CURRENT SENSOR DEVICE

Abstract

A current sensor device for measuring a current in a conductor comprising: current sensing means comprising a magnetic sensing element for contactlessly measuring the current; amplification means arranged to act in a first and second state, said amplification means in said first and second state being arranged for amplifying a first and second signal, respectively, from said current sensing means with an adjustable first gain and a second gain and a first and second bandwidth to yield a first and second amplified signal, respectively, wherein said first gain is higher than the second gain, wherein the first gain and the second gain are larger than 1; processing means for controlling at least said first gain, for detecting an event based on at least said second amplified signal and for producing a signal indicative of said event; an output terminal arranged for outputting a signal indicative of said current based on said first amplified signal; and an output terminal arranged for outputting said signal indicative of the event.

Claims

1. A current sensor device for measuring a current in a conductor comprising: current sensing means comprising a magnetic sensing element for contactlessly measuring the current, amplification means arranged to act in a first state and in a second state, said amplification means in said first state being arranged for amplifying a first signal from said current sensing means with an adjustable first gain and a first bandwidth to yield a first amplified signal, and said amplification means in said second state arranged for amplifying a second signal from said current sensing means with a second gain and a second bandwidth, yielding a second amplified signal, wherein said first gain is higher than the second gain, wherein the first gain and the second gain are larger than 1, processing means arranged for receiving said first and said second amplified signal, for controlling at least said first gain, for detecting an event based on at least said second amplified signal and for producing a signal indicative of said event, and an output terminal arranged for outputting a signal indicative of said current based on said first amplified signal, and an output terminal arranged for outputting said signal indicative of the event.

2. The current sensor device according to claim 1, wherein the second gain has a fixed, predetermined value.

3. The current sensor device according to claim 1, comprising means for time-division multiplexing the first amplified signal and the second amplified signal.

4. The current sensor device according to claim 1, wherein the event is a fault, preferably an overcurrent event.

5. The current sensor device according to claim 1, wherein the amplification means comprises a first amplifier arranged to act in the first state and a second amplifier, different from the first amplifier, to act in the second state.

6. The current sensor device according to claim 1, wherein a ratio of a voltage of the conductor in which the current is measured to a maximum operation voltage of the current sensor device is at least 2.

7. The current sensor device according to claim 1, wherein the current sensing means comprises one or more current sensing elements for providing said first and second signal, wherein the first and second signal are the same signal.

8. The current sensor device according to claim 1, wherein the current sensing means comprises a first current sensing element and a second current sensing element, different from the first current sensing element, wherein the first current sensing element is for outputting the first signal, and wherein the second current sensing element is for outputting the second signal.

9. The current sensor device according to claim 8, wherein the second current sensing element comprises a Hall sensor, arranged such that two terminals are fixedly used for biasing, and two different terminals are fixedly used for readout.

10. The current sensor device according to claim 1, wherein the processing means comprises at least one analogue-to-digital converter for converting the first and second amplified signal into a first and second digital signal, respectively, and digital signal processing circuitry for the controlling of at least said first gain, for the detecting of the event and for the producing of the signal indicative of said event.

11. The current sensor device according to claim 1, wherein the second bandwidth is higher than the first bandwidth.

12. The current sensor device according to claim 11, wherein a ratio of the second bandwidth to the first bandwidth is at least 2, preferably at least 10, more preferably at least 100.

13. The current sensor device according to claim 1, wherein the processing means comprises a switch, having a first input for receiving the first amplified signal and a second input for receiving the second amplified signal, wherein the switch is arranged for selecting between the first amplified signal and the second amplified signal for outputting from a single output of the switch.

14. The current sensor device according to claim 1, wherein the processing means is arranged for detecting the first amplified signal, and for controlling at least said first gain based on the detected first amplified signal.

15. Use of the current sensor device according to claim 1 for monitoring of a current generated by a battery.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] FIG. 1 is a block diagram of a first example of a current sensor device in accordance with embodiments of the present invention.

[0050] FIG. 2 is a block diagram of a second example of a current sensor device, comprising an analog-to-digital converter, in accordance with embodiments of the present invention.

[0051] FIG. 3 is a block diagram of a third example of a current sensor device, that is an analog current sensor device, in accordance with embodiments of the present invention.

[0052] FIG. 4 is a block diagram of a fourth example of a current sensor device, comprising two separate paths for generating the signal indicative of the current, and for generating the signal indicative of the event, in accordance with embodiments of the present invention.

[0053] FIG. 5 is a block diagram of a fifth example of a current sensor device, that is an analog current sensor device comprising two separate paths, in accordance with embodiments of the present invention.

