel140.

The monolithic construction discussed above has the benefit of high thermal stability in its optical alignment. This stability derives from the construction of the unit from a single, low expansion material such as Pyrex glass (e.g., any type of annealed borosilicate glass and/or glasses having a low coefficient of thermal expansion), fused silica, Zerodur or Cervit. However, in the application of infrared Fourier transform spectroscopy, often called FTIR, it may not be possible to fabricate the beamsplitter and compensating plate or panel130from the same material as the assembly. This may occur when the need for high transmission in the infrared (“IR”) is not consistent with available low expansion structural materials. In particular, the high IR transmission optical material may have a much higher thermal expansion coefficient.

Attaching optical elements having a thermal expansion coefficient different from the expansion coefficient of the remainder of the assembly could introduce wavefront distortion in the interfering optical beams or even result in mechanical failure under temperature changes. In order to take advantage of the permanent optical alignment afforded by a monolithic assembly, the connection between optical elements, e.g., beamsplitter and compensating plate or panel130, and the rest of the monolithic assembly should transmit minimal stress from this assembly to the optical elements under temperature changes.

Not only are the circuits, apparatuses, systems and methods described herein unique, but the various aspects of the present invention are also nonobvious. The aforementioned, deficient methods are not capable of operating over the broad, required voltage range needed to provide constant power to a component, such as an IR source, having a resistance that is changing (e.g., increasing, decreasing, oscillating, etc.) over time. Indeed, the conventional wisdom in the art has been a lack of concern over (i.e., has been not to address) the delivery of responsive amperage when addressing the power loss problem. However, the present invention operates to provide responsive (e.g., dynamic or changing) amperage, and is not limited by the delivery of such amperage. For example, when load resistance is low, one or more embodiments of the circuit, apparatus, system, etc. of the present invention operate to deliver power levels needed for achieving constant or substantially constant power operation. Such delivery may occur at lower voltages than the input power source but at higher amperage than the input power source would be capable of. As the load resistance (e.g., the resistance of the component, such as the IR source) rises with age (as further explained above and below), the circuit delivers the same or substantially the same power to the load resistance, by controlling a combination of dynamic or changing voltage and dynamic or changing amperage. In at least one embodiment, the circuit, system, apparatus, etc. may be limited only by the input power source voltage. In other words, the one or more circuits, apparatuses, systems and methods of the present invention dynamically deliver varying voltages and currents, and may do so in accordance with the following equations:

where P is the chosen constant or substantially constant power and R is the varying load resistance (e.g., the varying or changing resistance of the component, such as the IR source). Preferably, the power consumed by and/or delivered to the predetermined component is at least one of: (i) identical or substantially similar to the predetermined, preselected or chosen value of power; and (ii) constant or substantially constant. In one or more embodiments, the predetermined, electrical component (e.g., the radiation source110) may have a resistance that changes over time, thereby requiring the dynamic control or change of at least one of the voltage and the current of the predetermined component (e.g., the radiation source110) for providing or delivering constant or substantially constant power. The voltage may operate to be dynamic or changing in response to a changing resistance of the predetermined electrical component (e.g., the radiation source110), and the current may operate to be dynamic or changing in response to a changing resistance of the predetermined electrical component (e.g., the radiation source110), and both the voltage and current may operate to be dynamic or changing at once (i.e., both varying contemporaneously) in a dynamic or changing manner in response to a changing resistance of the predetermined electrical component (e.g., the radiation source110). The step of controlling or changing the varying voltages and currents may further include at least one of: (i) changing only the voltage while keeping the current constant in response to a changing resistance of the predetermined, electrical component; (ii) changing only the current while keeping the voltage constant in response to a changing resistance of the predetermined, electrical component; and (iii) changing a combination of the voltage and the current in response to a changing resistance of the predetermined, electrical component.

In accordance with at least one aspect of the present invention, a method for driving a power source in a stabilized and electrically efficient manner is provided (as shown inFIG. 5). The method may include: (i) determining at least one of electrical power consumed by and/or delivered to a predetermined component, such as the radiation source110, or a value proportional to the electrical power by at least one of multiplying and obtaining a product of at least two signals, wherein: a first signal of the at least two signals at least one of represents and is proportional to a first voltage of the predetermined component, such as the radiation source110, and a second signal of the at least two signals at least one of represents and is proportional to a current of the predetermined component, such as the radiation source110(see Step9001ofFIG. 5); (ii) comparing the determined electrical power and/or the determined multiplication product representing the electrical power consumed by and/or delivered to the predetermined component (e.g., the radiation source110) with a predetermined value of electrical power (e.g., a preset value of electrical power that the predetermined component needs to operate; a value of electrical power that a user of the predetermined component has set for the predetermined component; a factory setting of electrical power at which the predetermined component is desired to operate; a value of electrical power to be constantly maintained or achieved for delivery to and/or use by the predetermined component; a value that may be set remotely with respect to the control circuit; a value that may be set locally with respect to the control circuit; etc.) (see Step9002ofFIG. 5); and (iii) adjusting, maintaining or producing at least one of the voltage and current of the predetermined component (e.g., the radiation source110) in view of at least one of the at least two signals, the multiplication product, and the power determined to be delivered to and/or consumed by the predetermined objection (e.g., the radiation source110) such that the electrical power delivered to and/or consumed by the predetermined object (e.g., the radiation source110) is identical to or substantially the same as the predetermined value of electrical power, thereby achieving and/or maintaining constant and/or substantially constant power (see Step9003ofFIG. 5).

