Circuit segment with transmit / receive switch topology

Abstract

A circuit segment includes a coil, a low noise amplifier, a first switch, a power amplifier, and a second switch. The coil is configured for generating an oscillating magnetic field in a transmitting state and / or for detecting an external oscillating magnetic field in a receiving state. The low noise amplifier is connected in series to the coil. The first switch is connected in parallel to the low noise amplifier and is configured to short-circuit an input terminal of the low noise amplifier. The power amplifier is connected in series to the low noise amplifier. The second switch is arranged between a power amplifier output and a ground potential and is configured to ground the power amplifier output in the receive state. Thus, the shielding of the low noise amplifier can be improved, in particular during the emission state of the circuit segment.

Description

Field of the Invention

[0001] The present invention relates to a circuit segment having a transmit / receive switch topology for a circuit or a circuit, a method for bringing the circuit segment into its transmit state or its receive state, and a computer program for controlling a circuit segment having a transmit / receive switch topology. The present invention can be used in combination with a micro-magnetic resonator (MMR), which is sometimes also referred to as a magneto-mechanical oscillator (MMO). MMRs can be used, for example, in entertainment, sports, or medical applications for wireless remote tracking and sensing. For example, MMRs can be used for body tracking and sensing. Background Art

[0002] Various systems are known for implementing wireless remote tracking and sensing functions (e.g., for body tracking and sensing). Known wireless remote tracking and sensing systems include, in particular, optical systems having one or more cameras for capturing the position of passive or active tags, and electromagnetic tracking systems based on LC resonators. In addition, inertial motion capture techniques based on an inertial measurement unit (IMU) comprising a combination of a gyroscope, a magnetometer, and an accelerometer can be used to measure the rotation rate. In addition, mechanical, magnetic, or magnetic-mechanical systems for wireless remote tracking and sensing are known.

[0003] Magnetic-mechanical systems generally include MMRs for implementing wireless remote tracking and sensing functions. Wireless remote tracking and sensing functions generally include the magnetic excitation of the mechanical resonance of ferromagnetic objects. To this end, an MMR detector system can include electronics comprising one or more coils and an amplifier. For example, a transmitter coil can be used to generate an oscillating magnetic field to excite the mechanical resonance of a ferromagnetic object. The mechanical resonance of the ferromagnetic object generates an oscillating magnetic field, which can be detected by a sensor coil as an external oscillating magnetic field.

[0004] However, there is still a desire to provide MMRs that implement more sensitive and reliable tracking and sensing functions. Summary of the Invention

[0005] The present invention is based on the object of providing a circuit segment for a circuit or a circuit, which circuit segment provides an improved transmit / receive switch topology for the circuit. The present invention is further based on the object of providing an improved method for bringing the circuit segment into its transmit state or its receive state. In addition, the present invention is based on the object of providing a computer program for controlling a circuit segment having an improved transmit / receive switch topology.

[0006] According to the present invention, a circuit or a circuit segment of a circuit is provided. The circuit segment has a transmitting state and a receiving state. The circuit segment includes at least one coil or a first coil and a second coil, a low-noise amplifier, a first switch, a power amplifier, and a second switch. The at least one coil is configured to generate an oscillating magnetic field in the transmitting state and to detect an external oscillating magnetic field in the receiving state. The first coil is configured to generate an oscillating magnetic field in the transmitting state, and the second coil is configured to detect an external oscillating magnetic field in the receiving state. The low-noise amplifier is connected in series to the at least one coil or the first coil and the second coil and is configured to amplify a first voltage signal induced in the at least one coil or the second coil by the detected external oscillating magnetic field in the receiving state. The first switch is connected in parallel to the low-noise amplifier and is configured to short-circuit the low-noise amplifier by switching the first switch to its conducting state in the transmitting state or to its isolating state in the receiving state. The power amplifier is connected in series with its power amplifier output to the low-noise amplifier and is configured to amplify a received second voltage signal and to provide the amplified second voltage signal to the at least one coil or the first coil in the transmitting state, preferably, to generate an oscillating magnetic field in the transmitting state. The second switch is arranged to connect the power amplifier output to the ground potential and is configured to ground the power amplifier output by switching to its conducting state in the receiving state and to its isolating state in the transmitting state.

[0007] The present invention includes the recognition that it is beneficial to use a single coil for both generating an oscillating magnetic field and detecting an external oscillating magnetic field, for example, to save space. However, a first coil for generating an oscillating magnetic field in the transmitting state and a second coil for detecting an external oscillating magnetic field in the receiving state can also be employed. During the transmitting (Tx) phase, the power amplifier (PA) typically applies a relatively high voltage, such as 48V, to the coil. During the receiving (Rx) phase, a relatively weak signal (e.g., several mV) is typically detected by the coil and amplified by the low-noise amplifier (LNA). To avoid damaging, overdriving, or saturating the sensitive LNA, the LNA typically needs to be shielded from the high voltage during the Tx phase. However, known topologies for switching between the PA and the LNA do not provide sufficient insulation, especially during the Rx phase. In fact, in many known configurations, the insulation between the LNA and the PA is insufficient, such that noise, especially from the PA, can be a problem during the Rx phase. With the circuit segment, the insufficient insulation of such known topologies for switching between the Tx and Rx states of a coil, for example, in a micro magnetic resonance remote sensing and tracking system, can be overcome by using a first switch connected in parallel to the LNA.

