Circuit arrangement for determining the type and value of an input voltage and associated method

Abstract

The invention relates to a circuit arrangement by which the voltage type and the voltage value, in particular the average value, of an input voltage (Ue) of a power supply (SV) or a switched-mode power supply (SV) is determined. To this end the circuit arrangement (ME) is arranged such that the input voltage (Ue) of the power supply (SV) falls on the input side of the circuit arrangement (ME). The circuit arrangement (ME) comprises at least a differential amplifier (DIF) for converting the input voltage (Ue) into a useful signal (NS), which is rectified via a first rectifier unit (GL1) arranged on the output of the differential amplifier (DIF), which is assigned a first compensation diode (K1) such that the forward voltage of the first rectifier unit (GL1) is compensated. Furthermore the circuit arrangement comprises an inverter (INV) for generating an inverted useful signal (negNS) from the useful signal (NS). The inverted useful signal (negNS) is rectified by a second rectifier unit (GL2) arranged on the output of the inverter (INV), which is assigned a second compensation diode (K2) such that the forward voltage of the second rectifier unit (GL2) is compensated. Furthermore the circuit arrangement comprises a mixing unit (MS) by which a first output signal (AS1) is generated from the rectified useful signal (NS) and the rectified inverted useful signal (NegNS), from which a second output signal (AS2) is derived by means of a filter unit. From the first output signal (AS1) the voltage type of the input voltage (Ue) can be determined and from the second output signal (AS2) the voltage value, in particular the average value, of the input voltage.

Description

Technical Field

[0001] This invention generally relates to the field of electronic technology, and more particularly to the field of power electronics and power electronic circuits. Specifically, this invention relates to a circuit device that analyzes the input voltage of a power supply or switching power supply, i.e., determines the voltage value, especially the average value, and the corresponding voltage type of the input voltage. Furthermore, this invention relates to a related method for determining the voltage type of the input voltage of a power supply. Background Technology

[0002] In manufacturing and automation technologies, power supplies, or switching power supplies, are used extensively to power consumer devices such as electronic controllers, pumps, valves, and sensors. These consumer devices are supplied with suitable, often predefined, voltages by the power supply or switching power supply. Typically, this involves converting a high voltage level on the input side, such as 230V AC or 120V AC, to a lower and usually constant voltage level predefined for the consumer on the output side of the power supply (e.g., 24V DC as the rated output voltage and 28V DC as the maximum output voltage).

[0003] Power supplies or switching power supplies are typically supplied with grid voltage from a single-phase or three-phase power grid, especially a three-phase grid, as the input voltage. A single-phase power supply may, for example, be fed with an AC voltage (e.g., 230V AC) as the input voltage, which is typically the dropout between the so-called phase conductor and the so-called neutral conductor of the power grid. Therefore, such power supplies often include an input stage, for example, in the form of a rectifier unit, through which the AC voltage from the power grid is converted to a DC voltage for the power supply. The power supply or switching power supply then converts the mostly unstable input voltage to a constant output voltage or to a predefined supply voltage for the power consumption device, wherein the constancy of the output voltage and / or output current is achieved through regulation of the energy flow.

[0004] The constancy of the output voltage can cause, for example, the input current of the power supply to increase when the input voltage drops. This can, for example, lead to overheating or even damage to components of the power supply or switching power supply. Therefore, it is common practice, for safety reasons, to monitor the input voltage of the power supply and, if necessary, to cut off the power supply output when, for example, the input voltage falls below a predetermined value. To prevent the power supply, especially a single-phase power supply, from overheating or damage due to undervoltage on the input side or from the power grid, it is necessary to continuously and as accurately as possible measure the input voltage of the power supply, for example, using its own measuring circuitry, which uses, for example, a reference potential on the primary side of the power supply or ground potential.

[0005] Input voltage measurement can be performed, for example, by unidirectional rectification of the input voltage and using an ohmic voltage divider, in which a diode is provided for the phase conductor and neutral conductor of the supply voltage, respectively. However, this variation of input voltage measurement has the following disadvantages: for example, under idling or partial load conditions, a capacitive voltage divider is formed on the output side of the power supply or switching power supply by a so-called Y-type capacitor. The so-called Y-type capacitor is used for electromagnetic compatibility (EMC) to prevent undesirable mutual interference with other equipment. The Y-type capacitor is placed between the phase conductor or neutral conductor and the protective conductor or protective earth (PE). The capacitive voltage divider formed by the Y-type capacitor affects, for example, the reference potential or ground potential on the primary side, and the measurement of the input voltage, especially the average value or voltage level, can therefore become very inaccurate.

