Current source and current generation method

Abstract

To provide a current source having a response increased in speed.SOLUTION: A current source includes an operational amplifier 42 having a constant gain at a frequency lower than a certain frequency point and having a gain inversely proportional to the frequency at a frequency higher than the frequency point. A source resistance 48 is connected in series with an output terminal of the operational amplifier 42. The operational amplifier 42 controls a voltage across terminals of the source resistance 48 to a source voltage so that the gain of the operational amplifier 42 can serve to limit the variations of the source voltage and the output voltage across terminals of a load between high and low terminals 45 and 47 due to the operational amplifier 42. Feedback components 52 and 54 are connected to an input terminal of the operational amplifier 42 and receive a part of the output voltage to reduce the gain of the operational amplifier usable to control the source voltage across terminals of the source resistance 48.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The disclosed technology relates to test and measurement systems, and more particularly to current sources for use in test and measurement systems. [Background technology]

[0002] Many different types of test and measurement systems use current and voltage sources to apply current or voltage to a device under test. Without limitation, a source measure unit (SMU) provides one example, and typically applies a voltage or current to a device under test (DUT) that is coupled to the SMU. The SMU then measures the response of the DUT using a current meter, voltmeter, or similar. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-145758 A [Patent Document 2] JP 2014-207856 A [Non-patent literature]

[0004] [Non-Patent Document 1] "Keithley Source Measure Units," Tektronix / Keithley, [Online], [Retrieved July 24, 2020], Internet<https: / / jp.tek.com / keithley-source-measure-units> [Non-Patent Document 2] "Norton's theorem" article, Wikipedia (English version), [Online], [Retrieved July 24, 2020], Internet<https: / / en.wikipedia.org / wiki / Norton%27s_theorem> Summary of the Invention [Problem to be solved by the invention]

[0005] A current source may generate a current by applying a source voltage across a source resistance and pass the resulting current through the DUT. However, when the source resistance is smaller than the resistance of the DUT, the current source responds much slower to changes in the source voltage compared to when the source resistance is larger than the resistance of the DUT. An operational amplifier (op-amp) with a large gain can be used to make the source resistance appear large, but the gain of the op-amp begins to "roll off" at a relatively low frequency, which causes the apparent large resistance to "roll off" as well, becoming capacitive and reducing the speed and stability of the current source. This concern is becoming more pronounced due to the increasing need for high speed in current sources.

[0006] SUMMARY OF THE DISCLOSED EMBODIMENTS OF THE DISCLOSURE Embodiments of the disclosed apparatus and methods address shortcomings in the prior art. [Means for solving the problem]

[0007] In the following, examples useful for understanding the technology disclosed in the present application are presented. The embodiment of the technology may include one or more of the examples described below and any combination thereof.

[0008] Example 1 comprises at least one gain component having a constant gain at frequencies below a certain frequency point and a gain inversely proportional to frequency above the frequency point, the gain component having an input terminal and an output terminal; a source resistor connected in series with the output terminal of the gain component, the source resistor controlling the voltage across the source resistor to the source voltage such that the gain of the gain component limits the regulation of the output voltage across a load between the source voltage and the high and low terminals of the gain component; and a feedback component receiving at least a portion of the output voltage, the feedback component connected to the input terminal of the gain component and reducing the gain of the gain component that controls the source voltage across the source resistor.

[0009] Example 2 is the current source of Example 1, further comprising an inductance (inductor, coil) in series with the source resistance, the inductance being sized to provide an impedance equal to the resistance value of the source resistance at the frequency point.

[0010] Example 3 is the current source of either example 1 or 2, wherein the gain component includes an op-amp (operational amplifier).

[0011] Example 4 is the current source of any of Examples 1 to 3, wherein the feedback component includes a resistive attenuation circuit across the output terminal.

[0012] Example 5 is the current source of any one of Examples 1 to 4, wherein the feedback component includes an inverting attenuation circuit.

[0013] Example 6 is the current source of any one of Examples 1 to 5, in which the above current source is inserted in place of the source resistor of the second current source without gain reduction.

[0014] Example 7 is the current source of any one of Examples 1 to 6, in which the above current source is inserted in place of the source resistor of the second current source with a reduced gain.

