EP2539912B1 - Circuit assembly for operating a household appliance and corresponding method - Google Patents

Description

The invention relates to a circuit arrangement for operating a household appliance. It comprises a circuit input for applying an alternating supply voltage, a control device for controlling operating processes of the domestic appliance, as well as a voltage supply unit coupled to the control device - for example a power supply - for providing a DC operating voltage for the control device, namely from the AC supply voltage. The circuit arrangement also comprises an operator-actuatable push-button, via which the power supply unit can be coupled to the circuit input. The circuit arrangement also includes an electrical switch connected in parallel with the pushbutton. This can be switched by the control device between an electrically conductive switching state in which the voltage supply unit is coupled via this switch to the circuit input, and an electrically blocking switching state. The invention also relates to a corresponding method for operating a domestic appliance.

Such circuit arrangements and methods are already known from the prior art, namely, for example, from the publications WO 2009/071412 A1 and DE 10 2007 058 380 A1 , The first document describes an electronic circuit with a button, with the help of an operator can turn on the household appliance. A coil of an impulse relay is energized via the pushbutton, so that a power supply unit via the same relay is coupled after actuation of the pushbutton with a circuit input and thus with an electrical supply network. The relay can be opened by a control device again, by controlling a triac connected in parallel with the pushbutton. On the one hand, it is thus ensured that the domestic appliance can be switched off by the control device after completion of an operating process and thus can no longer absorb electrical energy; On the other hand, by using a bistable relay an already started operating process can be completed properly after failure and return of the mains voltage.

In the subject matter in the publication DE 10 2007 058 380 A1 the power supply is even supplied via two separate electrical switch with electrical energy, which are activated and closed after pressing the button, namely by a control device. One of the electrical switches is a bistable relay and also serves to lock a door of the domestic appliance. The other switch is a monostable relay, which is closed by the controller immediately after pressing the button. Both switches can be opened after completion of an operation process of the domestic appliance, and the domestic appliance consumes no electrical energy. US-A-4866955 discloses a circuit arrangement for operating a domestic appliance with a control device and a state detection device, which is designed to detect a switching state of the button and to output a switching state of the button reproducing state signal to the control device. It is an object of the invention to show a way how the functionality of a circuit arrangement of the type mentioned can be extended in comparison to the prior art.

This object is achieved by a circuit arrangement as well as by a domestic appliance and by a method having the features of the respective independent claim. Advantageous embodiments of the invention are the subject of the dependent claims and the following description. Advantageous embodiments of the invention according to each of the categories of circuit arrangement, domestic appliance and method correspond to advantageous embodiments according to the respective other categories, even if this is not explicitly mentioned herein.

A circuit arrangement according to the invention for operating a domestic appliance comprises a circuit input for applying a supply alternating voltage, a control device for controlling operating processes of the domestic appliance, a voltage supply unit coupled to the control device for providing a DC operating voltage for the control device from the AC supply voltage, a pushbutton actuatable by an operator via which the voltage supply unit can be coupled to the circuit input, and an electrical switch connected in parallel with the switch, which can be switched by the control device between an electrically conductive switching state in which the voltage supply unit is coupled to the circuit input and an electrically blocking switching state. The circuit arrangement comprises a state detection device coupled to the pushbutton and the control device, which detects a switching state of the button and outputs a switching state reproducing this state signal to the control device. The control device can switch the electrical switch depending on the status signal.

Furthermore, a decoupling device is connected between the electrical switch and the state detecting device. Such a decoupling device can serve to at least partially decouple the state detection device electrically from the electrical switch.

For a complete electrical decoupling of the state detection device from the electrical switch, the decoupling device may preferably have a diode whose cathode is coupled to the electrical switch and whose anode is connected to the state detection device. Additionally or alternatively, the decoupling device may have an ohmic resistance.

The functionality of the circuit arrangement in comparison with the prior art is thus improved by a separate from the power supply unit state detection device which detects the respective instantaneous switching state of the probe and outputs a status signal to the control device. This status signal characterizes the switching state of the button. It is further ensured by the decoupling device that - when the electrical switch is closed - the state detection device of the electrical supply network is at least partially electrically decoupled and the state signal is thus not corrupted. There are thus a clear detection of the instantaneous switching state of the button and a clear detection of an actuation of the button possible.

An operator can thus operate the button to turn off the home appliance. The control device then receives quasi a switch-off and can bring the electrical load, as well as other components of the household appliance in a safe state and then open the electrical switch to disconnect the domestic appliance from the electrical supply network. Switching off the household appliance is thus - unlike the subject matter in the publication WO 2009/071412 A1 via the control device; the electrical switch can not be independent of the Control device to be opened. This increases the reliability of the household appliance. Namely, the control device can bring the components of the domestic appliance to a safe state or switch them off properly before it disconnects itself and the entire household appliance from the supply network.