[0006] Furthermore, this measurement variation scheme cannot, for example, determine the voltage type of the input voltage. In the case of voltage supplied by a voltage source or power grid, DC voltage and AC voltage can be distinguished by voltage type. DC voltage is a voltage whose instantaneous value hardly changes or does not change at all over a long observation period. That is, the DC voltage has the same sign and (approximately) the same value at any given moment. AC voltage is a voltage whose polarity changes in a regular, repetitive manner, but whose time-averaged value is typically zero.

[0007] Another variation of determining the input voltage of a power supply or switching power supply can be done via a bidirectional rectifier or bridge rectifier and by means of a differential amplifier. The input voltage is rectified by the bidirectional rectifier or bridge rectifier, and the rectified input voltage is then supplied to the differential amplifier. However, this measurement variation has the following disadvantage: in the event of a network-side overvoltage (so-called a surge), the rectifier unit used to measure the input voltage must withstand the same overvoltage value as the rectifier unit on the power supply's input side. This can lead to high loads on the components used for input voltage measurement (e.g., diodes in the rectifier unit), or these components must be designed accordingly to withstand the potential overvoltages. This sizing can, for example, result in relatively high costs and relatively large space requirements due to the number and size of the required components. Summary of the Invention

[0008] Therefore, the objective of this invention is to describe a circuit device and a related method for determining the voltage type and the voltage value of the input voltage of a power supply or switching power supply in a simple and cost-effective manner.

[0009] This task is accomplished by the circuit arrangement and related methods described in the independent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0010] According to the invention, this task is solved by a circuit arrangement for determining the voltage type and voltage value, particularly the average value, of the input voltage. The circuit arrangement is arranged such that the input voltage of the power supply drops across the input side of the circuit arrangement. The circuit arrangement includes at least one differential amplifier for converting the input voltage into a useful signal, which is rectified via a first rectifier unit. The first rectifier unit is arranged at the output of the differential amplifier and is equipped with a first compensation diode, such that the forward voltage of the first rectifier unit is compensated. Furthermore, the circuit arrangement includes an inverter that generates an inverted useful signal from the useful signal. The inverted useful signal is rectified by a second rectifier unit arranged at the output of the inverter, wherein the second rectifier unit is equipped with a second compensation diode, such that the forward voltage of the second rectifier unit is compensated. Additionally, the circuit arrangement includes a mixing unit that generates a first output signal from the rectified useful signal and the rectified, inverted useful signal. In addition, the circuit device has a filter unit, such as an RC filter, on the output side, which generates a second output signal (e.g., the average value of a rectified input voltage signal) from the first output signal of the circuit device.

[0011] The main aspect of the solution proposed according to the invention lies in achieving accurate analysis of the input voltage of a power supply or switching power supply in a simple and low-cost manner. That is, determining the voltage type (AC or DC) and voltage value, especially the average value, of the input voltage as accurately as possible. Here, a first output signal is generated, based on which the voltage type (e.g., DC or AC) of the input voltage can be determined. A second output signal is derived from the first output signal, which can be used to accurately measure the voltage value, such as the average value, of the input voltage. Lower-cost components can be used by placing a rectifier unit, for example designed as a rectifier diode, on the output side, because measurements can be performed at a lower voltage level than on the input side of the circuit. The relatively high forward voltage of the corresponding rectifier unit or corresponding rectifier diode is compensated by a compensation diode assigned to the rectifier unit. This allows for very accurate measurement results, especially in determining the voltage value or average value of the input voltage.

[0012] Ideally, a second output signal (e.g., the average value of a rectified input voltage signal) is generated from a first output signal of the circuit device via a filter unit, such as an RC filter, arranged on the output side. In this way, the voltage type of the input voltage can be determined from the first output signal, and the voltage value or a measured value of the average value of the input voltage can be determined from the second output signal.

[0013] Therefore, ideally, for evaluation purposes, the first and second output signals can be forwarded to the control unit via a data connection (e.g., a process field network or, as the abbreviation Profinet, etc.). This control unit can be located locally or centrally and, for example, implemented as a microcontroller.

