The present disclosure relates generally to an electromagnetic cooking device, and more particularly to a user interface assembly for the electromagnetic cooking device.

BACKGROUND

Cooking appliances have become a necessity in our day to day activities to provide flexibility and convenience to a user. For example, an induction cooktop provides multiple tactile switches and light emitting diodes (LEDs) on their user interface panel to enable user interactions. However, the plethora of switches and LEDs generally creates confusion among the user while operating the induction cooktop as well as increase cost and size of the user interface. With an advent of innovations in power electronics, there is a need of cooking appliances where multiple functions such as power control, temperature control, and timer control, pause and resume are achieved by minimal number of buttons in a user-friendly manner.

In a conventional portable Induction cooktop, a generic display controller in combination with multiple tactile buttons is provided. Usually, 6 to 18 tactile buttons are used in a user interface of the conventional portable induction cooktop. Further, a TH1628B multiplexer is used with I2C interface with master board. User data input is taken from 12 to 18 keys and output is shown on a 4x7 segment display and 10 to 12 LEDs indicators are provided to render current status of the induction cooktop. To house these buttons, display and LEDs, a relatively large and a complex PCB is installed which influences an overall housing size of the conventional induction cooktop. In addition, the tactile switches which are widely used in the induction cooktop have limited switching life. Also, tactile switches lose their feel/connection due to rebounding issues which appear with time thus lead to loss of feedback to user.

In another conventional induction cooktop, a potentiometer for rotary control in user Interface of appliances is provided. However, this solution has significant limitations. The known potentiometer can be used as a rotary switch for a single function only and that too within a limited range, for example only for increase/decrease of power selection of the cooktop. Since potentiometer can execute only one function, multiple tactile switches must be used to provide other functionalities which again increase the form factor of Front panel of the cooktop disposing the user interface assembly.

Furthermore, the complex user interface of the conventional portable induction cooktop with relatively high number of buttons is not intuitive for a user. It requires time for a new user, especially who are shifting from conventional LPG or Kerosene stove to Induction cooktop, to understand and operate the functionalities of the cooktop. For elderly people and people who have difficulty in reading or understanding the instructions from an instruction manual, the learning curve is very steep which limits the acceptance of Induction cooktop as mainstream cooking appliance.

In view of the foregoing discussion, therefore, there exists a need to provide a compact user interface which provides ease of use to a user, as well as reduces component cost and form factor of an electromagnetic cooking device.

SUMMARY

Accordingly, a user interface assembly for an electromagnetic cooking device has been provided. The user interface assembly includes a front panel which interfaces with a power circuit. The front panel interfaces with the power circuit using 3 wires (data, clock & standby), along with 2 wires for power to front panel (5V) & Ground. A multiplexer on the front panel sends information to power circuit regarding keys pressed on the front panel of the user interface assembly. A microcontroller takes input from two tactile switches and a multifunctional rotary encoder switch. One of the tactile switches is used to toggle the mode of operation of the electromagnetic cooking device from power mode to timer mode and vice versa. The multiplexor gets information to drive LEDs and a display unit, from the microcontroller through a switching circuit. The use of rotary encoder switch interfacing on the front panel of the user interface assembly helps to replace tactile switches with transistors whose base is now controlled through microcontroller. The microcontroller receives user interaction signals from the rotary encoder switch. The use of the microcontroller on the front panel of the user interface assembly further enables to dim the LED string of a visual feedback assembly through transistors. A set of LEDs driven by the multiplexer indicate if the mode of operation is a Timer mode or a Power mode. Another LED may indicate if the IGBT is in ON state and no error is being encountered. This LED shall continue to glow until user puts IGBT in OFF state by button actuation manually or if there is any error. A third LED indicates if complete solution power is ON or OFF. The tactile switch to turn the device on/off is provided on front panel of the user interface assembly such that both MCU (Power circuit & Front panel) set/reset simultaneously.

The present disclosure uses a rotary encoder switch to reduce keys and LED indicators. Thus, it saves a lot on PCB size. Also, the microcontroller interfaces with multiplexer based on control algorithm to reduce LED indicators and input tactile switches. This also increases product life by reducing switching life of tactile switches. Further, implementing multifunction single rotary encoder switch makes the user interface assembly more user friendly and robust.

