Analogue front-end circuit for a battery system

Abstract

An analogue front-end circuit for a battery system has a circuit input configured for electrical connection to a voltage output of a battery of the battery system, a DC / DC converter configured to convert a DC input voltage applied to the circuit input and supplied by the battery into an AC link voltage, different from the DC input voltage, and a plurality of output channels each electrically coupled to the DC / DC converter. The DC / DC converter has an input side electrically coupled to the circuit input and an output side electrically coupled to a plurality of output channels. Each output channel has a respective analogue front-end unit configured to receive energy from the DC / DC converter for the supply thereof and to determine a battery state of the battery when the circuit input is electrically coupled to the voltage output of the battery.

Description

[0001] 120463P1488PC

[0002] ANALOG FRONTEND CIRCUIT FOR A BATTERY SYSTEM

[0003] The present invention relates to an analog front-end circuit for a battery system, for example a battery system for a photovoltaic system.

[0004] Battery systems, particularly those based on multiple lithium-ion batteries as battery cells, regularly include a battery management system (BMS) in addition to the battery cells. The BMS's tasks typically include the unified monitoring, control, and coordination of the battery cells within the system. The battery management system, in turn, primarily comprises other components such as a battery management chip (BMIC), an embedded microprocessor, and embedded software, as well as an analog front end (AFE). The AFE can be divided into several analog front-end units (AFEx, with x = 1, 2, ...), each of which individually or cumulatively provides the function(s) of an AFE.

[0005] An analog front end (AFE) in a battery system is responsible for acquiring and processing analog signals from the battery, particularly from its individual cells, and converting them into a format suitable for further digital processing. The tasks of an AFE in a battery system typically include one or more of the following functions: a) Voltage acquisition and measurement: The AFE measures the voltages across the individual battery cells. These measurements can then be used to monitor the state of charge (SoC) and / or the battery's state of health (SoH). b) Current measurement: Here, the AFE measures the current flowing into and out of the battery system. This data can, in turn, be used to calculate energy consumption and the remaining battery capacity.c) Temperature monitoring: This involves measuring the temperature of each battery cell to ensure the battery operates within safe conditions, as overheating can lead to damage or even dangerous situations. 120463P1488PC d) Signal conditioning: The AFE converts analog signals (e.g., voltage, current, temperature) into digital signals so they can be processed by a microcontroller or a battery management system (BMS). In addition to analog-to-digital conversion, this can include functions such as filtering and / or amplification. e) Isolation and protection: In some cases, the AFE can also provide isolation to ensure that high voltages, which may occur in the battery or individual battery cells, do not damage sensitive electronics within the battery system.

[0006] Overall, an AFE thus forms a component of a battery system that helps to provide the most accurate and reliable data possible about the condition and performance of the battery (battery condition data), which can be crucial for the safety and efficiency of the battery system.

[0007] Based on such battery status data, usually acquired in real time, the BMS can perform various protective functions, such as voltage protection, temperature protection, short-circuit protection, overcurrent protection, and insulation protection. The BMS can also be configured to perform additional functions related to the battery system. These additional functions might include voltage balancing management for battery cells or groups of battery cells, or external data communication. Data communication can specifically refer to data exchange with other battery systems or other components of a higher-level system. Such a higher-level system could be, for example, a plant that is battery-powered and / or uses the battery system as an energy storage system for energy supplied by the plant. Such a plant could, in particular, be or include a photovoltaic system.

[0008] Within an analog front end, several separate Analog Fronted Units (AFEx) can be used, each connected to only one group of battery cells. This group represents a true subset of all battery cells in the battery system controlled by the BMS, enabling the acquisition of battery state data. For example, systems are known where the number N of battery cells in the battery system is a multiple k of a specific smaller number m of battery cells, e.g., m = 16 (so that N = m ■ k), and each group of m adjacent battery cells has its own assigned AFEx. If the different AFEx have different power consumptions compared to each other, perhaps because their tasks differ at least partially, this generally leads to a correspondingly different load on the battery cell groups assigned to the respective AFEx.