The determining step (see step9001ofFIG. 5) may further comprise computing, calculating and/or creating at least one of: (i) the voltage of the predetermined component (e.g., the radiation source110); (ii) a voltage that is proportional to power (electrical) consumed by and/or delivered to the predetermined component (e.g., the radiation source110); (iii) the current of the predetermined component (e.g., the radiation source110); and (iv) a current that is proportional to electrical power consumed by and/or delivered to the component (e.g., the radiation source110). The computing, calculating and/or creating step may further include, or may be replaced with the step of, computing, calculating and/or creating (or generating) a product of source voltage and current, or any available signals proportional to source voltage and current, thereby obtaining a signal proportional to the electrical power delivered to and/or consumed by the predetermined component (e.g., the radiation source110).

Alternatively, in at least one embodiment where one or more of the steps are performed digitally, the computing, calculating and/or creating step may not employed or may be skipped. For example, the voltage, or a signal proportional to the voltage, delivered to the predetermined component may be measured and available, or stored, as a digital number. Typically, this is done by an analog-to-digital converter (also referred to as an “ADC”). Similarly, the current, or a signal proportional to the current, delivered to the predetermined component may be measured. Such a measurement step may further include a first step of creating a voltage proportional to the current, and a second step of converting that voltage to a number using an ADC. Having the two numbers, a computer or a processor (e.g., the computer or processor1104as further discussed below) then multiplies the two numbers together to form a number proportional to power. Based on this computed power, which is truly a measured power given the high accuracies of the mentioned ADC devices and methods, the computer or processor (e.g., the computer or processor1104as further discussed below) operates to alter at least one of the current, the voltage, and both the current and the voltage (or the product of voltage times current) delivered to the predetermined electrical component. The computer (e.g., the computer or processor1104as further discussed below) may execute such steps by creating one or more new command numbers for the one or more variables to be controlled, where the variables are at least one of the current, the voltage, and both the current and the voltage (or the product of voltage times current) delivered to the predetermined electrical component, and applying these numbers to one or more digitally responsive circuits, such as digital-to-analog converters (also referred to individually as a “DAC” or collectively as “DACs”), for the purpose of controlling these physical output variables. In one or more embodiments, the output voltages and/or currents of the DAC circuits may require supplementation in order to properly drive a predetermined electrical component at a constant or substantially constant power level. In such an instance, the supplementation may be provided via one or more power output stages to attain a constant or substantially constant power level. By way of example of at least one embodiment having one or more steps performed digitally, an analog output of a DAC circuit, whose value has been computed by a computer, may be wired directly to the aforementioned MAX15041 to represent the power (rather than the analog output of the MAX4210).

The comparing step (see Step9002ofFIG. 5) may further comprise obtaining the predetermined value of electrical power from a processor and/or database (see e.g., processors1103,1104discussed below). The predetermined value of electrical power may also be set electrically using a potentiometer (see e.g., the potentiometer (or “pot”)562as further discussed below and as shown inFIGS. 6A-6C; the pot652as further discussed below and as shown inFIG. 7; etc.). The comparing step may further comprising determining at least one of: (i) whether to increase or decrease at least one of the voltage of the predetermined component (e.g., the radiation source110), the current of the predetermined component (e.g., the radiation source110), the voltage that is proportional to electrical power consumed by and/or delivered to the predetermined component (e.g., the radiation source110) and the current that is proportional to electrical power consumed by and/or delivered to the predetermined component (e.g., the radiation source110); and (ii) how much to increase or decrease at least one of the voltage of the predetermined component (e.g., the radiation source110), the current of the predetermined component (e.g., the radiation source110), the voltage that is proportional to electrical power consumed by and/or delivered to the predetermined component (e.g., the radiation source110) and the current that is proportional to electrical power consumed by and/or delivered to the predetermined component (e.g., the radiation source110). Preferably, the increase or decrease is determined to achieve and/or maintain constant or substantially constant power delivered to and/or consumed by the predetermined component (e.g., the radiation source110).