[0015] Example 8 is a current source comprising a source voltage, at least one gain component having a constant gain below a frequency point and a gain inversely proportional to frequency above the frequency point, the gain component having an input terminal and an output terminal, a source resistor connected to the output terminal of the gain component, and a resistive circuit connected between the source resistor and the input terminal of the gain component, the resistive circuit being composed of at least two resistors related by a constant based on the gain.

[0016] Example 9 is the current source of example 8, wherein the gain component includes an operational amplifier.

[0017] Example 10 is the current source of example 9, further comprising a second operational amplifier (opamp) coupled between the high and low terminals of the current source.

[0018] Example 11 is the current source of any one of Examples 8 to 10, further comprising an inductor in series with the source resistor.

[0019] Example 12 is a method for generating a current, the method comprising: supplying power to at least one gain component having a constant gain at frequencies below a frequency point and a gain inversely proportional to frequency above the frequency point, the gain component having an input terminal and an output terminal; connecting a source resistor in series with the output terminal of the gain component, the gain component regulating a voltage across the source resistor to a source voltage such that the gain of the gain component limits a regulation of an output voltage across a load between the source voltage and a high terminal and a low terminal; and generating a feedback signal from a feedback component including at least a portion of the output voltage connected to the input terminal of the gain component, the feedback signal reducing the available gain of the gain component to control the source voltage across the source resistor.

[0020] Example 13 is the method of example 12, wherein generating the feedback signal from the feedback component includes generating the feedback signal from a resistor circuit having first and second resistors having values ​​proportional to each other.

[0021] Example 14 is the method of example 13, wherein the value of the second resistor is equal to a constant minus one multiplied by the value of the first resistor.

[0022] Example 15 is the method of example 14, further comprising the steps of connecting an inductor (inductor, coil) in series with the source resistance, and selecting a constant based on the point at which the frequency response of the inductor is equal to the resistance of the source resistance.

[0023] Example 16 is the method of any of Examples 13 to 15, wherein generating the feedback signal further comprises generating the feedback signal from an additional gain component including an operational amplifier.

[0024] Example 17 is the current source of any of Examples 12 to 16, wherein generating the feedback signal from the feedback component includes generating the feedback signal from an operational amplifier between the high and low terminals.

[0025] Example 18 is the current source of any of Examples 12-17, further comprising an inductor connected in series with the source resistor. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 shows an example of a conventional current source. [Diagram 2] FIG. 2 shows an example of a conventional current source. [Diagram 3] Figure 3 shows a diagram of the Norton model of a current source. [Figure 4] Figure 4 shows a schematic diagram of an embodiment of a current source with a gain component in the feedback path. [Diagram 5] Figure 5 shows an example of a current source with a Norton model for a wide frequency range. [Figure 6] Figure 6 shows an example of a current source with a Norton model for a wide frequency range. [Figure 7] FIG. 7 shows an embodiment similar to that of FIG. 6 but with an alternative voltage source. [Figure 8] FIG. 8 shows an embodiment similar to that of FIG. 5 but with the voltage source replaced. [Figure 9] FIG. 9 shows the embodiment of FIG. 4 incorporating the conventional current source of FIG. [Figure 10] FIG. 10 shows an embodiment similar to that of FIG. 2, but with reduced gain and a changed location of the voltage source. [Figure 11] FIG. 11 shows an embodiment similar to that of FIG. 2, but with reduced gain and a changed location of the voltage source. [Figure 12] FIG. 12 shows an embodiment similar to that of FIG. 2, but with reduced gain and a changed location of the voltage source. [Figure 13]FIG. 13 shows an embodiment in which multiple gain reducing current sources are nested. [Figure 14] FIG. 14 shows a test and measurement device that includes a current source. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] FIG 1 shows an example of a conventional current source, in which an op-amp (operational amplifier) ​​12 is powered by a voltage 14 and has a source resistance R S Voltage V across 18 S Multiply by 16. This gives us V S / R S The output current I is equal to S is generated. Impedance Z L The load, designated 19, is between the high output terminal 15 and the low output terminal 17. Z L R S If less than V S The rate at which the output current changes with a change in Z is determined by the gain bandwidth of the op amp, G. However, L R S If it is greater than R, this speed S Z for L The general equation is β=R S / (R S +Z L ) Z L < <R S When β ≈ 1, Z L >>R S If β ≒ R S / Z L The smaller β is, the slower the response of the current source will be.

