Patent ID: 12191931

DETAILED DESCRIPTION

The embodiments described herein provide devices, systems, and methods for full duplex multi-channel communication over a single isolation barrier (e.g., capacitive or inductive), even in opposite directions. On the transmitter side, the most suitable frequency range, signal generation method and signal strength may be chosen for a reliable transmission and reception. On the receiver side, signal reception and demodulation is implemented for proper data reconstruction.

The communication approach described herein may be based on Frequency Division Multiplexing (FDM) applied to a single communication channel in the adopted electrical galvanic isolation barrier. FDM involves sending different data flows by separating them in suitable frequency slots, which can be assigned to a different frequency carrier each, rather than in time slots like in time multiplexed communication. FDM can be also combined with amplitude, phase, and/or frequency modulation, where data can be encoded not only in the presence of a carrier frequency but, if desired, also in signal amplitude and/or phase or frequency shifts. Based on system requirements and isolation barrier constraints, the communication approach described herein may involve transmitting the necessary data by using a single isolation barrier.

Signals with carrier frequencies to be transmitted and received across the isolation barrier may be generated by known oscillator topologies such as LC oscillator, ring oscillator, relaxation, etc., and which can be directly or indirectly coupled to the isolation barrier. In case of direct coupling, the isolation barrier becomes a substantial element of the oscillator topology (e.g., the inductance or the capacitance of the oscillator resonator).

Receivers may support FDM and be based on band-pass filters for the selection of the desired carrier frequency. Once passed through the band pass filters, signals can be detected by peak detectors, as in OOK, if simple carrier encoding is applied, or by more complex state of the art demodulators in case that modulation techniques are applied. The filter requirements and topology depend on the carrier frequencies and amplitudes. Amplification of the filtered signal is optional and depends on the original signal amplitude. Detection of the received signal should in general determine the smallest possible overall propagation delay.

Described next, with reference to the figures, are exemplary embodiments of the devices, systems, and methods for implementing full duplex multi-channel communication over a single isolation barrier.

FIG.1illustrates an embodiment of a device100that includes a first electronic side102, a second electronic side104and an isolation barrier106galvanically isolating the first electronic side102and the second electronic side104from one another. The first and second electronic sides102,104may be semiconductor chips (dies), packages, modules, PCBs (printed circuit boards), etc. The isolation barrier106that galvanically isolates the first electronic side102and the second electronic side104from one another includes a signal coupler108that enables signaling between the first and second electronic sides102,104over the isolation barrier106via electromagnetic coupling. The isolation barrier106may be fully integrated in the first electronic side102or the second electronic side104, partly integrated in the first electronic side102and partly integrated in the second electronic side104, or implemented as a discrete component separate from the first and second electronic sides102,104. The signal coupler108is illustrated as an inductive coupler inFIG.1, having a first coil L1and a second coil L2galvanically isolated from one another but coupled via electromagnetic induction. The signal coupler108instead may be a capacitive coupler, for example.

Transceiver (TX/RX) circuitry110is included in both the first electronic side102and the second electronic side104of the device100. The transceiver (TX/RX) circuitry110implements, based on a frequency response profile of the isolation barrier106, full-duplex communication between the first and second electronic sides102,104of the device100using the same signal coupler108. The full-duplex communication between the first and second electronic sides102,104of the device100may be in a single direction as shown inFIG.1, or in both directions as shown inFIG.2. Accordingly, the transceiver circuitry110included in the first electronic side102and/or the second electronic side104may implement multi-channel communication over the isolation barrier106.

In general, the device100may be just a digital isolator or may include additional circuitry and functionality. In the case of a digital isolator, the first electronic side102of the device100is a primary side of the digital isolator and the second electronic side104of the device100is a secondary side of the digital isolator. The primary side102of the digital isolator100is electrically coupled to any type of electronic system or device112. The secondary side104of the digital isolator100is likewise electrically coupled to any type of electronic system or device114. In this example, the transceiver circuitry110included in both electronic sides102,104of the digital isolator100may simultaneously transmit a first signal from the primary side102to the secondary side104and a second signal from the secondary side104to the primary side102using the same signal coupler108and based on the frequency response profile of the isolation barrier106.

In another example, a microcontroller or other type of electronic system or device112such as a system board may be electrically coupled to the first electronic side102of the device100. One or more power modules or other type of power electronic system or device114may be electrically coupled to the second electronic side104of the device100. The second electronic side104of the device100may include a gate driver for each power transistor included in the power electronic system/device114and the first electronic side102of the device100may include control circuitry for the gate driver. In this example, the transceiver circuitry110included in both electronic sides102,104of the device100may simultaneously transmit a modulation signal such as a PWM (pulse width modulation) signal from the first electronic side102to the second electronic side104and a telemetry signal such as a current, voltage or temperature signal from the second electronic side104to the first electronic side102using the same signal coupler108and based on the frequency response profile of the isolation barrier106. Still other types of systems/devices may be coupled using the device100. Various embodiments of the communication system implemented by the device100are described in the following.

FIG.3illustrates an embodiment of the communication system implemented by the device100based on FDM (frequency division multiplexing) communication, e.g., in the case of an inductive isolation barrier106. The transceiver circuitry110included in both electronic sides102,104of the device100includes transmitter circuitry (TX)200and receiver circuitry (RX)202. The transmitter circuitry200on each electronic side102,104of the device100includes oscillators (‘OSC_PRI’, ‘OSC_SEC’)204which generate desired carrier frequencies fPRIn, fSECnthat are directly or indirectly coupled to the signal coupler108of the isolation barrier106. The receiver circuitry202on each electronic side102,104of the device100separate the frequency of interest through respective band-pass filters (‘BPF’)206whose center frequency matches the corresponding frequency carrier, and which is further revealed by peak detectors (‘PD’)208.

The FDM method may be used in combination with OOK (ON-OFF keying) for generating the signals that are to be applied to the terminals of the signal coupler108of the isolation barrier106, to transmit the data to the opposite side of the isolation barrier106. In one embodiment using OOK, input data (‘data_pri_in_n’, ‘data_sec_in_n’) represent bit-streams whose value can be a logic ‘0’ or a logic ‘1’. When an input datum for a forward or back channel is ‘0’, the respective oscillator204is turned off such that no carrier is generated and no signal is provided at the input of the signal coupler108. The transmitter part200is inactive, which allows reduced current consumption. When the datum is ‘1’, the respective oscillator204is turned on and a corresponding signal with the desired carrier frequency fPRIn/fSECnis generated and transmitted over the isolation barrier106. While the datum is ‘1’, the carrier is present and can be detected at the receiver side202.

The carrier frequency may be much higher than the data rate, enabling fast detection and small propagation delay. The choice of carrier frequencies is adjusted to the frequency response of the isolation barrier106, so that the isolation barrier106is sufficiently transparent for all carriers being transmitted. For example, in case that the isolation barrier106is a transformer used as a part of the resonator in the oscillators204, the transformer frequency response in the transmission direction should be inductive in the frequency range where the carrier frequencies are being generated. For a capacitive isolation barrier106, a capacitive response is required. Depending on the parasitic capacitances and inductances associated to the isolation barrier106, a purely inductive or capacitive frequency response may require careful design. Preferably, all data flows are transmitted simultaneously in both forward and back channels, over the same isolation barrier106.

According to one embodiment, each data flow corresponds to one carrier frequency, which can be filtered out and separated on the receiver side202, so that data can be properly decoded according to the OOK technique employed. However, this approach can be pushed only up to a certain extent due to limitations which depend on the isolation barrier106, chosen topology (e.g., whether the isolation barrier106is part of the carrier frequency generation), achievable filtering requirements, circuitry or chip technology constraints, amount of data to be sent simultaneously, etc. In case that one or more of these limits prove challenging and only a limited number of carriers can be sent/received at the same time, additional techniques may be applied, which may introduce some constraints in terms of some loss in simultaneity of information transmission.

For example, two or more data can be sent by using different carrier frequencies, where instead of having a single datum encoded per carrier frequency, a group of data can be encoded in the same carrier. In this case, the presence of a carrier at a certain frequency implies the communication of a fixed configuration of grouped data, while the absence of that carrier implies a different fixed configuration of those data is transmitted at once. Accordingly, if a carrier frequency is present, this implies for example that the data group {datum_a, datum_b, datum_c, . . . }={1,0,1, . . . } is transmitted, while if that carrier frequency is absent, this implies that {datum_a, datum_b, datum_c, . . . }={0,1,0, . . . } is transmitted.

In another example, time multiplexing may be applied to the same OOK carrier so that the same carrier sent/detected or not in different time slots is assigned to different data. In another example, different modulation schemes may be applied to the same carrier, such as amplitude or phase modulation, or a combination of both, with signal detection according to known techniques. The modulation is then used to encode the information which belongs to different data flows. In this case, the modulated carriers can either be transmitted with OOK or be constantly transmitted with the modulation scheme being time multiplexed for carrying different data at different time slots. Any combination of these techniques may be employed, e.g., time multiplexing with different modulation schemes, different carrier frequencies with time multiplexing, different modulation schemes with different carrier frequencies, etc.

FIG.4illustrates an embodiment of the full-duplex communication scheme implemented by the device100. According to this embodiment, an oscillator ‘OSC_PRI’204on the first electronic side102is tuned to a first carrier frequency fPRI1that corresponds to a first resonance frequency of the isolation barrier106. An oscillator ‘OSC_SEC’204on the second electronic side104is tuned to a second carrier frequency fSEC1that corresponds to a second resonance frequency of the isolation barrier106. A bandpass filter ‘BPF’206on the first electronic side12is tuned to the second carrier frequency fSEC1and a bandpass filter206on the second electronic side104is tuned to the first carrier frequency fPRI1, where the respective peak detector208outputs a corresponding recovered data signal ‘data_sec_out’, ‘data_pri_out’. Both electronic sides102,104may include one or more amplifiers300for providing signal amplification before and/or after the bandpass filtering. In one embodiment, the carrier frequency fSEC1of the oscillator OSC_SEC204on the second electronic side104is at a harmonic of the carrier frequency OSC_PRI of the first electronic side102.

Based on the injection locking theory of LC oscillators, oscillation frequencies at the primary and secondary sides of a transformer have a certain relation. Particularly, optimal results can be obtained if a carrier and its odd harmonics, e.g., the 3rdor the5th, are selected such that fPRI1=fSEC1or fPRI1=⅓·fSEC1, fPRI1=5·fSEC1or fPRI1=⅕·fSEC1, etc. For the simultaneous transmission from the first and second electronic sides102,104, frequencies should not be chosen freely and independently, but instead by setting one frequency with the other frequency already defined.

Due to the same injection locking constraint, two or more LC oscillators should not operate simultaneously at different frequencies at a single transmitter side, meaning that only one frequency can be transmitted at a time from one side (e.g., fPRI1, but not fPRI1and fPR12). This implies that if more than one data flow needs to be transmitted over the isolation barrier106in one direction with this particular topology, where the reactance of the isolation barrier106is part of a resonator, additional techniques must be applied as explained herein, e.g., by sending different carrier frequencies and/or using time multiplexing applied to the same OOK carrier.

Such techniques also can be applied to one-directional communication with more than one data flow, with no back channel, which allows a single carrier frequency to be chosen more freely. Exploiting the reactance of the isolation barrier106as a part of the resonator used for generating carrier frequencies, beside determining a constraint on the carrier frequencies, also determines a constraint on the carrier amplitudes. This is due to the necessary impedance shaping of the resonator so that oscillator locking is achieved at both sides, the quality factor of the resonator and the coupling effectiveness (coupling coefficient) which the particular isolating element offers from one side to the other. These parameters should be set to determine a frequency response of the resonator which includes the isolation barrier as qualitatively shown inFIG.5. Hence, the generated signal amplitudes follow the constraints set by that frequency response.

Despite the limit of a single data flow per direction which can be transmitted/received simultaneously, the main advantage of exploiting the reactance of the isolation barrier106in the resonator is that a reasonable signal amplitude for signal communication can be obtained at a reasonable current consumption or power expense. Indeed, the carrier frequencies may be generated by exploiting a resonance and by coupling the generated carrier across the isolation barrier106right where it is generated, without spending power in additional processes. With the simplest encoding (e.g., OOK), the presence or absence of a carrier frequency in one of the communication channels can be decoded as a logic 1 or a logic 0, respectively. More sophisticated encodings may consider the carrier sent through a communication channel to be modulated, e.g., in amplitude, frequency and/or phase within the bandwidth of the established communication channel, which depends on the band pass filters206, by modulating the values of the variable reactances accordingly (e.g., with switched fixed reactances or varactor devices in case of variable capacitances). The demodulation can be then carried out according to known demodulation schemes and architectures.

InFIG.4, the reactance of the isolation barrier106forms part of the resonance of the oscillators204on both sides102,104of the isolation barrier106. The device100operates with one oscillator204at each side102,104, with both oscillators204using the reactance of the isolation barrier106as an element of their respective resonator, which provides the frequency response of the isolation barrier106shown inFIG.5. The transceiver circuitry110simultaneously transmits the first carrier frequency fPRI1modulated with first data ‘data_pri_in’ via the oscillator204on the first electronic side102and the second carrier frequency fSEC1modulated with second data via ‘data_sec_in’ via the oscillator204on the second electronic side104. The transceiver circuitry110also simultaneously recovers the second data data_sec_in via the bandpass filter206on the first electronic side102and the first data data_pri_in via the bandpass filter206on the second electronic side104.

FIG.6illustrates another embodiment of the full-duplex communication scheme implemented by the device100. According to this embodiment, there is only one oscillator204and therefore only one carrier frequency. The reactance of the isolation barrier106is used as an element of the resonator of the single oscillator204and has frequency response shown inFIG.7.

The information encoding is in the shift of the single carrier frequency according to the setting of the variable reactance on the first or second electronic side102,104, with each frequency shift falling into an associated bandpass filter206. For example, if the starting condition for the variable reactances at the first and second electronic sides102,104are Xfirst_1and Xsecond_1, the oscillator20may start by generating a carrier frequency f1. The second electronic side104knows that it is receiving an f1carrier which is detected by the related bandpass filter206on the second electronic side104. With this knowledge, and by keeping the information associated to the occurrence that a carrier from the first electronic side102is being sent, the second electronic side104decides to communicate something to the first electronic side102by changing Xsecond_1to Xsecond_2and by shifting the single carrier, still generated at the first electronic side102, from f1to f2. At the same time, the second electronic side adapts its bandpass filter206so that the frequency shift is taken into account and the bandpass filter206can still detect the single carrier. The first electronic side102, which was previously seeing its own generated carrier falling into a bandpass filter206centered at f1, now sees a single carrier falling into a different bandpass filter206centered at f2. Hence, the single carrier, shifted by a reactance change at the second electronic side104, is still sending the same information from the first electronic side102to the second electronic side104without interruption, but the shift determined by a reactance change at the second electronic side104may concurrently indicate to the first electronic side102that something happened.

Something similar can happen if the first electronic side102decides to transmit a different information to the second electronic side104. The first electronic side102knows that it is generating an f1carrier, detected by a related bandpass filter206on the first electronic side102. With this knowledge, and by keeping the information associated to the occurrence that a carrier from the first electronic side102is being sent, the first electronic side102may decide to communicate something different to the second electronic side104by changing Xfirst_1to Xfirst_2and by shifting the single carrier, still generated at the first electronic side102, from f1to f2. At the same time, the first electronic side102adapts its bandpass filter206so that the frequency shift is taken into account and the bandpass filter206can still detect the single carrier. The second electronic side104, which was previously seeing a transmitted carrier falling into a bandpass filter206centered at f1, now sees a single carrier falling into a different bandpass filter206centered at f2. Hence, the single carrier, shifted by a reactance change at the first electronic side102, continues to send the same information from second electronic side104to the first electronic side102without interruption, but the shift determined by a reactance change at the first electronic side102could concurrently indicate to the second electronic side104that something happened.

Hence, the information encoding is in the shift of a single carrier inFIG.4, with the flow direction (second side to first or vice-versa) being determined based on whether the second electronic side104or the first electronic side102caused the frequency shift. As a particular case, certain information can be encoded by the single carrier frequency falling in none of the bandpass filters206on either side102,104which also coincides with no carrier frequency generated at all.

FIG.8illustrates the embodiment ofFIG.6simplified to show the transmission in a single direction from the first electronic side102to the second electronic side104.FIG.9illustrates the embodiment ofFIG.6simplified to show the transmission in a single direction from the second electronic side104to the first electronic side102.

According to the embodiment ofFIG.6, the reactance of the isolation barrier106is part of the resonator of a single oscillator204on only one side of the isolation barrier106and which transmits towards the other side but can still carry out bi-directional communication through a passive realization on the other side of the isolation barrier106. The single oscillator204is shown on the first electronic side102inFIGS.6,8and9but instead may be on the second electronic side104. In either case, the single oscillator204has a carrier frequency fTXthat corresponds to a resonance frequency of the isolation barrier106. A variable reactance ‘CPRI’ on the first electronic side102and a variable reactance ‘CSEC’ on the second electronic side104form an equivalent reactance ‘Ceq’. The equivalent reactance Ceq shifts the carrier frequency fTXto one of a plurality of shifted frequencies fPRI1. . . fPRIn, fSEC1. . . fSECn. A filter circuit on the first electronic side102has a respective bandpass filter206tuned for each shifted frequency fSEC1. . . fSECn, and a filter circuit on the second electronic side104has a respective bandpass filter206tuned for each shifted frequency fPRI1. . . fPRIn.

InFIGS.6through9, the device transceiver circuitry110sets the first variable reactance CPRIto a first reactance value based on first data ‘datapri_in_n’ at the first electronic side102and sets the second variable reactance CSECto a second reactance value based on second data ‘data_sec_in_n’ at the second electronic side104. The device transceiver circuitry110also simultaneously recovers the second data via the bandpass filter206of the filter circuit on the first electronic side102tuned to the corresponding frequency fSEC1. . . fSECnassociated with the second reactance value and the first data via the bandpass filter206of the second filter circuit on the second electronic side104tuned to the corresponding frequency fPRI1. . . fPRInassociated with the first reactance value. For a shift in the carrier frequency brought about by a change in the first variable reactance CPRIon the first electronic side102or by a change in the second variable reactance CSECon the second electronic side104, the device transceiver circuitry110changes the center frequency of each bandpass filter206on the electronic side102/104at which the shift in the variable reactance is implemented, by an amount corresponding to the shift in the carrier frequency.

FIG.10illustrates another embodiment of the full-duplex communication scheme implemented by the device100. According to this embodiment, the oscillators204on the first electronic side102are independent of and decoupled from the isolation barrier106by first capacitance decoupled voltage (‘V’) buffers400. The oscillators204on the second electronic side104likewise are independent of and decoupled from the isolation barrier106by second capacitance decoupled voltage buffers402. Accordingly, the isolation barrier106has a wideband frequency response as shown inFIG.11as compared to the narrowband frequency responses shown inFIGS.5and7.

FIG.12illustrates another embodiment of the full-duplex communication scheme implemented by the device100. According to this embodiment, the oscillators204on the first electronic side102are independent of and decoupled from the isolation barrier106by first directly coupled current (‘I’) buffers500. The oscillators204on the second electronic side104likewise are independent of and decoupled from the isolation barrier106by second directly coupled current buffers502. Accordingly, the isolation barrier106has a wideband frequency response as shown inFIG.11as compared to the narrowband frequency responses shown inFIGS.5and7.

Depending on the oscillator embodiment used, different transmitter implementations are described next for the full-duplex communication schemes shown inFIGS.3,4,6,8,9,10and12.

FIG.13illustrates a model of a first implementation that uses the reactance of the isolation barrier106, e.g., the inductance of a transformer, as part of the resonator in the oscillator204, as shown inFIGS.4and6. The upper half ofFIG.13shows a model for an inductive (transformer) barrier whereas the lower half ofFIG.13shows a capacitive barrier model. In either case, the oscillator204includes a negative transconductance (−Gm) and an LC resonant tank, where the isolation barrier106is one part of the resonator. For the single oscillator embodiment shown inFIGS.6,8, and9, the reactance of the isolation barrier106as considered in the model has a different frequency response than that for the dual oscillator embodiment shown inFIG.4and makes use of a single negative transconductance on the side where the single oscillator204is located. Also, only one of the two negative transconductances (−Gm) shown inFIG.13is used inFIGS.6,8, and9since only one oscillator204is present.

For the single oscillator embodiment shown inFIGS.6,8, and9, the reactance of the isolation barrier106is considered to be part of the resonator of the single oscillator204which resides on one side102/104of the isolation barrier106and which transmits towards the other side104/102. The device100ifFIGS.6,8, and9can carry out a bi-directional communication through a passive realization on the other side104/102of the isolation barrier106, which is used to implement the transmission in the opposite direction. The advantage of using a single oscillator204may be a lower overall power requirement with respect to a solution where an oscillator204is used at both sides102,104of the isolation barrier106.

The single oscillator204generates a transmitted signal with carrier frequency fTX, which corresponds to the resonance frequency of an LC tank, as shown inFIG.7. The isolation barrier106is shown as an inductive barrier inFIG.7.FIG.7also shows the frequency response which depends on the transformer coupling coefficient and on the impedances CPRI, CSECconnected either side of the isolation barrier106. The variable reactance CPRIon the first electronic side102and the variable reactance CSECon the second electronic side104form an equivalent reactance Ceq that shifts the carrier frequency fTXto one of a plurality of shifted frequencies fPRI1. . . fPRIn. That is, the carrier frequency fTXis set by the total equivalent reactance Ceq seen by the oscillator204, which in this example is the total equivalent reactance seen from the left side of the isolation barrier106. The total equivalent reactance Ceq is determined by the reactances CPRIand CSECat either side of the isolation barrier106inFIG.6, and also by considering the effect of the coupling coefficient of the isolation barrier106. At least one of the reactances CPRI, CSECat either side of the isolation barrier106is variable.

In the context of the simplified view ofFIG.6, the only variable reactance is the variable capacitance CPRIat the left side of the isolation barrier106, while a fixed capacitance value is kept for CSECat the right side of the isolation barrier106. By changing the value of capacitance CPRIamong n values, frequency fTXcan be shifted to a frequency fPR1. . . fPRIn. For each of these n frequencies, a corresponding band pass filter206is present on the second electronic side104of the device100to detect to which frequency the signal with carrier at frequency fTXwas shifted. In this way, one carrier frequency at fTX=fPRIj(j=1 . . . n) can be sent through any single jthright-side band pass filter206at a time.

In the context of the simplified view ofFIG.7where the only variable reactance is the variable capacitance CSECat the right side of the isolation barrier106, while a fixed capacitance value is kept for CPRIat the left side of the isolation barrier106. By changing the value of capacitance CSECamong m values, frequency fTXcan be shifted to a frequency fSEC1. . . fSECm. For each of these m frequencies, a corresponding band pass filter206is present on the first electronic side102of the device100to detect to which frequency the signal with carrier at frequency fTXwas shifted. In this way, one carrier frequency at fTX=fSECi(i=1 . . . m) can be sent through any single ithleft side band pass filter206at a time.

The embodiments illustrated inFIGS.8and9establish one carrier frequency at a time, combining both solutions, as shown inFIG.6, enables a simultaneous engagement of two communication channels in opposite directions (full duplex) across a single isolation barrier106by using a single oscillator204at one side102/104generating one carrier frequency at a time. As CPRIhas n values and CSECm values, up to k=m*n individual carrier frequencies can be generated, each of them falling into one pass band filter206at each side102,104.

Since changing the value of the variable reactance on either side102,104may be used to encode information through the corresponding shift of frequency fTX, so that the signal carrier can jump from one band pass filter206to another on the opposite side of the isolation barrier106, a corresponding adaption of the pass band frequency position is necessary on the side where the reactance is changed. This way, a correct detection of the information flow coming from the opposite side is maintained. For example, fTXmay be shifted from fTX1to fTX2by changing CSECwhile a signal transmitted from left to right was being detected by the band pass filter206with center frequency fPRI1. To maintain the detection of the unchanged (CPRIwas kept constant) information flow from left to right through the band pass filter206at center frequency fPRI1, also center frequency fPRI1should be shifted according to the same shift of fTX, so that before the change at CSECcenter frequency fPRI1=fTX1, while after the change at CSECcenter frequency fPRI1=fTX2. The center frequencies fPRI1. . . fPRInof all band pass filters206sitting on the right side should be shifted by the same value. This change can be achieved since both CSECand the band pass filters206at center frequencies fPRI1. . . fPRInsit on the same side of the isolation barrier106and hence the band pass filter206can be made adaptive according to the value set for CSEC.

A similar procedure can be defined if CPRIis used instead for shifting fTX. For example, fTXmay be shifted from fTX1to fTX2by changing CPRIwhile a signal transmitted from right to left was being detected by the band pass filter206with center frequency fSEC1. To keep the detection of the unchanged (CSECwas kept constant) information flow from left to right through the band pass filter206at center frequency fSEC1, also center frequency fSEC1should be shifted according to the same shift of fTX, so that before the change at CPRIcenter frequency fsEC1=fTX1, while after the change at CPRIcenter frequency fsEC1=fTX2. The center frequencies fSEC1. . . fSECmof all band pass filters206sitting on the left side should be shifted by the same value. This change can be achieved since both CPRIand the band pass filters206at center frequencies fSEC1. . . fSECmsit on the same side of the isolation barrier106and hence the band pass filter206can be made adaptive according to the value set for CPRI.

The oscillator frequency shifts and band pass filter center frequency shifts, according to the settings of the variable reactances CSECand OPRI, can be coded in a look up table similar to that shown in Table 1. The lookup table stores the available shifted center frequency options fTx11. . . fTxoo. The transceiver circuitry110retrieves the shifted center frequency from the lookup table that corresponds to the transmission reactance value provided by CSECand CPRI, and changes the center frequency of each bandpass filter206on the electronic side102/104at which the shift in the variable reactance is implemented to the corresponding shifted frequency retrieved from the lookup table.

Table 1 shows two reactance (capacitance in this example) values on each side102,104as an example: CPRI1, CPRI2, OSEC1, CSEC2, so that 2*2=4 shifted frequencies fTX11, fTX10, fTX01, and fTX00are available, with one communication channel activated simultaneously per each side102,104, as long as the carrier fTXgenerated by the single oscillator204is present. The band pass filter fPRI0for primary logic data 0 detects both shifted frequencies fTX00and fTX01. For logic data 1, the band pass filter fPRI1detects the sifted frequencies fTX10and fTX11. Band pass filter fSEC0for secondary logic data 0 detects both shifted frequencies fTX00and fTX10. For logic data 0, the band pass filter fSEC1detects the shifted frequencies fTX01and fTX11. The frequencies fTX01and fTX10may be the same frequency or different frequencies.

TABLE 12 × 2 Data Symbol Exampledata_pridata_secCPRICSECfTXfPRIfSEC11CPRI1CSEC1fTX11fPRI1fSEC110CPRI1CSEC0fTX10fPRI1fSEC001CPRI0CSEC1fTX01fPRI0fSEC100CPRI0CSEC0fTX00fPRI0fSEC0

At either electronic side102,104of the device100, the variable reactance CPRI/CSECforms part of the equivalent reactance Ceq that is configured to shift the carrier frequency fTXsuch that information encoding in either direction is implemented by changing the corresponding variable reactance. The filter circuits on both electronic sides102,104of the device100are frequency tuned based on the variable reactance. In the example given in Table 1, the transceiver circuitry110on either electronic side102,104of the device100can set the corresponding variable reactance CPRI/CSECto a first reactance value CPRI1/CSEC1to encode first data and to a second reactance value CPRI2/CSEC2to encode second data. The same transceiver circuitry110changes the frequency tuning of the filter circuit on that electronic side102,104of the device100if the corresponding variable reactance CPRI/CSECis changed from one reactance value to another reactance value.

More generally, information encoding is implemented by shifting a single carrier fTX, with the data flow direction (second side to first or vice-versa) being determined based on whether the second electronic side102or the first electronic side102caused the frequency shift. With the number of m and n value higher than two, the communication channels can support not only single bit binary data but full symbols of data as indicated in Table 2 and Table 3. And m and n do not necessarily need to have the same value, means that the size of the symbols in each direction can be customized to the individual needs (see Table 2 which shows a 4×2 data symbol example).

TABLE 24 × 2 Data Symbol Exampledata_pridata_secCPRICSECfTXfPRIfSEC111CPRI3CSEC1fTX31fPRI3fSEC1110CPRI3CSEC0fTX30fPRI3fSEC0101CPRI2CSEC1fTX21fPRI2fSEC1100CPRI2CSEC0fTX20fPRI2fSEC0011CPRI1CSEC1fTX11fPRI1fSEC1010CPRI1CSEC0fTX10fPRI1fSEC0001CPRI0CSEC1fTX01fPRI0fSEC1000CPRI0CSEC0fTX00fPRI0fSEC0

TABLE 34 × 4 Data Symbol Exampledata_pridata_secCPRICSECfTXfPRIfSEC1111CPRI3CSEC3fTX33fPRI3fSEC31110CPRI3CSEC2fTX32fPRI3fSEC21101CPRI3CSEC1fTX31fPRI3fSEC11100CPRI3CSEC0fTX30fPRI3fSEC01011CPRI2CSEC3fTX23fPRI2fSEC31010CPRI2CSEC2fTX22fPRI2fSEC21001CPRI2CSEC1fTX21fPRI2fSEC11000CPRI2CSEC0fTX20fPRI2fSEC00111CPRI1CSEC3fTX13fPRI1fSEC30110CPRI1CSEC2fTX12fPRI1fSEC20101CPRI1CSEC1fTX11fPRI1fSEC10100CPRI1CSEC0fTX10fPRI1fSEC00011CPRI0CSEC3fTX03fPRI0fSEC30010CPRI0CSEC2fTX02fPRI0fSEC20001CPRI0CSEC1fTX01fPRI0fSEC10000CPRI0CSEC0fTX00fPRI0fSEC0

Since the side that transmits (sends) by carrying out a reactance change knows which reactance value is applied on its side, not every shifted frequency (k=m*n) needs to be generated to ensure proper decoding of the data on the opposite side and a back calculation may be used to determine the unique value that the other side is applying. For example, the frequencies fTX01and fTX10may be the same frequency for the single bit binary data example in Table 1. More generally for both single bit binary data (e.g., Table 1) and full symbols of data (e.g., Tables 2 and 3), there may not be m*n different frequencies depending on how many shifted frequencies are generated/used. In another example, information can be encoded by the single carrier frequency fTXfalling in none of the bandpass filters on either side102,104which also coincides with no carrier frequency generated at all.

Another transmitter implementation, which is based onFIGS.10and12, is based on the oscillators204being indirectly coupled to the isolation barrier106by capacitance decoupled voltage buffers400(FIG.10) or directly coupled current buffers500(FIG.12). In either case, the isolation barrier106is decoupled from the oscillators204. The isolation barrier106, together with its associated reactances (parasitic or intentional ones), shows a sufficient broadband response which is possible through a proper sizing of the reactances associated to the isolation element.

In this case, the isolation barrier106can be considered as a broadband communication channel where more than one frequency carrier can be transmitted in either direction, e.g., as shown inFIG.11. As a result, the equivalent network which can be associated with the isolation barrier106together with added (parasitic or intentional) reactances (e.g., as shown inFIGS.10and12) has a relatively wideband passband response between a low frequency fLand a high frequency fHas shown inFIG.11, instead of a narrowband response as inFIG.5. The frequency span between fLand fHcan be used to host a number of carrier frequencies f1, f2, . . . , fnsent across the isolation barrier106in either direction, with transmitter and receiver circuitry200,202placed on both sides102,104. A corresponding number of sufficiently narrow band pass filters206can be used to detect the transmitted carriers, e.g., as previously explained herein.FIG.11schematically illustrates that the isolation barrier106may provide inductive or capacitive coupling, also as previously described herein.

FIG.11shows the input to output broadband response from either side of the isolation barrier106when properly dimensioned. In this example, the bandwidth between fLand fHis used to host three carriers at frequencies f1, f2, f3, which can be used to send information in either direction according to the embodiments shown inFIGS.10and12. If the isolation barrier106has a wideband frequency response as indicated byFIG.11, the transceiver circuitry110can include an oscillator204on the first electronic side102for each carrier frequency included in a first group of carrier frequencies within the wideband frequency response and an oscillator204on the second electronic side104for each carrier frequency included in a second group of carrier frequencies within the wideband frequency response. A bandpass filter206on the first electronic side102is tuned to each carrier frequency included in the second group of carrier frequencies, and a bandpass filter206on the second electronic side104is tuned to each carrier frequency included in the first group of carrier frequencies.FIGS.10and12both show such an implementation.

According to the wideband frequency response embodiment, the transceiver circuitry110simultaneously transmits a plurality of carrier frequencies from the first group modulated with first data ‘data_pri_in_1’ . . . ‘data_pri_in_n’ via the oscillators204on the first electronic side102and a plurality of carrier frequencies from the second group modulated with second data ‘data_sec_in_1’ . . . ‘data_sec_in_m’ via the oscillators204on the second electronic side104. The transceiver circuitry110also simultaneously recovers the second data via the bandpass filters206on the first electronic side102and the first data via the bandpass filters206on the second electronic side104.

InFIG.10, the coupling of the oscillators204to the isolation barrier106is implemented through capacitor decoupled voltage buffers400, which provide enough signal strength for a reliable transmission. The voltage buffers400are connected to the isolation barrier106through capacitors to decouple different drivers from each other in DC and to allow signals at different frequencies to be received at the same time while transmitting. To allow a reliable detection of the received signals, in AC the capacitive/inductive signal divider formed by the reactive elements of the isolation barrier106and all capacitances which connect the different voltage buffers400to the isolation barrier106should allow a sufficient amplitude for all the signals at the frequencies of interest. Capacitance and/or signal frequency values are selected accordingly.

Also, the capacitances added to decouple the voltage buffers400should not hinder the broadband response of the isolation barrier106. In general, the oscillators204can be of any type, e.g., square wave, sine wave or any other type. However, as explained in more detail later, sine wave oscillators are preferred since ideally a sine wave has only one spectral component, which allows a more reliable detection at the receiver side and less constraints among different transmitted/received frequency carriers. For an oscillator which generates an output signal different than a sine wave, harmonic frequencies of the same or another oscillator may spuriously fall into unintended frequency bands, with the possibility of causing a wrong signal detection. The driver implementation should fit to the oscillator signal type and, e.g., can be in the form of simple CMOS inverters with sufficient driving strength (e.g., suitable for square wave oscillators), or voltage followers based on a more linear push-pull implementation (for sine wave or triangular wave oscillators).

The driver should avoid introducing too large harmonic distortion, by creating harmonics which were not initially present in the spectrum of the oscillator signal and which may be also wrongly detected by spuriously falling into unintended frequency bands. The current consumption of this implementation where oscillators204are coupled to drivers is higher compared to the one where the isolation barrier106is part of the resonator of the oscillator204, but provides more freedom in the choice and spectral positioning of the different frequency carriers since, by decoupling the oscillator204from the isolation barrier106, the constraint regarding the frequency locking of the oscillator204does not hold any more. This means that fPRI1and fSEC1can be chosen more independently, and that more than one frequency carrier can be transmitted from one side (e.g., fPRI1and fPR2from the first side102, and fSEC1and fsEC2from the second side104), which increases system flexibility and amount of data which can be sent simultaneously. However, if the data amount is still not enough, additional techniques previously explained herein such as time multiplexing, different modulation schemes, different carrier frequencies, etc. can be used to increase the data variety and throughput.

The embodiment illustrated inFIG.12is similar to the embodiment illustrated inFIG.10but uses current buffers500to couple the oscillators204to the broad band isolation network. With the clear advantages of not requiring added capacitances and allowing an easier signal summation at both ends of the isolation network, the implementation with current buffers500is subject to all other constraints and considerations already mentioned for the implementation with voltage buffers400.

The receiver part of the device100may in general be the same for all transmitter embodiments. To separate the wanted frequency component in the spectrum, band-pass filters206may be used, whose center frequency is set around the wanted frequency carrier. Specific to the embodiment illustrated inFIGS.6,8and9, the band-pass center frequency is not fixed but instead adjusted according to the oscillator frequency set on turn based on the selected reactance value at either side of the isolation barrier106. Based on the coding example given in Table 1, for detecting data_pri_in_1on the second side104, depending on data_sec_in_1and data_sec_in_2, the band pass filter center frequency (fPRI1) is set to either fTX10, fTX11or fTX12. For detecting data_sec_in_1on the first side102, while depending on data_pri_in_1and data_pri_in_2, the fSEC1is to either fTX11or fTX21.

The band pass filter out of band roll off and attenuation is defined by the out of band suppression requirements to sufficiently reject the other frequency carriers and their harmonics. The requirements on filter out of band roll off and attenuation can be different and more or less demanding, depending on the chosen oscillator topology, the related harmonic content, the spectral spacing among the different frequency carriers, and how many carriers can or have to be hosted by the bandwidth offered by the isolation barrier106. Accordingly, for the embodiments illustrated inFIGS.10and12, sine wave oscillators204in combination with low distortion voltage or current buffers400,500are used.

For the embodiments illustrated inFIGS.4and6, the harmonic content beside the carrier is assumed to be low, since the resonator band pass response already filters it out by delivering a sufficiently clean sine wave, which is then immediately coupled to the isolation barrier106which is part of the resonator. In case that high order band pass filters are required, some suitable implementations could be switched gmC filters, or cascading 2-3 stages of second order filters. In case that a switched gmC filter is used in the embodiments ofFIGS.4and6, a wide band decoupling buffer may be used to decouple the filter from the resonators, so that the oscillator operation is not adversely affected.

For the embodiments inFIGS.10and12, the decoupling buffer ‘V’ may not be required if the decoupling offered by the decoupling capacitors or the current buffers500is sufficient. Depending on the signal amplitude resulting out of the band pass filters206, the filtered signal can be amplified by an amplifier300with a bandwidth sufficient for the filtered signal and moderate gain. The signal can be detected by suitable detectors206depending on the applied modulation schemes. With a typical OOK peak detector, whose detection time is relatively short with respect to the maximum allowed system input to output data propagation delay, may be used to identify whether a carrier is present or absent in a selected frequency band. With more advanced modulations (e.g., amplitude, phase, and/or frequency) known detectors can be used after the band pass filters206.

The embodiments described herein provide a communication technique applied to a single galvanic isolation barrier used as a combined communication channel to convey multiple electrical communication channels in either direction across the galvanic isolation barrier. The embodiments described herein provide for various implementations of signal generation, transmission and detection to enable the communication, by considering cases when the isolation network associated with the isolation barrier is set to offer a narrowband response and the isolation network is used as a part of a resonator, or when the isolation barrier is set to offer a wideband response and the isolation network used as an independent transmission means.

Although the present disclosure is not so limited, the following numbered examples demonstrate one or more aspects of the disclosure.

Example 1. A device, comprising: a first electronic side; a second electronic side; an isolation barrier galvanically isolating the first electronic side and the second electronic side from one another, the isolation barrier including a signal coupler configured to enable signaling between the first and second electronic sides over the isolation barrier via electromagnetic coupling; and transceiver circuitry included in both the first and second electronic sides and configured to implement, based on a frequency response profile of the isolation barrier, full-duplex communication between the first and second electronic sides using the same signal coupler.

Example 2. The device of example 1, wherein the second electronic side includes a gate driver for a power transistor, wherein the first electronic side includes control circuitry for the gate driver, and wherein the transceiver circuitry is configured to simultaneously transmit a modulation signal from the first electronic side to the second electronic side and a telemetry signal from the second electronic side to the first electronic side using the same signal coupler and based on the frequency response profile of the isolation barrier.

Example 3. The device of example 1 or 2, wherein the first electronic side is a primary side of a digital isolator, wherein the second electronic side is a secondary side of the digital isolator, and wherein the transceiver circuitry is configured to simultaneously transmit a first signal from the primary side to the secondary side and a second signal from the secondary side to the primary side using the same signal coupler and based on the frequency response profile of the isolation barrier.

Example 4. The device of any of examples 1 through 3, wherein the transceiver circuitry comprises: a first oscillator on the first electronic side and tuned to a first carrier frequency that corresponds to a first resonance frequency of the isolation barrier; a second oscillator on the second electronic side and tuned to a second carrier frequency that corresponds to a second resonance frequency of the isolation barrier; a first bandpass filter on the first electronic side and tuned to the second carrier frequency; and a second bandpass filter on the second electronic side and tuned to the first carrier frequency.

Example 5. The device of example 4, wherein the transceiver circuitry is configured to simultaneously transmit the first carrier frequency modulated with first data via the first oscillator and the second carrier frequency modulated with second data via the second oscillator, and wherein the transceiver circuitry is configured to simultaneously recover the second data via the first bandpass filter and the first data via the second bandpass filter.

Example 6. The device of example 4 or 5, wherein the second carrier frequency is a harmonic of the first carrier frequency.

Example 7. The device of any of examples 1 through 3, wherein the transceiver circuitry comprises: a single oscillator on the first electronic side and having a carrier frequency; a first variable reactance on the first electronic side; a second variable reactance on the second electronic side, the first variable reactance and the second variable reactance forming an equivalent reactance that is configured to shift the carrier frequency to one of a plurality of shifted frequencies; a first filter circuit on the first electronic side and having a bandpass filter tuned for the one of the plurality of shifted frequencies; and a second filter circuit on the second electronic side and having a bandpass filter tuned for the one of the plurality of shifted frequencies.

Example 8. The device of example 7, wherein the transceiver circuitry is configured to set the first variable reactance to a first reactance value based on first data at the first electronic side and to set the second variable reactance to a second reactance value based on second data at the second electronic side such that the equivalent reactance is set to a transmission reactance value and the carrier frequency is shifted to the one of the plurality of shifted frequencies, and wherein the transceiver circuitry is configured to simultaneously recover the second data via the bandpass filter of the first filter circuit tuned to a frequency associated with the second reactance value and the first data via the bandpass filter of the second filter circuit tuned to a frequency associated with the first reactance value.

Example 9. The device of example 7 or 8, wherein for a shift in the carrier frequency brought about by a change in the first variable reactance on the first electronic side or by a change in the second variable reactance on the second electronic side, the transceiver circuitry is configured to change a center frequency of each bandpass filter on the electronic side at which the shift in the variable reactance is implemented, by an amount corresponding to the shift in the carrier frequency.

Example 10. The device of example 9, wherein the transceiver circuitry comprises a lookup table that stores the plurality of shifted frequencies, and wherein the transceiver circuitry is configured to retrieve the one of the plurality of shifted frequencies and change the center frequency of each bandpass filter on the electronic side at which the shift in the variable reactance is implemented to the shifted frequency retrieved from the lookup table.

Example 11. The device of any of examples 1 through 3, wherein the isolation barrier has a wideband frequency response, and wherein the transceiver circuitry comprises: an oscillator on the first electronic side for each carrier frequency included in a first group of carrier frequencies within the wideband frequency response; an oscillator on the second electronic side for each carrier frequency included in a second group of carrier frequencies within the wideband frequency response; a bandpass filter on the first electronic side tuned to each carrier frequency included in the second group of carrier frequencies; and a bandpass filter on the second electronic side tuned to each carrier frequency included in the first group of carrier frequencies.

Example 12. The device of example 11, wherein the transceiver circuitry is configured to simultaneously transmit a plurality of carrier frequencies from the first group modulated with first data via the oscillators on the first electronic side and a plurality of carrier frequencies from the second group modulated with second data via the oscillators on the second electronic side, and wherein the transceiver circuitry is configured to simultaneously recover the second data via the bandpass filters on the first electronic side and the first data via the bandpass filters on the second electronic side.

Example 13. The device of example 11 or 12, wherein the oscillators on the first electronic side are independent of and decoupled from the isolation barrier by first capacitance decoupled voltage buffers, and wherein the oscillators on the second electronic side are independent of and decoupled from the isolation barrier by second capacitance decoupled voltage buffers.

Example 14. The device of example 11 or 12, wherein the oscillators on the first electronic side are independent of and decoupled from the isolation barrier by first directly coupled current buffers, and wherein the oscillators on the second electronic side are independent of and decoupled from the isolation barrier by second directly coupled current buffers.

Example 15. The device of any of examples 1 through 14, wherein the transceiver circuitry included in the first electronic side and/or the second electronic side is configured to implement multi-channel communication over the isolation barrier.

Example 16. A device, comprising: electronic circuitry; an isolation barrier galvanically isolating the electronic circuitry, the isolation barrier including a signal coupler configured to enable signaling over the isolation barrier via electromagnetic coupling; and transceiver circuitry configured to implement, based on a frequency response profile of the isolation barrier, full-duplex communication between the electronic circuitry of the device and electronic circuitry of another device using the same signal coupler.

Example 17. The device of example 16, wherein the transceiver circuitry comprises: an oscillator tuned to a first carrier frequency that corresponds to a first resonance frequency of the isolation barrier; and a bandpass filter tuned to a second carrier frequency that is a harmonic of the first carrier frequency.

Example 18. The device of example 17, wherein the transceiver circuitry is configured to simultaneously transmit the first carrier frequency modulated with first data via the oscillator and receive the second carrier frequency modulated with second data via the bandpass filter.

Example 19. The device of example 16, wherein the transceiver circuitry comprises: a single oscillator having a carrier frequency; a variable reactance forming part of an equivalent reactance that is configured to shift the carrier frequency to a first one of a plurality of shifted frequencies; and a filter circuit having a bandpass filter tuned for the one of the plurality of shifted frequencies.

Example 20. The device of example 19, wherein the transceiver circuitry is configured to set the variable reactance to a first reactance value to encode first data and to a second reactance value to encode second data.

Example 21. The device of example 19 or 20, wherein the transceiver circuitry is configured to change the frequency tuning of the filter circuit if the variable reactance is changed from one reactance value to another reactance value.

Example 22. The device of any of examples 16 through 18, wherein the isolation barrier has a wideband frequency response, and wherein the transceiver circuitry comprises: an oscillator for each carrier frequency included in a first group of carrier frequencies within the wideband frequency response; and a bandpass filter tuned to each carrier frequency included in a second group of carrier frequencies within the wideband frequency response.

Example 23. The device of example 22, wherein the transceiver circuitry is configured to simultaneously transmit a plurality of carrier frequencies from the first group modulated with first data via the oscillators and receive a plurality of carrier frequencies from the second group modulated with second data via the bandpass filters.

Example 24. The device of any of examples 15 through 23, wherein the transceiver circuitry is configured to implement multi-channel communication over the isolation barrier.

Example 25. A method of communicating data between first and second electronic sides of a device that are galvanically isolated from one another by an isolation barrier having a signal coupler that enables signaling between the first and second electronic sides over the isolation barrier via electromagnetic coupling, the method comprising: implementing, based on a frequency response profile of the isolation barrier, full-duplex communication between the first and second electronic sides using the same signal coupler, wherein implementing the full-duplex communication comprises: tuning a first oscillator on the first electronic side to a first carrier frequency that corresponds to a first resonance frequency of the isolation barrier; tuning a second oscillator on the second electronic side to a second carrier frequency that corresponds to a second resonance frequency of the isolation barrier; tuning a first bandpass filter on the first electronic side to the second carrier frequency; and tuning a second bandpass filter on the second electronic side to the first carrier frequency, or wherein implementing the full-duplex communication comprises: generating a carrier frequency via a single oscillator on the first electronic side; selecting a first variable reactance on the first electronic side and a second variable reactance on the second electronic side, the first variable reactance and the second variable reactance forming an equivalent reactance that is configured to shift the carrier frequency to one of a plurality of shifted frequencies; tuning a first filter circuit on the first electronic side based on the first variable reactance selected on the first electronic side; and tuning a second filter circuit on the second electronic side based on the second variable reactance selected on the second electronic side.

Terms such as “first”, “second”, and the like, are used to describe various elements, regions, sections, etc. and are also not intended to be limiting. Like terms refer to like elements throughout the description.

As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.

Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.