As a state signal, the state detection device can provide an electrical voltage and output to the control device. The electrical voltage may have at least a first property in an open switching state of the probe and at least one second property in a closed, ie actuated switching state of the probe. A property may be, for example, an amplitude value or a frequency value here. The state detection device may be coupled to an electrical contact element of the probe; then the state detection device is coupled in the closed switching state of the button to the electrical supply network, namely via the button. The state detection device can also be coupled to a DC voltage source, in particular to a DC voltage provided by the voltage supply unit, that is to say, for example, the DC operating voltage. The state detection device may include passive and / or active electronic components. It may have, for example, at least one diode and / or at least one transformer and / or at least one optocoupler and / or at least one ohmic resistor. In an embodiment of the invention, the state detection device may comprise, for example, an ohmic resistor or a series of resistors which are connected on the one hand to an electrical contact element of the probe and on the other hand to a detection input of the control device. The detection input may also be coupled via a parallel connection of an ohmic resistor and a first diode to a DC voltage source. Here, the cathode of the first diode may be coupled to the DC voltage source and its anode coupled to the detection input. The detection input may also be coupled via a parallel circuit to an ohmic resistance and a second diode to a reference potential, wherein preferably the cathode of the second diode are coupled to the detection input and its anode to the reference potential. In such an embodiment of the state detection device, a fraction of the DC voltage provided by the DC voltage source is present at the detection input of the control device in the open switching state of the button, namely, for example, two volts, three volts, four volts or five volts. In the closed switching state of the probe, the DC voltage of the DC voltage cases overlaps with a fraction of the AC supply voltage (mains voltage) and there is a pulsating electrical voltage at the detection input of the control device. This changes between two amplitude values, namely with the frequency of the alternating supply voltage. For example, this voltage may alternate between a first amplitude value of 2 volts and a second amplitude value of 5 volts.

By providing an electrical voltage as a state signal, which has at least a first and a second characteristic, the control device can clearly and without much computational effort recognize in which switching state the button is currently located. If the property of the electrical voltage changes, this can be detected directly at the detection input of the control device and the control device can close or open the electrical switch.

After detecting an actuation of the button on the basis of the state signal, the control device can change the switching state of the electrical switch. In particular, after detecting an actuation of the button in the conductive switching state of the electrical switch, the control device can switch the same switch into the electrically blocking switching state. This makes it possible to switch off the household appliance with the aid of the button. Before the control device opens the electrical switch, it can switch off at least one electrical consumer of the household appliance properly and thus bring it into a safe state. As already stated, faulty states of components of the domestic appliance are thus avoided.

In one embodiment, the control device opens the electrical switch after completing an operating process of the domestic appliance. It is thus possible to reduce the energy consumption of the household appliance as a whole to a minimum. The household appliance does not absorb any electrical energy after completing an operating process.

The electrical switch, with the aid of which the push button can be bridged, is preferably a bistable relay, that is to say, for example, an impulse relay, an adhesive relay or a similar relay. So the electrical switch is preferably one Switch, which has two mechanically stable switching states. He can thus maintain the conductive or blocking switching state, namely without a continuous control by the control device. The electrical switch is preferably switchable by applying a pulse of current between the conductive and the blocking switching state. By using a bistable relay, it is possible to properly complete an already started operating process of the domestic appliance even after such a power failure, which lasts a relatively long period of time.

In an alternative embodiment, the electrical switch is a monostable relay or a semiconductor switch. In this embodiment, the electrical switch remains in its electrically conductive switching state only during the control or the energy supply from the side of the control device.

The circuit arrangement can have an electrical energy store coupled to the electrical switch. Then, the electrical switch to maintain the conductive switching state can be supplied with electrical energy from the energy storage, namely in particular when the AC supply voltage (mains voltage) fails for a relatively short period of time. This embodiment proves to be particularly advantageous in particular in the embodiment in which the electrical switch is a simple, ie monostable relay or a semiconductor switch. If the AC supply voltage and thus also the DC operating voltage for the control device fails for a relatively short period of time, the electrical switch takes up the energy stored in the energy store in order to maintain its conductive switching state. The use of an energy storage also allows - especially in a monostable relay or a semiconductor switch - a safe shutdown of the household appliance in the event of a prolonged power failure and although the controller can turn off the component of the domestic appliance properly after detecting the failure of the AC supply voltage. Subsequently, the electric switch can also open, namely in particular by discharging the energy store. This can be achieved, for example, by short-circuiting the energy store to a reference potential. The control device can namely with electrical energy from the energy storage and / or energy from another energy storage, for example a DC link capacitor to be supplied after failure of the AC supply voltage.

The electrical switch, namely its control input - can be coupled to the power supply unit and / or with the button. Then, when the button is pressed by an operator, the electrical switch is almost automatically closed. Thus, the closing of the electrical switch is independent of the control device, the control device does not have to be "started up" so that the electrical switch is closed. The electrical switch is thus switched much faster than by means of the control device in its electrically conductive switching state. The control input of the electrical switch can, for example, be coupled to that output of the voltage supply unit to which the operating DC voltage for the control device or a further DC voltage is provided. Additionally or alternatively, the control input of the switch can be coupled to the button, namely in particular via a power supply. Such a power supply can have, for example, a rectifier-in particular a rectification diode-and / or at least one ohmic resistor and / or at least one capacitor.

An inventive household appliance comprises a circuit arrangement according to the invention or a preferred embodiment of this circuit arrangement.

A household appliance is understood to mean a device that is used for household management. This may be a large household appliance, such as a washing machine, a tumble dryer, a dishwasher, a cooking appliance, a cooker hood, a refrigerator, a Kühlgefrier combination or an air conditioner. But this can also be a small household appliance, such as a coffee machine or a food processor.