[0008] This is possible for the circuit segment due to its specific topology with the PA and LNA in series rather than in parallel. In fact, it has been found that for current semiconductor devices, it is generally preferable to have a series connection of the PA and LNA and to alternately short-circuit one of the PA and LNA. To this end, the first switch can short-circuit the LNA, and the second switch can ground the PA output.

[0009] This has the following advantages: During the Rx phase, the first switch can be isolated and the second switch can be conducting. Thus, the parasitic capacitance of the first switch when isolated does not degrade the Rx signal quality, and the second switch can effectively shorten any potential interference from the PA to ground. This allows the sensitive LNA to be neither damaged, overdriven nor saturated by shielding it from the high voltage during the Tx phase. This can be achieved by the specific topology of the circuit segment.

[0010] In particular, during operation of the circuit segment, in the Rx state, the first switch can be isolated and the second switch can be conducting. Then, the first voltage signal passes through the LNA and the second switch without entering the PA at its power amplifier output. The first voltage signal travels from the coil towards the LNA. In the Rx state, the power amplifier output can be grounded by switching the second switch to its conducting state. If the power amplifier output is grounded, interference from the noise generated by the PA can be prevented. Thus, the function of the second switch is to shorten any potential interference from the PA to ground during the Rx phase, and during the Tx phase, it has no negative side effects. Therefore, it is beneficial that the PA does not generate noise in the coil during the Rx phase, and during the Tx phase, the LNA can be advantageously protected from the high voltage of the PA.

[0011] Furthermore, during operation of the circuit segment, in the Tx state, the first switch can be conducting and the second switch can be isolated. The received second voltage signal can be amplified by the PA and pass through the first switch without passing through the LNA, i.e., the input terminals of the LNA are short-circuited. The amplified second voltage signal travels from the PA towards the coil. Advantageously, with the circuit segment, the LNA can be shielded from the high voltage during the Tx phase, such that the risk of damaging, overdriving or saturating the LNA can be significantly reduced.

[0012] Preferably, the power amplifier is configured to amplify the received second voltage signal and to provide an amplified second voltage signal of 10 V or greater, preferably 40 V or greater (e.g., on the order of 48 V). The first voltage signal received by the LNA can be 1 V or less, e.g., on the order of several mV. The external oscillating magnetic field can be generated by a ferromagnetic object of the microresonator and can be detected by a circuit segment in its receiving state. Thus, the term "external" refers to the exterior of the circuit segment.

[0013] Preferably, the circuit segment is part of a circuit that can consist of a plurality of individual electronic components (such as resistors, transistors, capacitors, inductors, and diodes) connected, for example, by wires or traces through which current can flow.

[0014] The amplification transistor in the LNA can be a junction gate field effect transistor (jFET). The PA can have an H-bridge output stage. The H-bridge is preferably an internal part of the PA and can be placed in a short-circuit mode. In particular, if the PA includes a preferably digitally switchable H-bridge, the PA may not require an additional switch because the H-bridge can be placed in a low-impedance state by switching, for example, one or two low-side transistors of the H-bridge to the conducting state. Thus, the circuit segment can be configured such that the power amplifier output is configured as an H-bridge that is configured to short-circuit the output terminals of the power amplifier output when in the receiving state.

[0015] Preferably, the first switch and / or the second switch belong to the transistor-based switch type. For example, the first switch and / or the second switch can be a field effect transistor, such as a metal oxide semiconductor field effect transistor (MOSFET). Optionally, at least one of the first switch and / or the second switch can be a p-i-n diode. However, MOSFETs are preferred over p-i-n diodes due to their generally lower cost. When using a MOSFET, it is further preferred that, in the switching operation, the low impedance of the MOSFET is used for conduction. This can be better than the high-impedance state because a MOSFET can have a significant residual capacitance when in the insulating state. This can avoid using generally expensive p-i-n diodes as switches. However, as a complement or alternative to the MOSFET, p-i-n diodes can still be used as switches.

[0016] As described above, preferably, the circuit segment includes a single coil for generating an oscillating magnetic field in the transmitting state and for detecting an external oscillating magnetic field in the receiving state. However, the circuit segment can also include a first coil for generating an oscillating magnetic field in the transmitting state and a separate second coil for detecting an external oscillating magnetic field in the receiving state. The two coils can be strongly inductively coupled, weakly coupled, or not coupled at all.

[0017] Optionally, the circuit segment may include a transformer connected in parallel with the low-noise amplifier and in parallel with the first switch, for transforming the first voltage signal provided by at least one coil before it enters the low-noise amplifier. The transformer (e.g., a cored transformer) can be used to amplify the first voltage signal before it enters the LNA. Additionally, using a transformer can be beneficial for impedance matching.

[0018] By using a transformer, insulation of the ground potential (DC decoupling) can be achieved. Due to the high current, the direct connection of the LNA is usually poor because the potentials of the two input ports will vary due to the resistance and inductance of the leads in the circuit, i.e., the common-mode signal. By using a transformer, the common-mode rejection ratio can be improved.