[0054] FIG. 6 is a block diagram of a sixth example of a current sensor device, comprising a first Hall sensor making use of current spinning and a second Hall sensor not making use of current spinning, in accordance with embodiments of the present invention.

[0055] In the different figures, the same reference signs refer to the same or analogous elements.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0056] The present invention will be described with respect to particular embodiments and with reference to certain drawings, but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

[0057] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0058] Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

[0059] It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. The term “comprising” therefore covers the situation where only the stated features are present and the situation where these features and one or more other features are present. The word “comprising” according to the invention therefore also includes as one embodiment that no further components are present. Thus, the scope of the expression “a device comprising means A and B” should not be interpreted as being limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

[0060] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0061] Similarly, it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

[0062] Furthermore, while some embodiments described herein include some, but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0063] Furthermore, some of the embodiments are described herein as a method or combination of elements of a method that can be implemented by a processor of a computer system or by other means of carrying out the function. Thus, a processor with the necessary instructions for carrying out such a method or element of a method forms a means for carrying out the method or element of a method. Furthermore, an element described herein of an apparatus embodiment is an example of a means for carrying out the function performed by the element for the purpose of carrying out the invention.

[0064] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0065] The invention will now be described by a detailed description of several embodiments of the invention. It is clear that other embodiments of the invention can be configured according to the knowledge of persons skilled in the art without departing from the technical teaching of the invention, the invention being limited only by the terms of the appended claims.

[0066] Reference is made to FIG. 1, which is a block diagram of a first example of a current sensor device in accordance with embodiments of the present invention. In a first aspect, the present invention relates to a current sensor device comprising current sensing means 1 for measuring a current. In this example, the current flows through a conductor 6 that is external to the current sensor device. The current sensor device further comprises amplification means 2 arranged to act in a first state and in a second state. The amplification means 2 in said first state are arranged for amplifying a first signal from said current sensing means with an adjustable first gain and a first bandwidth to yield a first amplified signal. The amplification means 2 in said second state are arranged for amplifying a second signal from said current sensing means with a second gain and a second bandwidth, yielding a second amplified signal. Herein, the first gain is higher than the second gain. The current sensor device further comprises processing means 3 arranged for receiving said first and said second amplified signal, for controlling at least said first gain, for producing a signal indicative of said current based on said first amplified signal, and for detecting an event based on at least said second amplified signal and for producing a signal indicative of said event. The processing means 3 may further be arranged for controlling the bandwidth of the amplification means 2. The current sensor device further comprises an output terminal 4 arranged for outputting said signal indicative of said current, in this example through a first output 51, and an output terminal 4 arranged for outputting said signal indicative of the event, in this example through a second output 52.

[0067] Reference is made to FIG. 2, which is a block diagram of a second example of a current sensor device in accordance with embodiments of the present invention. In this example, the current sensing means 1 comprises one or more current sensing elements for providing a first signal and a second signal. For example, multiple current sensing elements may have a single, common, output. As such, in this example, the first signal and the second signal are the same, common, signal. In other words, the one or more current sensing elements are arranged such that only a single current sensing means 1 output is generated. Although only a single current sensing element could be used in this case, using more than one current sensing element, interconnected so as to generate the common signal, may have advantages, such as a stronger and/or more accurate signal that is generated, e.g., a better signal-to-noise ratio and/or a lower offset.

[0068] In this example, the output signal of the single current sensing means 1, comprising the first and second signal, is split, and inputted in a first amplifier 21, corresponding to a first state of the amplification means, and, separately, in a second amplifier 22, different from the first amplifier 21 and corresponding to a second state of the amplification means. The first amplifier amplifies the signal outputted by the current sensing means 1, e.g., the first signal, with a first gain and a first bandwidth. The second amplifier amplifies the signal outputted by the current sensing means 1, e.g., the second signal, with a second gain and a second bandwidth. The first bandwidth may be the same as the second bandwidth, but it is preferred that the second bandwidth is as high as possible so as to achieve a fast event detection. It may, therefore, be advantageous to use a second bandwidth that is higher than the first bandwidth. The first gain is tuneable, by a processing unit 32 comprised in the processing means, for example, using one of the algorithms mentioned elsewhere in the description. The second gain may also be tuneable, e.g., by the processing unit 32 or by a different means, although the second gain may instead be fixed. However, it is at least possible to set the first gain to a higher value than the second gain, so that also weak currents may be accurately detected, i.e., so that the signal indicative of the current may accurately represent the current that is present on the conductor 6.