[0014] Furthermore, it is advantageous that the differential amplifier is implemented with high ohms on the input side. This allows for a simple reduction of the relatively high input voltage level (e.g., 84V to 278V) in the resulting useful signal to a significantly lower voltage level (e.g., 0.5V to 12.5V). Consequently, lower-cost components not designed for high voltages can be used in the rectifier unit.

[0015] According to a preferred embodiment of the circuit arrangement of the present invention, the first rectifier unit and its assigned first compensation diode, as well as the second rectifier unit and its assigned second compensation diode, are each designed as a dual-diode configuration. Here, the respective rectifier unit and the respective compensation diode are mounted, for example, in a single housing and thus ideally thermally coupled. This thermal coupling allows for the very simple elimination of temperature-dependent positive voltage and enables a relatively accurate assessment or measurement of the input voltage.

[0016] A suitable improvement of the present invention specifies that the differential amplifier and inverter are designed such that the internal auxiliary supply of the power supply can be used for the operating voltage of the differential amplifier and inverter. In this way, no additional voltage supply is required for the differential amplifier and inverter. The circuit arrangement can therefore be designed in a space-saving and cost-effective manner. For this purpose, a reference voltage (e.g., 5 volts) is further provided, which is used as a reference voltage by the differential amplifier and inverter on the input side. The output voltage of, for example, the differential amplifier or inverter is shifted by the corresponding value of the reference voltage using this reference voltage. Thus, only the existing voltage source and the reference potential or ground potential can be used for the voltage supply of the differential amplifier or inverter. The negative voltage source used for the supply of the differential amplifier or inverter can be saved.

[0017] The proposed task is further addressed by a method for determining the voltage type of the power supply's input voltage, using a first output signal based on the power supply's input voltage, which is detected by means of a circuit device according to the invention. For this purpose, after detecting the first output signal using the circuit device according to the invention, after initially determining or passing (Durchlaufen) the peak value of the first output signal, a wait is made until it falls below a first threshold. Thereafter, the following steps are iterated until a predetermined number of repetitions is reached: - When the first output signal is lower than the first threshold, save the timestamp and start the pre-given dead time; - Check whether the first output signal exceeds the second threshold after the pre-given dead time expires; and - If the first output signal exceeds the second threshold when the dead time expires, wait until the first output signal falls below the first threshold again, where the second threshold is greater than the first threshold.

[0018] After a predetermined number of repetitions is reached, the frequency of the input voltage is derived from the stored timestamps, and thus the type of the input voltage is derived.

[0019] Using the method according to the invention, the voltage type of the input voltage can be determined in a simple and robust manner. For this purpose, the frequency of the input voltage is derived, for example, from at least two stored timestamps. If, for example, a frequency in the range of 45 to 65 Hz can be determined, this is evaluated as being supplied with AC voltage. Ideally, using the method according to the invention, the voltage type of the input voltage can be identified even in the presence of interference with the mains voltage or the supply voltage, such as when switched on using a small isolation transformer.

[0020] Furthermore, it is advantageous to abort the method according to the invention if, after the dead time expires, the second threshold is not exceeded within a pre-given first duration, or if, after the pre-given second duration expires, the value is not lower than the first threshold. For example, the first duration and the second duration can be chosen to be the same or different values. The measurement or repeatable steps of the method according to the invention can, for example, be repeated until a favorable AC voltage supply is detected (e.g., 10 times). If no valid AC voltage is determined after a pre-given number of repetitions or after the first or second duration (e.g., 100 ms) expires, it is assumed that the DC voltage (e.g., from a battery) is used as the power supply voltage. Attached Figure Description

[0021] The invention is explained below by way of example with reference to the accompanying drawings. In the drawings: Figure 1A power supply having a circuit arrangement according to the invention for determining the voltage type and voltage value of an input voltage is schematically and exemplaryly shown. Figure 2 An exemplary embodiment of the circuit device according to the present invention is illustrated schematically. Figure 3 Detailed illustrations of an exemplary circuit arrangement according to the present invention are shown. Figure 4 An exemplary distribution of the first output signal generated by the circuit device according to the invention is shown, along with the corresponding derivation of the voltage type of the input voltage. Detailed Implementation

[0022] Figure 1 A single-phase power supply or a single-phase switching power supply SV is schematically and exemplaryly illustrated, comprising a circuit device ME according to the invention for determining the voltage type and value of the input voltage Ue of the power supply SV or the switching power supply SV. The exemplary power supply SV is supplied with the input voltage Ue by a power grid, which is formed, for example, by the voltage difference between a phase conductor L and a neutral conductor N of the power grid. That is, only one phase conductor L or one phase L of the power grid is used to supply the voltage to the power supply SV.