[0019] In addition, the transformer can be used to transform the impedance of the coil to be more suitable for the LNA. Generally, it is preferably to provide a relatively low impedance for at least one coil (i.e., the transmit and / or receive coil) to obtain good performance of the PA. However, the LNA generally operates optimally at a much higher coil impedance, at least when operating with very low noise. The transformer can solve this problem. The transformer enables the operation of a single-ended LNA in the circuit, which means that one of the input terminals of the LNA is grounded. Technically, this can be similar to improving the common-mode rejection ratio. The transformer can also be used to feed in some additional signals, such as pilots, i.e., additional very low-power signals.

[0020] Preferably, the circuit segment with the transformer includes a third switch connected in series between the low-noise amplifier and the transformer. In the operation of the circuit segment, the third switch is preferably isolated in the Tx state and conducting in the Rx state. Having the third switch connected in series between the low-noise amplifier and the transformer can have the advantage of further improving the suppression of unwanted signals. Specifically, the additional third switch can improve the immunity of the LNA during the Tx stage. Additionally, when there is a third switch connected in series between the LNA and the transformer, the amplified second voltage signal can interfere less with the LNA, and thus the acquisition can be accelerated.

[0021] In some embodiments on the LNA, it is preferred that not only is the LNA protected from damage (for which the first switch is usually sufficient), but also the residual transmit signal on the input of the LNA should be too low such that the LNA does not enter an undesired overdrive mode. Recovery from the overdrive mode usually may take time, and thus the time between transmit and receive may be longer than desired.

[0022] Only the first switch and the second switch may be employed. Optionally, other switches such as a third switch may be employed to implement other functions or achieve other advantages of the circuit segment. That is, since a switch typically still has a residual capacitance when open. This allows some signals to still be transmitted through the open switch, which is generally undesirable. Thus, an additional device for reducing the capacitance of the transistor output, i.e., a switch, may be employed. Typically, a MOSFET switch consists of two series-connected MOSFET transistors with opposite directions. To reduce the capacitance, a voltage may be applied to the common pin of the two transistors with respect to the terminal pins. This additional voltage may reduce the capacitance.

[0023] For example, as an addition to or an alternative to the third switch, the circuit segment may include a fourth switch that is connected in parallel to the LNA and is connected in parallel to the transformer. In the operation of the circuit segment, the fourth switch is preferably isolated in the Rx state and conducting in the Tx state. That is, if there are a third switch and a fourth switch, then preferably, in operation, the third switch is conducting and the fourth switch is isolated in the Rx state, and the third switch is isolated and the fourth switch is conducting in the Tx state.

[0024] When additional switch pairs (e.g., the third switch and the fourth switch) are employed, these switches can be used as a voltage divider. In the Tx state, the third switch may be of high impedance, and the fourth switch may be of low impedance. As a result, the unwanted residual Tx signal reaching the secondary winding of the transformer will see this voltage divider, and then only a minimal portion of this voltage will appear across the shorted fourth switch, which is the same voltage as across the input of the LNA.

[0025] If the fourth switch does not exist and only the third switch is present, the voltage division may be less efficient because the high impedance of the third switch will also be in series with the high impedance of the LNA input. In this case, the voltage division may only weakly reduce the voltage on the LNA input. However, in some applications, it may be sufficient to employ only the third switch without the fourth switch.

[0026] If the third switch does not exist and only the fourth switch is present, the voltage division may also be less efficient because in this case, the fourth switch is essentially parallel to the first switch, e.g., on the primary side of the transformer, where it may be of little help. Thus, although it is feasible to use only one switch (the third switch or the fourth switch), it is preferably to use the third switch and the fourth switch in pairs in the circuit segment.

[0027] Adding more switches can be beneficial for improving the voltage division effect. Then, the voltage division ladder can continue in the same way, i.e., the fifth switch will be in series again, and the sixth switch will be in parallel, and so on.

[0028] Preferably, the transformer is a symmetrical transformer. For example, in the circuit snippet, an electrical single-ended configuration can be converted to a balanced configuration using a symmetrical power amplifier, symmetrical switches, symmetrical coils, and a transformer with two symmetrical primary sides. Typically, a symmetrical PA has positive and negative power rails with the signal rise and fall centered exactly between the 0 volt points.

[0029] With a symmetrical transformer, common mode interference entering the LNA via at least one coil can be suppressed. In particular, the purpose of the symmetrical primary side of the transformer is to suppress common mode signals that can be captured by the coil.

[0030] The present invention also relates to a detector system for a micromagnetic resonator, which can be used for tracking and / or sensing, preferably for wireless remote tracking and / or sensing. The detector system includes one or more ferromagnetic objects that can oscillate mechanically (under the excitation of the mechanical resonance of the ferromagnetic objects). The detector system has the ability to excite such mechanical oscillations of the ferromagnetic objects by applying an oscillating magnetic field. In addition, the detector system has the ability to detect and check received external oscillating magnetic fields, which come from the mechanical oscillations of the ferromagnetic objects.