The adjusting step (see Step9003ofFIG. 5) may further comprise sending at least one of the determined electrical power consumed by and/or delivered to the predetermined component (e.g., the radiation source110), the signals and the multiplication product to a control circuit or system (see e.g., the circuit510and the system600as further discussed below and as shown inFIGS. 6A-7). In at least one embodiment, a driver electronic power control circuit (such as the circuit510discussed further below and as shown inFIG. 6A; another circuit510discussed further below and as shown inFIG. 6B; and yet another circuit510discussed further below and as shown inFIG. 6C) may stabilize power delivered to the component, such as the radiation source110, by computing consumed and/or delivered power. Preferably, as aforementioned, the power is computed by multiplying, or obtaining a product of, signals proportional to the source voltage (i.e., a voltage output by the predetermined component, such as the radiation source110) and the current (i.e., the current of the predetermined component, such as the radiation source110) (see Step9001inFIG. 5). The signals, the determined delivered and/or consumed power and/or the multiplication product may be sent (e.g., as “Feedback” or “information”) to the closed-loop control circuit and/or system (e.g., the circuit510and/or the system600as discussed further below), such as, but not limited to, a switching regulator (e.g., the first integrated circuit511, the MAX15041 or other similar circuit as further discussed below) to produce the requisite or a predetermined amount of voltage to operate the source at substantially constant and/or constant power. Additionally or alternatively, the power may be computed, calculated or created by multiplying, or obtaining a product of, the voltage of the predetermined component and the current of the predetermined component (see Step9001inFIG. 5). While the driver electronic circuit (e.g., the electrical circuits510and/or the system600discussed further below) is preferably utilized for a broadband thermal infrared source, one or more embodiments of the circuit may be utilized for other sources.

Additionally or alternatively, the aforementioned signals that are proportional to at least one of the voltage, the current and the power may be generated by a logarithmic amplifier and a antilogarithmic amplifier. A first logarithmic amplifier may be used to generate a voltage proportional to log (the voltage of the predetermined component, such as the radiation source110), and a second logarithmic amplifier may be used to generate a voltage proportional to log (a current passing through the predetermined component, such as the radiation source110). A summing amplifier may then be used to sum these two voltages, thereby creating a voltage proportional to the log of the current×voltage (i.e., the product of current and voltage). Finally, the antilog amplifier may be used to create a voltage proportional to power.

Preferably, the control circuits510(three embodiments of which are shown inFIGS. 6A-6C) and/or the control system600(best seen inFIG. 7), or a portion thereof, operates in a closed-loop fashion to maintain a constant or substantially constant power delivered to the predetermined component, such as the radiation source110. As shown by Step9004inFIG. 5, if the predetermined component is still in use, the determining, comparing and adjusting steps may be repeated or recycled as needed to achieve and/or maintain a constant or substantially constant electrical power delivered to and/or consumed by the predetermined component. If the predetermined component is not in use, the method may end. Additionally or alternatively, if at least one of the circuit and system (e.g., one or more of the circuits510and/or the system600) is operational, the steps may recycle or repeat automatically until the control circuit and/or system and/or the predetermined component is turned off.

Preferably, a first circuit and/or integrated circuit511(best seen inFIGS. 6A-6C), such as, but not limited to, the MAX15041 or other similar circuit as further discussed below, is used to compare the sample of the output voltage with the reference voltage. As aforementioned, the first circuit511may operate as a switching regulator that may be used to regulate voltage and/or current of the predetermined component. Preferably, a second circuit and/or integrated circuit512(best seen inFIGS. 6A-6C), such as, but not limited to, the MAX 4210B or any similar model (e.g., the MAX 4210/MAX 4211), is used to create, determine, calculate and/or compute a voltage and/or a current that is proportional to power consumed and/or delivered to the predetermined component (e.g., the radiation source110), and/or is used to create, determine, calculate and/or compute a product or digital value proportional to the product of the voltage and the current of the predetermined component, thereby obtaining power delivered to and/or consumed by the predetermined component. The signals, the determined consumed and/or delivered power and/or the multiplication product (collectively referred to as “the Feedback” or “the information”) may be sent to the first circuit or integrated circuit, such as, but not limited to, the circuit511, the MAX15041 or other similar circuit, a regulator, etc. in one of a plurality of ways known to those skilled in the art, including, but not limited to, a direct connection, a wireless connection, the use of a digital-to-analog converter (“DAC”), etc. The first integrated circuit may then use the signals, the consumed power, and/or the multiplication product to produce the modified voltage and/or current to operate the predetermined component, such as the radiation source110, at a constant or substantially constant power. Those skilled in the art would appreciate that the first circuit or integrated circuit (e.g., the integrated circuit511) may be at least one of an integrated circuit, a MAX15041, a switching regulator, and a closed-loop switching regulator, and that the second circuit or integrated circuit (e.g., the integrated circuit512) may be at least one of an integrated circuit, a MAX 4210B, a MAX 4210, and a MAX 4211. The signals and/or the multiplication product may be substantially digital in nature, with analog signals being converted into digital signals via analog-to-digital converters (“ADCs”), and the digital signals may be converted to analog signals via digital-to-analog converters (“DACs”).