[0023] For example, an input voltage Ue of 230V AC can be converted into a rectified intermediate circuit voltage U at the output side of the rectifier unit GL or at the input side of the intermediate circuit ZK via a rectifier unit GL, which serves as the input stage of the power supply SV. ZK Intermediate circuit voltage U ZK This relates to a reference potential M or a ground potential M. The intermediate circuit ZK may, for example, include an optional intermediate circuit capacitor C. ZK Furthermore, at least two Y-type capacitors Y1 and Y2 are connected in the intermediate circuit ZK, for example, for electromagnetic compatibility reasons. These Y-type capacitors Y1 and Y2 are arranged in the intermediate circuit ZK between the upper potential and the protective conductor PE or so-called protective ground PE, and between the reference potential or ground potential M and the protective conductor PE or so-called protective ground PE, respectively.

[0024] Most unstable input voltages Ue are converted by a power supply SV or a switching power supply SV at its output side into a constant output voltage Ua (e.g., a DC voltage of 4 to 28V) for powering one or more consumer devices, wherein the constantness of the output voltage Ua is achieved through regulation of the energy flow. For this purpose, the power supply SV further includes a switching converter SN, which is arranged at the output side of the intermediate circuit ZK. This switching converter SN has at least one periodically operating electronic switching element and can be implemented, for example, as a potential-isolated switching converter SN with DC isolation (e.g., a transformer) or a potential-constrained (i.e., non-potentially isolated) switching converter SN without DC isolation. The constant output voltage Ua can then be intercepted or supplied to one or more consumer devices at the output side of the switching converter SN.

[0025] Furthermore, the power supply SV has a circuit device ME according to the invention, which allows the determination of the voltage type and value of the input voltage Ue of the power supply SV or the switching power supply SV. Here, the circuit device ME is arranged such that the input voltage Ue of the power supply SV drops to the input terminal of the circuit device ME. For this purpose, the circuit device ME is connected, for example, on the input side via high-ohm resistors R1 and R2 to the phase conductor L and neutral conductor N on the input side of the switching power supply SV. Auxiliary voltage U H (e.g., 13V) This sets the voltage supply for the circuit device ME. An auxiliary supply already used in the power supply SV, for example, for control and / or signal units, can be used as an auxiliary voltage U. H Furthermore, this circuit device is connected to the reference potential or ground potential M of the intermediate circuit ZK of the power supply SV.

[0026] Two output signals AS1 and AS2 are provided on the output side by the circuit device ME. These output signals AS1 and AS2 can be forwarded to the local or central control unit SE, for example, via a data connection (e.g., a process field network, or Profinet for short). The control unit SE, which can be implemented as a microcontroller, can evaluate the output signals AS1 and AS2 accordingly. The voltage type of the input voltage Ue can be derived from the first output signal AS1, for example, using a method for determining the voltage type of the input voltage Ue of the power supply SV. That is, the voltage type of the first output signal AS1 can be derived from the input voltage Ue as subsequently determined by… Figure 4 As described in more detail, determine whether the input voltage Ue is an AC voltage or a DC voltage. The second output signal AS2 can be used to accurately determine the voltage value or average value of the input voltage Ue.

[0027] Figure 2An exemplary embodiment of a circuit device ME according to the invention for determining the voltage type and value of the input voltage Ue of a power supply SV is now schematically shown, wherein the circuit device is arranged such that the input voltage Ue of the power supply SV is also applied to the input side of the circuit device ME. For this purpose, the input side of the circuit device is connected, for example, to the phase conductor L and the neutral conductor N of the single-phase voltage supply of the power supply SV or switching power supply SV, wherein the differential voltage between the phase conductor L and the neutral conductor N is applied as the input voltage Ue to the input of the circuit device ME or the differential amplifier DIF of the circuit device ME. The differential amplifier DIF converts the input voltage Ue, which has a relatively high voltage level (e.g., 84 to 278 V), into a useful signal NS with a low voltage level (e.g., 0.5 to 12.5 V). The differential amplifier DIF is designed to be high ohms on the input side.