The user interface assembly in accordance with an embodiment of the present invention, provides conventional gas stove like control on induction cooktop by utilizing multifunctional rotary encoder switch (Power increase and decrease, timer increase and decrease, pause and resume function), LED Flame Intensity Indicator & power/timer selection and error indication on LED display. The user interface includes a dedicated microcontroller and a rotary encoder switch. The rotary encoder switch is configured to enable pause and resume functionality of the induction cooktop in accordance with an embodiment of the present invention. The rotary encoder switch can be rotated by the user to achieve a functionality of increase/decrease of the selected entity (power or time). The rotary encoder switch can also work as a push/pull switch to pause and subsequently resume the operation of the cooktop when pressed by a user. For example, a user may press the rotary encoder switch once to pause the operation of the cooktop. Subsequently, the user may want to resume the operation of the cooktop. So, the user can press the rotary encoder switch again to resume the operation of the cooktop. Further, the user interface assembly in accordance with the present invention advantageously provides a PCB size reduction, less tactile switches (one for Power On – Off and other for Power/ Time toggle) and compact size of housing. The overall cost of the induction cooktop solution is reduced as the additional element cost (microcontroller and rotary encoder switch) is overshadowed by decrease in cost of the PCB size, housing size and a smaller number of tactile switches.

An object of the embodiments herein is to provide a user interface assembly for an electromagnetic cooking device having reduced number of buttons on the front panel.

Another object of the embodiments herein is to provide a user interface assembly for an electromagnetic cooking device having a rotary encoder switch to enable manipulation of timer or power settings and Pause and resume function of the cooking device.

Another object of the embodiments herein is to provide a user interface assembly for an electromagnetic cooking device having a tactile switch to toggle the mode of operation of the user interface module between a timer mode and a power mode.

Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow. It will be appreciated that numerous modifications and variations in addition to those mentioned herein will occur to those skilled in the art. Accordingly, it is intended that the invention not be limited to the disclosed embodiment, but it have the full scope permitted by the language of the appended claims.

BRIEF DESCRIPTION OF FIGURES

The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
FIGs. 1A and 1B illustrate a user interface assembly of a conventional electromagnetic cooking device;
FIG. 2 is a block diagram showing different modules of an electromagnetic cooking device, according to embodiments disclosed herein;
FIG. 3 illustrates different parts of an electromagnetic cooking device, according to embodiments disclosed herein;
FIG. 4A illustrates a front panel of the user interface assembly, according to embodiments disclosed herein;
FIG. 4B illustrates a Printed Circuit Board which forms a part of the front panel of the user interface assembly, according to embodiments disclosed herein;
FIG. 5 illustrates a front panel of the user interface assembly providing recesses for disposing rotary encoder switch, tactile switches and a display unit, according to embodiments disclosed herein;
FIG. 6 illustrates a method for generating heat in a cooking utensil using electromagnetic waves, according to embodiments disclosed herein;
FIG. 7 illustrates a block diagram showing circuit components for generating heat in a cooking utensil using electromagnetic waves, according to embodiments disclosed herein;
FIG. 8A is a block diagram disclosing different modules and components of a user interface assembly of an electromagnetic cooking device, according to embodiments disclosed herein;
FIG. 8B is a schematic diagram of the user interface assembly of an electromagnetic cooking device, according to embodiments disclosed herein;
FIG. 9 is a flow chart illustrating generation of a mode signal by pressing a tactile switch on the user interface assembly by a user, according to embodiments disclosed herein;
FIG. 10 is a flow chart illustrating manipulation of display based on rotation of the rotary encoder switch by a user, according to embodiments disclosed herein;
FIG. 11 is a flow chart illustrating generation of a pause signal when a user presses the rotary encoder switch, according to embodiments disclosed herein; and
FIG. 12 is a table illustrating the bits used for indication of errors as well as power level selection by a user, same is used by front panel controller to indicate the power level selection on the led strip (Flame intensity low medium high and off) according to embodiments disclosed herein.