[0031] The detector system includes circuitry including the circuit segments described above to achieve both capabilities.

[0032] The circuit segment is arranged and configured to generate an oscillating magnetic field in a transmitting state for exciting the mechanical resonance of a ferromagnetic object, so that the ferromagnetic object then generates an external oscillating magnetic field, which can be detected by the circuit segment in its receiving state. Preferably, the ferromagnetic object is or includes a permanent magnet. The mechanical resonance can be excited by means of an oscillating magnetic field emitted by the coil of the circuit segment in the Tx state. The oscillating permanent magnet in the detector system can generate an external oscillating magnetic field, which is picked up by the coil and amplified by the LNA. In body tracking or sensing, in the detector system, the oscillation (i.e., mechanical resonance) is excited by the coil in the Tx state. The oscillation induces a voltage, i.e., a first voltage signal, in the coil that senses the oscillation in the Rx state. The detector system has the following advantages: due to the specific topology of the circuit segment, in the Rx state, the PA does not generate noise in the LNA, and during the Tx state, the LNA is protected from the high power of the PA. Therefore, the detector system can work relatively accurately and reliably.

[0033] In the operation of a detector system, for example in combination with a micromagnetoresistor, an oscillating magnetic field can be generated by one or more coils, which are powered / driven by at least one PA of a circuit segment. Tracking of the micromagnetoresistor can be achieved based on a comparison of the detected amplitude of the external oscillating magnetic field. Thus, if spatial information is required, multiple coils should be employed, for example at least the coils there. Sensing can be achieved using the micromagnetoresistor based on the detection of the self-decay frequency of the detected external oscillating magnetic field. The self-decay frequency is a property of the micromagnetoresistor and can be different from the excitation frequency in the Tx phase. For sensing, one coil, one LNA, and one PA are sufficient.

[0034] The invention also relates to a method of operating the above-mentioned circuit segment. Operating the circuit segment can include putting the circuit segment in its transmit state or its receive state. The method includes the following steps:

[0035] - Switching the first switch to its conducting state to short-circuit the low-noise amplifier and switching the second switch to its isolating state to put the circuit segment into its transmit state, and

[0036] - Switching the first switch to its isolating state and switching the second switch to its conducting state to short the power amplifier output to ground. In the method, preferably, the Tx state and the Rx state are time-division multiplexed to put the circuit segment into its receive state.

[0037] The method can also include switching the first switch from its conducting state to its isolating state, or vice versa, after a first predefined time period that starts when the second switch is switched from its conducting state to its isolating state, or vice versa. Additionally or alternatively, the method can also include switching the second switch from its conducting state to its isolating state, or vice versa, after a second predefined time period that starts when the first switch is switched from its conducting state to its isolating state, or vice versa. Thus, the situation can be considered where the actual switching time of the transistor may be different from the time for controlling the transistor to switch. That is, there may be a time delay, and this delay specific to the transistor can be different for turning on and off. Using the method, the first and / or second switches at the PA, for example, can be shortened, but some additional time is added until the LNA switch (e.g., the first switch) is turned off, especially if there is a residual current flowing through the coil.

[0038] Additionally or alternatively, the method may further include switching the first switch to its conducting state while the second switch remains in its conducting state, or may include switching the second switch to its conducting state while the first switch remains in its conducting state. This is because it may also be beneficial to briefly open both switches (i.e., the first switch and the second switch) to quickly reduce any residual current in the coil to zero.

[0039] Optionally, in the method, the first switch may be opened relatively slowly, for example, slower than the second switch. Thus, LNA overload can be avoided.

[0040] The invention also relates to a computer program for controlling the above circuit segment. The computer program includes program code, such as executable instructions, for causing the circuit segment to switch from its transmitting state to its receiving state or vice versa by implementing the above method when run on a computing device such as a personal computer (PC), a field programmable gate array (FPGA), a microcontroller or a complex programmable logic device (CPLD), a processor, a processing circuit or other computing device. The invention also relates to a non-transitory computer-readable data medium storing the computer program. In summary, the invention relates to a circuit or a circuit segment of a circuit, the circuit segment having a transmitting state and a receiving state. The circuit segment includes at least one coil, a low noise amplifier, a first switch, a power amplifier and a second switch. The at least one coil is configured to generate an oscillating magnetic field in the transmitting state and / or to detect an external oscillating magnetic field in the receiving state. The low noise amplifier is connected in series to the at least one coil and is configured to amplify a first voltage signal induced in the at least one coil. The first switch is connected in parallel to the low noise amplifier and is configured to short-circuit the input of the low noise amplifier in the transmitting state. The power amplifier is connected in series with its power amplifier output to the low noise amplifier and is configured to amplify a received second voltage signal and to provide the amplified second voltage signal to the at least one coil in the transmitting state for generating an oscillating magnetic field. The second switch is arranged to connect the power amplifier output to the ground potential and is configured to ground the power amplifier output by switching to its conducting state in the receiving state. Thus, particularly during the transmitting state of the circuit segment, shielding of the low noise amplifier can be improved.