[0028] The first rectifier unit GL1, particularly a unidirectional rectifier GL1 or a rectifier diode GL1, is disposed on the output side of the differential amplifier DIF. The useful signal NS generated by the differential amplifier DIF is rectified by the first rectifier unit and then guided to the mixing unit MS. The first rectifier unit GL1 is equipped with a first compensation diode K1, which compensates for the voltage displacement caused by the forward voltage of the first rectifier unit GL1. Ideally, the first rectifier unit GL1 and the first compensation diode K1 can be designed as a so-called dual diode. That is, the two units GL1 and K1 are mounted in a common housing and thus thermally coupled, thereby easily and effectively eliminating the temperature-dependent forward voltage.

[0029] The compensation diode is also equipped with a first pull-up resistor R3, which connects the (signal) line to a higher voltage potential. The first pull-up resistor is positioned between the anode of the first compensation diode K1 and the auxiliary voltage U. H Between. For example, the auxiliary voltage U that already exists in the power supply SV for supplying voltage to, for example, internal control and / or signal units. H (For example, 13V) is also used as the voltage supply for the differential amplifier DIF or as the operating voltage U of the differential amplifier DIF. H In addition, the differential amplifier DIF has a connection to a reference or ground potential M.

[0030] Furthermore, the circuit device ME according to the invention includes an inverter INV, which also converts the internal auxiliary voltage U H Used for voltage supply or as operating voltage, and also has a connection to a reference or ground potential M. The inverter INV converts the useful signal NS generated by the differential amplifier DIF into the inverted useful signal negNS.

[0031] The second rectifier unit GL2, particularly a unidirectional rectifier GL2 or a rectifier diode GL2, is located on the output side of the inverter INV. The inverted useful signal negNS generated by the inverter INV is rectified by the second rectifier unit and then guided to the mixing unit MS. The second rectifier unit GL2 is also equipped with a second compensation diode K2, which compensates for the voltage shift caused by the forward voltage of the second rectifier unit GL2. Ideally, the second rectifier unit GL2 and the second compensation diode K2 are also designed as a so-called dual diode. The second rectifier unit GL2 and the second compensation diode K2 are also arranged in a common housing and are thus thermally coupled, thereby allowing for very simple and effective elimination of temperature-dependent forward voltage.

[0032] The second compensation diode K2 and the second rectifier unit GL2 are respectively equipped with second and third pull-up resistors R4 and R5. The second pull-up resistor R4 is arranged between the anode of the second compensation diode K2 and the auxiliary power supply U. H Between. The third pull-up resistor R5 is placed between the anode of the second rectifier unit GL2 and the auxiliary power supply U. H between.

[0033] To save, for example, the negative operating voltage -U used in differential amplifier DIF or inverter INV. H Alternatively, the internal auxiliary power supply of the power supply SV can be used. H In addition, a reference voltage Uref (e.g., 5V) is provided.

[0034] Then, in the mixing unit MS, the useful signal NS from the differential amplifier DIF and the inverted useful signal negNS from the inverter INV are combined into a first output signal AS1. This first output signal is used, for example, to determine the voltage type of the input voltage Ue. That is, whether the input voltage Ue is an AC voltage or a DC voltage can be derived from the first output signal AS1.

[0035] Furthermore, the circuit device ME has a filter unit. This filter unit is designed, for example, as an RC filter and includes a resistor R. F and capacitor C F A second output signal AS2 can be generated from the first output signal AS1 using a filter unit. This second output signal represents, for example, the average value of the first output signal AS1. The second output signal AS2 can be used, for example, to determine the input voltage Ue or the average value of the input voltage with relatively high accuracy.

[0036] Then, the first output signal AS1 and the second output signal AS2 can be forwarded to the local or central control unit SE via a data connection (e.g., Profinet), by which the local or central control unit can evaluate the output signals AS1 and AS2 accordingly.

[0037] exist Figure 3 Similarly, an exemplary and schematic circuit arrangement ME according to the invention is shown for determining the voltage type and voltage value of the input voltage Ue of the power supply SV, wherein from Figure 3 In particular, exemplary embodiments of the differential amplifier DIF or inverter INV can be seen.