DETAILED DESCRIPTION

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a nonexclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The embodiments herein achieve user interaction with an electromagnetic cooking device via a user interface assembly. The user interface assembly includes a first tactile switch configured to generate a mode signal based on a number of actuations of the first tactile switch. The mode signal corresponds to at least one of a timer mode of operation or a power mode of operation of the electromagnetic cooking device. A rotary encoder switch is provided on the interface and is configured to manipulate timing settings in the timer mode of operation and power settings in the power mode of operation, when the user rotates the rotary encoder switch in a clockwise or in an anticlockwise direction. The rotary encoder switch generates an encoding signal based on degree and direction of rotation of the rotary encoder switch by the user. A microcontroller is connected to the rotary encoder switch and configured to generate output signals upon processing the encoding signal. Further, a switching circuit is connected to the microcontroller, the first tactile switch and at least one power source. The switching circuit generates a plurality of switching signals based on the output signals of the microcontroller and the mode signal. A multiplexer is connected to the switching circuit and configured to receive at least one of the plurality of switching signals and generate a plurality of display signals. A display circuit connected to the multiplexer, a display unit and a plurality of illumination devices, such that the display circuit processes the display signals to render a change in each of the display unit and the plurality of illumination devices, the change representative of the encoding signal and the mode signal.
In an embodiment, during the timer mode of operation the microcontroller is configured to increase a time of operation of the electromagnetic cooking device upon clockwise rotation of the rotary encoder switch and decrease the time of operation of the electromagnetic cooking device upon anticlockwise rotation of the rotary encoder switch. The multiplexer of the user interface assembly is further connected to a power-controller using a serial data communication interface. A power circuit disposed under the glass panel is connected to the power-controller. The power-controller is configured to control the power circuit in accordance with the rotation of the rotary encoder in a manner such that a clockwise rotation of the rotary encoder switch increases a heat output of the electromagnetic cooking device, and an anticlockwise rotation of the rotary encoder switch decreases the heat output of the electromagnetic cooking device.

In an embodiment, the power circuit includes a semiconductor switching module connected to the power-controller and a resonant tank circuit. The operation of the resonant tank circuit is controlled by the semiconductor switching module based on a power signal, such that the power circuit is configured for controlling the heat output generated in the electromagnetic cooking device based on the power signal. The semiconductor switching module includes a driver device to provide a soft start to an Insulated Gate Bipolar Transistor (IGBT). The driver device is configured to provide a soft start to the IGBT by generating an ON_OFF signal, such that the frequency of the ON_OFF signal is incremented in predetermined steps by the driver device from a base frequency value to a frequency-value corresponding to the encoding signal.

In an embodiment, one of the output signals generated by the microcontroller is configured to control a visual feedback, such that at least one parameter of the visual feedback is representative of the heat output of the electromagnetic cooking device. Furthermore, the microcontroller is configured to receive a plurality of ERR signals from the power-controller, and generate at least one of the output signals to control the visual feedback, based on processing of the plurality of ERR signals. In another embodiment, the microcontroller processes the plurality of ERR signals to halt the operations associated with the electromagnetic cooking device. The rotary encoder switch generates a PAUSE signal, such that the microcontroller processes the PAUSE signal to halt the operations associated with the electromagnetic cooking device. The rotary encoder switch is configured to enable pause and resume functionality of the electromagnetic cooking device in accordance with an embodiment of the present invention. The rotary encoder switch can be rotated by the user to achieve a functionality of increase/decrease power in the power mode of operation of the electromagnetic cooking device, or increase/decrease time in the timer mode of operation of the electromagnetic cooking device. The rotary encoder switch can also work as a push/pull switch to pause and subsequently resume the operation of the electromagnetic cooking device. For example, a user may press the rotary encoder switch once to pause the operation of the electromagnetic cooking device. When the user presses the rotary encoder switch, a PAUSE signal is generated at one of the pins of the rotary encoder switch. Subsequently, the user may want to resume the operation of the electromagnetic cooking device. So, the user can press the rotary encoder switch again to resume the operation of the electromagnetic cooking device. When the user presses the rotary encoder switch again, a RESUME signal is generated at one of the pins of the rotary encoder switch.

In an embodiment, the user interface assembly further includes a second tactile switch to switch the device ON/OFF and is configured to synchronize the reset operation of the microcontroller and the power-controller when the user actuates the second tactile switch. The front panel of the user interface assembly includes a plurality of recesses for disposing the rotary encoder switch, the first tactile switch, the second tactile switch and the display unit.

Referring now to the drawings, and more particularly to FIGS. 1 through 12, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.

Figures 1A and 1B illustrate two examples of user interface assembly 100 of a conventional electromagnetic cooking device of the prior art. The user interface assembly 100 includes multiple circuit components integrated to a printed circuit board to enable user interaction with a conventional electromagnetic cooking device. It includes multiple tactile switches 110, light emitting diodes 120 and a display 130. Since such conventional user interfaces had multiple tactile buttons and LEDs, they were bulky as well as inconvenient for user interactions.

Referring to Fig. 2, an electromagnetic cooking device 200, and its components are explained in accordance with an embodiment of the present invention. The cooking device 200 provides a user interface assembly 210 for user interactions with the cooking device. A power circuit 220 is provided to generate electromagnetic waves adjacent to a glass panel 230. The electromagnetic waves interact with the material of the cooking utensil (not shown) to generate heat, and hence achieve cooking. A visual feedback assembly 240, such as a LED string, is provided under the glass panel to provide a visual feedback to the user based on the heat output selected by the user using the user interface assembly. In an embodiment, the visual feedback can be a Flame Intensity Indicator visible through the glass panel 230. Although the example of a visual feedback has been shown as a LED string forming a Flame Intensity Indicator , it must be understood that the any type of visual feedback can be used, such as use of thermochromic ink pattern, LCD screen or OLED screen.

