CIRCUIT ARRANGEMENT

Description

[0001] The invention relates to a circuit arrangement.

[0002] Circuit arrangements, such as current regulators, are used in a control cabinet. In a control cabinet, industrial loads are often supplied with a low-voltage direct current. The direct current network is fed from the mains voltage, for example, by one or more power supplies. In a direct current network, the supply energy is much more limited than in an alternating current network. For example, in modular systems or through simultaneous operation, the direct current network can become overloaded, resulting in failure or faulty operation of the system or individual components.

[0003] One cause of an overload can be a limitation caused by excessive charging energy from an energy storage device.

[0004] An energy storage module, such as an uninterruptible power supply (UPS) or a capacitor module, requires electrical energy to charge the energy storage module. This electrical energy is limited by an upstream component, such as a power supply or a fuse. Other components may also require fluctuating additional amounts of electrical energy. The energy storage device can be designed as a two-pole or four-pole device. To achieve greater availability of the electrical energy storage device, it is charged as quickly as possible. If too much electrical energy is required to charge the energy storage device, this limits the upstream energy source, usually resulting in a voltage drop. The input voltage is monitored to prevent overloading the upstream energy source. If the input voltage falls below a certain value, the charging process is aborted.

[0005] Another cause of an overload can be a limitation caused by connecting a capacitive load or a short circuit of a DC / DC converter.

[0006] A DC / DC converter converts the electrical input energy to suit one or more consumers. If a load is connected to the output, this can lead to a limitation of the DC / DC converter, particularly in the case of a large capacitive load. To keep the voltage drop as small as possible, the current limit is delayed, for example, or the converter can briefly deliver a significantly higher electrical output power for up to a few seconds. A brief peak current consumption or overload in the event of a fault can cause the converter to absorb a lot of energy. This can cause an unacceptably high voltage drop at the converter input. An upstream rectifier or power supply (AC / DC converter) or a DC / DC converter can reach the limit and reduce the output voltage, which can disrupt other consumers connected in parallel.

[0007] The loads connected to the power grid, for example, in the case of converters, are switched off by an input voltage monitor (VLO). Other loads continue to operate incorrectly and may issue incorrect signals. Upon restart, the load is switched on again, possibly supported by a soft-start device.

[0008] A direct current power supply is known from DE 10 2005 027 211 A1. The direct current power supply comprises a control unit, by means of which the voltage provided by an energy storage device can be converted essentially to the level of the specified compensation voltage. During normal operation, a battery charging circuit charges the energy storage device. A control unit monitors the input voltage via a connection. If this falls below a specified threshold, the control unit controls the control unit such that the specified compensation voltage remains constant at the output. For this purpose, energy from the energy storage device is utilized. However, phases of low energy demand are not used to charge the energy storage device.

[0009] The document WO 03 / 010877 A1 discloses a control system for a power converter and methods for controlling the operation of such a power converter.

[0010] The document US 5 399 956 A discloses a backup battery system for a portable electronic device.

[0011] The document EP 0 847 124 A1 discloses an emergency power supply device for provisional power supply in the event of a failure of the main power supply.

[0012] The document US 2002 / 126836 A1 discloses a circuit for comparing the relative powers of two signals and for providing an indication of the larger of the two signals.

[0013] US 2003 / 006650 discloses a multi-threshold regulator system 700 in Figure 7. The regulator system 700 includes a primary voltage regulator 602, a dynamic load 128, and a secondary voltage regulator 606.

[0014] It is therefore the object of the present invention to provide a circuit arrangement that reacts more flexibly to fluctuating energy requirements.

[0015] This object is achieved by the subject matter having the features according to the independent claims. Advantageous embodiments are the subject of the dependent claims, the description, and the drawings.

[0016] The present invention is based on the finding that operational reliability can be increased if the input voltage is compared with upper and lower threshold values and the output voltage is increased or reduced according to the comparison.

[0017] According to a first aspect, the object is achieved by a circuit arrangement according to claim 1.

[0018] This achieves the technical advantage that, by comparing the input voltage with an upper and lower threshold, it is detected that the output voltage has reached a critical value, at which point the output voltage is either increased or decreased. This allows an energy storage device to be charged with electrical energy when an upper threshold is exceeded, ensuring that a charged energy storage device is available when needed. This increases operational reliability.