[0069] In this example, the second current sensor device comprises a switch 31, that has two input ports, for receiving an output from the first amplifier 21, that is the first amplified signal, separately from an output from the second amplifier 22, that is the second amplified signal. The switch 31 has a single output port, and is configured for outputting, through the single output port, either the first amplified signal, or the second amplified signal. Thereby, the processing means may alternatingly receive and possibly process the first amplified signal, and the second amplified signal. As such, in this example, the switch 31 functions as means for time-division multiplexing of the first and second amplified signal.

[0070] In this example, the processing unit 32 comprises an analog-to-digital converter. Said analog-to-digital converter converts the first amplified signal to a first digital signal, and the second amplified signal to a second digital signal. The processing unit 32 may determine, based on the first amplified signal it receives, the first gain to which the first amplifier 21 is to be set. For example, the processing unit 32 may change the first gain until a suitable value for the first gain is selected that may result in an accurate determination of the current. In particular, the first gain may be optimized so that the analog-to-digital conversion may result in a first digital signal that accurately represents, i.e., indicates, the current. Said optimization of the first gain may be performed, for example, by using one of the algorithms mentioned elsewhere in the description. Said, digital, signal indicative of the current is subsequently outputted by the output terminal 4, which outputs the signal indicative of the current through a first output 51. The processing unit 32 may furthermore be used to control the switch 31, so as to determine which of the first and second amplified signal is passed by the switch 31.

[0071] In this example, when the second amplifier signal is inputted in the processing unit 32 and converted, by the analog-to-digital converter, into the second digital signal, the processing unit 32 detects whether an event, e.g., an overcurrent event, occurred. For example, the second digital signal may be compared with a reference digital signal representative for an event. Herein, the second gain is preferably set such that, when the second digital signal is equal to or greater than the reference digital signal, the second amplified signal, corresponding to the second digital signal, does not saturate the second amplifier 22 or the analog-to-digital converter, so that the event may be accurately determined. The reason is that the reference digital signal, i.e., the overcurrent threshold, usually corresponds to a high current that is, in a typical situation, far above a saturation limit for the first amplified signal. That is, when the first gain and first amplified signal were to be used for detecting the event, and whenever saturation (e.g., of the first amplifier 21 or of the analog-to-digital converter) occurs, it may be unclear whether an event occurred, or whether, instead, the current is rather outside the present scale yet still below the overcurrent threshold, and the first gain is only to be reduced so as to bring the first amplified signal back within scale. An overcurrent, e.g., due to a short-circuit, may occur at any time, even when a low current is being measured based on the first signal. Based on the comparison, the processing unit 32 may produce a signal indicative of said event. Said signal indicative of the event is subsequently outputted by the output terminal 4, which outputs the signal indicative of the event through a second output 52. Herein, the output terminal 4 may comprise output circuitry, such as an output buffer. In this example, the outputted signal indicative of the event may be a digital signal.

[0072] In this example, the output terminal 4 is arranged for determining whether the signal inputted in the output terminal 4 is the signal indicative of the current, or the signal indicative of the event, and output each signal through the corresponding output 51 or 52. This may be achieved, for example, by a signal from the processing unit 32. Alternatively, the processing unit may output the signal indicative of the current and the signal indicative of the event to separate output terminals, each connected to a corresponding output 51 or 52.

[0073] The signal indicative of said event is not limited to a particular signal scheme. For example, the processing unit 32 may produce a signal only when an event occurred.

[0074] Alternatively, the processing unit 32 may produce a signal only when no event occurred. Still alternatively, the processing unit 32 may produce a first signal, e.g., a high signal, when an event occurred, and a second signal, different from the first signal, e.g., a low signal, when no event occurred.

[0075] Reference is made to FIG. 3, which is a block diagram of a third example of a current sensor device in accordance with embodiments of the present invention. Similar as in the second example, the first signal and the second signal are the same signal. In this example, the amplification means comprises a single amplifier 2. The single amplifier 2 is controlled by a controller 37 of the processing means to amplify the signal outputted by the current sensing means 1 by, alternatingly, a first gain and a second gain, i.e., to act in the first state and second state, respectively. As such, the single amplifier 2 produces, alternatingly, a first amplified signal and a second amplified signal. The signal output by the amplifier can be seen as a time-division multiplexed signal of the first and second amplified signal: in one time slot the first amplified signal is outputted and in the next time slot the second amplified signal.