[0009] Furthermore, each AFEx requires a regular supply voltage, specifically a DC supply voltage, which is significantly lower than the output voltage of a group of (usually series-connected) battery cells assigned to the respective AFEx. The resulting voltage conversion can be lossy, especially when performed conventionally using a regulating transistor.

[0010] It is an object of the invention to provide a circuit for supplying energy to an analog front end for a battery system (“analog front end circuit”), with which an energy-efficient supply of a plurality of analog front end units, AFEx, of the analog front end of the battery system can be achieved.

[0011] To solve this problem, an analog front-end circuit according to claim 1 is proposed. Various embodiments and further developments of the solution are the subject of the dependent claims.

[0012] terms

[0013] Some of the terms used herein to describe the present solution are explained in more detail below:

[0014] The terms “battery system”, battery management system (BMS), “analog front end” (AFE) and “analog front end unit” (AFEx) have already been introduced and explained previously.

[0015] The term “analog front-end circuit”, as used herein, refers to an electrical circuit that implements an analog front end (AFE) for a battery system and is configured to transfer electrical energy from a battery to multiple AFEx of the analog front end for power supply purposes.

[0016] The term "battery," as used herein, refers to an electrochemical storage device for electrical energy. For this purpose, a battery can, in particular, contain a plurality of galvanic cells (battery cells) as energy storage units. The battery cells can, in particular, be connected in series or parallel. Other circuit configurations are also possible. A "battery" can, in particular, be a battery module comprising several battery cells within a larger, overall battery system, which in turn comprises several such battery modules, each battery module having its own AFE (Automatic Energy Storage Unit).

[0017] The term "accumulator", as used herein, refers to a rechargeable battery.

[0018] The term "DC / DC converter," as used herein, refers to a DC-DC converter; that is, an electrical circuit that converts an input DC voltage into a DC voltage with a higher, lower, or inverted voltage level. Within the scope of this solution, DC / DC converters that reduce the input voltage to a lower voltage level are particularly suitable.

[0019] The term "electrically coupled," or simply "coupled," and variations thereof as used herein, refers to a current-conducting electrical connection intentionally present within an electrical circuit, for example, by means of a conductor on a printed circuit board or by means of a cable. The connection between two components of the circuit can be direct (i.e., without any intervening components, such as passive or active elements) or indirect via one or more other components of the circuit, whereby mere electrical conductors are not considered "components" in this context. Unintended electrical connections, such as short circuits, shunts, or current paths of any leakage currents (e.g., in the event of defects or degradation), are not covered by the term "electrical coupling" as used herein.

[0020] The term "channel," as used herein, refers to a channel in an electrical circuit (circuit), in this case the analog front-end circuit, and denotes a continuous electrical connection between two points through which current can flow. It thus represents a possible current connection between various components such as resistors, capacitors, sources (like batteries or generators), and other components. A channel can take various forms, depending on whether it is a direct connection, part of a circuit, or a "detour" created by other circuit components, especially components such as resistors or capacitors. A 120463P1488PC

[0021] An "input channel" is a channel in an electrical circuit through which an input voltage or current is supplied to the circuit. Conversely, an "output channel" is a channel in the electrical circuit through which an output voltage or current is drawn from the circuit.

[0022] Any terms used herein, such as "comprises," "includes," "includes," "features," "has," "with," or any other variant thereof, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or features a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent in such method or apparatus.

[0023] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive "or" and not an exclusive "or". For example, a condition A or B is satisfied by any of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0024] The terms "ein" or "eine," as used here, are defined as "one or more." The terms "ein anderer" and "ein Weitere," as well as any other variant thereof, are to be understood as "at least one more."

[0025] The term "plural", as it may be used here, is to be understood in the sense of "two or more".

[0026] The terms "first", "second", "third", and similar terms in the description and claims are used to distinguish between similar or otherwise identically named elements and not necessarily to describe a sequential, spatial, or chronological order. It is understood that the terms used in this way are interchangeable under suitable circumstances and that the embodiments of the solution described herein may also function in orders other than those described or illustrated here.