Referring to Fig. 3, the user interface assembly 210 provides two tactile switches 310 and 320, a rotary encoder switch 330 and a display panel 340. Illumination devices 350 and 360 are provided adjacent to each of the tactile switches 310 and 320 respectively. In an embodiment, illumination devices 350 and 360 are LEDs. The electromagnetic cooking device 200 further includes a housing 370, which houses the power circuit, and the wiring connections. The housing 370 may also accommodate a fan assembly, a buzzer, proximity sensors, weight sensors and thermal management components associated with the electromagnetic cooking device 200. Further, the glass panel 230 may overlap a visual feedback assembly 240. In an embodiment, the visual feedback assembly may include LED strings which form a circular shape and provide the visual appearance of a flame Intensity Indicator when operational. The visual appearance of the Flame Intensity Indicator may be further accentuated by providing opaque coatings 380 in a predetermined pattern ( as an option) under the glass panel 230.
A front panel 410 which forms part of the user interface assembly 210 of the electromagnetic cooking device 200 is shown in Fig. 4A. The front panel includes a printed circuit board (PCB) which is used to print the interconnection circuitry of the components of the user interface assembly 310. The printed circuit board may have connection ports to connect the components such as tactile switches 420 and 430, rotary encoder switch 440 and display unit 450 As shown in Fig. 4B, the printed circuit board can have a front side 410A and a rear side 410B.

Referring to Fig 5, the front panel 410 further includes a cover 510 which covers the printed circuit board, and gives an aesthetic look to the front panel 410. The cover 510 provides multiple recesses to dispose the components of the user interface assembly 210. In an embodiment, recess 520 is provided to dispose a first tactile switch 420. The tactile switch 420 may be used to toggle the mode of operation of the electromagnetic cooking device. When the user presses the tactile switch 420 once, a timer mode of operation is selected. Subsequently, when the user presses the tactile switch 420 again, a power mode of operation is selected. Recess 530 is provided to dispose a second tactile switch 430. The tactile switch 430 may be used to switch the electromagnetic cooking device 200 from off to on state, or on to off state. Recess 540 is provided to dispose a rotary encoder switch 330. A user may turn the rotary encoder switch 330 to manipulate the power/time settings of the electromagnetic cooking device 200. Recess 550 is provided to dispose a display unit 450. In an embodiment, the display unit 450 may be a seven segment display. The display unit 450 provides a display of the values of the power or timer settings selected by the user and also display types of errors, and indications for plate hot and Pause features. When the user rotates the rotary encoder switch 330, the values on the display unit may change in accordance with the rotation of the rotary encoder switch 330 by the user, and the mode of operation selected by the user using the tactile switch 420.

Fig. 6 elaborates the operation of an electromagnetic cooking device 200. A power circuit 610 is connected to coils 630 using the wires 620. When a High frequency alternating current is passed through the coil 630, an oscillating magnetic field 640 is generated due to the presence of electromagnets 660 surrounding the coil. As shown in the figure, the oscillating magnetic field 640 can interact with a ferromagnetic cookware 650 kept on top of the glass panel 230 to induce eddy current in the cookware. This, in turn, generates heat and cooks the food kept in the cookware 650.

Fig. 7 further describes the operation of the electromagnetic cooking device 200, and the components of the power circuit 610. The power circuit 610 includes a resonant tank circuit 710 primarily responsible to generate heat. A power-controller 720 is a part of the power circuit 610, and can interface with the front panel PCB 410 of the user interface 210 using a serial data communication interface 750. In an embodiment, the serial data communication interface is an I2C interface. The power-controller is configured to control the power circuit in accordance with the rotation of the rotary encoder switch 330 in a manner such that a clockwise rotation of the rotary encoder switch 330 increases a heat output of the electromagnetic cooking device 200, and an anticlockwise rotation of the rotary encoder switch 330 decreases the heat output of the electromagnetic cooking device 200. The power-controller 720 is further connected to a semiconductor switching module connected to the power-controller 720. The semiconductor switching module includes an insulated-gate bipolar transistor (IGBT) Gate driver 730 and an IGBT 740. The IGBT is a three-terminal power semiconductor device primarily used as an electronic switch. The operation of the resonant tank circuit is controlled by the semiconductor switching module based on a power signal generated by the power-controller 720, such that the power circuit 610 is configured for controlling the heat output generated in the electromagnetic cooking device 200 based on the power signal. On selection of a power value in the power mode of operation of the electromagnetic cooking device 200 by rotating the rotary encoder switch 330 on the user interface, the cooking device 200 takes 2-3 seconds to progressively achieve the required power. This feature is termed as soft start. The IGBT Gate driver 730 provides a soft start to the IGBT 740.

In an embodiment, the Gate driver 730 is configured to provide a soft start to the IGBT 740 by generating an ON_OFF signal with variable frequency. The frequency of the ON_OFF signal is incremented in predetermined steps by the IGBT Gate driver 730 from a base frequency value to a target frequency value. The target frequency value may correspond to an encoding signal generated by the rotary encoder switch 330, when the user rotates the rotary encoder switch 330. In an embodiment, the target frequency values corresponding to attributes associated with the rotation of the rotary encoder switch by a user may be pre-stored in the memory of the power-controller 720. This means that every power selection is defined with frequency and current limit whenever a user selects a particular power. The power-controller is configured to divide that frequency into 4 -5 stages and power jumps from one frequency to other frequency with time delay. The base frequency used for this operation is generally in the range of 30 to 35 kHz (that is above the audio range). In an embodiment, the power circuit may be designed as a closed loop, as is known in the art, to support best output on selected power with ferrite load condition, to reduce stress on IGBT and increase power devices life.

Figures 8A and 8B describe the user interface assembly and its operation in detail. Fig. 8A illustrates the high-level modules of the user interface assembly 210 of an electromagnetic cooking device 200, while Fig. 8B illustrates the schematic diagram of these modules on the Front Panel PCB 410. A rotary encoder switch 810 is provided to be rotated in a clockwise or anticlockwise direction by a user. This user interaction generates an encoding signal DT based on degree and direction of rotation of the rotary encoder switch 810 by the user. A microcontroller 820 is connected to the rotary encoder switch 810 to receive the encoding signal DT at one of its I/O ports. The microcontroller 820 is configured to generate multiple output signals on its I/O ports upon processing the encoding signal DT.

In an embodiment, the output signals generated by the microcontroller are represented in the schematic diagram by SW1, SW2, SW3 and SW4. A switching circuit 830 is connected to the microcontroller 820, the first tactile switch 860A and a power source 870. The switching circuit receives the output signals SW1, SW2, SW3 and SW4 from the microcontroller 820. A 1-level switching circuit may be formed by connecting one of the output signals from the microcontroller 820 to the base of a p-n-p transistor Q2. The emitter of the p-n-p transistor Q2 may be connected to one of the I/O ports (SAG1/KS1) of the multiplexer 840, while the collector port may be connected to another port KEY1 of the multiplexer 840 to define a base voltage level. The base of the p-n-p transistor Q2 may further be connected to a 5V power source 870. The present invention utilizes this switching circuit to reduce multiple hardware tactile switch and replaces it with semiconductor switches driven by a microcontroller. This 1-level switching circuit may be scaled to a 4-level switching circuit, to receive the 4 output signals SW1, SW2, SW3 and SW4 from the microcontroller, at the base of p-n-p transistors Q2, Q3, Q4 and Q5. A tactile switch 860A is connected to KEY1 and one of the I/O ports of the multiplexer 840. The tactile switch 860A is configured to generate a mode signal SAG2/KS2 based on a number of actuations of the tactile switch 860A. The mode signal SAG2/KS2 corresponds to either a timer mode of operation or a power mode of operation of the electromagnetic cooking device. The switching circuit 830 generates switching signals SAG1/KS1, SAG3/KS3, SAG4/KS4 and SAG6/KS6 based on the output signals SW1, SW2, SW3 and SW4 of the microcontroller and the mode signal SAG2/KS2. The multiplexer 840 is connected to the switching circuit 830 and configured to receive at least one of the switching signals at its I/O ports. The multiplexer 840 generates display signals GRID1, GRID 2, GRID3 and GRID4. A display circuit 850 is connected to the multiplexer 840, a display unit 450 and two illumination devices 880A and 880B, such that the display circuit processes the display signals to render a change in the display unit 450 and the illumination devices 880A and 880B. This change is representative of the encoding signal DT and the mode signal SAG2/KS2.

In an embodiment, the second tactile switch 860B is used to switch the cooking device 200 from an off to on state or on to off state. Fig. 8B shows the connection of the second tactile switch 860B to the microcontroller 820. The circuit connections of the second tactile switch with microcontroller 820 and power-controller 720 is configured to synchronize the reset operation of the microcontroller 820 and the power-controller 720 when the user actuates the second tactile switch 860B. Still referring to Fig. 8B, connections 890 enable the interconnections to be made between different components of the schematic diagram. In an embodiment, connection J4 is a programming port used for programming the microcontroller 820 using the Single Wire Interface module (SWIM). Connection CONN1 is used to interconnect wires ERR1, ERR2, PC3_DATA, PB4_STB and PB5_CLK to provide serial data communication between the power-controller 720, multiplexer 840 and microcontroller 820. In an embodiment, CONN1 is the connector on the front panel PCB which is connected to power circuit through a ribbon connector.

Referring to Fig. 9, a selection of mode of operation of the electromagnetic cooking device 200 is described herein using blocks in a flow chart. In an embodiment, at step 910, a user may press a tactile switch 860B, herein mentioned as K6, to turn on the electromagnetic device 200. At step 920, the user may press the tactile switch 860A, herein mentioned as K2, to change the mode of operation of the electromagnetic cooking device 200. If the tactile switch K2 is actuated for the first time, or odd number of times, the voltage levels at KEY1 and SAG2/KS2 are altered by the multiplexer 840 to generate a timer mode signal. Based on the values of KEY1 and SAG2/KS2, the timer mode of operation is set for the electromagnetic cooking device. Any rotation of the rotary encoder switch 810 will change the values in the display unit 450 corresponding to timer settings. For example, when the timer mode of operation is set, a user may rotate the rotary encoder switch 810 clockwise to increase the timer value displayed in the display unit 450. Similarly, if the tactile switch K2 is actuated for the second time, or even number of times, the voltage levels at KEY1 and SAG2/KS2 are altered by the multiplexer 840 to generate a power mode signal. Based on the values of KEY1 and SAG2/KS2, the power mode of operation is set for the electromagnetic cooking device. Any rotation of the rotary encoder switch 810 will change the values in the display unit 450 corresponding to power settings. For example, when the power mode of operation is set, a user may rotate the rotary encoder switch 810 anti-clockwise to decrease the power value displayed in the display unit 450.

Fig. 10 describes the method of manipulating the settings of the electromagnetic cooking device 200. In a timer mode of operation, the timer settings may be manipulated. In a power mode of operation, the power settings may be manipulated. The rotary encoder switch 810 is rotated by a user to manipulate these settings in the cooking device 200. Based on the rotation of the rotary encoder switch 810, a change is rendered in the display unit 450. In an embodiment, the change rendered in the display unit 450 may be a change in the value displayed on the display unit 450. This method of manipulation of settings is described in steps 1010 to 1070 of the flow chart shown in Fig. 10. At step 1010, a mode signal is generated by a first tactile switch based on a number of actuations of the first tactile switch by a user, wherein the mode signal corresponds to at least one of a timer mode of operation or a power mode of operation of the electromagnetic cooking device. At step 1020, timing settings in the timer mode of operation and power settings in the power mode of operation are manipulated when the user rotates a rotary encoder switch in a clockwise or in an anticlockwise direction. At step 1030, an encoding signal is generated by the rotary encoder switch based on degree and direction of rotation of the rotary encoder switch, and at step 1040, output signals are generated by a microcontroller connected to the rotary encoder switch upon processing the encoding signal. At step 1050, a plurality of switching signals are generated by a switching circuit connected to the microcontroller, the first tactile switch and at least one power source, based on the output signals of the microcontroller and the mode signal. At step 1060, a plurality of display signals are generated based on processing of the switching signals by multiplexer and at step 1070 the display signals are processed by a display circuit connected to the multiplexer, a display unit and a plurality of illumination devices, to render a change in each of the display unit and the plurality of illumination devices, wherein the change is representative of the encoding signal and the mode signal. Based on the rotation of the rotary encoder switch, and based on the mode signal, the display unit may show a changed value. Further, based on the selection of the mode of operation of the electromagnetic cooking device 200 as described in accordance with Fig. 9, the display signals may change the state of illumination devices 880A and 880B. In an embodiment, the illumination devices are light emitting diodes (LEDs). When the timer mode of operation is selected by the user, LED 880A may be switched on, while LED 880B may be switched off. Similarly, when the power mode of operation is selected by the user, LED 880A may be switched off, while LED 880B may be switched on.

Referring to Fig. 11, a method and system to halt the operation of the electromagnetic cooking device 200 will now be described. At step 1110, the user may select a power mode of operation or a timer mode of operation using the first tactile switch 860A. At step 1120, the rotary encoder switch 810 may be pressed by a user to halt the operation of the cooking device 200. At step 1130, a determination is made by the microcontroller 820 that the rotary encoder switch 810 is pressed. This determination is made by the microcontroller 820 based on processing of a PAUSE signal, PSW, generated by the rotary encoder switch 810. The PSW signal is generated by the rotary encoder switch at pin E, as shown in block 810 of Fig. 8B. The PSW signal raises an interrupt in the microcontroller 820 to toggle pause function with recall feature. If the rotary encoder switch 810 is pressed, the operation of the cooking device 200 is halted. This means that the state of the microcontroller 820 on the Front Panel 410 of the user interface assembly 210, and power-controller 720 in the power circuit 610 is preserved. Further, the heat generation using the power circuit 610 is suspended. In an embodiment, this is achieved by suspending the generation of power signal by the power-controller 720 in the power circuit 610. If the rotary encoder switch 810 is pressed again, at step 1140, the operation of the cooking device 200 is resumed. At this step, the PSW signal can be representative of a RESUME signal generated by the rotary encoder switch. This means that the state of the microcontroller 820 on the Front Panel 410 of the user interface assembly 210 and power-controller 720 in the power circuit 610 are recalled, and the heat generation is resumed.

Fig. 12 illustrates a table which is used during serial data communication between the power-controller 720 and the microcontroller 820. The power-controller can use two bits sent over two wires to the front panel to provide a feedback of power selection by a user to the microcontroller 820. These bits are shown as ERR1 and ERR2 in the schematic diagram of Fig. 8B. Based on the processing of voltage levels of these bits ERR1 and ERR2 at one its input ports, the microcontroller can generate an output signal at PC6 port, as shown in block 820 of Fig. 8B, to control a visual feedback. At least one parameter of the visual feedback is representative of the heat output of the electromagnetic cooking device selected by the user using the components of the user interface assembly 210. The PC6 port is connected to the base of an n-p-n transistor Q1. The collector of Q1 is connected to the visual feedback assembly 240 through a connection CONN2, while the emitter is connected to ground. In an embodiment, visual feedback assembly 240 includes a LED string arranged to form a Flame Intensity Indicator under the glass panel 230. Further, the LED string assembly may be provided an 18V power supply using the Viper flyback from SMPS provided in the housing 370. In an embodiment, and as shown in Fig. 12, if the ERR1 is at a LOW or ‘0’ voltage level, and ERR 2 is at a HIGH or ‘1’ voltage level, it means that the power selection done by the user in the range of 600-1000 Watts. In this case, microcontroller 820 provides a PWM signal at PC6 port to illuminate a Flame Intensity Indicator at a low intensity. Alternatively, the lower number of LEDs may be illuminated to represent the low power selection of the range 600-1000W. If the ERR1 is at a HIGH or ‘1’ voltage level, and ERR2 is at a LOW or ‘0’ voltage level, it means that the power selection done by the user in the range of 1200-1600 Watts. In this case, microcontroller 820 provides a PWM signal at PC6 port to illuminate a Flame Intensity Indicator at a medium intensity. Alternatively, the relatively higher number of LEDs may be illuminated to represent the medium power selection of the range 1200-1600W. If the ERR1 is at a HIGH or ‘1’ voltage level, and ERR2 is at a HIGH or ‘1’ voltage level, it means that the power selection done by the user in the range of 1800-2000 Watts. In this case, microcontroller 820 provides a PWM signal at PC6 port to illuminate a Flame Intensity Indicator at a high intensity. Alternatively, all the LEDs may be illuminated to represent the high power selection of the range 1800-2000W. If the ERR1 is at a LOW or ‘0’ voltage level, and ERR2 is also at a LOW or ‘0’ voltage level, it means that the cooking device is on standby due to removal of a cookware 650 from the glass panel 230, or the cooking device 200 has a fault or in pause mode. In an embodiment, the detection of removal of the cookware 650 may be done by measuring current across the coil 630 ( No load condition) of the cooking device 200. In this case, the operation of the cooking device is halted, and the generation of heat is suspended.

It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Claims:1. A user interface assembly for an electromagnetic cooking device, the user interface assembly comprising:
a first tactile switch configured to generate a mode signal based on a number of actuations of the first tactile switch, wherein the mode signal corresponds to at least one of a timer mode of operation or a power mode of operation of the electromagnetic cooking device;
a rotary encoder switch configured to manipulate timing settings in the timer mode of operation and power settings in the power mode of operation, when the user rotates the rotary encoder switch in a clockwise or in an anticlockwise direction, wherein the rotary encoder switch generates an encoding signal based on degree and direction of rotation of the rotary encoder switch by the user;
a microcontroller connected to the rotary encoder switch and configured to generate output signals upon processing the encoding signal;
a switching circuit connected to the microcontroller, the first tactile switch and at least one power source, wherein the switching circuit generates a plurality of switching signals based on the output signals of the microcontroller and the mode signal;
a multiplexer connected to the switching circuit and configured to receive at least one of the plurality of switching signals and generate a plurality of display signals; and
a display circuit connected to the multiplexer, a display unit and a plurality of illumination devices, such that the display circuit processes the display signals to render a change in each of the display unit and the plurality of illumination devices, the change representative of the encoding signal and the mode signal.

2. The user interface assembly for an electromagnetic cooking device of claim 1, wherein during the timer mode of operation the microcontroller is configured to increase a time of operation of the electromagnetic cooking device upon clockwise rotation of the rotary encoder switch and decrease the time of operation of the electromagnetic cooking device upon anticlockwise rotation of the rotary encoder switch.

3. The user interface assembly for an electromagnetic cooking device of claim 1, wherein the multiplexer is further connected to a power-controller using a serial data communication interface, wherein a power circuit is connected to the power-controller, wherein the power-controller is configured to control the power circuit in accordance with the rotation of the rotary encoder in a manner such that a clockwise rotation of the rotary encoder switch increases a heat output of the electromagnetic cooking device, and an anticlockwise rotation of the rotary encoder switch decreases the heat output of the electromagnetic cooking device.

4. The user interface assembly for an electromagnetic cooking device of claim 3, wherein the power circuit comprises:
a semiconductor switching module connected to the power-controller and a resonant tank circuit, wherein the operation of the resonant tank circuit is controlled by the semiconductor switching module based on a power signal, such that the power circuit is configured for controlling the heat output generated in the electromagnetic cooking device based on the power signal.

5. The user interface assembly for an electromagnetic cooking device of claim 4, wherein the semiconductor switching module comprises a driver device to provide a soft start to an Insulated Gate Bipolar Transistor (IGBT).by generating an ON_OFF signal, such that the frequency of the ON_OFF signal is incremented in predetermined steps by the driver device from a base frequency value to a frequency-value corresponding to the encoding signal.

6. The user interface assembly for an electromagnetic cooking device of claim 1, wherein at least one of the output signals generated by the microcontroller is configured to control a visual feedback, such that at least one parameter of the visual feedback is representative of the heat output of the electromagnetic cooking device, wherein the microcontroller is configured to receive a plurality of ERR signals from the power-controller, and generate the at least one of the output signals to control the visual feedback, based on processing of the plurality of ERR signals by the microcontroller.

7. The user interface assembly for an electromagnetic cooking device of claim 6, wherein the microcontroller processes the plurality of ERR signals to halt the operations associated with the electromagnetic cooking device and the rotary encoder switch generates a PAUSE signal, such that the microcontroller processes the PAUSE signal to halt the operations associated with the electromagnetic cooking device.

8. The user interface assembly for an electromagnetic cooking device of claim 1, comprises a second tactile switch configured to synchronize the reset operation of the microcontroller and the power-controller when the user actuates the second tactile switch.

9. The user interface assembly for an electromagnetic cooking device of claim 1, comprising a front panel including a plurality of recesses for disposing the rotary encoder switch, the first tactile switch, the second tactile switch and the display unit.

10. A method for user interaction with an electromagnetic cooking device comprising:
generating a mode signal by a first tactile switch based on a number of actuations of the first tactile switch by a user, wherein the mode signal corresponds to at least one of a timer mode of operation or a power mode of operation of the electromagnetic cooking device;
manipulating timing settings in the timer mode of operation and power settings in the power mode of operation when the user rotates a rotary encoder switch in a clockwise or in an anticlockwise direction;
generating an encoding signal by the rotary encoder switch based on degree and direction of rotation of the rotary encoder switch;
generating output signals by a microcontroller connected to the rotary encoder switch upon processing the encoding signal;
generating a plurality of switching signals by a switching circuit connected to the microcontroller, the first tactile switch and at least one power source, based on the output signals of the microcontroller and the mode signal;
generating a plurality of display signals based on processing of the switching signals by multiplexer; and
processing the display signals by a display circuit connected to the multiplexer, a display unit and a plurality of illumination devices, to render a change in each of the display unit and the plurality of illumination devices, wherein the change is representative of the encoding signal and the mode signal.