[0028] Figure 2 shows another form of a conventional current source that faces the same problem. In this form, the source voltage V S 16 is the source resistance R S An operational amplifier 20 is powered by a voltage 22 and is connected between the source resistor 18 and the low terminal 17. A load 19 is between the high terminal 15 and the low terminal 17.

[0029] In operation, the amplifier sees a feedback term β, which is the sum of the source resistance and the load resistance Z L is equal to the sum of β=R S / (R S +Z L )

[0030] If load Z L is the source resistance R S For larger values, β is less than 1, and in this condition the circuits of Figures 1 and 2 respond slowly to changes in the source voltage. For example, when β = 0.1, the current source responds 10 times slower than when β is equal to 1. This results in a delay in the circuit operation in typical high-frequency operation.

[0031] One possible solution is to use a larger source resistance. However, to generate a large current, a larger source voltage is required. The power consumption of the source resistance would increase. The present embodiment allows for a reduction in source voltage and power consumption while maintaining a relatively fast speed. Essentially, the present embodiment allows a relatively low resistance value to "appear" relatively large, allowing the generation of relatively large currents at relatively high frequencies, without suffering from the problems of power consumption and high voltage requirements.

[0032] Norton's theorem, sometimes called the Mayer-Norton theorem, states that any linear electrical circuit containing only voltage and current sources and resistors can be replaced by a high and low terminal through an equivalent current source in parallel with an equivalent resistance. Figure 3 shows this model, with a resistor R in Current source I in parallel with 32 S 30.

[0033] The embodiments of the present application utilize an attenuator circuit to limit the gain of the gain component. Although the embodiments of the present application show an op-amp, any gain component including a transistor can be used. The magnitude or value of the other components depends, at least in part, on the gain of the gain component. Gain components as used herein have a higher gain at low frequencies than at high frequencies. As used herein, the term "low frequency" refers to a frequency at which the gain of the gain component is constant. The term "high frequency" refers to a frequency at which the gain of the gain component is inversely proportional to the frequency.

[0034] 4 shows a schematic diagram of an embodiment of a current source. The current source has a source voltage 36, which is coupled to a source resistance R S The feedback component 38 may be in series with the gain component 34 or may be in the feedback component of the gain component 38. The feedback component 38 reduces the gain of the gain component 40. The gain component 40 has positive and negative input terminals and an output terminal and a return terminal. The gain component 40 has a constant gain below a certain frequency point, above which the gain is inversely proportional to the frequency. The gain component 40 regulates the voltage across the source resistor 34 to be the source voltage 36. The gain of the gain component 40 limits the regulation of the output voltage across the load 19 between the high and low terminals. The feedback component 38 receives at least a portion of the output voltage of a current source connected to the input of the gain component, and the feedback component reduces the gain of the gain component available to control the source voltage across the source resistor.

[0035] According to the embodiment of the present application, the gain can be controlled to maintain a constant gain up to a higher frequency, thereby allowing the current source resistance to be kept high for the same high frequency. In addition, the inductor (coil) L S , L S =RS The magnitude of k / G is R S where k is the gain set by the attenuation circuit and G is the gain-bandwidth of the amplifier. In the following non-limiting examples, k is assumed to be 10 for simplicity.

[0036] 5 shows an embodiment of a current source incorporating an attenuation circuit of R2 / (R1+R2) to reduce the gain of the gain component. Note that while the figure shows a specific current source architecture and gain components, the embodiment applies to any current source simply utilizing any gain component.

[0037] 5, the current source comprises a voltage source 46 connected to the inverting (negative) input terminal of an operational amplifier 42, which is powered by a voltage 44. The output terminal of the operational amplifier 42 is connected to a source resistor R, also called a current limiting resistor. S The other input terminal of the operational amplifier 42 is connected to the output terminal of an attenuation circuit which functions as a gain reducing feedback component. In this embodiment, the attenuation circuit is comprised of two resistors 52 and 54. Resistor 54 is connected between the non-inverting (positive) input terminal of the operational amplifier 42 and the low terminal 47, and resistor R1 52 is connected between the non-inverting input terminal of the operational amplifier and the high terminal 45. A load, not shown here, exists between the high and low terminals 45 and 47. As described above, the attenuation circuit can be used As the value of k Select k1 where resistor 54, let's call it R2, is equal to (k-1)R1. k = (R1 + R2) / R1 Using 10 as an illustrative value of k, if R1 is 1 kilohm, R2 is 9 kilohm.