[0076] The multiplexed signal is inputted in a switch 33 having a single input, and two outputs: a first output connected to an output terminal 41; and a second output connected to an analog comparator 36. The switch 33 separates the time-division multiplexed signal such that the first amplified signal is outputted through the first output of the switch 33, to the output terminal 41, and such that the second amplified signal is outputted through the second output of the switch 33, to the comparator 36. The output terminal 41 outputs a signal indicative of said current based on said first amplified signal. The signal indicative of said current may comprise said first amplified signal. As said first amplified signal depends on the first gain, it may be preferred to also output a signal indicative of said first gain. For example, the first amplified signal and the signal indicative of the first gain may be time-division multiplexed. Said output terminal 41 may comprise an output buffer, comprising a memory (e.g., a flip-flop) or cache for temporarily storing the signals indicative of said current. The signals may be stored until a readout unit, which may be external to the current sensor device, connected to the output terminal 41, is ready for receiving and/or processing the signals.

[0077] The comparator 36 may compare the second amplified signal to a predetermined threshold value (for example, determine whether the amplified signal is greater or equal to the predetermined threshold value), to determine whether an event occurred, and produces, based on said comparison, a signal indicative of the event. An output terminal 42 outputs said signal indicative of the event. The output terminal 42 may comprise an output buffer.

[0078] Reference is made to FIG. 4, which is a block diagram of a fourth example of a current sensor device in accordance with embodiments of the present invention. In this example, the current sensor device comprises two separate, parallel paths: a first path 71 dedicated to determining a current, and a second path 72 dedicated to determining whether an event occurred. The use of two separate, parallel paths may be robust and efficient. In this example, the current sensing means comprises two separate current sensors 11 and 12. In this example, the first current sensor 11, that is for generating a first signal, comprises at least one shunt resistor for generating a voltage drop over the conductor 6. Said voltage drop may be detected using a differential amplifier. Based on the resistance of the shunt resistor, and the voltage drop, the current through the conductor 6 may be determined. The shunt resistor may be external to the circuit. In this example, the second current sensor 12, that is for generating a second signal, comprises at least one magnetic sensing element, such as a Hall sensor. In an alternative example, the first current sensor 11 could instead comprise the magnetic sensing element, and the second current sensor 12 could instead comprise the shunt resistor. Still alternatively, both the first 11 and second current sensor 12 may comprise a magnetic sensing element.

[0079] In the first path 71, the first signal, generated by the first current sensor 11, is amplified, by a first amplifier 21, with a first gain, that is controlled by a first processing unit 32, thereby generating a first amplified signal. The first amplified signal is inputted in the first processing unit 32. The first processing unit 32 determines the first gain based on the first amplified signal, e.g., using one of the algorithms used elsewhere in the description for optimizing the first gain, and controls the first amplifier 21 so as to amplify the first signal with the first gain. In addition, the first processing unit 32 produces a signal indicative of the current based on the first amplified signal, which is subsequently outputted by an output terminal 41.

[0080] In the second path 72, the second signal, generated by the second current sensor 12, is amplified, by a second amplifier 22, with a second gain, thereby generating a second amplified signal. In this example, the second gain is fixed. A second processing unit 34 receives the second amplified signal, and determines, based on the second amplified signal, whether an event occurred. A signal indicated of said event is, then, outputted by an output terminal 42. The second processing unit 34 may comprise an analog comparator, for comparing the second amplified signal to a predetermined reference signal (e.g., voltage reference). Alternatively, the second processing unit 34 may comprise analog-to-digital conversion means and digital comparison means.

[0081] Reference is made to FIG. 5, which is a block diagram of a fifth example of a current sensor device in accordance with embodiments of the present invention. A single signal is produced by a current sensing means 1. Said signal is split over two parallel paths: a first path 73 for generating an output signal indicative of said current, and a second path 74 for generating and outputting a signal indicative of an event. inputted into both a first amplifier 21 and a second amplifier 22.

[0082] In the first path 73, a first amplified signal generated by the first amplifier 21 is inputted into a first processing unit 32 and into an output terminal 41. As before, said first processing unit 32 determines the first gain based on the first amplified signal, and controls the gain of the first amplifier 21. The output terminal 41 outputs a signal indicative of the current based on the first amplified signal. For example, the first amplified signal itself may be output (possibly after output buffering in the output terminal 41). In such embodiments, preferably, a signal indicative of the first gain is also output. This may be done through the output terminal 41, or through a separate output terminal (not shown). As another example, the part of the processing means intended for determining the first gain (e.g., based on an algorithm as explained above) may be located in a microprocessor that, in addition, determines the current based on the output signal indicative for the current. In that case, said microprocessor may base the determined current on both the output signal indicative of the current, and on the first gain. In that case, no separate output terminal for outputting the first gain is needed, as the first gain may, e.g., be stored in the microprocessor.

[0083] Alternatively, the first amplified signal may first be processed, wherein said processing may, for example, comprise filtering and/or clamping and/or adding an offset.