[0027] The terms "configured" or "set up" to perform a specific function (and their respective variations), as used here, mean that a device or component thereof already exists in a configuration or setting capable of performing the function, or at least is adjustable—i.e., configurable—so that it can perform the function after appropriate adjustment. Configuration can be achieved, for example, by adjusting process parameters or by using switches or similar devices to activate or deactivate functionalities or settings. In particular, the device may have several predefined configurations or operating modes, allowing configuration by selecting one of these.

[0028] One aspect of the present solution concerns an analog front-end circuit for a battery system. The analog front-end circuit features:

[0029] (i) a circuit input configured for electrical connection to a voltage output of a battery of the battery system;

[0030] (ii) a DC / DC converter configured to convert a DC input voltage supplied by the battery, applied to the circuit input, into an intermediate AC voltage other than the DC input voltage; and

[0031] (iii) a plurality n of output channels each electrically coupled to the DC / DC converter.

[0032] The DC / DC converter has: an input side that is electrically coupled to the circuit input, and an output side that is electrically coupled to a plurality of output channels.

[0033] Each output channel has an analog front-end unit configured to receive power from the DC / DC converter to its supply and to determine the battery's state of charge when the circuit input is electrically coupled to the battery's voltage output.

[0034] In this analog front-end circuit, the battery's output voltage (as a whole) is converted into the intermediate AC voltage 120463P1488PC by a single DC / DC converter. The output side of the DC / DC converter then supplies the various output channels, particularly in parallel, and thus the different AFEx units with power. All AFEx units are therefore powered from the same arrangement of battery cells, and not, as is conventional, from separate groups of battery cells. This allows the power consumption of the AFEx units to be distributed evenly across the battery cells, even if the different AFEx units have different power consumption requirements, for example, because they perform different tasks within the AFE's task spectrum or perform their tasks at different times. This eliminates the need for additional balancing.Such a design can also contribute to more efficient use of the energy drawn from the battery. In particular, it can counteract the varying discharge times of different battery cell groups and thus optimize the overall battery discharge time.

[0035] The following describes various exemplary embodiments of the analog front-end circuit, which can be combined with each other as desired, unless this is expressly excluded or technically impossible.

[0036] In some embodiments, the DC / DC converter includes a switching regulator electrically coupled to the circuit input and a transformer. The transformer comprises a primary inductor, LP, electrically coupled to the switching regulator and a plurality of secondary inductors, Lsi, with each output channel having its own associated secondary inductor as a power source. The switching regulator thus forms a (single) input channel of the DC / DC converter, while its output supplies a corresponding number of output channels via the multiple secondary inductors. The transformer can, in particular, serve to reduce the battery output voltage to a lower intermediate AC voltage and simultaneously provide galvanic isolation of the output channels from the battery. This allows for larger turns ratios and thus correspondingly higher voltage reductions.The switching regulator serves to generate a transformable alternating voltage from the battery's DC output voltage by repeated, especially periodic, switching. It can be controlled, or be controllable, in particular via an optocoupler or a MOSFET. 120463P1488PC.

[0037] The DC / DC converter can have a dedicated rectifier for each output channel to rectify the AC voltage supplied by the respective secondary inductor. The rectifier can consist of a single diode or have a more complex design, in particular multiple diodes, for example as part of a rectifier bridge circuit.

[0038] Furthermore, each output channel of the DC / DC converter can include a low-dropout regulator (LDO) for converting the voltage supplied by the secondary inductor associated with the output channel and rectified by the output channel's rectifier to DC. The LDO is configured to supply power to the analog front-end unit of the output channel. Thus, a combination of the transformer and one LDO per output channel is used for DC conversion. While the transformer is particularly well-suited to supplying large voltage differences between its input and output voltages, the advantages of the downstream LDO lie primarily in its ability to provide good voltage stabilization (smoothing) within the conversion parameters it can perform.The transformer thus serves in particular to perform a first voltage conversion to a voltage level (intermediate AC voltage) at which the LDO can operate in a suitable operating range (lower voltage difference between its respective input and output voltages) during its subsequent, second voltage conversion, and in particular in a particularly energy-efficient manner.

[0039] The analog front-end circuit can be designed in particular as follows:

[0040] (i) to accept at most a certain maximum DC input voltage at the circuit input and

[0041] (ii) When this maximum DC input voltage is applied to the circuit input and the DC / DC converter is operated accordingly, the voltage drop at the associated LDO for each output channel is to be at most 50%, in particular at most 25%, of the rectified voltage supplied by the associated rectifier. In this way, the voltage drop, or correspondingly the voltage ratio between the voltages at the inputs and outputs of the LDO, is effectively limited so that the LDO can operate efficiently, and in particular energy-efficiently, within a favorable operating range. 120463P1488PC

[0042] The transformer can be designed such that, with respect to each of its secondary inductances Lsi, it has a respective turns ratio Uj between the number of turns NLP of LP and Ni_si of Lsi, for which Uj = NLP / Ni_si ≥ 10. This allows the transformer to bear the main load with respect to the DC / DC conversion, while the LDOs only need to generate a significantly smaller voltage difference per conversion. Consequently, they can operate efficiently, and especially energy-efficiently, within a favorable operating range, particularly with regard to voltage stabilization, in order to supply the associated AFEx with a substantially stable DC voltage.

[0043] In some embodiments, only a true, non-empty subset of the output channels is coupled to the switching regulator for feedback purposes, thus providing a control loop. In particular, exactly one of the output channels can be coupled to the switching regulator for feedback purposes. This minimizes the effort required to provide feedback for establishing control via the switching regulator. This is especially advantageous when the various output channels are at least largely identical in design, such that the voltage waveform of a voltage, particularly a DC voltage, detected as a controlled variable in one of the output channels is similar to, and in particular essentially identical to, that in the other output channel(s).

[0044] In some embodiments, the analog front-end circuit further comprises a controller configured to perform at least one of the following functions: (i) controlling a switching device configured to electrically couple or decouple the circuit input with the DC / DC converter, depending on its control; (ii) controlling at least one of the analog front-end units AFEx, in particular all of them. Option (i) can thus be used, in particular, to de-energize the DC / DC converter and all subsequent circuit components, such as the AFEx, whether for energy-saving standby operation, for maintenance purposes, or when the battery system is not in use. Other reasons are also conceivable.

[0045] Option (ii) offers the advantage that the AFEx controls and, if applicable, the control of the switching device can be efficiently combined in a single control unit. This allows, in particular, the control system to be designed so that at least parts of it can be used multiple times. For example, a circuit section of the control system, such as the same 120463P1488PC, can be used for multiple purposes.

[0046] The microprocessor can be configured to handle various control tasks, such as controlling multiple AFEx units, e.g., using time-division multiplexing.

[0047] In some embodiments, at least a first output channel Ki and a second output channel K2 are balanced such that, during operation of the analog front-end circuit, their respective power inputs Pi for Ki and P2 for K2 correspond at least to the extent that Pi = P2 (1 ± 0.1). Here, Pi and P2 can represent, in particular, time-dependent profiles (Pi,2(t)), maximum values ​​(Pi,2 = max(Pi,2(t)), or time-averaged average values ​​(Pi,2 = avg(Pi,2(t)) of the respective power inputs. Such balancing can be particularly advantageous if the various balanced output channels are redundantly designed, for example, to perform the same task(s) within the analog front-end circuit.

[0048] Alternatively, according to some other embodiments, at least a first output channel K1 and a second output channel K2 can be designed differently such that, during operation of the analog front-end circuit in at least one operating state, their respective power consumptions Pi for Ki and P2 for K2 differ from each other to such an extent that P2 > 1. Such a different design can be particularly advantageous if the different output channels have to perform different tasks within the analog front-end circuit in at least one operating state, which entail different power requirements. For example, the AFEx in the first output channel K1 could be configured for temperature measurement in addition to voltage measurement at its assigned battery cells, and the AFEx in the second output channel K2 could be configured for current measurement in addition to voltage measurement at its assigned battery cells.The associated measurement methods could and typically will have different power requirements.