[0038] FIG. 6 illustrates an embodiment including a resistive circuit as described with respect to FIG. 5 and an inductor 50. As mentioned above, the inductor has a resistance of L S =R SIt has a magnitude of k / G, where k is the gain set by the attenuation circuit and G is the gain-bandwidth of the amplifier. This extends the frequency over which the current source maintains its resistance.

[0039] Figure 7 shows a similar architecture to Figure 6, but with an additional voltage source. In this embodiment, the voltage source 60 is connected to a current source I a 62 and current resistance R a 64. The source voltage is equal to the current multiplied by the resistance, V S =I a R a and the source current is the current source current multiplied by the current resistance divided by the source resistance, I S =I a R a / R S It is.

[0040] FIG. 8 shows a similar architecture to FIG. 5, but with the voltage source moved to be connected between the non-inverting input terminal of amplifier 42 and the intermediate node of the resistive attenuation circuit.

[0041] 9 shows an embodiment incorporating the current source 40 of FIG. 6 into the current source of FIG. 2 without gain reduction. In this example, a voltage source 46 is connected to one input terminal of an operational amplifier 42, which is powered by a voltage 44. The output terminal of the operational amplifier 42 is connected to an inductor L S 50, which in turn is connected to the source resistor R S The other input terminal of the op-amp 42 is connected to a resistor network which is a gain reducing feedback component. In this embodiment, the resistor network includes two resistors 52 and 54. Resistor 54 is connected between the input terminal of the op-amp 66 and ground, and resistor 52 is connected between the input terminal of the op-amp and high terminal 45. A load 49 is between the high and low terminals 45 and 47, respectively.

[0042] In this embodiment, a second operational amplifier 66 powered by a voltage 67 has a source resistor 48 Inductor50 and the "opposite" side (i.e., the current source 4 0 output terminal) and ground Imaginary Short death, Second op amp 66 The output terminal of the second operational amplifier 66 is connected to the low terminal 47. In this embodiment, the second operational amplifier 66 is connected to the summing node / Current source 40 The load should be set so that the output terminal is kept at ground. 49 These architectures are merely examples and can be modified and still fall within the scope of the following claims.

[0043] 10-12 show an embodiment similar to FIG. 2, except that op-amp 66 has gain reduction feedback components in the form of R1 68 and kR1 70, and gain component 72. In FIGS. 10-12, the gain feedback is inverted so that 70 has a value of k1R1 rather than (k1-1). Voltage source 46 in FIG. 10 is connected to source resistor 48 as in the previous embodiment. In FIG. 11, the voltage source is moved to the opposite side of source resistor 48 and connected to the inverting (negative) input terminal of op-amp 66. In FIG. 12, voltage source 46 is connected between the gain reduction feedback circuit and the non-inverting (positive) terminal of op-amp 66.

[0044] Figure 13 shows an embodiment combining several current sources, each with a gain reduction. A current source with gain reduction is shown in box 80, replacing the source voltage and source resistance in the right part of the figure. A second inductor 82 connects this current source to be part of the left current source, which includes amplifier 66 with gain reduction by resistors R2 86 and R3 88 (R3 is equal to k2R2), and amplifier 89. The two constants k1 and k2 are not related to each other, but each constant is related to the gain of the respective current source.

[0045] In any embodiment, including the alternative architecture utilizing a damping circuit, a current source I SThe damping circuit behaves as if the resistive circuit were a small resistor, using less power and generating less heat, while allowing for the generation of a relatively large current. Similarly, the damping circuit may include a resistive circuit, an inductor, or a combination of the two.

[0046] The feedback β described above in these embodiments is a constant k multiplied by the source resistance divided by the sum of k times the source resistance and the load resistance, β=kR S / (kR S +Z L ) becomes Z L For the value of β to be significantly smaller, Z L must be k times larger. Z L Even when this value is reached, the speed of response is still k times faster than it would be without the inductor-resistor circuit.

[0047] In the field of test and measurement systems, the test and measurement instrument may have a current source internal to it so that the system can apply current to the device under test. Figure 14 shows a block diagram of one embodiment of a test and measurement instrument. As can be readily appreciated by those skilled in the art, the test and measurement instrument 90 may include additional components not shown in Figure 14.