[0019] According to the invention, if the input voltage (Uacc) is greater than the first upper threshold value (U1), the setpoint is increased and the first increasing device (112a) is switched on, thus increasing the output voltage by a first value. Furthermore, according to the invention, if the input voltage (Uacc) is greater than the second upper threshold value (U2), the setpoint is increased and the second increasing device (112b) is switched on, thus increasing the output voltage by a second value. This achieves the technical advantage that an increased output voltage is made available when a particularly high input voltage is available, with which an energy storage device can then be charged, for example.

[0020] In an advantageous embodiment, the circuit arrangement is configured to compare the value of the electrical output voltage with a maximum output voltage limit. If the comparison reveals that the value of the electrical output voltage is greater than the maximum output voltage limit, the output voltage value is set to the maximum output voltage limit or the circuit arrangement is shut down. This achieves the technical advantage that, by increasing the upper threshold value, the output voltage cannot assume values that lie above a maximum possible output voltage. This increases operational reliability.

[0021] According to the invention, if the input voltage (Uacc) is less than the first lower threshold (U3), the setpoint is reduced and the first reducing device (114a) is switched on, thus reducing the output voltage by a third value. Furthermore, if the input voltage (Uacc) is less than the second lower threshold (U4), the setpoint is reduced and the second reducing device (114b) is switched on, thus reducing the output voltage by a fourth value. This achieves the technical advantage that the output voltage is reduced when a particularly low input voltage is available. The energy storage device can then be discharged.

[0022] According to the invention, the circuit arrangement comprises a plurality of boosting devices, each of which is assigned an upper threshold value. This achieves the technical advantage that the individual boosting devices are switched on in staggered steps according to the level of the input voltage, thus increasing the output voltage. This allows the output voltage to be adjusted with particularly fine steps.

[0023] According to the invention, the circuit arrangement comprises a plurality of reduction devices, each of which is assigned a lower threshold value. This achieves the technical advantage that the individual reduction devices are switched on in staggered steps depending on the input voltage level, thus reducing the output voltage. This allows the output voltage to be adjusted with particularly fine steps.

[0024] In an advantageous embodiment, the circuit arrangement is configured to compare the value of the electrical output voltage with a minimum output voltage limit. If the comparison reveals that the value of the electrical output voltage is lower than the minimum output voltage limit, the output voltage value is set to the minimum output voltage limit or the circuit arrangement is shut down. This achieves the technical advantage of ensuring a minimum voltage level for safe operation or preventing malfunctions by shutting down if the supply or output voltage falls below a minimum.

[0025] In an advantageous embodiment, the circuit arrangement comprises a voltage divider for providing an upper threshold and / or a lower threshold. This provides the technical advantage that, with the aid of the voltage divider, a plurality of upper or lower thresholds can be provided in a simple manner, enabling fine-tuning.

[0026] In a further advantageous embodiment, the comparison device comprises a comparator. This achieves the technical advantage that the circuit arrangement can be constructed using reliable, readily available, and inexpensive components.

[0027] According to a second aspect, the object is achieved by a method according to claim 8.

[0028] This achieves the technical advantage that, based on a comparison of the input voltage with an upper and a lower threshold, it is detected that the output voltage has reached a critical value. The output voltage is then increased or reduced by increasing or decreasing the correction factor. This allows an energy storage device to be charged with electrical energy when an upper threshold is exceeded, ensuring that an energy storage device charged with electrical energy is available when needed. This increases operational reliability. Voltage reserves are therefore used when the input voltage is above the threshold to charge an energy storage device, which is discharged when the input voltage is below a threshold.

[0029] According to the invention, a value of an electrical input voltage (Uacc) is compared with a first upper threshold value (U1), and a value of the correction factor (K) is increased by a first upper correction value (K1) if the comparison shows that the value of the input voltage (Uacc) is greater than the first upper threshold value (U1). Furthermore, according to the invention, a value of an electrical input voltage (Uacc) is compared with a second upper threshold value (U2), and a value of the correction factor (K) is increased by a second upper correction value (K2) if the comparison shows that the value of the input voltage (Uacc) is greater than the second upper threshold value (U2). This achieves the technical advantage that the correction factor, and thus the electrical output voltage, are increased, and the method is continued with an increased correction factor.The first correction value can be a fixed, predefined correction value. Furthermore, a plurality of upper threshold values can be provided, with each of the threshold values being assigned a different correction value, e.g., a fixed correction value. This allows for a gradual increase in the correction factor, which enables particularly fine-tuned current control.

[0030] In a further advantageous embodiment, the value of the correction factor is compared with an upper limit, and the correction factor is set to the upper limit if the value of the correction factor is greater than the upper limit. This achieves the technical advantage that the value of the correction factor cannot assume unacceptably high values. This increases operational reliability.

[0031] In a further advantageous embodiment, the value of the correction factor is compared with an upper correction factor limit, and if the comparison shows that the value of the correction factor is greater than the upper correction factor limit, the value of the correction factor is set to the upper correction factor limit. This achieves the technical advantage that the value of the correction factor, and thus the output voltage, cannot assume values that exceed a maximum possible output voltage by increasing the upper threshold. This increases operational reliability.

[0032] According to the invention, a value of an electrical input voltage (Uacc) is compared with a first lower threshold value (U3), and a value of the correction factor (K) is reduced by a first lower correction value (K3) if the comparison shows that the value of the input voltage (Uacc) is less than the first lower threshold value (U3). Furthermore, according to the invention, a value of an electrical input voltage (Uacc) is compared with a second lower threshold value (U4), and a value of the correction factor (K) is reduced by a second lower correction value (K4) if the comparison shows that the value of the input voltage (Uacc) is less than the second lower threshold value (U4). This achieves the technical advantage that the correction factor, and thus the electrical output voltage, is reduced, and the method is continued with a reduced correction factor.The lower correction value can be a fixed, predefined correction value. Furthermore, a plurality of lower threshold values can be provided, with each threshold value being assigned a different correction value, e.g., a fixed correction value. This allows for a gradual increase in the correction factor, which enables particularly fine-tuned current control.

[0033] In a further advantageous embodiment, the value of the correction factor is compared with a lower limit, and the correction factor is set to the lower limit if the value of the correction factor is smaller than the lower limit. This achieves the technical advantage that the value of the correction factor cannot assume unacceptably small values. This increases operational reliability.

[0034] In a further advantageous embodiment, the value of the correction factor is compared with a lower correction factor limit, and if the comparison shows that the value of the correction factor is less than the lower correction factor limit, the value of the correction factor is set to the lower correction factor limit. This achieves the technical advantage that, by reducing the lower threshold, the value of the correction factor and thus the output voltage cannot assume values below a minimum output voltage that ensures safe operation. This increases operational reliability.

[0035] In a further advantageous embodiment, the value of the correction factor is compared with a shutdown limit, and if the comparison shows that the value of the correction factor is lower than the shutdown limit, a shutdown process is triggered. This achieves the technical advantage that, if a minimum supply or output voltage is undershot, malfunctions are prevented by shutdown. Initiating the shutdown process can involve generating and transmitting a shutdown signal, which can be used to shut down a current regulator or a circuit arrangement.

[0036] According to a third aspect, the object is achieved by a computer program having a program code for executing such a method when the program code is executed on a computer.

[0037] Further embodiments are explained with reference to the accompanying drawings. They show: Fig. 1a schematic representation of a circuit arrangement, Fig. 2a resolved partial circuit arrangement of the Fig. 1 shown circuit arrangement, and Fig. 3 a flow diagram of a method.

[0038] The Fig. 1 shows a circuit arrangement 100.

[0039] The circuit arrangement 100 has a first terminal 102 for connecting a positive electrical supply voltage and a second terminal 104 for connecting a negative electrical supply voltage. Furthermore, the circuit arrangement 100 has an energy storage device 108 having a capacitor 110. Furthermore, the circuit arrangement 100 has a comparison device 106, a plurality of boosting devices 112a, 112b, ..., 112m, and a plurality of reducing devices 114a, 114b, ..., 114n.

[0040] The increasing devices 112a, 112b, ..., 112n and the reducing devices 114a, 114b, ..., 114m are electrically connected to the comparison device 106 via electrical lines.

[0041] Furthermore, the boosting devices 112a, 112b, ..., 112n are electrically connected to the first terminal 102 via electrical lines, while the reducing devices 114a, 114b, ..., 114m are electrically connected to the second terminal 104 via electrical lines. Furthermore, the boosting devices 112a, 112b, ..., 112n and the reducing devices 114a, 114b, ..., 114m are electrically connected to the energy storage device 108 via electrical lines, which outputs an output voltage Uo.

[0042] An input voltage Uacc is supplied to the comparison device 106. Furthermore, a first upper threshold value U1, a second upper threshold value U2, and m further upper threshold values Um are supplied to the comparison device 106. Furthermore, a first lower threshold value U3, a second lower threshold value U4, and n further lower threshold values Un are supplied to the comparison device 106. The number of upper threshold values corresponds to the number of increase devices 112a, 112b, ..., 112n, and the number of lower threshold values corresponds to the number of decrease devices 114a, 114b, ..., 114m.

[0043] Upon receipt of a start signal S, the circuit arrangement 100 is activated. During operation, the input voltage Uacc is compared with the first upper threshold value U1, with the second upper threshold value U2, with the first lower threshold value U3, and with the second lower threshold value U4. If the comparison performed by the comparison device 106 shows that the input voltage Uacc is greater than the first upper threshold value U1, the boosting device 112a is switched on, thus increasing the electrical voltage at the energy storage device 108 by a first value.

[0044] If the comparison performed by the comparison device 106 shows that the input voltage Uacc is above the second upper threshold value U2, the boosting device 112b is switched on, thus increasing the electrical voltage at the energy storage device 108 by a second value. Furthermore, a setpoint of the current limit of a current regulator is increased. This continues until the respective mth upper threshold value Um has been exceeded, whereupon the respective mth boosting device 112m is switched on, thus increasing the voltage at the energy storage device 108.

[0045] If, however, the comparison performed by the comparison device 106 shows that the input voltage Uacc falls below the first lower threshold value U3, the reduction device 104a is switched on, thus reducing the electrical voltage at the energy storage device 108 by a third value, so that the energy storage device 108 is discharged again. Furthermore, the setpoint of the current limit of a current regulator is reduced.

[0046] If the comparison performed by the comparison device 106 shows that the input voltage Uacc falls below the second lower threshold value U4, the reduction device 114b is switched on, thus reducing the electrical voltage at the energy storage device 108 by a fourth value, so that the energy storage device 108 is further discharged. Furthermore, the setpoint of the current limit of the current regulator is reduced. This continues until the respective nth lower threshold value Un is undershot, whereupon the respective nth reduction device 114n is switched on, thus reducing the voltage at the energy storage device 108.

[0047] If the input voltage Uacc rises above the second lower threshold U4 and the first lower threshold U3 again, the reducing devices 114a and 114b are switched off again. If the input voltage Uacc continues to rise, namely above the second upper threshold U2 and above the first upper threshold U1, the increasing devices 112a, 112b are switched on again. Furthermore, the setpoint of the current limit of the current regulator is further increased. Thus, during operation, the current limit is continuously regulated to a maximum value. Thus, the value of the input voltage Uacc remains within a specified value range, which ensures safe operation.

[0048] During operation, the current limit dynamically adapts continuously to the respective load conditions. At high loads with low reserve, the load is reduced, for example, by reducing the electrical energy used to charge the energy storage device 108. At lower loads, the electrical energy is increased again. During a short-term peak current consumption, the current limit is reduced as the input voltage Uacc decreases, and when the input voltage Uacc increases, the current limit is increased again.

[0049] A first time constant can be assigned to the first upper threshold U1, and a second time constant can be assigned to the second upper threshold U2. The first time constant is greater than the second time constant, so that when the second upper threshold U2 is exceeded, the current limit setpoint is changed more quickly than when the first lower threshold U1 is exceeded.

[0050] Furthermore, a third time constant can be assigned to the first lower threshold U3, and a fourth time constant can be assigned to the second lower threshold U4. The third time constant is greater than the fourth time constant, so that when the second lower threshold U4 is exceeded, the setpoint of the current limit is changed more quickly than when the first lower threshold U3 is exceeded.

[0051] A difference is formed between the value of the input voltage Uacc and, for example, the first upper threshold value U1 or the first lower threshold value U3. Based on the difference, a value for a time constant is then determined with which the energy storage device 108 is charged or discharged. If the difference is large, a high value, for example, a disproportionately high value, is determined for the time constant, while if the difference is small, a small value, for example, a disproportionately low value, is determined for the time constant. Thus, if the difference is large, the energy storage device 108 is charged or discharged quickly, whereas if the difference is small, the energy storage device 108 is charged and discharged slowly.

[0052] Fig. 2 shows a resolved subcircuit arrangement 200 of the circuit arrangement 100.

[0053] The subcircuit arrangement 200 has the first terminal 102 for a supply voltage. Furthermore, the subcircuit arrangement 200 has the energy storage device 108, which has the capacitor 110.

[0054] Furthermore, the subcircuit arrangement 200 includes an amplifier 202 for amplifying the electrical voltage of the capacitor 110, which provides the output voltage Uo. Further components of the circuit arrangement are a first switch 204, which is designed as a normally open contact 206, and a second switch 208, which is designed as a normally closed contact 210. Furthermore, the subcircuit arrangement 200 includes four comparison devices 212-218, each of which includes a comparator 236-242. Alternatively, the comparison devices 212-218 can include Schmitt triggers. Furthermore, the subcircuit arrangement 200 includes three diodes 228-232, a ground terminal 234, and four ohmic resistors 220-226.

[0055] The comparison device 212 is supplied with the output voltage Uo and a maximum output voltage limit UH, wherein the maximum output voltage limit UH represents a maximum electrical output current. On the output side, the comparison device 212 is electrically connected via the diode 228 to the first switch 204, which is configured as a normally open contact 206, so that when the threshold value UH is exceeded, the circuit arrangement 100 can be switched off by opening the first switch 204.

[0056] The input voltage Uacc and a minimum output voltage limit UL are supplied to the comparator 214 for shutdown, e.g., when the input voltage Uacc is too low or for an input voltage Uacc of 0 volts. The comparator 214 is electrically connected on the output side to the second switch 208, designed as a break contact 210, and thus causes the break contact 210 to open when the input voltage Uacc falls below the minimum output voltage limit UL, thus shutting down the circuit arrangement 100.

[0057] The first lower threshold value U3 is supplied to the comparator 218, with the input voltage Uacc also being supplied to the comparator 218. On the output side, the comparator 216 is connected via the diode 230 and the ohmic resistor 222 to the amplifier 202 and the capacitor 110, which in turn is connected to a ground terminal 234.

[0058] The second lower threshold U4 is fed to the comparator 216, which is also supplied with the input voltage Uacc. On the output side, the comparator 216 is electrically connected to the amplifier 202 and the capacitor 110 via the diode 232 and the ohmic resistor 224.

[0059] The ohmic resistor 220 is arranged between the capacitor 110 and the first switch 204, and the ohmic resistor 226 and the diode 228 are arranged in series between the output of the comparison device 214 and the output of the comparison device 212.

[0060] After switching on, capacitor 110 is discharged and generates an output voltage Uo of 0 volts across amplifier 202. The input voltage Uacc has a higher value than the first lower threshold U3, the second lower threshold U4, and the minimum output voltage limit UL. Furthermore, the maximum output voltage limit UH is greater than the input voltage Uacc.

[0061] Upon a start signal S, the first switch 204 is closed and the second switch 208 is opened. The capacitor 110 is then charged with electrical energy via the resistor 220.

[0062] If the level of the output voltage Uo reaches the threshold value UH, the electrical voltage on the capacitor 110 is maintained.

[0063] However, if the input voltage Uacc falls below the first lower threshold U3, the electrical voltage at the capacitor 110 is reduced via the ohmic resistor 222 until the input voltage Uacc again exceeds the first lower threshold U3 and the capacitor 110 is recharged via the ohmic resistor 220. The ohmic resistor 222 and the capacitor 110 form, for example, the third time constant with which the setpoint of the current limit is changed.

[0064] If, however, the input voltage Uacc drops below the second lower threshold U4, the electrical voltage across capacitor 110 is reduced via resistor 224 until the current input voltage Uacc again exceeds the second lower threshold U4. In this case, resistor 224 and capacitor 110 form, for example, the fourth time constant with which the setpoint of the current limit is changed.

[0065] However, if the input voltage Uacc falls below the minimum output voltage limit UL, the capacitor 110 is completely discharged.

[0066] The Fig. 2 The subcircuit arrangement 200 shown can be expanded by further inputs for a first upper limit value U1 and a second upper limit value U2, which are connected to further comparison devices, wherein, upon exceeding the first upper threshold value U1, the output voltage Uo is increased by charging the capacitor 110. If the input voltage Uacc exceeds the second upper threshold value U2, the capacitor 110 is also charged, thus increasing the output voltage Uo.

[0067] Instead of the Fig. 1 In the circuit arrangement 100 shown, the function of the circuit arrangement 100 can be realized by a computer program which is formed only from software components or from a combination of software and hardware components.

[0068] The Fig. 3 shows a flowchart of a process. In this process, a correction factor K is determined and continuously updated to calculate the current limit. To implement the process, the computer program is executed on a computer using program code.

[0069] In a first step, it is checked whether the value of the correction factor K is above a specified upper limit value OB. If the value of the correction factor K is above the upper limit value OG, the correction factor K cannot be increased further due to physical limits, such as a maximum supply voltage. In this case, the value of the correction factor K is set to the value of the upper limit value OG.

[0070] If, however, the value of the correction factor K is below the upper limit OG, the next step checks whether the electrical input voltage Uacc is above the first upper threshold U1. If the value of the input voltage Uacc is above the first upper threshold U1, the value of the correction factor K is increased by a first upper correction value K1.

[0071] The first upper correction value K1 can be a fixed, predetermined value, or the first correction value K1 is determined from the value of the input voltage Uacc and the value of the upper threshold value U1. For example, the difference between the input voltage Uacc and the first upper threshold value U1 can be calculated to create a disproportionately large correction value K in the case of a large difference and a disproportionately large correction value K in the case of a small difference. A large difference exists if the value of the difference between the input voltage Uacc and the first upper threshold value U1 is above a limit value. A small difference exists if the value of the difference between the input voltage Uacc and the first upper threshold value U1 is below the limit value.

[0072] In a further step, it is checked whether the input voltage Uacc exceeds the second upper threshold U2. If the input voltage Uacc exceeds the second upper threshold U2, the correction factor K is increased by a second upper correction value K2.

[0073] The second upper correction value K2 can be a fixed, predetermined value, or the second correction value K2 is determined in the same way as the first correction value K1. For example, the difference between the input voltage Uacc and the value of the second upper threshold value U2 can be calculated in order to create a disproportionately large correction value K in the case of a large difference and a disproportionately large correction value K in the case of a small difference. A large difference exists when the value of the difference between the input voltage Uacc and the second upper threshold value U2 is above a limit value. A small difference exists when the value of the difference between the input voltage Uacc and the second upper threshold value U2 is below the limit value.

[0074] In a further step, a check is carried out to determine whether the now obtained correction factor K, due to the increase by the first upper correction value K1 and / or second upper correction value K2, has a value greater than an upper correction factor limit OG. If this is the case, the value of the current correction factor K is set to the value of the upper correction factor limit OG. This prevents the correction factor K from assuming impermissibly high values.

[0075] In the next step it is checked whether the value of the correction factor K is smaller than a lower limit value UG.

[0076] If the value of the correction factor K is below the lower limit UG, the correction factor K cannot be reduced any further. The lower limit UG defines a minimum electrical output voltage at which reliable operation is possible. In this case, i.e., if the value of the correction factor K is below the lower limit UG, the value of the correction factor K is set to the lower limit UG.

[0077] In a further step, the value of the correction factor K is compared with the first lower threshold U3. If the value of the input voltage Uacc is less than the third lower threshold U3, the value of the correction factor K is reduced by a first, lower correction value K3.

[0078] The first lower correction value K3 can be a fixed, predetermined value, or the first lower correction value K3 is determined in the same way as the first upper correction value K1. For example, the difference between the input voltage Uacc and the first lower threshold value U3 can be calculated in order to create a disproportionately large correction value K in the case of a large difference and a disproportionately large correction value K in the case of a small difference. A large difference exists when the value of the difference between the input voltage Uacc and the first lower threshold value U3 is above a limit value. A small difference exists when the value of the difference between the input voltage Uacc and the first lower threshold value U3 is below the limit value.

[0079] In a further step, the value of the correction factor K is compared with the second lower threshold value U4. If the value of the correction factor K is below the second lower threshold value U4, the value of the correction factor K is reduced by a second lower correction value K4.

[0080] The second lower correction value K4 can be a fixed, predetermined value, or the second lower correction value K4 is determined in the same way as the first correction value K1. For example, the difference between the input voltage Uacc and the second lower threshold value U4 can be calculated in order to create a disproportionately large correction value K in the case of a large difference and a disproportionately large correction value K in the case of a small difference. A large difference exists when the value of the difference between the input voltage Uacc and the second lower threshold value U4 is above a limit value. A small difference exists when the value of the difference between the input voltage Uacc and the second lower threshold value U4 is below the limit value.

[0081] In a further step, a check is carried out to determine whether the now obtained correction factor K, due to the reduction by the first lower correction value K3 and / or the second lower fourth correction value K4, has a value that is smaller than a lower correction factor limit UK. If this is the case, the value of the current correction factor K is set to the value of the lower correction factor limit UK. This prevents the correction factor K from assuming impermissibly small values.

[0082] In a further step, the correction factor is compared with a shutdown limit value AG. If the comparison shows that the value of the correction factor K is less than the shutdown limit value AG, a shutdown process is triggered. Triggering can include generating and sending a shutdown signal, with which a current regulator or the circuit arrangement 100 can be switched off in whole or in part. LIST OF REFERENCE SYMBOLS

[0083] 100Circuit arrangement 102First connection 104Second connection 106Comparator 108Energy storage 110Capacitor 112aIncreasing device 112bIncreasing device 112cIncreasing device 114aReducing device 114bReducing device 114cReducing device 200Subcircuit arrangement 202Amplifier 204First switch 206Make contact 208Second switch 210Open contact 212Comparator 214Comparator 216Comparator 218Comparator 220Resistance 222Resistance 224Resistance 226Resistance 228Diode 230Diode 232Diode 234Ground 236Comparator 238Comparator 240Comparator 242Comparator AGShutdown limit value KCorrection factor K1First upper correction value K2Second upper correction value K3First lower correction value K4Second lower correction value OGUpper limit value OKUpper correction factor limit value SStart signal U1First upper threshold value U2Second upper threshold value U3First lower threshold value U4Second lower threshold value UaccInput voltage UGLower limit value UHMaximum output voltage limit value UKLower correction factor limit value ULMinimum output voltage limit value Ummth upper threshold value Unnth lower threshold value UoOutput voltage

Claims

1. A circuit arrangement (100) for determining a target value of a current limit of a current regulator, the circuit arrangement (100) comprising: - an energy storage (108), which outputs an output voltage (Uo); - a comparator device (106) for comparing a value of an electrical input voltage (Uacc) with a first upper threshold value (U1), with a second upper threshold value (U2), with a first lower threshold value (U3) and with a second lower threshold value (U4); - a first increasing device (112a); - a second increasing device (112b); - a first reducing device (114a); - a second reducing device (114b); - wherein, if the input voltage (Uacc) is greater than the first upper threshold value (U1), the target value is increased and the first increasing device (112a) is switched on, thus increasing the output voltage by a first value; - wherein, if the input voltage (Uacc) is greater than the second upper threshold value (U2), the target value is increased and the second increasing device (112b) is switched on, thus increasing the output voltage by a second value; - wherein, if the input voltage (Uacc) is smaller than the first lower threshold value (U3), the target value is reduced and the first reducing device (114a) is switched on, thus reducing the output voltage by a third value; - wherein, if the input voltage (Uacc) is smaller than the second lower threshold value (U4), the target value is reduced and the second reducing device (114b) is switched on, thus reducing the output voltage by a fourth value; - wherein a first time constant is assigned to the first upper threshold value (U1), and a second time constant is assigned to the second upper threshold value (U2), wherein the first time constant is greater than the second time constant, so that when the second upper threshold value (U2) is exceeded, the target value of the current limit is changed more quickly than when the first upper threshold value (U1) is exceeded; - wherein a third time constant is assigned to the first lower threshold value (U3), and a fourth time constant is assigned to the second lower threshold value (U4), wherein the third time constant is greater than the fourth time constant, so that when the second lower threshold value (U4) is exceeded, the target value of the current limitation is changed more quickly than when the first lower threshold value (U3) is exceeded.