[0038] The differential amplifier DIF of the circuit device ME can be implemented as an operational amplifier circuit, for example. For this purpose, the differential amplifier DIF includes an operational amplifier OP1, which uses, for example, an auxiliary voltage U. H The positive operating voltage is used, and the negative operating voltage terminal of the operational amplifier is connected to a reference or ground potential M. Furthermore, the differential amplifier DIF includes two input resistors R1 and R2 on the input side, which are implemented as high-ohms and, for example, have the same resistance value. Additionally, two other resistors R6 and R7 are provided, which are implemented as low-ohms compared to the input resistors R1 and R2 and, for example, may also have the same resistance value. Here, the first resistor R6 of the differential amplifier DIF is connected to the reference voltage Uref, and the second resistor R7 is arranged in the feedback of the differential amplifier DIF. A first rectifier unit GL1 is arranged on the output side of the differential amplifier DIF or its operational amplifier OPI, and a first compensation diode K1 is arranged in the feedback of the differential amplifier circuit DIF.

[0039] As in Figure 3 As exemplarily shown, the inverter INV can also be designed as an operational amplifier circuit with operational amplifier OP2. Operational amplifier OP2 also uses, for example, an auxiliary voltage U. HThe positive operating voltage is used, and the negative operating voltage terminal of the operational amplifier is connected to a reference or ground potential M. The positive input terminal of the operational amplifier OP2 of the inverter INV is connected, for example, to the reference voltage Uref. The useful signal NS generated by the differential amplifier DIF is fed to the negative input terminal of the operational amplifier OP2 of the inverter INV via the first resistor R8 of the inverter INV. The second resistor R9 of the inverter INV is placed in the feedback of the operational amplifier OP2 of the inverter INV, wherein the two resistors R8 and R9 of the inverter INV have the same resistance value in order to invert the useful signal NS. The second rectifier unit GL2 for rectifying the inverted useful signal negNS is arranged on the output side of the inverter INV or the operational amplifier OP2, and the second compensation diode is arranged in the feedback of the inverter circuit INV.

[0040] The rectified useful signal NS from the differential amplifier DIF and the rectified, inverted useful signal negNS are then fed to the mixing unit MS and mixed into the first output signal AS1. Then, the signal is filtered by the RC filter unit R... F C F The second output signal AS2 is derived from the first output signal AS1.

[0041] Figure 4 The time distribution of the first output signal AS1 generated by the circuit device ME according to the invention is illustrated, and the voltage type of the input voltage Ue is derived from the first output signal according to the method according to the invention.

[0042] Here, time t is plotted on the horizontal axis and voltage -U is plotted on the vertical axis. The intersection of the vertical and horizontal axes also lies at the reference voltage Uref (e.g., at 5V). Furthermore, dashed lines are plotted on the vertical axis for 0V, for a first threshold SW1, and for a second threshold SW2, where the first threshold SW1 is closer to the reference voltage Uref than the second threshold SW2. Alternatively, thresholds with hysteresis can also be used. The first output signal AS1, due to rectification by the two rectifier units GL1, GL2 of the circuit device ME, has, for example, a time distribution of a pulsed DC voltage, where the wave has a peak value Û.

[0043] To evaluate the input voltage Ue or the first output signal AS1, after the method according to the invention begins, the system first waits for the first passage of the peak value Û of the first output signal from the peak value Û, and then waits for it to fall below a first threshold SW1. If it is determined, for example, at the first time t1, that the value is below the first threshold SW1, a first timestamp is saved and a pre-given dead time T begins. t Within a pre-defined dead time T tAfter the second time t2 expires, check or wait until the second threshold SW2 is exceeded. After exceeding the second threshold SW2, wait for the first output signal AS1 to fall below the first threshold SW1 again. If it falls below the first threshold SW1 again at the third time t3, then save the second timestamp again and start the pre-given dead time T. t During the dead time T t After the fourth time t4 expires, check again to see if the second threshold SW2 has been exceeded. If so, wait again for the value to fall below the first threshold SW1, and save the timestamp when it is determined at the fifth time t5 that the first output signal AS1 is below the first threshold SW1.

[0044] Step "When the first output signal AS1 is lower than the first threshold SW1, save the timestamp and start the pre-given dead time T" t "Check within a pre-given dead time T" t "After the expiration, does the first output signal (AS1) exceed the second threshold SW2?" and "When the first output signal AS1 is in the dead time T..." t If the second threshold SW2 is exceeded upon or after the expiration date, the process of waiting until the first output signal AS1 falls below the first threshold SW1 again is repeated until a predetermined number of repetitions, such as 10 repetitions, is reached. After this, the frequency of the first output signal AS1 and thus the input voltage Ue can be derived from at least two stored timestamps. If this frequency is in the range of 45 to 65 Hz, the input voltage Ue can be evaluated as an AC voltage.