[0041] It should be understood that the circuit segment of claim 1, the detector system of claim 10, the method of claim 11 and the computer program of claim 14 have similar and / or identical preferred embodiments, particularly as defined in the dependent claims.

[0042] It should be understood that the preferred embodiments of the invention may also be any combination of the dependent claims or the above embodiments with the corresponding independent claims.

[0043] Referring to the embodiments described below, these and other aspects of the present invention will be apparent. In particular, the present invention includes the following technical advantages: By utilizing the specific topology of the circuit segment, shielding of the low-noise amplifier can be achieved. This is accomplished through effective decoupling between the Tx state and the Rx state of the circuit segment. In particular, the circuit segment provides improved isolation of the LNA from the noise in the Rx state. This results in improved noise interference properties and improved Rx signal quality properties of the circuit segment. Technically, this advantage is achieved through the specific topology of the circuit segment such that during the Rx phase, the capacitance of the first switch does not degrade the Rx signal quality, and the second switch very effectively shorts any potential interference from the PA to ground. Therefore, the risk of damaging, overdriving, or saturating the LNA can be significantly reduced. Thus, the circuit segment as part of the detector system can be used to implement sensitive and reliable tracking and sensing functions in, for example, in vivo tracking and sensing, e.g., as part of the micro-magnetic resonators employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In the following drawings:

[0045] FIG. 1 schematically and exemplarily shows a circuit segment having a topology known in the prior art,

[0046] Figure 2 schematically and exemplarily shows a detector system for a micro-magnetic resonator, the detector system including a ferromagnetic object and a circuit having a circuit segment according to the present invention,

[0047] Figure 3 schematically and exemplarily shows a circuit segment according to the present invention, which can be used in a detector system for a micro-magnetic resonator,

[0048] Figure 4 schematically and exemplarily shows a circuit segment according to the present invention, which can be used in a detector system for a micro-magnetic resonator and additionally includes a transformer,

[0049] Figure 5 schematically and exemplarily shows a circuit segment according to the present invention, which can be used in a detector system for a micro-magnetic resonator, and includes a transformer and additionally a third switch and a fourth switch,

[0050] Figure 6 schematically and exemplarily shows another circuit segment according to the present invention, which can be used in a detector system for a micro-magnetic resonator,

[0051] Figure 7 schematically and exemplarily shows Figure 6 the first primary side, the second primary side, and the secondary side of the transformer of the circuit segment are inductively coupled,

[0052] Figure 8 Another circuit segment according to the present invention is schematically and exemplarily shown, which can be used in a detection system for a micro magnetic resonator.

[0053] Figure 9 Another circuit segment according to the present invention is schematically and exemplarily shown, which can be used in a detection system for a micro magnetic resonator.

[0054] Figure 10 Schematically and exemplarily shown Figure 6 a second sub-unit of the circuit segment of, which has a simplified differential mode signal with constructive superposition, and

[0055] Figure 11 Schematically and exemplarily shown Figure 6 a second sub-unit of the circuit segment of, which has a suppressed simplified differential mode signal. Detailed implementation

[0056] FIG. 1 schematically and exemplarily shows a circuit segment 100 having a topology known from the prior art (e.g., WO2015 / 043612A1). The circuit segment 100 includes a power amplifier 102 connected in parallel with a low-noise amplifier 104. The power amplifier 102 is connected in series to a first switch 106, and the low-noise amplifier 104 is connected in series to a second switch 108. In operation, the first switch 106 can be conductive, and the second switch 108 can be isolated, or vice versa. Thus, in the transmit state of the circuit segment 100, the first switch 106 is conductive and the second switch 108 is isolated, such that the amplified voltage signal can be provided from the power amplifier 102 to the coil 110 for generating an oscillating magnetic field. Further, in the receive state of the circuit segment 100, the second switch 108 is conductive, and the first switch 106 is isolated, such that the voltage signal induced in the coil 110 by an external oscillating magnetic field can be provided to the low-noise amplifier 100 and amplified by the low-noise amplifier 100. There are several requirements for the switches 106, 108, such as low loss when conductive, low capacitance when isolated, and a fast transition time between the two modes (i.e., the transmit state and the receive state).

[0057] However, it has been found that with this known topology, although it is sufficient to protect the low-noise amplifier 104, it does not provide sufficient isolation regarding noise. This noise emanates from the power amplifier 102 and the power supply (not shown) connected thereto and enters the low-noise amplifier 104. This is caused by the compromise between the transmit-phase requirements and the receive-phase requirements of the first switch 106, which has an excessive capacitance when isolating in the receive state while having a low resistance when optimized to conduct in the transmit state. This compromise is an inherent dilemma of this topology. Thus, a microresonator detection system for a microresonator including the circuit segment 100 typically suffers from noise interference and thus has limited receive-state signal quality.

[0058] Figure 2 Schematically and exemplarily shown is a detector system 200 for a microresonator, the detector system 200 including a ferromagnetic object 202 as a permanent magnet and a circuit 204 including a circuit segment 206. The circuit segment 206 does not suffer from the inherent dilemma of the topology of the circuit segment 100 described with respect to FIG. 1. In the circuit segment 206, the power amplifier 208 and the low-noise amplifier 210 are not connected in parallel as in the circuit segment 100, but in series. This has the advantage that during the receive phase, the first switch 212 can be isolated and the second switch 214 can be conducting, such that the capacitance of the first switch 212 does not degrade the signal quality of the first voltage signal induced in the coil 216 and amplified by the low-noise amplifier 210. Additionally, the second switch 214 effectively shorts any potential interference from the power amplifier 208 to ground 218.