[0084] In the second path 74, a second amplified signal generated by the second amplifier 22 is inputted into an analog comparator 34 that compares the second amplified signal with a threshold to determine whether an event occurred, and produces a signal indicative of an event. Instead, however, a digital comparator could be used, comprising an analog-to-digital converter for generating, based on the second amplified signal, a digital signal, and digital circuitry for processing said digital signal. Said signal indicative of the event is subsequently output by an output terminal 42.

[0085] In a fourth aspect, the present invention relates to a current sensor device comprising current sensing means for measuring a current, comprising a first Hall sensor and a second Hall sensor. The first Hall sensor is arranged such that a direction of a biasing current applied to a Hall plate of the first Hall sensor for biasing is alternated between at least two different directions. Herein, the readout terminals and the biasing current terminals may also be interchanged, resulting in four possible configurations, wherein the connection may be changed between said four configurations. This corresponds to 4-phase current spinning, as is well-known in the art. A voltage for readout of the first Hall sensor is typically detected in a direction perpendicular to the direction of the applied biasing current. The second Hall sensor is arranged such that two terminals are fixedly used for biasing, and two different terminals are fixedly used for readout. Optionally, the direction of the biasing current may be fixed, for example using a constant voltage source. The current sensor device further comprises amplification means arranged to act in a first state and in a second state. The amplification means in said first state are arranged for amplifying a first signal from the first Hall sensor of said current sensing means with a first gain and a first bandwidth to yield a first amplified signal. The amplification means in said second state are arranged for amplifying a second signal from the second Hall sensor of said current sensing means with a second gain and a second bandwidth, yielding a second amplified signal. The current sensor device further comprises processing means arranged for receiving said first and said second amplified signal, for detecting an event based on at least said second amplified signal and for producing a signal indicative of said event. The current sensor device further comprises an output terminal arranged for outputting a signal indicative of said current based on said first amplified signal, and an output terminal arranged for outputting said signal indicative of the event.

[0086] Reference is made to FIG. 6, which is a block diagram of a sixth example of a current sensor device in accordance with embodiments of the present invention. In this example, the sensing means for measuring a current on a conductor 6 comprises a first Hall sensor 11 for generating a first signal, and a second Hall sensor 12 for generating a second signal, different from the first Hall sensor 11. A switch 7, controlled by a processing unit 32, determines a direction of a biasing current applied through a Hall plate of the first Hall sensor 11. The switch 7 further determines a direction of a voltage for readout of the first Hall sensor 11, that is typically perpendicular to the direction of the biasing current. The switch 7 further selects the terminals of the Hall plate that are connected to the biasing current and for the readout. By alternating the direction, for example by rotating said directions at regular angle intervals (sometimes called “current-spinning” in the field), the first signal generated by the first Hall sensor 11 may be very accurate.

[0087] The first signal may be amplified by a first amplifier 21, by a first gain and a first bandwidth, yielding a first amplified signal. The first gain may be tuneable, e.g., by the processing unit 32, but that is not essential for embodiments of the fourth aspect. Instead, the first gain may be fixed. The first amplified signal is subsequently received by output terminal 41, that may comprise an output buffer, for outputting of a signal indicative of the current on the conductor 6, based on said first amplified signal.

[0088] The second signal may be amplified by a second amplifier 22, by a second gain and a second bandwidth, yielding a second amplified signal. A direction of the biasing current and a direction of a voltage for readout through a Hall plate of the second Hall sensor 12 is fixed (so that no current-spinning is performed for the second Hall sensor 12). For example, the second Hall sensor 12 is fixedly biased with a voltage source. The second amplified signal generated by the second amplifier 22 is inputted into an analog comparator 34 to determine whether an event occurred, and a signal indicative of said event may be generated and outputted by an output terminal 42. As, in this example, the directions of the biasing and voltage for the second Hall sensor 12 are fixed, no delay on said determination of the event is possible.

[0089] An advantage of this scheme is that efficient offset removal may be achieved with respect to the first signal (e.g., due to 2-phase or 4-phase current spinning). At the same time, the second signal may suffer from a large offset, but may be faster, as no processing of the 2 or 4 phases is required.

[0090] Although in this example, that is an embodiment of the fourth aspect, the first and second signal are processed in separate, parallel paths, the fourth aspect is not limited thereto. For example, time-division multiplexing, as described in several of the examples of the first aspect, may also be applied in different embodiments of the fourth aspect.

[0091] It is to be understood that although preferred embodiments, specific constructions and configurations, as well as materials, have been discussed herein for devices according to the present invention, various changes or modifications in form and detail may be made without departing from the scope of this invention. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks.