Wireless transceiver resynchronization options during wireless management of subsystems

A communication circuit includes network formation circuitry configured to establish a wireless network between a primary wireless transceiver and a secondary wireless transceiver. The communication circuit also includes data transfer circuitry configured to perform data transfers between the primary wireless transceiver and the secondary wireless transceiver. The communication circuit further includes resynchronization circuitry configured to resynchronize the secondary wireless transceiver with the established wireless network within a target time interval.

BACKGROUND

As new electronic devices are developed and integrated circuit (IC) technology advances, new IC products are commercialized. One example IC product for electronic devices is a communication circuit with a wireless transceiver. There are many different wireless communication protocols and related wireless transceivers to support different ranges of wireless data transfer, different levels of security, frequencies used, and/or other variations. In some systems, wireless transceivers may be added to simplify wiring and facilitate replacement or repair of subsystem components/modules. For example; there are systems with a controller and multiple subsystems, where the controller and each of the subsystems need to communicate with each other. Use of wires between the controller and each subsystem as well as wires between subsystems is problematic when space is limited. Such wires make installation; removal, and/or replacement of each subsystem more challenging (e.g., the wires related to each subsystem need to be connected during installation, disconnected when servicing/removing, and reconnected after servicing/removing, which is difficult when space is limited). In this example, the addition of wireless transceivers would simplify the wiring between the controller and the subsystems and/or the wiring between the subsystems with the above-noted benefits. However, the addition of wireless transceivers may prevent compliance with safety standards of a system.

One example system that could benefit from wireless transceivers is an electric vehicle with a battery management system (BMS), resulting in a wireless BMS (WBMS). However, according to standard ISO 26262, battery monitoring devices need to provide Automotive Safety Integrity Level D (ASIL-D). There are two solutions for ASIL-D compliance: 1) the battery monitoring device can use separate measurement chains for temperature, voltage, and other events; or 2) the battery monitoring device can have built in tests to ensure that the probability of a failure meets the standard's requirements. In either instance, data must be transferred between a main controller and the subsystems of the WBMS within a certain time interval to ensure the safety of the system. The current standard specifies this interval as less than 100 ms. If a wireless transceiver loses synchronization with an established network, the probability of non-compliance with such safety standards increases.

SUMMARY

In at least one example, a communication circuit comprises network formation circuitry configured to establish a wireless network between a primary wireless transceiver and a secondary wireless node. The communication circuit also comprises data transfer circuitry configured to perform data transfers between the primary wireless transceiver and the secondary wireless transceiver. The communication circuit further comprises resynchronization circuitry configured to resynchronize the secondary wireless transceiver with the established wireless network within a target time interval.

In another example, a system comprises: a primary wireless transceiver adapted to be coupled to a controller of the system; and a secondary wireless transceiver adapted to be coupled to a subsystem of the system. The primary wireless transceiver and the secondary wireless transceiver are configured to establish a wireless network. The secondary wireless transceiver is configured to: identify a resynchronization trigger; and perform resynchronization with the established wireless network within a target time interval in response to the identified resynchronization trigger.

In yet another example, a method is performed by a communication circuit between a controller and a subsystem. The method comprises: establishing a wireless network with another communication circuit to transfer data between the controller and the subsystem; identifying a resynchronization trigger; and performing resynchronization with the established wireless network within a target time interval in response to the identified resynchronization trigger.

The same reference number is used in the drawings for the same or similar (either by function and/or structure) features.

DETAILED DESCRIPTION

Some example embodiments include a communication circuit with a wireless transceiver configured to perform resynchronization with an established wireless network as needed. The communication circuit may be an integrated circuit (IC) or other circuit. In some example embodiments, the wireless transceiver is part of a system with a controller in communication with subsystems via communication circuits that support wireless communications. In some example embodiments, the system includes a primary wireless transceiver and secondary wireless transceivers. The primary wireless transceiver is in communication with the controller (e.g., via a wired coupling), while each secondary wireless transceiver is in communication with a respective subsystems (e.g., via respective wired couplings). In operation, the primary wireless transceiver and the secondary wireless transceivers are configured to establish a wireless network and transfer data to each other as needed. Each secondary wireless transceiver is also configured to: identify a resynchronization trigger; and perform resynchronization with the established wireless network within a target time interval in response to the identified resynchronization trigger. The resynchronization options vary depending on whether a given secondary wireless transceiver is in an active wireless transceiver state (sometimes referred to herein as an active state) or a reset wireless transceiver state (sometimes referred to herein as a reset state).

In one example embodiment, the system is an electric vehicle and the communication circuits are part of a wireless subsystem management system such as a wireless battery management system (WBMS). For a WBMS, the primary wireless transceiver is part of a primary communication circuit included with a battery management unit (BMU) of the WBMS. The BMU includes, for example, a printed circuit board (PCB) with the controller and the primary communication circuit coupled via a wired coupling. Also, each secondary communication circuit is part of a respective cell monitor unit (CMU) of the WBMS. Each CMU includes, for example, a PCB with a respective secondary communication circuit and a respective monitor circuit coupled via a wired coupling. Each CMU may additionally include other components such as an adjustment controller to adjust operations of a monitored electrical component (e.g., a rechargeable battery). Each CMU is thus configured to monitor a monitored electronic component, provide data to the BMU, receive adjustment control signals or instructions back from the BMU, and adjust a respective monitored electronic component based on the adjustment instructions.

With the resynchronization options described herein, the communication circuits for a system with a controller and subsystems provide a wireless interface to facilitate wiring, replacement, and/or repair of the subsystems. In some example embodiments, each of the subsystems has similar components (e.g., a PCB, a communication circuit that supports wireless communications, and other components coupled to the communication circuit) and functionality. For example, in a WBMS, each of the subsystems includes a respective PCB with a communication circuit and a CMU configured to perform monitoring and/or adjustments with regard to a respective battery cell. Without limitation to their particular functionality, individual subsystems or related modules are replaceable in some example embodiments (i.e., the subsystems or related modules are modular in that they can be easily attached, detached, and/or replaced as needed). Together, the controller and the subsystems of a WBMS control charging of multiple battery cells (e.g., coupled in series and/or in parallel) and detect if a particular battery cell or related subsystem is not working properly. In some example embodiments, wireless communications between a controller and the subsystems of a system comply with a target time interval. Without limitation, the target time interval may be related to a safety standard (e.g., an automotive safety standard).

FIG.1is a block diagram of a system100in accordance with an example embodiment. In some example embodiments, the system100is an electric vehicle with battery management subsystems, or another system with subsystems. As shown, the system100includes a controller102in communication with subsystems112A-112N via wireless communication channels (not shown). To support such communications between the controller102and the subsystems112A-112N, the controller102is coupled via a wired coupling105to a primary communication circuit104. The controller102is also coupled to other components132of the system100via a communication interface130. The communication interface130may be a controller area network (CAN) or other communication interface. Also, each of the subsystems112A-112N includes a respective secondary communication circuit114in communication with the primary communication circuit104via respective wireless communication channels. As shown for the subsystem112A, the secondary communication circuit114is coupled to a respective monitor circuit122via a wired coupling115. The controller102is this able to communicate with each respective monitor circuit122of the subsystems112A-112N and vice versa via a combination of wired and wireless communications. Such communications may be for battery management system (BMS) operations or management of another type of monitored electrical component126.

Adding wireless communications to the system100using the primary communication circuit104and each secondary communication circuit114facilitates repair and/or replacement of some or all of the components of the subsystems112A-112N. However, such wireless communications may introduce unacceptable delays if synchronization between a primary wireless transceiver106of the primary communication circuit104and a secondary wireless transceiver116of a given secondary communication circuit114is lost. Accordingly, in the example ofFIG.1, the primary communication circuit104and/or each secondary communication circuit114is configured to perform resynchronization operations within a target time interval as needed (e.g., if synchronization with an established network is lost). With the resynchronization operations, wireless data transfers between the controller102and each of the subsystems112A-112N (via the primary communication circuit104and each secondary communication circuit114) are supported, while ensuring these wireless data transfers are performed within a target time interval even if synchronization is lost.

In operation, each of the subsystems112A-112N uses its respective monitor circuit122to monitor parameters of a monitored electrical component126. In some example embodiments, the monitored electrical component126is a rechargeable battery. Without limitation, the monitored parameters may include a voltage across the monitored electrical component126and/or a current through the monitored electrical component126. The monitored parameters (or related values) are transferred to the controller102, which analyses the monitored parameters (or related values) and determines whether any adjustments are needed. If adjustments are needed for a given subsystem, the controller102provides adjustment control signals to the given subsystem. As shown, each of the subsystems112A-112N includes a respective adjustment controller124, which is configured to adjust operations of a respective monitored electrical component126based on any adjustment control signals received from the controller102.

In some example embodiments, the primary communication circuit104is an IC with a primary wireless transceiver106. The primary wireless transceiver106includes circuitry and related programming/instructions to support a wireless network stack. As shown, the primary wireless transceiver106includes network formation circuitry108configured to establish a wireless network between the primary wireless transceiver106in communication with the controller102and a secondary wireless transceiver (e.g., the secondary wireless transceiver116inFIG.1) in communication with or part of a given subsystem. The primary wireless transceiver106also includes data transfer circuitry110configured to perform data transfers between the primary wireless transceiver106and a secondary wireless transceiver (e.g., the secondary wireless transceiver116inFIG.1). As shown, the primary wireless transceiver106further includes resynchronization circuitry111. The resynchronization circuitry111is configured to support resynchronization of a secondary wireless transceiver (e.g., the secondary wireless transceiver116inFIG.1) with an established wireless network within a target time interval.

In the example ofFIG.1, the secondary communication circuit114may be an IC that includes the secondary wireless transceiver116. The secondary wireless transceiver116includes circuitry and related programming/instructions to support a wireless network stack. As shown, the secondary wireless transceiver116includes network formation circuitry118configured to establish a wireless network between the secondary wireless transceiver116in communication with a given monitor circuit122and the primary wireless transceiver106in communication with the controller102. As another option, the secondary wireless transceivers of different subsystems may communicate wirelessly with each other as part of an established wireless network. The secondary wireless transceiver116also includes data transfer circuitry120configured to perform data transfers between the secondary wireless transceiver116and the primary wireless transceiver106. As another option, data transfers occur between the secondary wireless transceivers of different subsystems.

As shown, the secondary communication transceiver116further includes the resynchronization circuitry121. The resynchronization circuitry121is configured to resynchronize the secondary wireless transceiver116with an established wireless network within a target time interval. Example resynchronization operations include identifying if the secondary communication transceiver116is in an active state or a reset state. If the secondary communication transceiver116is in the active state, resynchronization options may include using a configuration channel or data channel within a frequency hopping schema of the established wireless network to resynchronize the secondary wireless transceiver with the established wireless network. If the secondary wireless transceiver116is in the reset state, resynchronization options may include: scanning multiple channels within a frequency hopping schema of the established wireless network to identify an active channel; and resynchronizing the secondary wireless transceiver116with the established wireless network based on the identified active channel.

In some example embodiments, resynchronization circuitry (e.g., the resynchronization circuitry121) is configured to: identify the secondary wireless transceiver as being in an active state or a reset state; and if the secondary wireless transceiver is identified as being in an active state, use a configuration channel within a frequency hopping schema of the established wireless network to resynchronize the secondary wireless transceiver with the established wireless network. In such example embodiments, the resynchronization circuitry is configured to: switch to a next available configuration channel within the frequency hopping schema in response to the secondary wireless transceiver losing synchronization with the established wireless network; and wait in a receive mode at the next available configuration channel until a next packet is received from the primary wireless transceiver.

In some example embodiments, resynchronization circuitry (e.g., the resynchronization circuitry121) is configured to: identify the secondary wireless transceiver as being in an active state or a reset state; and if the secondary wireless transceiver is identified as an active state, use a data channel within a frequency hopping schema of the established wireless network to resynchronize the secondary wireless transceiver with the established wireless network. In such example embodiments, resynchronization circuitry is configured to: estimate a number of missed superframes of the established wireless network in response to the secondary wireless transceiver losing synchronization with the established wireless network; and use the estimated number of missed superframes to resynchronize the secondary wireless transceiver with the established wireless network. A superframe is discussed below.

In some example embodiments, resynchronization circuitry (e.g., the resynchronization circuitry121) is configured to: identify the secondary wireless transceiver as being in an active state or a reset state; if the secondary wireless transceiver is identified as being in a reset state, scan multiple channels within a frequency hopping schema of the established wireless network to identify an active channel; and resynchronize the secondary wireless transceiver with the established wireless network based on the identified active channel. In such example embodiments, the resynchronization circuitry is configured to scan all channels within the frequency hopping schema within the target time interval. As another option, scanning the channels within a frequency hopping schema of the established wireless network to identify an active channel may be performed when the secondary wireless transceiver is identified as being in an active state.

FIG.2is a block diagram of another system200in accordance with an example embodiment. With the system200, wireless management of subsystems222A-222N (examples of the subsystems112A-112N inFIG.1) is provided with resynchronization options within a target time interval as described herein. InFIG.2, the system200includes a lower voltage domain202(e.g., 12, 24, or 48 volts) with control circuitry204. Meanwhile, the subsystems222A-222N are in a higher voltage domain203(e.g., several hundreds of volts) compared to the control circuitry204. As shown, the control circuitry204includes a microcontroller102A (an example of the controller102inFIG.1) and a primary communication circuit104A (an example of the primary communication circuit104inFIG.1). The control circuitry204may also include a communications bridge208between the microcontroller102A and the primary communication circuit104A. In the example ofFIG.2, a main electronic control unit (ECU)250for the system200is coupled to the control circuitry204via a communication interface130A (an example of the communication interface130inFIG.1). In operation, the primary communication circuit104A is configured to perform primary wireless transceiver operations, including resynchronization operations for an active wireless transceiver and/or a reset wireless transceiver as described herein.

As shown, the subsystem222A includes a module230A. The module230A may include a PCB with a secondary communication circuit114A (an example of the secondary communication circuit114inFIG.1), a monitor circuit122A (an example of the monitor circuit122inFIG.1), and an adjustment controller124A (an example of the adjustment controller124inFIG.1). The module230A is coupled to a monitored electrical component126A (an example of the monitored electrical component126inFIG.1). The subsystems222B-222N each include a respective module230B-230N coupled to a respective monitored electrical component126B-126N. In some example embodiments, the monitored electrical components126A-126N are rechargeable batteries or other components with a variable status. Without limitation, each the modules230B-230N include the same type of components (e.g., a secondary communication circuit, a monitor circuit, and an adjustment controller) as the module230A.

InFIG.2, the secondary communication circuit114A is configured to perform secondary wireless transceiver operations, including active wireless transceiver resynchronization operations and/or reset wireless transceiver resynchronization operations as described herein. Also, the monitored electronic components126A-126N may be coupled together to provide a combined function. As shown, the system200includes switches240,242, and component245. In some example embodiments, the component245is a motor/engine. In this case, closing the circuit at switches240and242results in current flowing through the engine/motor to operate a vehicle. When the vehicle is parked or turned off, the switches240and242are open. In the example ofFIG.2, the switches240and242are controlled by a control signal252from the microcontroller102A. The control signal252is conveyed to the switches240and242, for example, via interface216. In the example ofFIG.2, the microcontroller102A may also receive a current sense signal248via interface218, where the current sense signal248is generated from a loop244or related sensor246.

In operation, the primary communication circuit104A is configured to send data to and receive data from the microcontroller102A via a wired coupling (e.g., the communications bridge208). The primary communication circuit104A is also configured to send data to and receive data from one or more of the secondary communication circuits114A-114N via respective wireless communication channels (not shown). In some example embodiments, resynchronization operations are performed as needed. As an example, the primary communication circuit104A may support configuration channels within a frequency hopping schema of an established wireless network. Such configuration channels enable secondary communication circuits that lose synchronization with an established wireless network to resynchronize within a target time interval.

Also, each of the secondary communication circuit114A-114N is configured to send data to and receive data from a respective monitor circuit122A-122N via a respective wired couplings115A-115N (examples of the wired coupling115inFIG.1). Each of the secondary communication circuits114A-114N is also configured to send data to and receive data from the primary communication circuit104A and/or another of the secondary communication circuits114A-114N via wireless communication channels (not shown). In some example embodiments, resynchronization operations as performed as needed by one or more of the secondary communication circuits114A-114N. Without limitation, example resynchronization operations include identifying if a secondary wireless transceiver is in an active state or a reset state. If the secondary wireless transceiver is in the active state, resynchronization options may include using a configuration channel or data channel within a frequency hopping schema of the established wireless network to resynchronize the secondary wireless transceiver with the established wireless network. If the secondary wireless transceiver is in the reset state, resynchronization options may include: scanning multiple channels within a frequency hopping schema of the established wireless network to identify an active channel; and resynchronizing the secondary wireless transceiver with the established wireless network based on the identified active channel.

FIG.3Ais a diagram of a wireless management network protocol300in accordance with an example embodiment. The protocol300supports data transfers between a primary wireless transceiver (e.g., the primary wireless transceiver106inFIG.1) and secondary wireless transceivers (each secondary wireless transceiver116inFIG.1) in a system (e.g., the system100inFIG.1, or the system200inFIG.2) with managed subsystems.

InFIG.3A, time is divided into slots and the primary wireless transceiver transmits packets in the downlink (DL) slot, while the secondary wireless transceivers transmit their packets in respective uplink (UL) slots. The time interval that includes a single DL slot (for the primary wireless transceiver to transmit packets) and all UL slots (for each secondary wireless transceivers to transmit packets) is called a superframe interval. In the wireless management network protocol300, one superframe is represented. Over time, the wireless management network protocol300may use a plurality of such superframes (one superframe after another superframe, etc.) to support data transfers between: 1) a primary wireless transceiver and a secondary wireless transceiver; or 2) a secondary wireless transceiver and another secondary wireless transceiver. WhileFIG.3Ashows data communications involving multiple secondary wireless transceivers, there are scenarios (e.g., in a scanning/joining phase) when only the primary wireless transceiver and a single secondary wireless transceiver exchange information that is needed for the secondary wireless transceiver to join a network.

In the wireless management network protocol300, resynchronization operations are performed as needed. Without limitation, example resynchronization operations include identifying if a secondary wireless transceiver is in an active state or a reset state. If the secondary communication transceiver is in the active state, resynchronization options may include using a configuration channel or data channel within a frequency hopping schema of the established wireless network to resynchronize the secondary wireless transceiver with the established wireless network. If the secondary wireless transceiver is in the reset state, resynchronization options may include: scanning multiple channels within a frequency hopping schema of the established wireless network to identify an active channel; and resynchronizing the secondary wireless transceiver with the established wireless network based on the identified active channel.

An overview of some example resynchronization options is now given. First, a secondary wireless transceiver can be in one of two states, an active state or a reset state, when synchronization is lost. Since the conditions surrounding these two states vary, they are treated as separated events with different resynchronization procedures.

Active device resynchronization occurs when the following conditions are met: 1) the secondary wireless transceiver is in an active state (i.e., the secondary wireless transceiver was not been reset); 2) a wireless network between the primary wireless transceiver and the secondary wireless transceiver has already been established; 3) the wireless network is assumed to still be active (i.e. the primary wireless transceiver is still transmitting to the secondary wireless transceivers); 4) the secondary wireless transceiver has maintained the frequency hopping schema of the established wireless network; and 5) the secondary wireless transceiver has lost synchronization with the primary wireless transceiver (i.e., no other errors have occurred).

One active wireless transceiver resynchronization option is to use configuration channels. For this option, a frequency hopping schema is selected by the primary wireless transceiver and a related frequency hopping table or other data structure is distributed to the secondary wireless transceivers during network formation. Since the configuration channels are a small subspace of the available channels, one resynchronization option inserts the configuration channels in the frequency hopping schema. For example, in the WBMS protocol, there are 40 total channels split into 37 data channels and 3 configuration channels. Therefore, after the frequency hopping table is generated by the primary wireless transceiver using only the data channels, the configuration channels are inserted at even spaces into the frequency hopping schema as shown inFIG.3B.

FIG.3Bis a diagram320of transceiver resynchronization using configuration channels in accordance with an example embodiment. In the example ofFIG.3B, a configuration channel is inserted at every fifth index of the frequency hopping schema. When a secondary wireless transceiver loses synchronization, the secondary wireless transceiver will switch to the next configuration channel and wait in receive mode until the next packet is received from the primary wireless transceiver. However, if the secondary wireless transceiver loses synchronization in the last data channel before a configuration channel, the drift may cause the secondary wireless transceiver to miss the resynchronization packet. Therefore, the secondary wireless transceiver may switch to the subsequent configuration channel if needed. UsingFIG.3Bas an example, if a secondary wireless transceiver loses synchronization while in data channel 9, the secondary wireless transceiver will wait in configuration channel 2. However, if the secondary wireless transceiver loses synchronization in data channel 15, the secondary wireless transceiver will skip configuration channel 2 and will wait in configuration channel 1 to receive the next packet from the primary wireless transceiver.

In some example embodiments, the maximum resynchronization delay is given as:
maximum delay=tsf(TCC+1),  Equation (1)
where TCCis the period of the configuration channels and tsfis the superframe time. The maximum delay is thus proportional to the frequency of configuration channels in the frequency hopping schema. However, if the configuration channels are used by other wireless devices they could suffer from increased interference. Additionally, if the configuration channels are only used for resynchronization, inserting the configuration channels into the frequency hopping schema also creates dead time for the synchronized wireless transceivers and data transmission delays. The next resynchronization option addresses the potential limitations of using configuration channels in the frequency hopping schema for resynchronization.

Another active wireless transceiver resynchronization option is to use data channels of the frequency hopping schema for resynchronization. With this option, configuration channels are not needed for resynchronization. Instead, a secondary wireless transceiver maintains the time elapsed (telapsed_since_sync) since the last primary wireless transceiver packet was received. In some example embodiments, the value of tsyncas well as tsfand the maximum drift (tmax_drift) are used to approximate the total drift (ttotal_drift) as:

In some example embodiments, ttotal_driftis used to approximate the number of missed superframes (nsf) as well as the next frequency (channelnext) that a secondary wireless transceiver should use for resynchronization. More specifically, nsfmay be calculated as:

nsf=ttotal⁢drift+telapsedSincesynctsf.Equation⁢(3)
In some example embodiments, channelnextis calculated as:
channelnext=frequency hopping table[index of (channellast)+nsf)].  Equation (4)
Accordingly, the maximum delay is based on ttotal_driftand the number of missed superframes before a secondary wireless transceiver begins resynching. For example, assuming ttotal_driftis less than one superframe and two missed packets from the primary wireless transceiver triggers a secondary wireless transceiver to start resynchronization, the maximum delay would be three superframes. This second resynchronization approach decreases the amount of dead time in the frequency hopping schema and has a faster resynchronization time compared to using configuration channels for resynchronization.

In some example embodiments, reset wireless transceiver resynchronization is performed when the following conditions are met: 1) the secondary wireless transceiver has been reset; 2) communication between the primary wireless transceiver and the secondary wireless transceiver has already been established; 3) the established network is assumed to still be active (i.e., the primary wireless transceiver is still transmitting to the secondary wireless transceivers); and 4) the secondary wireless transceivers retained the network configuration from the last connection.

Using the previous network information, a reset secondary wireless transceiver can intelligently scan through multiple channels during each superframe to determine the active channel and resynchronize to the established network. The scan time is defined as the amount of time the lost secondary wireless transceiver needs to scan a channel to determine if the network is active on that channel. To determine the active channel, the following information may be stored in memory (e.g., non-volatile memory): the frequency hopping schema, tsf, and the guard time (tguard) before the primary wireless transceiver transmits at the beginning of each superframe. In some example embodiments, tguardalong with the symbol rate (ds), the number of preamble symbols (sp), the number of syncword symbols (ss), and a buffer time (tbuffer) are used to calculate the scan time (tscan) as:
tscan=tguard+ds(sp+ss)+tbuffer.  Equation (5)
In some example embodiments, a lost secondary wireless transceiver will scan through the channels using the frequency hopping schema information stored in memory. The number of channels (nchannels) that can be scanned in one superframe is based on tscanand the size of the superframe. In some example embodiments, nchannelsis calculated as:

nchannels=tsftscan.Equation⁢(6)
The maximum number of superframes (nsf) it takes for a reset wireless transceiver to resynchronize to the established network depends on the number of data channels (ndata) that can be scanned during each superframe. In some example embodiments, nsfis calculated as:

nsf=ndatanchannels+1.Equation⁢(7)
For example, if 10 channels can be scanned in one superframe and there are 20 data channels, then the reset secondary wireless transceiver will resynchronize to the established network within three superframes. This approach allows a reset secondary wireless transceiver to resynchronize with an established network in a decreased number of superframes and this enables the network to continue operating while complying with the target time interval.

FIG.4is a diagram of a WBMS400in accordance with an example embodiment. As shown, the WBMS400includes battery cells402A-402H (e.g., Li-ion cells) in series. Each of the battery cells402A-402H is coupled to a respective module404A-404H (examples of the modules230A-230N inFIG.2) to form respective subsystems (e.g., the battery cell402A and the module404A is an example of a subsystem as described herein). The modules404A-404H may perform monitoring, adjustment, data transfers, and/or resynchronization operations as described herein.

In the example ofFIG.4, the WBMS400includes control circuitry204A (an example of the control circuitry204inFIG.2) with a microcontroller102B (an example of the controller102inFIG.1, or the microcontroller102A inFIG.2), a primary communication circuit104B (an example of the primary communication circuit104inFIG.1, or the primary communication circuit104A inFIG.2), and a communication interface130B (an example of the communication interface130inFIG.1, or the communication interface130A inFIG.2). In the example ofFIG.4, the microcontroller102B and the primary communication circuit104B communicate via a wired transceiver protocol such as a Universal Asynchronous Receiver-Transmitter (UART) protocol, a serial peripheral interface (SPI) protocol, or other wired transceiver protocol. Also, the communication interface130B may be a vehicle communication interface such as a controller area network (CAN) interface, an Ethernet interface, or other communication interface. As shown, the control circuitry204A is coupled to an antenna408for wireless communications with the modules404A-404H. In operation, the primary communication circuit104B is configured to perform wireless data transfers and resynchronization operations as described herein.

With the WBMS400, the functionality of the battery cells402A-402H is combined and the combined functionality of all of the battery cells402A-402H is monitored and adjusted as needed. For example, the performance of the battery cells402A-402H may degrade over time. In such case, adjustment or replacement of a specific one of the battery cells402A-402H or other components of the modules404A-404H may be needed. By using the primary communication circuit104B and the secondary communication circuits414A-414H for wireless data transfers between the microcontroller102B and modules404A-404H such replacement is facilitated while supporting monitoring, adjustment, status update, parameter transfer, and/or other operations related to the battery cells402A-402H. The use of resynchronization operations with the WBMS400ensures wireless communications for battery management system operations comply with a target time interval (e.g., a safety standard). Without limitation, example resynchronization operations include identifying if a secondary wireless transceiver is in an active state or a reset state. If the secondary communication transceiver is in the active state, resynchronization options may include using a configuration channel or data channel within a frequency hopping schema of the established wireless network to resynchronize the secondary wireless transceiver with the established wireless network. If the secondary wireless transceiver is in the reset state, resynchronization options may include: scanning multiple channels within a frequency hopping schema of the established wireless network to identify an active channel; and resynchronizing the secondary wireless transceiver with the established wireless network based on the identified active channel.

FIG.5is a block diagram of a BMU502and a CMU522in accordance with an example embodiment. In some example embodiments, the BMU502and the MCU522are part of a BMS, such as a WBMS, for a system (e.g., the system100inFIG.1, the system200inFIG.2, or the WBMS400inFIG.4). The MCU502may include, for example, a PCB or other unit with a safety microcontroller504(an example of the controller102inFIG.1, the microcontroller102A inFIG.2, of the microcontroller102B inFIG.4) and a communication circuit506(e.g., the primary communication circuit104inFIG.1, the primary communication circuit104A inFIG.2, or the primary communication circuit104B inFIG.4) coupled to each other via a wired coupling105A (an example of the wired coupling105inFIG.1). The microcontroller504is also coupled to a vehicle network via communication interface540(an example of the communication interface130inFIG.1, the communication interface130A inFIG.2, or the communication interface130B inFIG.4).

In the example ofFIG.5, the communication circuit506includes resynchronization circuitry111A (an example of the resynchronization circuitry111inFIG.1). The communication circuit506may additionally include other components such as those described for the primary communication circuit104inFIG.1. In some example embodiments, the communication circuit506is configured to perform the operations described for the primary communication circuit104inFIG.1, the primary communication circuit104A inFIG.2, or the primary communication circuit104B inFIG.4.

The CMU522may include, for example, a PCB or other unit with a monitor circuit538(an example of the monitor circuit122inFIG.1, or one of the monitor circuits122A-122N inFIG.2) and a communication circuit526(e.g., the secondary communication circuit114inFIG.1, one of the secondary communication circuits114A-114N inFIG.2, or one of the secondary communication circuits114A-114H inFIG.4) coupled to each other via a wired coupling115A (an example of the wired coupling115inFIG.5).

In the example ofFIG.5, the communication circuit526includes resynchronization circuitry121A (an example of the resynchronization circuitry121inFIG.1). The communication circuit526may additionally include other components such as those described for the secondary communication circuit114inFIG.1. In some example embodiments, the communication circuit526is configured to perform the operations of the secondary communication circuit114inFIG.1, one of the secondary communication circuits114A-114N inFIG.2, or one of the secondary communication circuit114A-114H inFIG.4.

In the example ofFIG.5, the wireless connection between the communication circuits506and526is referred to as a black channel516because the wireless connection does not comply with standards of the safety microcontroller504and the monitor circuit538. In order to ensure communications between the safety microcontroller504and the monitor circuit538comply with a communications latency standard, the communication circuit506includes the resynchronization circuitry111A and the communication circuit526includes the resynchronization circuitry121A. Without limitation, example resynchronization operations include identifying if a secondary communication transceiver is in an active state or a reset state. If the secondary communication transceiver is in the active state, resynchronization options may include using a configuration channel or data channel within a frequency hopping schema of the established wireless network to resynchronize the secondary wireless transceiver with the established wireless network. If the secondary wireless transceiver is in the reset state, resynchronization options may include: scanning multiple channels within a frequency hopping schema of the established wireless network to identify an active channel; and resynchronizing the secondary wireless transceiver with the established wireless network based on the identified active channel.

As another option, a secondary wireless transceiver in an active state may initiate resynchronization in response to missing a predefined number of primary wireless transceiver downlinks. As another option, a secondary wireless transceiver in a reset state may detect a start-up sequence after reset based on a valid non-volatile memory space. If the reset was manually triggered, a flag could be used to initiate resynchronization. As another option, if the reset was not manually triggered, the secondary wireless transceiver may scan the configuration channels within the frequency hopping schema of the established wireless network to detect if an active network formation sequence is ongoing. If not, the secondary wireless transceiver can switch to resynchronization using the data channels (e.g., based on received signal strength indication or “RSSI” sensing). If the secondary wireless transceiver then detects the correct channel and the primary wireless transceiver ID does not match, the second wireless transceiver may perform normal pairing operations.

In some example embodiments, a secondary wireless transceiver detects its reset state based on a valid non-volatile memory space. In a scenario where the non-volatile memory space of the secondary wireless transceiver is not valid, the primary wireless transceiver may eventually restart the network (e.g., after a prolonged duration, after an expected maximum time allowed for a secondary wireless transceiver to resynchronize, and/or after a command from the safety microcontroller).

FIG.6is a diagram of a communication circuit600(an example of the primary communication circuit104inFIG.1, the primary communication circuit104A inFIG.2, the primary communication circuit104B inFIG.4, the communication circuit506inFIG.5, the secondary communication circuit114inFIG.1, one of the secondary communication circuits114A-114N inFIG.2, one of the secondary communication circuits114A-114H inFIG.4, or the communication circuit526inFIG.5) in accordance with an example embodiment. As shown, the communication circuit600includes a main central processing unit (CPU)602, a Joint Test Action Group (JTAG) interface604, read-only memory (ROM)606, Flash memory608, and static random-access memory (SRAM)610.

The communication circuit600also includes a radio frequency (RF) core612(e.g., to provide the primary wireless transceiver106or the secondary wireless transceiver116inFIG.1). In the example ofFIG.6, the RF core612includes a transit chain614and a receive chain616coupled to antenna terminals615and617. The receive chain616is coupled to a sampler618, which outputs samples of received data to analog-to-digital converters (ADCs)620and622. The digitized samples are provided to a digital signal processor (DSP) modem626. As shown, the transmit chain614and the sampler618are also coupled to a digital phase-locked loop (PLL)624to manage timing of receive operations and/or transmit operations. Other example components of the RF core612include a processor628, SRAM630, and ROM632.

As shown, the communication circuit600also includes hardware peripherals and modules640. Without limitation, examples of the hardware peripherals and modules640include: serial communications interfaces (e.g., I2C, I2S, SPI, etc.); one or more UARTs, a direct memory access (DMA) interface; general programmable input/outputs (GPIOs); an encryption module (e.g., AES-256); a hashing module (e.g., SHA2-512); timers; an error correction code (ECC) module; a cryptosystem module (e.g., RSA); a watchdog timer; and a real-time clock (RTC) module.

In the example ofFIG.6, the communication circuit600further includes circuitry650such as a low-dropout regulator (LDO), clocks, references, and a direct-current to direct-current (DC/DC) converter. In some example embodiments, the communication circuit600also includes a sensor interface660with various components to support sensor operations. Without limitation, example components of the sensor interface660include: a sensor controller; a digital-to-analog converter (DAC), an ADC, a comparator, a digital sensor interface (IF), a capacitive touch IF, a time-to-digital converter, and SRAM. With the communication circuit600, a wired transceiver (e.g., the UART or SPI modules of the hardware peripherals and modules640) and a wireless transceiver (e.g., the RF core612) are configured to perform network formation, data transfer, and resynchronization as described herein.

In some example embodiments, a secondary wireless transceiver (e.g., the secondary wireless transceiver116inFIG.1, or related components of the communication circuit600inFIG.6) is configured to: identify a resynchronization trigger; and perform resynchronization with the established wireless network in response to the identified resynchronization trigger within a target time interval. In some example embodiments, if the secondary wireless transceiver is in as an active state, the secondary wireless transceiver is configured to use a configuration channel within a frequency hopping schema of the established wireless network to resynchronize with the established wireless network. In such embodiments, the secondary wireless transceiver is configured to: switch to a next available configuration channel within the frequency hopping schema in response to losing synchronization with the established wireless network; and wait in a receive mode at the next available configuration channel until a next packet is received from the primary wireless transceiver.

In some example embodiments, if the secondary wireless transceiver is in as an active state, the secondary wireless transceiver is configured to use a data channel within a frequency hopping schema of the established wireless network to resynchronize with the established wireless network. In such example embodiments, the secondary wireless transceiver is configured to: estimate a number of missed superframes of the established wireless network in response to losing synchronization with the established wireless network; and use the estimated number of missed superframes to resynchronize the secondary wireless transceiver with the established wireless network.

In some example embodiments, if the secondary wireless transceiver is in a reset state, the secondary wireless transceiver is configured to: scan multiple channels within a frequency hopping schema to identify an active channel; and resynchronize with the established wireless network based on the identified active channel. In such example embodiments, the secondary wireless transceiver is configured to scan all channels within the frequency hopping schema within the target time interval.

FIG.7is a flowchart of a communication circuit method700in accordance with an example embodiment. The method700is performed, for example, by a communication circuit (e.g., the primary communication circuit104inFIG.1, the primary communication circuit104A inFIG.2, the primary communication circuit104B inFIG.4, the communication circuit506inFIG.5, the secondary communication circuit114inFIG.1, one of the secondary communication circuits114A-114N inFIG.2, one of the secondary communication circuits114A-114H inFIG.4, or the communication circuit526inFIG.5) between a controller and a subsystem (see e.g.,FIG.1). As shown, the method700includes establishing a wireless network with another communication circuit to transfer data between the controller and the subsystem at block702. At block704, a resynchronization trigger is identified. At block706, resynchronization with the established wireless network is performed within a target time interval in response to the identified resynchronization trigger.

In some example embodiments, performing resynchronization at block706includes: identifying an active wireless transceiver state; and in response to identifying the active wireless transceiver state, using a configuration channel within a frequency hopping schema of the established wireless network to resynchronize with the established wireless network. In such example embodiments, performing resynchronization may include switching to a next available configuration channel within the frequency hopping schema in response to losing synchronization with the established wireless network; and waiting in a receive mode at the next available configuration channel until a next packet is received from the primary wireless transceiver.

In some example embodiments, performing resynchronization at block706includes: identifying an active wireless transceiver state; and in response to identifying the active wireless transceiver state, using a data channel within a frequency hopping schema of the established wireless network to resynchronize with the established wireless network. In such example embodiments, performing resynchronization includes: estimating a number of missed superframes of the established wireless network in response to losing synchronization with the established wireless network; and using the estimated number of missed superframes to resynchronize the secondary wireless transceiver with the established wireless network.

In some example embodiments, performing resynchronization at block706includes: identifying a reset wireless transceiver state; in response to identifying the reset wireless transceiver state, scanning multiple channels within a frequency hopping schema to identify an active channel; and resynchronizing with the established wireless network based on the identified active channel. In such example embodiments, the secondary wireless transceiver is configured to scan all channels within the frequency hopping schema within the target time interval.