The first circuit or integrated circuit (e.g., the integrated circuit511) may include at least one switching regulator and/or at least one closed-loop switching regulator to produce at least one of the varied or changed voltage and the varied or changed current to operate the predetermined component at constant or substantially constant power. The switching regulator and/or the at least one closed-loop switching regulator (see e.g., element511ofFIGS. 6A,6B and/or6C) may further include a first regulator and a second regulator, the first regulator operating to produce at least one of the varied or changed voltage to operate the predetermined component at constant or substantially constant power and the second regulator operating to produce the varied or changed current to operate the predetermined component at constant or substantially constant power. The first regulator may be any voltage regulator known to those skilled in the art, including, but not limited to at least one of: a voltage regulator, a voltage switching regulator, a voltage regulator with an operational amplifier (“op amp”), a transistor regulator, silicon controlled rectifiers (“SCR”), a voltage stabilizer, and the MAX15041 (see e.g., element511ofFIG. 6). The second regulator may be any current regulator known to those skilled in the art, including, but not limited to, a transistor, a current regulator, an operational amplifier (“op amp”), a field-effect transistor, a junction gate field-effect transistor (“JFET”), one or more current regulator diodes, a current source, a current source with thermal compensation, a voltage regulator current source, and the MAX15041 (see e.g., element511ofFIG. 6).

In accordance with at least one aspect of the present invention,FIGS. 6A-6Cshow diagrams of three embodiments of an electrical circuit510for maintaining or providing a constant or substantially constant power for a component, such as the radiation110source, for reducing and/or minimizing power decay within the component, such as the radiation110source, and for providing an improved electrical component driver, infrared source driver or a power source in general. As aforementioned, the first integrated circuit511is a switching regulator that would normally be used to regulate voltage and/or current of the predetermined component. The MAX15041 or any other similar circuit as discussed herein may be used as the switching regulator and uses synchronous DC-DC conversion to achieve good efficiency over a wide range of output voltages and/or currents of the predetermined component. The second integrated circuit512operates to create a voltage and/or a current which is proportional to power consumed. The MAX 4210B may be used for the second integrated circuit. The schematics ofFIGS. 6A-6Cshow how the two integrated circuits511,512may be connected together in accordance with the invention. If the MAX15041 is connected conventionally, the power adjustment potentiometer (or “pot”)562is preferably connected to the predetermined component, such as the radiation source110. The pot562may be, but is not limited to, a three-terminal resistor with a sliding contact that operates as a voltage divider. As aforementioned, the pot562may be used to set the predetermined power value for the predetermined component. The MAX4210B operates to sense a voltage drop across the 0.091 Ohm resistor and multiplies that value by the voltage appearing on pin 5 thereof. Additionally or alternatively, the power may be adjusted remotely. The product, which is in the form of a voltage, appears on pin 8, which is where the pot is connected.

In at least one embodiment, one or more components of the combined integrated circuit (e.g., the control circuit510) may be employed as follows: The six (6) capacitors (see elements520inFIGS. 6A-6C) may be 2.2 uf/100 volts ceramics, which is a part already used on the power supply printed circuit board (or “PCB”) or on the prototype board (see e.g., element668inFIG. 7) and having a Digi Key number of 445-4497-1-ND. The 47 uH inductor (see element521inFIGS. 6A-6C) may be a Digi-Key 587-1700-1-ND. Alternatively, a 100 uH inductor may be used (as is used as the inductor672in the system600best seen inFIG. 7). While one or more calculations preferably call for a 39 uH inductor, if that type of inductor is not available, the closest type of inductor may be employed, such as the 47 uH inductor (element521shown inFIGS. 6A-6C). The 0.091 Ohm resistor (element522inFIGS. 6A-6C) may be a Digi-Key RL16R.091FCT-ND. The arrow pointers from pins 5 and 7 of the MAX4210B (and directed towards the 0.091 Ohm resistor (element522inFIGS. 6A-6C)) each indicate a respective “Kelvin Connection”, which is a four wire-contact method for measuring resistance that eliminates the errors from lead resistance and clip resistance. The 78L05 (element524inFIGS. 6A-6C) regulates 5 volts for the MAX4210B. The MAX15041 has a 5 volt regulator, but, in one or more embodiments, the 5 volt regular of the MAX15041 may not be useable externally and must be bypassed (See pin 1 thereof as shown in at leastFIGS. 6A and 6B).

While in at least one embodiment (see the system600inFIG. 7) the snubbing network, R7 and C10 are not used, in one or more embodiments such components are used. As such, in one or more embodiments, one or more pads should be employed in the event the snubbing network, R7 and/or C10 are used.

While the loop compensation network on pin 4 of the MAX15041 may change from one embodiment of the circuit to the next, the network on pin 4 as shown inFIGS. 6A-6Cmay be employed in at least one embodiment.