[0048] The test and measurement instrument 90 includes one or more ports 92, which may be any electrical transmission medium. The test and measurement instrument 90 may be any device capable of generating a signal and then making a measurement of the device under test, such as, but not limited to, a current source, a source measure unit, or a digital multimeter, as described above. The ports 92 may include a receiver, transmitter, or transceiver. The ports 92 may be coupled to a signal source or a combination signal source and current meter 94, which may include any of the current sources described above. For simplicity, only one processor is shown in FIG. 14, but one skilled in the art will appreciate that multiple processors 96 of various types may be used in combination rather than a single processor 96. The processor 96 is electrically coupled to the signal source 94 and assists in measuring, displaying, or storing the current of the connected device under test.

[0049] One or more processors 96 may be configured to execute instructions from memory 98 and may perform any method or related steps indicated by such instructions. Memory 98 may be implemented as a processor cache, random access memory (RAM), read-only memory (ROM), solid-state memory, a hard disk drive, or other form of memory. Memory 98 serves as a medium for storing data, computer program products, and other instructions.

[0050] A user input 100 is coupled to the one or more processors 98. The user input 100 may include a keyboard, mouse, trackball, touch screen, or any other control device available to a user through a GUI on a display 102. The display 102 may be a digital screen, cathode ray tube-based display, or any other monitor that displays waveforms, measurements, and other data to a user. Although the components of the test and measurement instrument 90 are depicted as being integrated within the test and measurement instrument 90, one skilled in the art will appreciate that any of these components may be external to the test instrument 90 and may be coupled to the test instrument 90 in any conventional manner, such as by wired or wireless communication medium or mechanism. For example, in some embodiments, the display 92 may be remote from the test and measurement instrument 90.

[0051] The embodiments described herein allow for a wide dynamic range of current with accuracy at all current levels. These embodiments allow a user to accurately measure both low and high currents in a device without modifying the ammeter. For example, if a device is previously receiving a low current and suddenly receives a large current, the ammeter of the embodiments disclosed herein can accurately measure both low and high currents.

[0052] In this disclosure, the singular forms "a," "an," and "the" include plural referents unless the context dictates otherwise. The term "or" is meant to be inclusive and mean either any, some, or all of the listed items. The terms "comprises," "comprising," "includes," "including," or other variations are intended to cover a non-exclusive inclusion, such that a process, method, or product consisting of a list of elements does not necessarily include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or device. Relative terms such as "about," "approximately," "substantially," and "generally" are used to indicate possible variations of ±10% of the stated or understood value.

[0053] The disclosed technology can be easily changed into various modifications and alternative forms. In the present application, specific embodiments are shown in the drawings and described in detail as examples. However, these examples disclosed in the present application are presented for the purpose of clarity of explanation and are not intended to limit the broad concepts disclosed in the specific embodiments described in the present application, unless expressly limited. Thus, the disclosed technology is intended to cover all modifications, equivalents, and alternatives of the described embodiments in the light of the attached drawings and claims.

[0054] References to aspects, examples, or the like in the specification indicate that the described items may include a particular feature, structure, or characteristic. However, each disclosed aspect may or may not include such a particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same aspect, unless specifically stated otherwise. Furthermore, when a particular feature, structure, or characteristic is described in connection with a particular aspect, such feature, structure, or characteristic may also be used in connection with other disclosed aspects, regardless of whether such feature is explicitly described in connection with such other disclosed aspects.

[0055] Aspects of the disclosed technology can operate on specially created hardware, firmware, digital signal processors, or specially programmed general-purpose computers, including processors that operate according to programmed instructions. The term "controller" or "processor" in this application contemplates microprocessors, microcomputers, ASICs, and dedicated hardware controllers, among others. Aspects of the disclosed technology can be implemented in computer-available data and computer-executable instructions, such as one or more program modules, executed by one or more computers (including a monitoring module) or other devices. Generally, program modules include routines, programs, objects, components, data structures, and the like, which, when executed by a processor in a computer or other device, perform particular tasks or implement particular abstract data formats. The computer-executable instructions may be stored in computer-readable storage media, such as hard disks, optical disks, removable storage media, solid-state memory, RAM, and the like. As will be appreciated by those skilled in the art, the functionality of the program modules may be combined or distributed as desired in various embodiments. Furthermore, such functionality may be embodied in whole or in part in firmware or hardware equivalents, such as integrated circuits, field programmable gate arrays (FPGAs), etc. Certain data structures may be used to more effectively implement one or more aspects of the disclosed techniques, and such data structures are considered to be within the scope of the computer-executable instructions and computer-usable data described herein.

[0056] The disclosed aspects may, in some cases, be implemented in hardware, firmware, software, or any combination thereof. The disclosed aspects may also be implemented as instructions carried by or stored on one or more computer-readable media that may be read and executed by one or more processors. Such instructions may be referred to as computer program products. A computer-readable medium as described herein means any medium that can be accessed by a computing device. By way of example, and not limitation, computer-readable media may include computer storage media and communication media.

[0057] Computer storage media means any medium that can be used to store computer-readable information. By way of example and not limitation, computer storage media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital video disc (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, and any other volatile or non-volatile removable or non-removable media implemented in any technology. Computer storage media excludes signals themselves and transitory forms of signal transmission.

[0058] A communication medium refers to any medium capable of communicating computer readable information. By way of example, and not limitation, communication media may include coaxial cables, fiber optic cables, air, or any other medium suitable for communicating electrical, optical, radio frequency (RF), infrared, acoustic, or other types of signals.

[0059] Although specific embodiments have been illustrated and described for purposes of illustration, it will be understood that various modifications can be made without departing from the spirit and scope of the disclosed teachings. Accordingly, the invention should not be limited, except as by the appended claims. [Explanation of symbols]

[0060] 19 Load 30 current source 32 Resistance 34 Source Resistance 36 Source Voltage 38 Feedback Components 40 Gain Components 42 Operational Amplifiers 44 Voltage 45 High terminal 46 Voltage Source 47 Low terminal 48 Source Resistance 49 Load 50 Inductor (coil) 52, 54 resistance circuit 60 Voltage Source 62 Current source 64 Current resistance 66 Operational Amplifiers 67 Voltage 68, 70 Feedback Components 72 Gain Components 82 Second inductor (coil) 86 Resistance 88 Resistance 89 Amplifier 90 Test and measurement equipment 92 Port 94 Signal source 96 processors 98 Memory 100 User input section 102 Display section

Claims

1. A current source comprising: at least one gain component having a constant gain below a frequency point and a gain inversely proportional to frequency above the frequency point, the gain component having an input terminal and an output terminal; a source resistor connected in series with the output terminal of the gain component, the gain component controlling a voltage across the source resistor to a source voltage such that a gain of the gain component limits variations in the source voltage due to the gain component and in the output voltage across a load between the high and low terminals of the current source; a feedback component receiving at least a portion of the output voltage, the feedback component being connected to the input terminal of the gain component, the feedback component reducing a gain of the gain component controlling the source voltage across the source resistor; an inductance in series with the source resistor, which has an impedance equal to the resistance of the source resistor at the frequency point; A current source comprising:

2. A current source, comprising: a voltage source for providing a source voltage; at least one gain component having a constant gain below a frequency point and a gain inversely proportional to frequency above the frequency point, the gain component having a first input terminal connected to the voltage source and an output terminal coupled to the high terminal of the current source; a source resistor connected in series with the output terminal of the gain component, the gain component controlling a voltage across the source resistor to the source voltage such that the gain of the gain component limits variations in the source voltage due to the gain component and in the output voltage across a load between the high and low terminals of the current source; a resistor circuit consisting of two resistors in series, a first end connected to the high terminal and a second end connected to the low terminal, with a node between the two resistors connected to a second input terminal of the gain component; an inductance in series with the source resistor, the inductance providing an impedance equal to the resistance of the source resistor at the frequency point; Equipped with A current source in which the values ​​of the two resistors of the resistor circuit are related by a constant based on the gain of the gain component.

3. providing power to at least one gain component having a constant gain below a frequency point and a gain inversely proportional to frequency above the frequency point, the gain component having an input terminal and an output terminal; connecting a source resistor in series with the output terminal of the gain component, the gain component controlling a voltage across the source resistor to a source voltage such that a gain of the gain component limits variations in output voltage across the source voltage and a load between a high terminal and a low terminal; generating a feedback signal from a feedback component comprising at least a portion of the output voltage coupled to the input terminal of the gain component, the feedback signal reducing the available gain of the gain component to control the source voltage across the source resistor; connecting an inductor in series with the source resistor; selecting a constant based on the point at which the frequency response of said inductor is equal to the resistance value of said source resistor; A method of generating electric current comprising:

4. 4. The method of claim 3, wherein generating the feedback signal from the feedback component comprises generating the feedback signal from a resistive circuit having first and second resistors having proportional values.

Images