In a method according to the invention for operating a domestic appliance with a circuit arrangement, operating processes of the domestic appliance are controlled by a control device. An AC supply voltage is applied to a circuit input of the circuit arrangement. A voltage supply unit coupled to the control device is connected to the circuit input via a Button coupled. The voltage supply unit provides a DC operating voltage for the control device from the AC supply voltage. It is connected in parallel to the switch electrical switch between an electrically conductive switching state, in which the power supply unit is coupled to the circuit input, and an electrically blocking switching state by the control device. A switching state of the button is detected by means of a coupled to the button and the control device state detection device, and the switching state of the button reproducing state signal is output by the state detection device to the control device. The control device switches the electrical switch depending on the status signal. Furthermore, the state detection device is at least partially electrically decoupled from the electrical switch by means of a decoupling device connected between the electrical switch and the state detection device.

The preferred embodiments presented with reference to the circuit arrangement according to the invention and their advantages apply correspondingly to the domestic appliance according to the invention and to the method according to the invention.

Further features of the invention will become apparent from the claims, the figures and the description of the figures. All the features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures can be used not only for the respectively specified combination but also in other combinations or also alone.

The invention will now be explained in more detail with reference to individual preferred embodiments, as well as with reference to the accompanying drawings.

Fig. 1

in schematischer Darstellung ein Hausgerät mit einer Schaltungsanordnung gemäß einer ersten Ausführungsform;

Fig. 2

in schematischer Darstellung ein Hausgerät mit einer Schaltungsanordnung gemäß einer zweiten Ausführungsform;

Fig. 3 bis 8

in schematischer Darstellung jeweils ein Beispiel für ein Steuerungsteil eines elektrischen Schalters der Schaltungsanordnung;

Fig. 9

in schematischer Darstellung eine weiteres Beispiel für ein Steuerungsteil eines elektrischen Schalters der Schaltungsanordnung;

Fig. 10 bis 12

in schematischer Darstellung jeweils ein Beispiel für eine Entkopplungseinrichtung der Schaltungsanordnung;

Fig. 13

in schematischer Darstellung eine Zustandserkennungseinrichtung der Schaltungsanordnung;

Fig. 14

in schematischer Darstellung eine Schaltungsanordnung gemäß einer dritten Ausführungsform mit einer weiteren Zustandserkennungseinrichtung.

Show it:

Fig. 1

a schematic illustration of a domestic appliance with a circuit arrangement according to a first embodiment;

Fig. 2

a schematic illustration of a domestic appliance with a circuit arrangement according to a second embodiment;

Fig. 3 to 8

in schematic representation, in each case an example of a control part of an electrical switch of the circuit arrangement;

Fig. 9

a schematic representation of another example of a control part of an electrical switch of the circuit arrangement;

10 to 12

in schematic representation, in each case an example of a decoupling device of the circuit arrangement;

Fig. 13

a schematic representation of a state detection device of the circuit arrangement;

Fig. 14

a schematic representation of a circuit arrangement according to a third embodiment with a further state detection device.

An in Fig. 1 Household appliance 1 shown comprises a circuit arrangement 2. The circuit arrangement 2 serves to operate a household appliance 1. It comprises a control device 3, which serves to control operating processes of the domestic appliance 1. For example, the controller may control the operating processes in accordance with stored operating programs. In the control of the operating processes, the control device 3 controls at least one electrical load of the domestic appliance 1. The control device 3 may include a microcontroller and / or a digital signal processor and / or a memory.

The circuit arrangement 2 comprises a circuit input 4 with a first input connection 5 and a second input connection 6. Between the input connections 5, 6 an alternating supply voltage U _{V can be} applied. The AC supply voltage U _V is the mains voltage of an external electrical supply network. The circuit input 4 can be coupled to the electrical supply network, namely via a mains filter and a cable. Of the first input terminal 5 is connected to a phase conductor 7, and the second input terminal 6 is connected to a neutral conductor 8 (zero conductor).

By contrast, the control device 3 is connected to a reference potential 9, which is galvanically isolated from the circuit input 4. The reference potential 9 is thus a different potential from the potential provided at the neutral conductor 8.

The circuit arrangement 2 comprises a voltage supply unit 10, which may comprise a power supply unit. It may, for example, have a switched-mode power supply and / or a capacitor power supply. The voltage supply unit 10 is used to provide from the AC supply voltage U _V a DC operating voltage U _B , namely with respect to the reference potential 9. The amplitude of the DC operating voltage U _B may, for example, in a range from 2 volts to 9 volts. It can be for example 5 volts.

The power supply unit 10 is connected to the neutral conductor 8. In addition, the voltage supply unit 10 can be coupled to the first input terminal 5, namely via an electrical switch 11. A decoupling device 12 is integrated in the phase conductor 7 between the electrical switch 11 and the voltage supply unit 10.

In principle, the electrical switch 11 may be a semiconductor switch. In the embodiment, the switch 11 is a relay, so for example a bistable relay or a simple monostable relay. The switch 11 comprises two contact elements, namely a movable contact element 13, as well as a stationary contact element 14. If the movable contact element 13 is brought into contact with the stationary contact element 14, an electrical connection between the first input connection 5 and the voltage supply unit 10 is established. The electrical switch 11 also includes a control part 15, which is coupled in the embodiment via a first control line 16 and a second control line 17 each having a control output of the control device 3. The control device 3 can control the electrical switch 11 via the control lines 16, 17.

The circuit arrangement 2 also has a button 18, which can be actuated by an operator of the domestic appliance 1. The button 18 includes an operating element 19, as in the embodiment according to Fig. 1 two electrical switches 20, 21. If the operating element 19 is actuated by an operator, the switches 20, 21 are closed for the duration of the actuation. The switches 20, 21 thus remain in the closed switching state during the actuation of the operating element 19. Via the switch 21, the voltage supply unit 10 can be coupled to the first input terminal 5, namely via the decoupling device 12. Namely, the switch 21 is connected firstly to the first input terminal 5 and on the other hand connected via the decoupling device 12 to the power supply unit 10.

Via the switch 20, the first input terminal 12 can be coupled to an input 22 of a state detection device 23. An output 24 of the state detection device 23 is connected to a detection input 25 of the control device 3.

The state detection device 23 has the functions of detecting a switching state of the button 18. Namely, the input 22 via the switch 20 of the button 18 to the circuit input 4 can be coupled. Thus, if the button 18 is actuated, the supply AC voltage U _V is applied to the input 22. The state detection device 23 converts this alternating supply voltage U _V into a state signal 26 and outputs the state signal 26 to the control device 3, namely at its detection input 25. The state signal 26 can have different properties, for example, depending on whether the button 18 is currently actuated or not. In the non-actuated state of the button 18, ie in the open state of the switch 20, the status signal 26 may have a first property, such as a first amplitude value and / or a first frequency value. In the actuated state of the button 18, the status signal 26 may have at least one second property, such as a second amplitude value and / or a second frequency value.

Based on the status signal 26, the control device 3 can detect whether an actuation of the button 18 is present or not. If the button 18 is turned off State of the domestic appliance 1 - so when the electric switch 11 is open - operated, the control device 3 closes the electrical switch 11. This bypasses the button 18, which can be released by the operator. The power supply unit 10 generates the DC operating voltage U _B and the domestic appliance 1 is turned on. The control device 3 can control the operating processes of the domestic appliance 1. After completion of an operating process, the control device 3 finds the switch 11 so that the voltage supply unit 10 is decoupled from the circuit input 4. The household appliance 1 is switched off. If the button 18 in the on state of the domestic appliance 1 - that is, when the switch 11 is closed - actuated, the control device 3 detects selbige actuation. After detecting the operation, the control device 3 brings all electrical consumers of the domestic appliance 1 in a safe state; namely the electrical consumers are switched off properly. The controller 3 then opens the electric switch 11, and the domestic appliance 1 is turned off.

In Fig. 13 an example of the state detection device 23 is shown. Between the input 22 and the output 24, a series of resistors 27 is connected, namely, for example, a series of three ohmic resistors 27. The output 24 is also coupled via a parallel circuit of an ohmic resistor 28 and a diode 29 to a DC voltage source. In the example, this is the voltage supply unit 10, so that the output 24 is coupled via the said parallel circuit with the operating DC voltage U _B. On the other hand, the output 24 is coupled via a parallel connection of a second diode 30 and a further ohmic resistor 31 to the reference potential 9. The cathode of the first diode 29 is connected to the DC voltage source and the anode of the first diode 29 to the output 24; the cathode of the second diodes 30 is connected to the output 24 and its anode to the reference potential 9. The state signal 26 is an electrical voltage U _Z in the example. The voltage U _Z may have the following properties: If the button 18 is not actuated, the input 22 is free of the alternating supply voltage U _V. At the output 24 is a fraction of the DC operating voltage U _B at. In the non-actuated state of the probe 18, the amplitude of the voltage U _{Z is} equal to a fraction of the amplitude of the DC operating voltage U _B and may for example be two volts or three volts. In the non-actuated state of the button 18, the voltage U _{Z is} a DC voltage. in the actuated state of the probe 18, however, is applied to the input 22, the AC supply voltage U _V , and a fraction of which is superimposed with the DC operating voltage U _B. The voltage U _Z thus alternates between a first and a second amplitude value, namely for example between two volts and five volts. The voltage U _Z changes with the frequency of the supply AC voltage U _V. In such a manner, the controller 3 can reliably, unambiguously and quickly recognize whether the button 18 has been operated or not. The detection can be in both an open as well as closed switch 11, as at the input 22 only when the button 18 via the then closed contact element 20, a signal is applied, ie there is no repercussions on this signal when the contact element 13 is closed.

In Fig. 2 the domestic appliance 1 is shown with the circuit arrangement 2 according to a further embodiment of the invention. The circuit arrangement 2 according to Fig. 2 is essentially the same as Fig. 1 - In the following, only the differences will be discussed. The circuit arrangement 2 comprises an electrical energy store 32, which can be used functionally. The energy store 32 may comprise, for example, a capacitor which is connected between the control line 16 and the reference potential 9. So the energy storage 32 is coupled to the switch 11. In addition, the circuit arrangement 2 according to Fig. 2 a branching unit 33, which is connected between the energy storage 32 and the control device 3 and is additionally coupled to the voltage supply unit 10. The branching unit 33 can, for example, include a circuit node which connects the control device 3, the energy store 32 and the voltage supply unit 10 to one another. The branching unit 33 thus picks up the DC operating voltage U _B.

In the example according to Fig. 2 is provided between the switch 11 and the control device 3, a single control line 16.

Another difference is that the button 18 comprises a single switch 20, via which both the state recognition device 23 and the decoupling device 12 are coupled to the first input terminal 5 can. For this purpose, the decoupling device 12 is connected directly to the input 22 of the state recognition device 23.

In relation to Fig. 1 mentioned characteristics and combinations of features as well as in relation to Fig. 2 mentioned features and feature combinations can be combined with each other.

By using the energy store 32, the switch 11 can be kept in the closed switching state even if the AC supply voltage U _V fails. With electrical energy from the energy storage 32, the closed state of the switch 11 can be maintained for a certain period of time. This proves to be particularly helpful in a monostable relay as well as a semiconductor switch. If necessary, the control device 3 can also be supplied with electrical energy from the energy store 32, namely after a failure of the alternating supply voltage U _V. But for this purpose, but also a memory can be used.

By tapping the operating DC voltage U _B or another DC voltage through the branching unit 33, the electrical switch 11 can be moved immediately after pressing the button 18 in its electrically conductive switching state. This is then done independently of the control device 3. After pressing the button 18, the branching unit 33 accesses namely the DC operating voltage U _B or the other DC voltage to the power supply unit 10 and the control part 15 of the switch 11 is energized without the need for control by the control device 3 , Thus, the switch 11 is closed much faster than without the connection to the power supply unit 10th

The circuit arrangement 2 according to the in Fig. 2 embodiment shown can also be performed without energy storage 32 and the branching device 33. In this case, the control part 15 of the switch 11 is driven by the control device 3.

In the 10 to 12 an example of the decoupling device 12 is shown in each case. It comprises a first connection 12a, which is connected to the pushbutton 18, one second terminal 12 b, which is connected to the switch 11, and a third terminal 12 c, which is connected to the power supply unit 10. As in Fig. 10 1, the decoupling device 12 may comprise a diode 34 whose anode is connected to the first terminal 12a and whose cathode is connected to the terminals 12b, 12c. In the example according to Fig. 12 The decoupling device 12 additionally comprises a further diode 35 whose anode is connected to the second terminal 12b and whose cathode is connected to the cathode of the diode 34 and the third terminal 12c. In the example according to Fig. 11 For example, the diode 34 is replaced by an ohmic resistor and / or a negative temperature coefficient (NTC) and / or a positive temperature coefficient (PTC) 36. Such an embodiment of the decoupling device 12, as shown in the 10 to 12 Thus, the supply AC voltage U _V does not affect the state signal 26 in the closed state of the switch 11, so that an actuation of the button 18 can be clearly identified. This applies in particular to the circuit arrangement 2 according to FIG Fig. 2 in which the decoupling device 12 is connected directly to the input 22 of the state detection device 23. In the circuit 2 according to Fig. 1 Also assumes the switch 21 of the button 18, the decoupling of the state detection device 23 of the switch 11. The decoupling device 12 according to the FIGS. 11 and 12 , namely with the diode 35, also serves to rectify the AC supply voltage U _V.

In the Fig. 3 to 8 Examples of the control part 15 of the switch 11 are shown. As already stated, the switch 11 may be a bistable relay, a simple monostable relay or a semiconductor switch. Fig. 3 shows a control part 15, as in the circuit 2 according to Fig. 1 can be used. In this example, the switch 11 is a bistable relay, ie it has two mechanically stable switching states. The control part 15 comprises a first coil 37 and a second coil 38. The first coil 37 is connected via the control line 16 to the control device 3; On the other hand, the first coil 37 is connected to the reference potential 9. The second coil 38 is on the one hand connected to the control device 3, namely via the second control line 17; On the other hand, it is connected to the reference potential 9. By energizing the first coil 37 with a current pulse, the switch 11 can be closed, and the movable contact element 13 comes into contact with the fixed contact element 14. By applying the second coil 38 with a current pulse of the switch 11 is opened.

In the example according to Fig. 4 the electrical switch 11 is a bistable latching relay. The control part 15 includes a single coil 39, which is coupled on the one hand via the control line 16 to the control device 3 and on the other hand to the reference potential 9. By energizing the coil 39 with a current pulse, the switch 11 can be switched between the closed and the open switching state.

In the example according to Fig. 5 The control part 15 includes a single coil 40. Here, the switch 11 is a simple monostable relay. The movable contact element 13 is thus only in contact with the stationary contact element 14 when electrical current flows through the coil 40. The coil 40 is thus energized continuously by means of the control device 3 for maintaining the closed switching state of the switch 11. Especially in this embodiment, the use of the energy storage 32 ( Fig. 2 ) as particularly advantageous. Electric current also flows through the coil 40 when the alternating supply voltage U _V fails for a short period of time. The closed switching state of the switch 11 can thus be maintained.

The control part 15 according to Fig. 6 essentially corresponds to the according Fig. 3 , The switch 11 is a bistable relay with two coils 37, 38. The coils 37, 38 are here coupled on the one hand to the DC operating voltage U _B and on the other hand in each case to the collector of an NPN bipolar transistor 41, 42. The respective emitters of the bipolar transistors 41, 42 are connected to the reference potentials 9. The base of the bipolar transistor 41 is coupled to the control device 3 via the control line 16, and the base of the bipolar transistor 42 is connected to the control device 3 via the control line 17. Thus, the control of the switch 11 by means of the bipolar transistors 41, 42 takes place.

The electric switch 11 according to Fig. 7 is also a bistable relay. It comprises a coil 43 which - depending on the current direction of a current pulse - attracts or pushes away the movable contact element 13. For this purpose, the coil 43 on the one hand with a Switch 44 and on the other hand connected to a switch 45. The switches 44, 45 can be realized as transistors. On both sides, the coil 43 via the respective switch 44, 45 either with the reference potential 9 or with a DC voltage - for example, the DC operating voltage U _B - are connected. Thus, the current direction can be controlled by the coil 43: If the coil 43 is coupled via the switch 45 with the DC operating voltage U _B and the switch 45 to the reference potential 9, the current flows in a first direction; however, if the coil 43 is coupled via the switch 44 to the reference potential 9 and via the switch 45 to the DC operating voltage U _B , then the current flows in the second direction. If the coil 43 is coupled to the reference potential 9 on both sides, then no current flows.

The switch 11 according to Fig. 8 essentially corresponds to the according Fig. 6 in which the base of the bipolar transistor 41 responsible for closing the movable contour element 13 is coupled via an ohmic resistor 46 to a DC voltage source which supplies a DC voltage V. The DC voltage V can also be the DC operating voltage U _B or a separate DC voltage. The DC voltage V is supplied by the voltage supply unit 10 (FIG. Fig. 1 and 2 ) provided. Such a design ensures that the switch 11 is automatically closed immediately after pressing the button 18, namely independently of the control device. 3

In Fig. 14 is a variation of the in Fig. 2 shown circuit arrangement 2 with a further state detection device 23 and with in Fig. 10 shown decoupling device 12 shown.

In the state detecting device 23 of this modification, an ohmic resistor 27 and a diode 52 are connected in series between the input 22 and the output 24. Furthermore, the output 24 is coupled via a parallel connection of a further ohmic resistor 31 to the reference potential 9. The cathode of the diode 52 is connected to the ohmic resistor 27 and the anode of the diode 52 to the input 22. The ohmic resistors 27 and 31 represent a voltage divider and are designed such that at the output 24, the state signal 26 can not exceed a permissible for the input 25 of the control unit 3 maximum voltage. The diode 52 serves as a "one-way" rectifier circuit, ie that the negative Half-waves of the voltage applied to the inputs 5 and 6 AC voltage U _{V are} cut off. In this example, the status signal 26 is therefore always a positive electrical voltage U _Z , which can be easily evaluated by the control unit 3, in particular by a microcontroller. Furthermore, this circuit arrangement has the in Fig. 10 shown decoupling device 12. The diode 34 of the decoupling device 12 again causes no reaction to the status signal 26 in the case of a closed contact element 13 is possible. Thus, the position of the switch 20 of the button 18 can be detected by the control device 3 in the case of an open and closed contact element 13. The voltage U _Z may have the following properties: If the button 18 is not actuated, the input 22 is free of the alternating supply voltage U _V. At the output 24 is no voltage. In the non-actuated state of the button 18, the voltage U _{Z is} equal to zero. In the actuated state of the button 18, however, is applied to the input 22, the AC supply voltage U _V and is rectified by the diode 52. The voltage U _Z thus alternates between zero and an amplitude value, which results from the selection of the resistors 27 and 31, namely for example between zero volts and five volts. The voltage U _Z changes with the frequency of the supply AC voltage U _V. In such a manner, the controller 3 can reliably, unambiguously and quickly recognize whether the button 18 has been operated or not. The contact element 13 may, as in the preceding examples via a in the Fig. 14 not shown control part 15 are actuated, which is connected for driving the control part 15 with the control device 3 via control lines 16 and / or 17, not shown, with the control device 3.

In this modification, the power supply unit 10 is designed as a switching power supply. Therefore, a rectifier circuit 53 is provided between the contact 14 and the contact 12b. For the in Fig. 14 Other embodiments of the power supply unit 10 may be provided, then the rectifier circuit 53 may be omitted depending on the design.

The circuit arrangement 2 according to this modification can also be combined with all the control parts 15 described above.

Fig. 9 shows an alternative embodiment of the switch 11 and a circuit for driving it. The switch 11 is also a bistable relay, such as a surge relay. The control part 15 includes a coil 47; by energizing the coil 47 with a current pulse, the switching state of the movable contact element 13 changes. The coil 47 is coupled on the one hand with the DC operating voltage U _B or another DC voltage; on the other hand, it is connected to the collector of an NPN bipolar transistor 48. The emitter of the bipolar transistor 48 is connected to the reference potential 9. Its base is connected to the control input 11a of the control part 15. In this embodiment, the control input 11a of the switch 11 is coupled via an ohmic resistor 49 and a diode 50 to the button 18, namely, for example, with that contact element of the button 18, which is also connected to the state detection device 23. The anode of the diode 15 is coupled to the push button 18 and its cathode to the control input 11 a. The control input 11a is also coupled via a capacitor 51 to the reference potential 9. The diode 50, the resistor 49 and the capacitor 51 represent a total of a small capacitor power supply. These components and the connection with the button 18 ensure that the switch 11 is closed immediately after pressing the button 18, regardless of the control device. 3

The detection of the actuation of the button 18 with a closed contact element 13 can be done with the state detection devices 23 shown in FIG. 23 or 24.

Since different types of bistable relay are used in terms of their performance, additional, designed for high-power operation relay can be used and although parallel to the switch 11, an additional switch - for example, a relay - are used, via which at least one electrical load the household appliance 1 is supplied with electrical energy. The control of the additional switch can be done in an analogous manner, as the control of the switch 11. Such an additional switch is then preferably designed for operation with currents up to 16 amps.

The control device 3 may also be a plurality of microcontrollers which communicate with each other via an internal communication bus. For example, a first microcontroller may be connected to the state detection device 23 - it can then recognize the instantaneous switching state of the button 18. A second microcontroller can be used to control the switch 11. The first and the second microcontroller can exchange data with each other via the communication bus. Both microcontrollers may be coupled to the power supply unit 10.

Overall, a circuit arrangement 2 is provided with which a clear recognition of the actuation of the button 18 is made possible. The control device 3 can automatically detect whether the button 18 has been actuated by an operator in the switched-on state of the domestic appliance 1 and thus the domestic appliance 1 should be switched off safely. The control device 3 can also switch off the household appliance 1 automatically after completion of an operating process. Such an automatic switch-off is also possible after failure of the supply AC voltage U _V. This can detect the control device 3, for example, based on a reduced amplitude of the DC operating voltage U _B , when selbige voltage is provided to a capacitor of the power supply unit 10. So a safe switching off the household appliance is also possible in the case of failure of the AC supply voltage U _V. By using a bistable switch 11, an already started operating process can be properly completed even after a prolonged failure of the supply AC voltage U _V persists.

For the electrical supply of consumers, such as a heater or a motor, or sensors of the household appliance 1, the circuit arrangements described above 2, not shown, branch points. For example, the AC supply voltage U _V between the reference potential 9 and the contact element 14 can be tapped. Furthermore, the DC operating voltage UB can also serve to supply the consumers or the sensors of the domestic appliance 1. The branching points for the consumers or sensors are preferably incorporated in the circuit arrangement 2 in such a way that opening of the contact element 13 also interrupts the electrical supply of the consumers or sensors.

LIST OF REFERENCE NUMBERS

1

household appliance

2

circuitry

3

control device

4

circuit input

5, 6

input connectors

7

phase conductor

8th

neutral

9

reference potential

10

Power supply unit

11

electrical switch

12

decoupling device

12a, 12b, 12c

connections

13

movable contact element

14

stationary contact element

15

control part

11a, 11b

control inputs

16, 17

control lines

18

button

19

operating element

20, 21

switch

22

entrance

23

State detector

24

output

25

detection input

26

state signal

27

resistors

28

resistance

29

diode

30

diode

31

resistance

32

energy storage

33

branching unit

34

diode

35

diode

36

Resistance / NTC / PTC

37, 38

Do the washing up

39

Kitchen sink

40

Kitchen sink

41, 42

Bipolar transistors

43

Kitchen sink

44, 45

switch

46

resistance

47

Kitchen sink

48

Bipolar transistor

49

resistance

50

diode

51

capacitor

52

diode

53

Rectifier circuit

U _V

AC supply voltage

U _B

Reverse Standoff

U _Z

tension

V

DC

Claims (16)

1. Circuit arrangement (2) for operating a domestic appliance (1), comprising:

   - a circuit input (4) for application of a supply alternating voltage (U_V),

   - a control device (3) for controlling operating processes of the domestic appliance (1),

   - a voltage supply unit (10), which is coupled with the control device (3), for providing an operating direct voltage (U_B) for the control device (3) from the supply alternating voltage (U_V),

   - a button (18), which is actuable by an operator and by way of which the voltage supply unit (10) can be coupled with the circuit input (4), and

   - an electrical switch (11), which is connected in parallel with button (18) and which is switchable by the control device (3) between an electrically conductive switching state in which the voltage supply unit (10) is coupled with the circuit input (4) and an electrically blocking switching state,