Preferably, the power path is as straight and direct as possible over the topography or structure of a printed circuit board (“PCB”) (or of a socketed prototyping board, which may be alternatively used for a PCB in one or more embodiments, such as, but not limited to, the prototyping board668inFIG. 7). In the prototyping board used in the embodiment shown inFIG. 7, the “P” ground (see e.g., element(s)526inFIGS. 6A-6C) runs next to the power path. In at least one embodiment, such as in the layout for the system600shown on the prototyping board668inFIG. 7, the “Q” ground (see e.g., elements528inFIGS. 6A-6C) runs under everything else. Such a layout may be critical in one or more embodiments. The “P” and “Q” grounds preferably get connected in one place only, i.e., at location “EP” (stands for extended paddle) under the MAX15041 (best seen inFIGS. 6A and 6B). Preferably, the extended paddle or “EP” operates to conduct heat. Alternatively, other means for conducting heat known to those skilled in the art may be employed.

In one or more embodiments, the 78L05 (element524inFIGS. 6A-6C) may be connected to the circuit in one or more different ways. For example, as shown inFIG. 6A, the 78L05 (element524inFIG. 6A) is connected directly to the connection extending between the 47 uH inductor (element521), the capacitors (elements520) and the resistor (element522). Alternatively and preferably, as shown inFIG. 6B(which depicts the same diagram as shown inFIG. 6Awith the following exception), the 78L05 (element524inFIG. 6B) is instead connected to the connection extending between the capacitors (elements520shown on the top left portion ofFIG. 6B) and the 10K resistor connected to the MAX15041. Additionally or alternatively, as shown inFIG. 6C, the 78L05 (element524inFIG. 6C) may similarly be connected to the connection extending between the capacitors (elements520shown on the top left portion ofFIG. 6C) and the MAX15041.

Those skilled in the art will also appreciate that further modifications may be made to the schematics shown inFIGS. 6A-6B. For example, as best seen inFIG. 6C, while the circuit510may still employ one or more of the same components (e.g., the first integrated circuit511, the second integrated circuit512, the capacitors520, and the other elements521,522,524,526,528,562, etc. as aforementioned and further discussed below), the circuit510may include components (which may be in addition or alternative to components shown inFIGS. 6A-6Bor which may be specific components used for implementing connections diagrammatically represented inFIGS. 6A-6B), such as, but not limited to, the J5 Molex being connected to the predetermined component, such as the IR source (e.g., the radiation source110); a fixed resistor563, etc. That said, the circuits510shown inFIGS. 6A-6Call operate similarly (if not identical) to maintain a constant or substantially constant power and/or provide a predetermined or preselected amount of power to the predetermined component, such as the IR source (e.g., the radiation source110), thereby reducing, minimizing or eliminating power decay within the predetermined component.

In general, it may be desirable to limit the power level to the predetermined component, such as the IR source (e.g., the radiation source110), to a range of values such that damage to the predetermined component is prevented while maintaining adjustment sensitivity. For example, as shown inFIG. 6C, the fixed resistor563acts with potentiometer562to limit the maximum power that may be set and delivered to the resistance load of the predetermined component, such as the IR source (e.g., the radiation source110). For example, inFIGS. 6A and 6B, the circuits510may operate to deliver between about 7 watts and about 20 watts whereas the circuit510ofFIG. 6Cmay be limited to deliver between about 7 watts and about 15 watts.

While a control circuit or system may be based on the circuits510shown inFIGS. 6B-6Cas aforementioned, the control circuit or system600(best seen inFIG. 7) was based substantially on the circuit510shown inFIG. 6A. For example the MAX15041 (see element662inFIG. 7) was employed. While the system600ofFIG. 7also differs from the circuits510ofFIGS. 6A and 6Bin several ways, such differences may change depending on the circumstances surrounding the need(s) to be solved by the circuit, apparatus or system of the present invention. Indeed, for at least one or more embodiments, a circuit or system may be built using the exact schematic shown inFIG. 6Bor the schematic shown inFIG. 6C. The system600drives a 14.0 Ohm resistor (element623as shown inFIG. 7). By way of a conducted experiment using the system600, the pot652was set so that the output was 12.96 volts, 12 watts having been delivered to the resistor623. A new source has a resistance of ˜8 Ohms. When the resistance curve was extrapolated for an old source (e.g., a source that has about 6000 hours of time on it or more), it was found that the resistance of the old source increased to about 40 Ohms. As an additional experiment conducted and as discussed above regardingFIG. 8, a similar increase in resistance was shown for a radiation source.

In accordance with an aspect of the present invention, the constant power driver, circuit, and/or system (e.g., circuit510, system600, etc.), and methods of using same, may operate to deliver 12 watts (or any other predetermined value of constant or substantially constant electrical power as described above) in all cases (or in certain scenarios), thereby solving the “aging source problem” discussed above. Preferably, the system600includes a power regulator632. Additionally, the system600may use a power sensor664(or more than one power sensor664) on the PCB or the prototyping board668to help regulate the power, and, in the very least, to confirm that the electrical power being delivered to and/or consumed by the predetermined component (e.g., the radiation source110) is remaining constant or substantially constant.

Because the power is constant (or substantially constant) and stable in accordance with one or more aspects of the present invention, the source may warm up slowly in one or more embodiments. Preferably, the source warms up slowly. Given the new and unique circuit designs shown in at leastFIGS. 6A-6CandFIG. 7, the design desirably provides an overall efficiency exceeding 90 percent. Indeed, the new circuit design of the present invention and the aforementioned methods of providing constant or substantially constant power exceed expectations.

As shown inFIG. 7, a perspective view of a system600of the new power circuit is shown. The red item622at the top left of the system600is the 0.091 Ohm resistor. The system600employs ten (10) inches of wire wrap wire, and the aforementioned Kelvin connection(s). As aforementioned, while the inductor may be (and is preferably) a smaller inductor, a 100 uH inductor (see element672inFIG. 7) was used for the system600. The 78L05 component in the system600is the TO92 component (element no.766inFIG. 7).

Using the new circuit design discussed herein, all the parts thereof may be very small, and less than a watt of power may be lost in the regulator. Even for the system600shown inFIG. 7, no component was detectably warm except for the resistor623during the experiment conducted.

As shown inFIG. 8, the source resistance changed quite rapidly and linearly over the first 2000 hours. This is in approximated concordance with a (1-decaying exponential) behavior. As such, the switch mode nature of the one or more power circuits510is compliant with a large range of resistances. The discontinuities in the curve ofFIG. 8indicate one or more switches in the polarity across the predetermined component, such as the IR source (e.g., the radiation source110). Previously, without the use of the one or more circuits510and/or the system600, there would normally be a significant diode effect where the resistance is different in each direction. Use of one or more embodiments of the present invention avoids or resists the diode effect. Specifically, if the polarity of the predetermined component is reversed, the methods disclosed herein, the one or more circuits510and/or the power system600compensates for such diode effects.

As shown inFIGS. 9A-9D, constant, consistent power was provided (best seen inFIG. 9D) to the predetermined component, e.g., a radiation source (which, in this particular instance, was a silicon carbide source even though other radiation sources may be used, such as the radiation source110) while resistance changed over time (best seen inFIG. 9A). Even though resistance changed over time as shown inFIG. 9A, the voltage and the current of the predetermined component was controlled dynamically over the same period of time (as shown inFIGS. 9B-9C) to achieve the constant, consistent power provided (as shown inFIG. 9D).

There are many ways to compute power, digital as well as analog. In at least one embodiment, a computer may be dedicated to the control and the monitoring of the power circuit, such as the one or more control circuits510and/or the power control system600. As shown in the schematic view ofFIG. 10, system1101operates to provide and/or maintain the constant, stable or substantially constant, stable power to the predetermined component, such as the radiation source110, as discussed above in accordance with one or more aspects of the present invention. The system1101may include at least a first processor (also may be referred to as a “computer”)1104, and at least a second processor (also may be referred to as a “computer”)1103. The processors1103,1104may operate as one or more databases to store information for use by the processors1103,1104. The processors1103,1104may be used to maintain or provide constant power in accordance with one or more aspects of the present invention. The at least one second processor and/or database1103may be used by, or together with, the at least one first processor1104. For example, the processors1103,1104may store any predetermined values (e.g., the predetermined value of electrical power as aforementioned) for use by a power control circuit or system (e.g., the one or more control circuits510, the control system600, etc.). The processors1103,1104may be connected to each other by way of a connection1108(e.g., a network connection), and the processors1103,1104may be connected to the control circuit and/or the control system600via a connection1102(e.g., a network connection) (as best seen inFIG. 10). The processors1103,1104may be located in the same telecom network or in different telecom networks (e.g., the predetermined component may be controlled remotely). If a computer is used in at least one embodiment of the present invention, the computer may sense source current and/or voltage with one or more analog-to-digital converters. The computer could then provide command voltage to the regulator via a digital-to-analog converter. The DACs and/or the ADCs may be included in the computer, such as the processors1103,1104, or may be included as a portion of the one or more power circuits510and/or the system600.

As an alternative or additional embodiment, the one or more power circuits510and/or the power system600may be digitally or substantially digitally implemented as shown inFIG. 11. A substantially digital implementation of the power control circuit and/or system1500may include a current measuring circuit1510, a voltage measuring circuit1520, one or more analog signals1530,1540, one or more ADCs1550,1560, a digital multiplier1570(which may be part of a processor or a computer1580), and a power stage1590. The current measuring circuit1510operates to provide an analog signal1530proportional to the current in the controlled or predetermined component1501(e.g., such as an IR source; the radiation source110; etc.). Any current measuring circuit known to those skilled in the art may be used as the current measuring circuit1510. The analog signal1530may physically be a voltage. The voltage measuring circuit1520operates to provide an analog signal1540proportional to the voltage across the controlled or predetermined component1501(e.g., such as an IR source; the radiation source110; etc.). The analog signal1540also may physically be a voltage. A first analog-to-digital converter (ADC1)1550operates to create a digital, numerical representation of the current signal1530. A second analog-to-digital converter (ADC2)1560creates a digital, numerical representation of the voltage signal1540. The digital multiplier1570operates to receive the digital outputs of ADC11550and ADC21560, and the digital multiplier1570further operates to multiply the digital outputs of ADC11550and ADC21560together, thereby creating a digital product1578accurately representative and proportional to the power dissipated in the controlled or predetermined component1501(e.g., such as an IR source; the radiation source110; etc.). The digital multiplier1570may be part of a larger digital system1580, which may be a computer or processor (e.g., one of the computers or processors1103,1104), microprocessor, microcontroller, or personal computer, or digital computer board, or may operate outside of a computer program. One or more interface circuits known to those skilled in the art, such as, but not limited to, line drivers, multiplexers and demultiplexers, deserializers, buffers, registers, etc., may be employed to convey the digital signals from the ADCs1550and1560and make them useable by the computer1580and the digital multiplier1570.

The circuit and/or system1500may operate in a loop, and the loop may be closed in a number of ways. A suitable DAC command value1575may first be generated from the output of the digital multiplier1570using a digital product1578and the processing step1581. This causes DAC1585to provide a feedback input1584to the power stage1590, which also may receive a desired, commanded power input1589from a commanded power value1587. The commanded power input1589may be a reference value that properly scaled feedback input1584must meet when the loop is closed. Additionally or alternatively, the commanded power input1589may be the actual desired power level to be delivered to the controlled or predetermined component1501(e.g., such as an IR source; the radiation source110; etc.). Power stage1590, which is capable of the full, requisite power level required by component1501, then acts to provide the commanded power to component1501.

The loop may also be closed using the computer1580, which acts via the processing step1581. The computer1580uses the output (also referred to as the digital product)1578of the digital multiplier1570and the commanded power value1587to compute the DAC command1575by the processing step1581. The DAC command1575then controls the power stage1590via the output1584of the DAC1585, thereby causing commanded power to be provided to component1501.

It will be appreciated that the power stage1590may have many forms. Regardless of the form, the power stage1590operates to control at least one of the current, the voltage, and the product of current and voltage delivered to the predetermined component1501(e.g., such as an IR source; the radiation source110; etc.), these values being derived, in the closed loop operation, from the commanded power1587, and the digitally measured and multiplied values of the actual current and voltage employed by the predetermined component1501(e.g., such as an IR source; the radiation source110; etc.). As a concrete example, a suitably scaled analog output (e.g., the output1584) of a DAC circuit (e.g., DAC1585), the value of the output having been computed by the computer1580, may be wired directly to the aforementioned MAX15041, which may operate as the power stage1590in one or more embodiments of the circuit and/or system1500. The digital multiplier1570, used with inputs (i.e., input into the multiplier1570) from the ADCs1550and1560(i.e., output from the ADCs1550and1560), and suitably scaled in the processing step1581, may form the input1575to the DAC1585, which then generates the output1584. In this way, the aforementioned second integrated circuit512(e.g., an analog multiplier MAX 4210 or some other similar circuit as described herein) may be replaced by the digital implementation disclosed herein.

Such improvement of power delivery and minimization and/or reduction of power loss as discussed herein is important for precision instrumentation applications. Indeed, as one example of such precision instrumentation application as best seen in the diagram view shown inFIG. 12and as best seen in the perspective view shown inFIG. 13, it is a further object of the present invention to provide a Fourier Spectrometer (“FTIR”) using the one or more power circuits510and/or the system600of the present invention to provide a constant or substantially constant and stable or substantially stable power supply to the source thereof. The one or more power circuits510and/or system600may be used in at least one optical instrument, such as a Fourier Spectrometer, to create an optical spectrum from a light/radiation beam and/or electrical signal created from the light beam (e.g., from the broadband beam source, such as the radiation source110). In at least one embodiment, the Fourier Spectrometer may incorporate a broadband thermal source while employing the one or more power circuits510and/or the system600as discussed herein. While other components of such an improved Fourier Transform Spectrometer (FTIR) may be of any design known in the art, the improved Fourier Transform Spectrometer preferably includes at least one of the one or more source driver circuits510and/or the system600(also referred to as the “infrared (“IR”) source driver”) as discussed herein to stabilize the input light source (e.g., the thermal light source). At least one embodiment of the FTIR may include a Fourier Modulator including a Michelson interferometer, a the broadband beam source (e.g., the radiation source110) collimated by a first optical system and incident on the Michelson interferometer (e.g., the interferometer100) therein, a second optical system collecting light transmitted by the Michelson interferometer (e.g., the interferometer100) and transmitting it to a sample region, a third optical system collecting light from the sample region and focusing it into a detector region, an optical detector (e.g., the detector60, the detector142; etc.) located in the detector region converting the transmitted light from the sample region into an electrical signal, and a Fourier analyzer comprising one or more electronics and software that operate to convert the electrical signal into an optical spectrum.

Turning to the details ofFIG. 12,FIG. 12is a schematic diagram of a Fourier Transform Spectrometer System1200incorporating at least one embodiment of the power control circuit510disclosed. A raw power source1140, which in one embodiment may be any DC voltage between 9 and 36 volts, may operate to provide power to energize various the one or more modules shown, including the power control circuit510, which operates to regulate the power of a light source1138(e.g., a thermal light source, such as, but not limited to the radiation source110). The thermal light source1138is connected to the control circuit510by a cable1139(e.g., a simple two-wire cable with a shield). In some embodiments, the control system510may not calculate power directly but may require assistance of an external computer, such as the computer or the processor1104(or, alternatively, the computer or processor1103as shown inFIG. 10). A connection1180denotes a connection to the computer1104facilitating the computer1104's control of the control system510for the purpose of stabilizing the power in the light source1138. Additionally or alternatively, a computer, such as the computer1104, may be at least one of part of, enclosed in and integral with the control circuit510for the purpose of stabilizing the power in the light source1138. An optical beam1190, after suitable collimation (e.g., as discussed above), is directed into an interferometer, such as an interferometer1155(or the interferometer100as discussed above). To obtain an optical spectrum, the optical path difference (“OPD”) of interferometer1155(or of the interferometer100as discussed above) must be precisely controlled by means known to those skilled in the art of Fourier Transform Spectrometer design. This control is done by an OPD control1150, which operates under command of the computer1104through an electrical connection1168. An output optical beam1158is passed to one or more sample optics1160, and the output optical beam1158functions or operates to contain or access the sample under study, and transmit through, or reflect off the sample. The sample optics1160then recollects the light remaining after interaction with the sample and sends the optical beam1163to a detector-digitizer1165. A digital, numerical signal is then sent over an electrical connection1167to the computer1104, which analyzes the digital, numerical signal to form a spectrum, or transmits the signal to another computer (e.g., the computer1103as shown inFIG. 10) via a network connection (e.g., connection1108as seen inFIG. 10) including, but not limited to, an internet connection, a wireless connection, etc., for the purpose of computing and displaying the spectrum. The connections1167and1168are actually bidirectional, allowing the computer1104to adjust parameters on the detector-digitizer1165, and possibly to trigger the detector-digitizer1165, based on a signal reported by the OPD control1150over the connection1168.

FIG. 13is a perspective view of a practiced Fourier Transform Spectrometer System, such as the Fourier Transform Spectrometer System1200as diagrammatically shown inFIG. 12, in accordance with one or more aspects of the present invention. One or more items shown inFIG. 12are evident inFIG. 13, and the functions and references of those items are as described above in reference toFIG. 12. Indeed, those skilled in the art will appreciate that the elements (e.g., the circuit510, the computer1104, the OPD control1150, the light source1138, the one or more sample optics1160, etc.) of the system1200ofFIG. 13may operate in the same or similar fashion to those like-numbered elements of the system1200shown inFIG. 12as discussed above or any additional like-numbered elements discussed further herein below.

Any methods of the present invention, such as the methods for using the power control circuit and/or system, may be stored on a computer-readable storage medium. A computer-readable storage medium used commonly, such as, but not limited to, a hard disk, a flash memory, a CD, a DRAM or the like, an optional combination thereof, a server/database, etc. may be used to cause a processor, such as, the processors1103,1104of the aforementioned computer system1101to perform the steps of the methods disclosed herein. The computer-readable storage medium may be a non-transitory computer-readable medium, and/or the computer-readable medium may comprise all computer-readable media, with the sole exception being a transitory, propagating signal. The computer-readable storage medium may include media that store information for predetermined or limited or short period(s) of time and/or only in the presence of power, such as, but not limited to Random Access Memory (RAM), register memory, processor cache(s), etc.

In accordance with at least one aspect of the present invention, the methods, systems, and computer-readable storage mediums related to the processors, such as, but not limited to, the processor of the aforementioned computer, etc., as described above may be achieved utilizing suitable hardware, such as that illustrated in the figures. Functionality of the invention may be achieved utilizing suitable hardware, such as that illustrated inFIG. 10. Such hardware may be implemented utilizing any of the known technologies, such as standard digital circuitry, any of the known processors that are operable to execute software and/or firmware programs, one or more programmable digital devices or systems, such as programmable read only memories (PROMs), programmable array logic devices (PALs), etc. The processors1103,1104(as shown inFIG. 10) may also include and/or be made of one or more microprocessors and/or nanoprocessors. Still further, the various aspects of the invention may be implemented by way of software and/or firmware program(s) that may be stored on suitable storage medium (e.g., computer-readable storage medium, hard drive, etc.) or media (such as floppy disk(s), memory chip(s), etc.) for transportability and/or distribution.