[0059] Figure 3 Schematically and exemplarily shown is what can be in reference Figure 2A circuit segment 300 used in the detector system 200 of the described micro-magnetic resonator. The circuit segment 300 basically corresponds to the circuit segment 200, but is shown and described with further details. The circuit segment 300 includes a power amplifier 302, and the power amplifier is connected in series with its power amplifier output 304 to a low-noise amplifier 306. The power amplifier 302 has a reference terminal 308 connected to ground 310. The circuit segment 300 includes a first switch 312, which is connected in parallel with the low-noise amplifier 306 and can be used to short-circuit the input of the low-noise amplifier 306 by switching to its conducting state in the transmitting state of the circuit segment 300. Thus, in the receiving state of the circuit segment 300, the first switch 312 is switched to its isolating state. Therefore, in the receiving state, the first voltage signal induced in the coil 314 can be transmitted to the low-noise amplifier 306 and amplified by the low-noise amplifier 306. The circuit segment 300 includes a second switch 316, which connects the power amplifier output 304 to ground 310, such that by switching the second switch 316 to its conducting state, the power amplifier output 304 can be grounded in the receiving state of the circuit segment 300. Thus, in the transmitting state of the circuit segment 300, the second switch 316 can be switched to its isolating state, such that the amplified second voltage signal can be transmitted from the power amplifier 302 to the coil 314 via the conducting first switch 312. The second terminal of the coil 314 is connected to ground 318. Grounds 310 and 318 are electrically connected.

[0060] Figure 4 Schematically and exemplarily shows a circuit segment 400, which can replace the Figure 2 circuit segment 206 and detector system 200 for the micro-magnetic resonator described in the reference. The circuit segment 400 includes a power amplifier 402, a first switch 404, a second switch 406, and a coil 408, which are arranged and configured as described in the reference Figure 3 The power amplifier reference terminal 414 is connected to ground 416. The power amplifier output 418 can be grounded by switching the second switch 406 to its conducting state. One end of the coil 408 is connected in series with the first switch 404, and the other end of the coil 408 is grounded 420.

[0061] In addition, circuit segment 400 includes transformer 410. Transformer 410 is connected in parallel to low-noise amplifier 412 and is connected in parallel to first switch 404 for transforming the first voltage signal provided by coil 408 before it enters low-noise amplifier 412. Transformer 410 has a primary side 422 and a secondary side 424. Using its primary side 422, transformer 410 is connected in parallel to first switch 404. Using its secondary side 424, transformer 410 is connected in parallel to low-noise amplifier 412. In addition, using its secondary side 424, transformer 410 is connected to ground 426.

[0062] Figure 5 Circuit segment 500 is schematically and exemplarily shown, which can replace circuit segment 206 in the detector system for microresonator 200 described with reference to Figure 2 Circuit segment 500 includes power amplifier 502, which has a reference terminal 504 connected to ground 506 and a power amplifier output 508 connected to first switch 510. First switch 510 can be switched to its conducting state in the transmitting state of circuit segment 500 for transmitting the amplified second voltage signal to coil 512. Using one end thereof, coil 512 is connected to ground 514. In the receiving state of circuit segment 500, first switch 510 is switched to its isolating state, and second switch 516 is switched to its conducting state. Second switch 516 connects power amplifier output 508 to ground 506, such that in the receiving state, power amplifier 502 is grounded at its power amplifier output 508. In addition, in the transmitting state of circuit segment 500, second switch 516 is switched to its isolating state.

[0063] As circuit segment 400 described with reference to Figure 4 Circuit segment 500 also includes transformer 518, which has a primary side 520 connected in parallel to first switch 510. The secondary side 522 of transformer 518 is connected in series to third switch 524 and is connected in parallel to fourth switch 526. In addition, using its secondary side 522, transformer 518 is connected to ground 528. Third switch 524 and fourth switch 526 act as a voltage divider, where third switch 524 isolates in the transmitting state and conducts in the receiving state. Thus, in the transmitting state, fourth switch 526 conducts, and in the receiving state, fourth switch 526 isolates. Third switch 524 is connected in series to low-noise amplifier 530, and fourth switch 526 is connected in parallel to low-noise amplifier 530. In particular, by using third switch 524 and fourth switch 526, low-noise amplifier 530 can be further protected such that the amplified second voltage signal provided by power amplifier 502 and the transmitting state of circuit segment 500 can less interfere with low-noise amplifier 530.

[0064] In circuit segment 500, a third switch 524 and a fourth switch 526 are included considering that switches 510 and 516 are not ideal. Residual interference from the amplified second voltage signal to the LNA 530 can be further reduced by switches 524 and 526.