2. The circuit arrangement (100) according to claim 1, wherein the circuit arrangement (100) is configured to compare the value of the electrical output voltage (Uo) with a maximum output voltage limit value (UH), and if the comparison indicates that the value of the electrical output voltage (Uo) is greater than the maximum output voltage limit value (UH), to set the value for the output voltage (Uo) to the value of the maximum output voltage limit value (UH) or to switch off the circuit arrangement (100).

3. The circuit arrangement (100) according to one of the preceding claims, wherein the circuit arrangement (100) comprises a plurality of increasing devices (112a, 112b, ..., 112n), wherein each of the increasing devices (112a, 112b, ..., 112n) is assigned a respective upper threshold value (U1, U2, ..., Un).

4. The circuit arrangement (100) according to one of the preceding claims, wherein the circuit arrangement (100) comprises a plurality of reducing devices (114a, 114b, ..., 114n), wherein each of the reducing devices (114a, 114b, ..., 114n) is assigned a respective lower threshold value (U3, U4, ..., Um).

5. The circuit arrangement (100) according to one of the preceding claims, wherein the circuit arrangement (100) is configured to compare the value of the electrical output voltage (Uo) with a minimum output voltage limit value (UL), and if the comparison indicates that the value of the electrical output voltage (Uo) is smaller than the minimum output voltage limit value (UH), to set the value for the output voltage (Uo) to the minimum output voltage limit value (UH), or to switch off the circuit arrangement (100).

6. The circuit arrangement (100) according to one of the preceding claims, wherein the circuit arrangement (100) comprises a voltage divider for providing an upper threshold value (U1, U2, ..., Un) and / or a lower threshold value (U3, U4, ..., Um).

7. The circuit arrangement (100) according to one of the preceding claims, wherein the comparator device (106) comprises a comparator (236 - 242).

8. A Method for determining a correction factor (K) for determining a target value of a current limit of a current controller, the method comprising: - comparing a value of an electrical input voltage (Uacc) with a first upper threshold value (U1), - increasing a value of the correction factor (K) by a first upper correction value (K1) if the comparison indicates that the value of the input voltage (Uacc) is greater than the first upper threshold value (U1), - comparing a value of an electrical input voltage (Uacc) with a second upper threshold value (U2), - increasing a value of the correction factor (K) by a second upper correction value (K2) if the comparison indicates that the value of the input voltage (Uacc) is greater than the second upper threshold value (U2), - comparing the value of the electrical input voltage (Uacc) with a first lower threshold value (U3), - reducing a value of the correction factor (K) by a first lower correction value (K3) if the comparison indicates that the value of the input voltage (Uacc) is smaller than the first lower threshold value (U3), - comparing a value of an electrical input voltage (Uacc) with a second lower threshold value (U4), - reducing a value of the correction factor (K) by a second lower correction value (K4) if the comparison indicates that the value of the input voltage (Uacc) is smaller than the second lower threshold value (U4).

9. The method according to claim 8, wherein the value of the correction factor (K) is compared with an upper limit value (OG), and the value of the correction factor (K) is set to the value of the upper limit value (OG) if the value of the correction factor (K) is greater than the upper limit value (OG).

10. The method according to one of the preceding claims 8 or 9, wherein the value of the correction factor (K) is compared with an upper correction factor limit value (OK), and if the comparison indicates that the value of the correction factor (K) is greater than the upper correction factor limit value (OK), the value for the correction factor (K) is set to the upper correction factor limit value (OK).

11. The method according to one of the preceding claims 8 to 10, wherein the value of the correction factor (K) is compared with a lower limit value (UG), and the value of the correction factor (K) is set to the value of the lower limit value if the value of the correction factor (K) is smaller than the lower limit value (UG).

12. The method according to one of the preceding claims 8 to 11, wherein the value of the correction factor (K) is compared with a lower correction factor limit value (UK), and if the comparison indicates that the value of the correction factor (K) is smaller than the lower correction factor limit value (UK), the value for the correction factor (K) is set to the lower correction factor limit value (UK).

13. The method according to one of the preceding claims 8 to 12, wherein the value of the correction factor (K) is compared with a switch-off limit value (AG), and if the comparison indicates that the value of the correction factor (K) is smaller than the switch-off limit value (AG), a switch-off process is triggered.

14. A computer program comprising a program code for executing the method according to any one of claims 8 to 13 when the program code is executed on a computer.