   characterised in that the circuit arrangement (2) comprises a state detection device (23), which is coupled with the button (18) and the control device (3) and which is constructed for the purpose of detecting a switching state of the button (18) and to deliver to the control device (3) a state signal (26) reproducing the switching state of the button (18), wherein the control device (3) is constructed for the purpose of switching the electrical switch (11) in dependence on the state signal (26) and that the circuit arrangement (2) comprises a decoupling device (12), which is connected between the electrical switch (11) and the state detection device (23) and which is constructed for the purpose of electrically decoupling the state detection device (23) at least in part from the electrical switch (11).
2. Circuit arrangement (2) according to claim 1, characterised in that the state detection device (23) comprises a rectifier, particularly a diode (52), which is connected with the button (18) and with a voltage divider, and that the state signal (26) can be derived at the voltage divider.
3. Circuit arrangement (2) according to claim 1, characterised in that the state detection device (23) comprises a circuit arrangement in which connected between an input (22) and an output (24) of the state detection device (23) is at least one resistance (27), in which the output (24) is coupled with a direct voltage source by way of a parallel connection of a further resistance (28) and a diode (29) and in which the output (24) is coupled with the reference potential (9) of the circuit arrangement (2) by way of a parallel connection of a second diode (30) and a further resistance (31).
4. Circuit arrangement (2) according to any one of claims 1 to 3, characterised in that the decoupling device (12) comprises a resistive impedance (36) and/or a first diode (34), the cathode of which is coupled with the electrical switch (11) and the anode of which is coupled with the state detection device (23).
5. Circuit arrangement (2) according to claim 4, characterised in that the decoupling device (12) comprises a second diode (35), the anode of which is connected with the switch (11) and the cathode of which is connected with the cathode of the first diode (34) and the voltage supply unit (10).
6. Circuit arrangement (2) according to any one of the preceding claims, characterised in that the state detection device (23) is constructed for the purpose of delivering to the control device (3) an electrical voltage (U_Z) as state signal (26), which in an open switching state of the button (18) has at least one first characteristic and in a closed switching state of the button (18) has at least one second characteristic.
7. Circuit arrangement (2) according to any one of the preceding claims, characterised in that the control device (3) is constructed for the purpose of changing the switching state of the electrical switch (11) after recognition of actuation of the button (18) on the basis of the state signal (26), particularly for switching the electrical switch (11) to the electrically blocking switching state after recognition of actuation of the button (18) in the conductive switching state of the same switch (11).
8. Circuit arrangement (2) according to any one of the preceding claims, characterised in that the control device (3) is constructed for the purpose of switching the electrical switch (11) to the electrically blocking switching state after the end of an operating process of the domestic appliance.
9. Circuit arrangement (2) according to any one of the preceding claims, characterised in that the electrical switch (11) is a bistable relay.
10. Circuit arrangement (2) according to claim 9, characterised in that the bistable relay comprises two coils (37, 38), wherein the coils (37, 38) are coupled on the one hand with an operating direct voltage U_B of the voltage supply unit (10) and on the other hand each with the collector of an NPN bipolar transistor (41, 42), the respective emitters of which are connected with the reference potential (9) of the circuit arrangement (2), and that the respective bases of the NPN bipolar transistors (41) are coupled with the control device (3) by way of control lines (16).
11. Circuit arrangement (2) according to claim 10, characterised in that the base of the bipolar transistor (41) responsible for closing the switch (11) is coupled by way of a resistive impedance (46) with a direct voltage source which provides a direct voltage V when the button (18) is actuated.
12. Circuit arrangement (2) according to claim 11, characterised in that the bistable relay comprises a coil (43), which opens or closes the switch (11) in dependence on the respective flow direction of a current pulse and which is connected with a first switch (44) and with a second switch (45), wherein one side of the coil (43) is connected by way of the first switch (44) and the other side of the coil (43) is connected by way of the second switch (45) with a direct voltage (V) or with a reference potential (9), and that the first and second switches (44, 45) can be activated by way of signal lines (16, 17) which are connected with the control device (3).
13. Circuit arrangement (2) according to any one of the preceding claims, characterised in that the circuit arrangement (2) comprises an electrical energy store (32) coupled with a control input (11 a, 11 b) of the electrical switch (11) and the electrical switch (11) can be supplied with electrical energy from the energy store (32) for maintenance of the conductive switching state.
14. Circuit arrangement (2) according to any one of the preceding claims, characterised in that a control input (11 a, 11 b) of the electrical switch (11) is coupled with the voltage supply unit (10) and/or with the button (18) so that on actuation of the button (18) by the operator the electrical switch (11) is switchable from the electrically blocking to the electrically conductive switching state.
15. Domestic appliance (1) with a circuit arrangement (2) according to any one of the preceding claims.
16. Method of operating a domestic appliance (1) with a circuit arrangement (2), wherein operating processes of the domestic appliance (1) are controlled by a control device (3), comprising the steps:

    - applying a supply alternating voltage (U_V) to a circuit input (4) of the circuit arrangement (2),

    - coupling a voltage supply unit (10), which is coupled with the control device (3), with the circuit input (4) by way of a button (18),

    - providing an operating direct voltage (U_B) for the control device (3) from the supply alternating voltage (U_V) by the voltage supply unit (10) and

    - switching an electrical switch (11), which is connected in parallel with the button (18), between an electrically conductive switching state in which the voltage supply unit (10) is coupled with the circuit input (4) and an electrically blocking switching state by the control device (3),

    characterised in that a switching state of the button (18) is detected by means of a state detection device (23) coupled with the button (18) and the control device (3), that a state signal (26) reproducing the switching state of the button (18) is delivered to the control device (3), wherein the control device (3) switches the electrical switch (11) in dependence on the state signal (26), and that the state detection device (23) is electrically decoupled at least in part from the electrical switch (11) by means of a decoupling device (12) connected between the electrical switch (11) and the state detection device (23).

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