[0049] In some embodiments, n = 2, meaning the analog front-end circuit has exactly two AFEx units. Accordingly, if there is one AFEx unit per output channel, the number of output channels can also be n = 2. This configuration is particularly suitable when the two AFEx units are to perform different tasks within the analog front-end circuit, although some of these tasks may overlap. For example, both AFEx units could be configured to perform voltage measurements (on their respective assigned battery cells) to monitor the battery, while one of the AFEx units is also configured to measure temperature. 120463P1488PC

[0050] In some embodiments, the analog front-end circuit further includes the battery, with the circuit input being electrically connected to the battery's voltage output. In this case, the analog front-end circuit can thus already encompass the entire battery system.

[0051] The battery can, in particular, comprise a plurality m of battery cells connected in series, for example, grouped into a battery cell stack. In this case, m = 32 is particularly suitable. When using lithium-ion battery cells, depending on the design and specific battery cell type (e.g., UCOO2, LiMnCh, LiFePCL, Li2FePO4F), nominal battery output voltages in the range of approximately 100 V to approximately 125 V can be achieved. Such a configuration can be particularly advantageous for battery systems used in photovoltaic applications.

[0052] Further advantages, features and application possibilities of the present solution will become apparent from the following detailed description in the context of the figures.

[0053] This shows:

[0054] Fig. 1 shows a battery system with an analog front-end circuit according to a first embodiment;

[0055] Fig. 2 shows a battery system with an analog front-end circuit according to a second embodiment, which is a special variant of the more general analog front-end circuit from Fig. 1, in which the DC / DC converter specifically includes a transformer for voltage conversion; and

[0056] Fig. 3 shows a battery system with an analog front-end circuit derived from Fig. 2 according to a third embodiment, in which the DC / DC converter additionally has an LDO for each output channel.

[0057] In the figures, identical reference symbols denote identical, similar, or corresponding elements. Elements depicted in the figures are not necessarily shown to scale. Rather, the various elements depicted in the figures are represented in such a way that their function and general purpose are understandable to a person skilled in the art. Connections and couplings between functional units and elements shown in the figures can, unless expressly stated otherwise, also be implemented as indirect connections or couplings. 120463P1488PC

[0058] Fig. 1 shows an exemplary embodiment of a battery system BS with an analog front-end circuit AFE. The battery system BS comprises a battery B with a plurality m of battery cells C1 ... Cm connected, in particular in series, which can be accumulator cells, for example of the lithium-ion type. For example, the battery B can contain thirty-two (m = 32) lithium-ion battery cells connected in series.

[0059] The voltage output of battery B is electrically connected to a circuit input of the AFE via the terminals ln+ and In, so that the AFE can be supplied with electrical energy from battery B via the circuit input.

[0060] Within the analog front-end circuit AFE, the circuit input is electrically coupled to an input side of a DC / DC converter W via a switch S, which is controllable by a controller CTRL. The DC / DC converter W is configured to convert an input DC voltage VE (in Fig. 1, VE » VB) applied to its input side into several secondary DC voltages at different, in particular lower, voltage levels. Specifically, the converter W is designed here as an example to have n = 2 output channels, here designated Ki and K2, each with a voltage output such that, during operation of the converter W, the voltage outputs supply a supply voltage si or s2 to the two output channels Ki and K2, respectively. The converter can, in particular, be configured such that the two supply voltages Vsi and Vs2 are, at least substantially, equal, i.e., that Vsi = Vs2 or at least Vsi ≤ Vs2.

[0061] Each of the output channels K1 and K2 contains an analog front-end unit AFEx, specifically AFE1 or AFE2, supplied by the respective supply voltage Vsi or Vs2.

[0062] The analog front-end units AFE1 and AFE2 are each configured individually (as shown) or at least cumulatively to measure, and in particular continuously monitor, the cell voltage Vq of an assigned subset of the set of m battery cells. Additionally, at least one of the AFEx units can be equipped with a function for measuring or otherwise determining the battery temperature. For this purpose, the battery B can have temperature sensors TS at various locations, which deliver a measurement signal characteristic of the respective local temperature to the assigned AFEx unit. Further functionalities of the AFEx units are also conceivable. Figure 1 shows, by way of example, a measurement of the battery current using a shunt (120463P1488PC).

[0063] The resistance R is illustrated, where the AFEi measures a voltage VR across the shunt resistance R, from which the battery current can be determined using Ohm's law if the resistance value of R is known.

[0064] The CTRL controller, which can be configured as a single unit (control unit), can additionally be configured to communicate with the AFEx, particularly to control the AFEx. This can be done in parallel for each AFEx or—as illustrated in Fig. 1—serially, such that only the first AFEx communicates with the CTRL controller and exchanges control signals, while the second and any subsequent AFEx can only communicate indirectly with the CTRL controller via the first AFEx or are controlled solely by the first AFEx. For this purpose, a communication link, in particular a wired (e.g., electrical or optical) communication link, exists between the first AFEx and the second and each subsequent AFEx.

[0065] To fulfill its tasks, the CTRL control system may in particular have a microcontroller unit (MCU), for example to generate control commands for controlling the AFEx and to output them to at least the first AFEx.

[0066] The measuring leads shown in Fig. 1 for measuring voltages and temperatures are not (or no longer) shown in Figures 2 and 3 for the sake of simplicity.

[0067] Fig. 2 shows a specific embodiment of the battery system BS from Fig. 1, in which the internal structure of the DC / DC converter W is defined in more detail. Specifically, the DC / DC converter W is transformer-based and, for this purpose, comprises a transformer T, a switching regulator SR, and a rectifier D for each output channel Ki or K2. The switching regulator SR is located on the input side of the DC / DC converter W and serves to convert the input DC voltage E into an input AC voltage to supply the primary side of the transformer T. On the secondary side, the transformer T has a secondary coil for each output channel Ki or K2. If these secondary coils have the same number of turns, the n transformer outputs will have correspondingly identical output AC voltages, which will be referred to below as the "intermediate AC voltage(s)" V. z be designated.

[0068] The rectifiers D serve to convert the intermediate alternating voltages V z to rectify the voltages so that the supply voltages Vsi and Vs2 can each be delivered as DC voltages to the 120463P1488PC. Suitable rectifiers include individual diodes or more complex rectifier circuits, such as rectifier bridges, etc.

[0069] From one of the two output channels, specifically output channel K2 in this example, a feedback loop Fb leads back to the switching regulator SR to close a control loop for its operation. The switching regulator SR can be controlled, in particular, by means of an optocoupler or a MOSFET transistor in the feedback loop Fb. This enables the SR to adjust its switching behavior, especially its switching frequency, depending on the supply voltage Vs2 present in the feedback output channel K2, thus achieving voltage regulation with respect to the supply voltage Vs2.

[0070] Due to the symmetrical design of the two secondary sides of the transformer T and the output channels K1 and K2 coupled to it, this single control loop or regulation is sufficient to simultaneously achieve a corresponding voltage regulation for the other supply voltage Vsi.

[0071] Fig. 3 shows another embodiment of a battery system BS with an analog front-end circuit derived from Fig. 2 according to a third embodiment, in which the DC / DC converter W additionally has a low-dropout regulator LDO for each output channel Ki or K2. The LDOs are also regulated DC-DC converters and serve to further stabilize, in particular to smooth, the intermediate AC voltage Vz rectified by the rectifier D in the respective output channel Ki or K2.

[0072] Overall, the AFE performs a DC-DC conversion of the input DC voltage VE, which essentially corresponds to the battery voltage VB. This conversion begins with a transformer-based DC / DC conversion, which can involve a significant voltage reduction. A second DC-DC conversion then takes place for each output channel via a downstream LDO, primarily to stabilize the supply voltage Vsi or Vs2 provided to the associated AFEx. Each LDO is controlled by a feedback signal Adj, output by the associated AFEx and dependent on the supply voltage Vsi or Vs2 applied to the respective AFEx, thus forming a control loop for that LDO. 120463P1488PC

[0073] In the specific example above, for a battery B with m = 32 lithium-ion battery cells, the battery voltage VB, and thus essentially also the input voltage Vß, can be approximately 100 V, while the intermediate AC voltage Vz is only about 7.5 V due to the voltage reduction by the transformer T. A supply voltage si or s2 of approximately 6 V can then be provided downstream of the LDO to power the AFEx.

[0074] The power supply for the two AFEx units is thus provided via a dual-channel DC / DC converter, which includes the switching regulator SR, the transformer T, and, for each channel, a rectifier D and an LDO, which is controlled by the corresponding AFEx with a feedback signal Adj. The LDO typically converts in a range of lower voltage drops than the transformer T (however, above its dropout voltage, below which it essentially only acts as a quasi-ohmic resistor and no longer regulates). Since the energy is drawn from the entire battery B, the cells are always loaded evenly, even if the load on the AFEx units differs, for example, due to their partially different tasks. This eliminates the need for additional balancing. Our DC / DC converter can be completely disconnected from battery B using the switch S, thereby reducing standby power consumption.

[0075] While at least one exemplary embodiment has been described above, it should be noted that a large number of variations exist. It should also be noted that the described exemplary embodiments are merely non-limiting examples, and it is not intended to restrict the scope, applicability, or configuration of the systems, devices, and methods described herein. Rather, the preceding description will provide the person skilled in the art with guidance for implementing at least one exemplary embodiment. It is understood that various modifications to the function and arrangement of the elements described in an exemplary embodiment can be made without deviating from the subject matter defined in the appended claims. 120463P1488PC

[0076] REFERENCE MARK LIST

[0077] Adjustable feedback loop for LDO

[0078] AFE Analog Front End Circuit

[0079] AFEx Analog Front End Unit, x = 1, 2 ...

[0080] B Battery or battery module, each with a plurality m of battery cells

[0081] BMS Battery Management System

[0082] BS battery system

[0083] C1...Cm battery cells of battery B

[0084] CTRL control or control unit

[0085] D Rectifier, especially diode, in the output channel

[0086] Fb feedback loop (control loop for switching regulator) ln+ positive pole of the circuit input of the AFE

[0087] In. negative pole of the AFE circuit input

[0088] AI, 2 output channels

[0089] LSI / 2 Secondary inductances of the transformer T

[0090] LP Primary inductance of the transformer T

[0091] LDO Low-Drop-out Regulator m Number of battery cells in battery B n Number of output channels

[0092] R resistance, in particular ohmic shunt resistance

[0093] S Switching device, in particular switches

[0094] SR switching regulator

[0095] TT transformer

[0096] VB Output voltage of battery B (battery voltage)

[0097] VE Input DC voltage of the DC / DC converter W

[0098] VR voltage across shunt resistance

[0099] Vsi / 2 Supply voltage of the associated AFEx z Intermediate AC voltage

[0100] W DC / DC converter (direct current converter)

Claims

120463P1488PC REQUIREMENTS 1. Analog front-end circuit (AFE) for a battery system (BS), wherein the analog front-end circuit (AFE) comprises: a circuit input (ln+, In-) configured for electrical connection to a voltage output of a battery (B) of the battery system (BS); a DC / DC converter (W) configured to convert an input DC voltage supplied by the battery (B) at the circuit input (ln+, In-) into an intermediate AC voltage (Vz) different from the input DC voltage; and a plurality n of output channels (Ki; K2) each electrically coupled to the DC / DC converter (W); wherein the DC / DC converter (W) comprises: an input side electrically coupled to the circuit input (ln+, In-) and an output side configured to electrically supply each of the output channels (Ki; K2) with energy supplied by the DC / DC converter (W) during its operation; and wherein each output channel (Ki;K2) each an analog front-end unit (AFE1; AFE2) is configured to receive power from the DC / DC converter (W) to supply it and to determine the battery state of battery (B) when the circuit input (ln+, In-) is electrically coupled to the voltage output of battery (B).