[0045] If, after the dead time Tt expires, the second threshold SW2 is never exceeded within a pre-given first duration (e.g., 100 ms), or after the second duration expires, for example, after the first passage of the peak value Û of the first output signal AS1, the execution of the method can be aborted or the input voltage Ue can be evaluated as a DC voltage. Furthermore, if, for example, the frequency of the first output signal AS1 cannot be detected from the stored timestamps after a pre-given number of repetitions of the method steps, the input voltage Ue can also be evaluated as a DC voltage. The method for determining the voltage type of the input voltage Ue of the power supply SV can, for example, be executed in the control unit SE. The evaluation of the first and second output signals AS1, AS2 can then, for example, be forwarded to a local or central control, evaluation, and / or display unit for display or, accordingly, further processing.

Claims

1. A circuit device (ME) for determining the voltage type and voltage value of the input voltage (Ue) of a power supply (SV), characterized in that, The circuit device (ME) is arranged such that the input voltage (Ue) of the power supply (SV) drops to the input side of the circuit device (ME), and the circuit device (ME) includes at least: - A differential amplifier (DIF) for converting the input voltage (Ue) into a useful signal (NS), the useful signal being rectified via a first rectifier unit (GL1) disposed at the output of the differential amplifier (DIF) and the first rectifier unit being provided with a first compensation diode (K1). - An inverter (INV) for generating an inverted useful signal (negNS) from the useful signal (NS), wherein the inverted useful signal (negNS) is rectified via a second rectifier unit (GL2), the second rectifier unit being disposed at the output of the inverter (INV) and the second rectifier unit being provided with a second compensation diode (K2). - A mixing unit (MS) for generating a first output signal (AS1) from a rectified useful signal (NS) and a rectified inverted useful signal (NegNS), and - Filter unit (R) F C F The filter unit is configured to generate a second output signal (AS2) from the first output signal (AS1).

2. The circuit device according to claim 1, characterized in that, For evaluation purposes, the first output signal (AS1) and the second output signal (AS2) can be forwarded to the control unit (SE) via a data connection.

3. The circuit device according to claim 1 or 2, characterized in that, The differential amplifier (DIF) is implemented as high ohms on the input side.

4. The circuit device according to claim 1 or 2, characterized in that, The first rectifier unit (GL1) and the assigned first compensation diode (K1), as well as the second rectifier unit (GL2) and the assigned second compensation diode (K2), are each designed as dual diodes.

5. The circuit device according to claim 1 or 2, characterized in that, The differential amplifier (DIF) and the inverter (INV) are designed such that the auxiliary supply (U) of the power supply (SV) H It can be used as the operating voltage for the differential amplifier (DIF) and the inverter (INV).

6. A method for determining the voltage type of the input voltage (Ue) of a power supply, characterized in that, A first output signal (AS1) based on the input voltage (Ue) of the power supply (SV) is detected using the circuit device (ME) according to any one of claims 1 to 5. After the first pass of the peak (Û) of the first output signal (AS1), wait for it to fall below the first threshold (SW1), and Then iterate through the following steps until the predetermined number of repetitions is reached: - When the first output signal (AS1) is lower than the first threshold (SW1), save the timestamp and start the pre-given dead time (T). t ); - Check at the pre-given dead time (T) t After the expiration date, does the first output signal (AS1) exceed the second threshold (SW2)? - If in the dead time (T) t If, after the expiration date, the first output signal (AS1) exceeds the second threshold (SW2), then wait until the first output signal (AS1) falls below the first threshold again, wherein the second threshold (SW2) is greater than the first threshold (SW1); and After the predetermined number of repetitions is reached, the frequency of the input voltage (Ue) is derived from the stored timestamps.

7. The method according to claim 6, characterized in that, If the second threshold (SW2) is not exceeded within a first pre-given duration after the dead time (Tt) expires, the method is terminated.

8. The method according to claim 6 or 7, characterized in that, If the threshold (SW1) is not lowered after the second, pre-given duration expires, the method is terminated.

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