[0065] Figure 6 Circuit segment 600 is schematically and exemplarily shown, which can replace the circuit segment 206 in the detector system of the micromagnetic resonator 200 described with reference Figure 2 Circuit segment 600 includes a power amplifier 602 having a differential power amplifier output pair 604 and 606. The first power amplifier output 604 is connected to a first switch 608, and the first switch 608 connects the first power amplifier output 604 to ground 610. The second power amplifier output 606 is connected to a second switch 612, and the second switch 612 connects the second power amplifier output 606 to ground 610. The power amplifier 602, the first switch 608, and the second switch 612 constitute the first sub-unit 614 of the circuit segment 600. The first sub-unit 614 is connected to the second sub-unit 616 of the circuit segment 600. The second sub-unit 616 includes a third switch 618 connected in series with the first power amplifier output 604 to the first terminal of the coil 620. In addition, the second sub-unit 616 includes a fourth switch 622, and the fourth switch 622 is connected in series with the second power amplifier output 606 to the second terminal of the coil 620. The second sub-unit 616 further includes a transformer 624 coupled in parallel to a low-noise amplifier 626. The transformer 624 has two primary sides. Its first primary side 628 is coupled in parallel with the first end 630 (terminal 1) and the second end 632 (terminal 2) to the third switch 618. Its second primary side 634 is coupled in parallel with the third end 636 (terminal 3) and the fourth end 638 (terminal 4) to the fourth switch 622. The secondary side 640 of the transformer is coupled in parallel with the fifth end 642 (terminal 5) and the sixth end 644 (terminal 6) to the low-noise amplifier 626.

[0066] As Figure 7 shown, the coils of the first primary side 628, the second primary side 634, and the secondary side 640 are all coupled. The purpose of the symmetric primary sides 628, 634 of the transformer 624 is to suppress potential common-mode signals that may be captured by the coil 620.

[0067] As Figure 10 shown, the desired differential-mode signals 1000 add constructively and thus appear between terminal 5 and terminal 6, the secondary side 640 of the transformer 624. As Figure 11 shown, in contrast, the common-mode signals 1100 cancel out and thus no voltage appears between terminals 5 and 6.

[0068] Different from the first sub-unit 614, the third sub-unit 650 schematically and exemplarily shown in Figure 8 can be used and connected to the second sub-unit 616 described in the reference Figure 6 to implement another circuit segment 800, which can replace the circuit segment 206 in the detector system of the micro-magnetic resonator 200 described in the reference Figure 2 The third sub-unit 650 includes a power amplifier 652 and a first switch 654 connecting two differential power amplifier outputs 656 and 658.

[0069] Figure 9 The fourth sub-unit 660 is schematically and exemplarily shown, which can be used and connected to the second sub-unit 616 described in the reference Figure 6 to implement another circuit segment 900. The fourth sub-unit 660 can be used as part of the circuit segment 206, particularly as part of the power amplifier 208 in the detector system of the micro-magnetic resonator 200 described in the reference Figure 2 The fourth sub-unit 660 includes a power amplifier 662 connected to a voltage source 664. The power amplifier 662 includes a full H-bridge output stage, which includes four switches 666, 668, 670, 672 that can be switched individually. Since the power amplifier 662 includes an H-bridge, no additional switches (such as Figure 2 switch 214 or Figure 6 switches 608 and 612 in Figure 8 or switch 654 in

[0070] are required in addition to the power amplifier 662, because the H-bridge can be placed in a low-impedance state by switching the low-side transistors of the H-bridge to the conducting state.

[0071] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0072] A single unit or device can implement the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used advantageously.

[0073] Processes such as amplifying a first voltage signal, amplifying a received second voltage signal, etc., performed by one or more units or devices can be performed by any other number of units or devices. These processes, particularly the method of putting the circuit segment into its transmitting state or its receiving state, can be implemented as program code means of a computer program and / or dedicated hardware.

[0074] A computer program can be stored / distributed on a suitable medium provided together with or as part of other hardware, such as an optical storage medium or a solid-state medium, but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

[0075] In some embodiments, the present invention also includes a computer program for controlling the above-mentioned circuit segment. The computer program includes program code, such as executable instructions, for causing the circuit segment to switch from its transmitting state to its receiving state or vice versa by implementing the above method when running on a computing device such as a personal computer (PC), a field-programmable gate array (FPGA), a microcontroller or a complex programmable logic device (CPLD), a processor, a processing circuit or other computing devices.

[0076] In some embodiments, the computer program is stored in one or more memories. In some embodiments, the memory includes a non-transitory computer-readable medium. For example, the memory can include any one or a combination of volatile memory elements (e.g., random access memory RAM, such as DRAM and SRAM, etc.) and non-volatile memory elements (e.g., ROM, flash memory, solid state, EPROM, EEPROM, hard disk drive, magnetic tape, CDROM, etc.). The memory can communicate with one or more computing devices. In some embodiments, the present invention includes a non-transitory computer-readable medium storing, for example, a computer program.

[0077] Any reference signs in the claims shall not be construed as limiting the scope.