2. Analog front-end circuit (AFE) according to claim 1, wherein the DC / DC converter (W) comprises: a switching regulator (SR) electrically coupled to the circuit input (ln+, In-); a transformer (T) with a primary inductance, LP, electrically coupled to the switching regulator (SR), and a plurality of secondary inductances, Lsi, wherein an associated secondary inductance is arranged as an energy source in each of the output channels.

3. Analog front-end circuit (AFE) according to claim 2, wherein the DC / DC converter (W) has an associated rectifier (D) for each output channel (Ki; K2) for rectifying the alternating voltage supplied by the respective secondary inductor.

4. Analog front-end circuit (AFE) according to claim 3, wherein each output channel (Ki; K2) of the DC / DC converter (W) has a low-dropout regulator (LDO) for 120463P1488PC DC conversion of the voltage supplied by the secondary inductor associated with the output channel (Ki; K2) and rectified by the rectifier (D) associated with it of the output channel (Ki; K2), and the low-dropout regulator (LDO) is configured to supply electrical power to the analog front-end unit (AFE1; AFE2) of the output channel (Ki; K2).

5. Analog front-end circuit (AFE) according to claim 4, wherein the analog front-end circuit (AFE) is designed: to accept at most a certain maximum input DC voltage at the circuit input (ln+, In-); and when this maximum input DC voltage is applied to the circuit input (ln+, In-) and the DC / DC converter (W) is operated in conjunction with this, to cause a voltage drop at the associated low-dropout regulator (LDO) for each output channel (Ki; K2) which is at most 50%, in particular at most 25%, of the rectified voltage supplied by the associated rectifier (D).

6. Analog front-end circuit (AFE) according to any one of claims 3 to 5, wherein the transformer (T) has a respective turns ratio Uj between the turns NLP of LP and Ni_si of Lsi with respect to each of its secondary inductances Lsi, for which Uj = NLP / NLSI 10.

7. Analog front-end circuit (AFE) according to one of the preceding claims, wherein only a true, non-empty subset of the set of output channels (Ki; K2) is coupled to the switching regulator (SR) in a feedback manner to provide a control loop (Fb).

8. Analog front-end circuit (AFE) according to claim 7, wherein exactly one of the output channels (Ki; K2) is coupled to the switching regulator (SR) for providing the control loop (Fb).

9. Analog front-end circuit (AFE) according to any of the preceding claims, further comprising a controller (CTRL) configured to perform at least one of the following functions: Controlling a switching device (S) that is configured to electrically couple or decouple the circuit input (ln+, In-) with the DC / DC converter (W) depending on its control; 120463P1488PC Control at least one of the analog front-end units (AFEi; AFE2).

10. Analog front-end circuit (AFE) according to one of the preceding claims, wherein at least a first output channel K1 and a second output channel K2 are designed to be balanced such that, during operation of the analog front-end circuit (AFE), their respective power inputs Pi for Ki and P2 for K2 correspond at least to such an extent that Pi = P2 (1 ± 0,1) holds.

11. Analog front-end circuit (AFE) according to any one of claims 1 to 9, wherein at least a first output channel K1 and a second output channel K2 are designed differently such that, when the analog front-end circuit (AFE) is operated in at least one operating state, their respective power inputs Pi for Ki and P2 for K2 differ from each other to such an extent that Pi / P2 > 1 ,1 applies.

12. Analog front-end circuit (AFE) according to one of the preceding claims, wherein n = 2.

13. Analog front-end circuit (AFE) according to one of the preceding claims, further comprising the battery (B), wherein the circuit input (ln+, In-) is electrically connected to the voltage output of the battery (B).

14. Analog front-end circuit (AFE) according to claim 13, wherein the battery (B) comprises a plurality m of battery cells connected in series.

15. Analog front-end circuit (AFE) according to claim 14, wherein m = 32.

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