[0078] The present invention relates to a circuit segment including a coil, a low-noise amplifier, a first switch, a power amplifier and a second switch. The coil is configured to generate an oscillating magnetic field in a transmitting state and / or to detect an external oscillating magnetic field in a receiving state. The low-noise amplifier is connected in series to the coil. The first switch is connected in parallel to the low-noise amplifier and is configured to short-circuit the input terminals of the low-noise amplifier. The power amplifier is connected in series to the low-noise amplifier. The second switch is arranged between the power amplifier output and the ground potential and is configured to ground the power amplifier output in the receiving state. Thus, in particular during the transmitting state of the circuit segment, the shielding of the low-noise amplifier can be improved.

Claims

1. A circuit or a circuit segment (300) of a circuit, the circuit segment (300) having a transmitting state and a receiving state and comprising: - at least one coil (314) configured to generate an oscillating magnetic field in the transmitting state and to detect an external oscillating magnetic field in the receiving state; or a first coil and a second coil, the first coil being configured to generate an oscillating magnetic field in the transmitting state, the second coil being configured to detect an external oscillating magnetic field in the receiving state, - a low-noise amplifier (306) serially connected to the at least one coil (314) or the first coil and the second coil and configured to amplify a first voltage signal induced in the at least one coil (314) or the second coil by the detected external oscillating magnetic field in the receiving state, - a first switch (312) connected in parallel to the low-noise amplifier (306) and configured to short-circuit the input terminals of the low-noise amplifier (306) by switching the first switch (312) to its conducting state in the transmitting state or to its isolating state in the receiving state, - a power amplifier (302) serially connected to the low-noise amplifier (306) with a power amplifier output (304) and configured to amplify a received second voltage signal and to provide the amplified second voltage signal to the at least one coil (314) or the first coil in the transmitting state, and - a second switch (316) arranged between the power amplifier output (304) and a ground potential (310) and configured to ground the power amplifier output (304) by switching to its conducting state in the receiving state and to its isolating state in the transmitting state.

2. The circuit segment (300) according to claim 1, wherein The first switch (312) and / or the second switch (316) is of a transistor-based switch type.

3. The circuit segment (300) according to claim 2, wherein, The first switch (312) and / or the second switch (316) is a FET.

4. The circuit segment (300) according to at least one of the preceding claims, wherein, The first switch (312) and / or the second switch (316) is a PIN diode.

5. The circuit segment (300) according to any one of the preceding claims, wherein, The power amplifier output (304) is configured as an H-bridge configured to short-circuit the output terminals of the power amplifier output (304) when in the receiving state.

6. The circuit segment (300) according to at least one of the preceding claims, comprising a transformer (410) connected in parallel to the low-noise amplifier (306) and connected in parallel to the first switch (312) for transforming the first voltage signal provided by the at least one coil (314) or the second coil before it enters the low-noise amplifier (306).

7. The circuit segment (300) according to claim 6, wherein, A third switch is serially connected between the low-noise amplifier (306) and the transformer (410).

8. The circuit segment (300) according to any one of the preceding claims, comprising a fourth switch, the fourth switch being connected in parallel with the low-noise amplifier (306) and in parallel with the transformer (410).

9. The circuit segment (300) according to any one of the preceding claims, comprising the following to achieve a balanced configuration: a symmetric power amplifier as the power amplifier (302), a symmetric switch, a symmetric coil as the at least one coil (314), and a transformer (410) having two symmetric primary sides.

10. A detector system for tracking and / or sensing micro-magnets, the detector system comprising: - a circuit comprising the circuit segment (300) according to at least one of the preceding claims, and - a ferromagnetic object, wherein the circuit segment (300) is arranged and configured to generate an oscillating magnetic field in its transmission state to excite the mechanical resonance of the ferromagnetic object, such that in its reception state the ferromagnetic object generates an external oscillating magnetic field that can be detected by the circuit segment (300).

11. A method of operating a circuit segment (300) according to any one of claims 1-9, the method comprising the steps of: - switching the first switch (312) to its conducting state to short-circuit the low-noise amplifier (306), and switching the second switch (316) to its isolating state, thereby putting the circuit segment (300) into its transmission state, and - switching the first switch (312) to its isolating state, and switching the second switch (316) to its conducting state, to ground the power amplifier output (304), thereby putting the circuit segment (300) into its reception state.

12. The method according to claim 11, comprising switching the first switch (312) from its conducting state to its isolating state or vice versa after a first predefined time period, the first predefined time period starting when the second switch (316) is switched from its conducting state to its isolating state or vice versa; or comprising switching the second switch (316) from its conducting state to its isolating state or vice versa after a second predefined time period, the second predefined time period starting when the first switch (312) is switched from its conducting state to its isolating state or vice versa.

13. The method according to claim 11, comprising switching the first switch (312) to its conducting state while the second switch (316) is still in its conducting state, or comprising switching the second switch (316) to its conducting state while the first switch (312) is still in its conducting state.

14. A computer program for controlling a circuit segment (300) according to any one of claims 1 to 9, the computer program comprising program code which, when run on a computing device, is configured to cause the circuit segment (300) to switch from its transmitting state to its receiving state or vice versa by implementing the method according to any one of claims 11 to 13.

15. A non - transitory computer - readable data medium storing the computer program according to claim 14.

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