Abstract: A system and method of determining the status of an appliance door is provided. The status of the door of the appliance can be determined based an output signal provided by a door switch coupled in series with a latch motor feedback. A change in the output signal of the door switch can be indicative of either the opening of the appliance door or the actuating of the latch motor. The source of the change in an output of the door switch can be determined based on the latch command provided to the latch motor. The appliance can be controlled based on the status of the appliance door.

Abstract: A power supply for a high frequency heating is provided. When processes from a non-oscillation to an oscillation of a magnetron are finely classified, the non-oscillation (a start mode), the oscillation (a start mode), and the oscillation (a steady mode) are obtained. A problem resides in an unstable state immediately after the oscillation. When a PWM setting value at this time is set to a value lower than a PWM setting value in the steady mode, even if the PWM setting value during the steady mode is set to a maximum output value, the input current is not controlled to a large current including the over-shoot immediately after the oscillation. After the magnetron shifts to a stable state, the PWM setting value shifts to a PWM setting value of an actual steady mode, so that the over-shoot of the input current can be suppressed as much as possible.

Abstract: A microwave processing apparatus is provided with an oscillator, a power amplifier, a heating chamber that accommodates an object to be heated, a power feeder which is disposed on a wall surface of the heating chamber, which receives an output transmitted from a microwave generator and which radiatively feeds the microwave into the heating chamber, and a power detector that detects the power reflected from the power feeder to the power amplifier. The microwave processing apparatus determines a plurality of points of heating frequencies by using top several points of minimum point frequencies of the reflected power, and performs frequency hopping heating within a predetermined unit time.

Abstract: A microwave oven comprises a cooking cavity and a RF generation module configured to deliver microwave energy into the cooking cavity. A controller is operatively associated with the RF generation module. The controller receives and processes a signal indicative of current state of an associated energy supplying utility for determining whether to operate the microwave oven in one of a normal operating mode and an energy savings mode in response to the received signal. The controller is configured to at least temporarily block the signal when the RF generation module is activated if a frequency of the signal is at least partially degraded by a frequency of the RF generation module.

Abstract: A system, method, and computer-readable medium for controlling power applied to a heating element. A rectifier receives AC voltage supplied from an AC voltage supply and rectifies the AC voltage to DC voltage. A pulse-width modulation controller generates and transmits a pulse-width modulation signal, and a DC voltage modulator receives the DC voltage from the rectifier and the pulse-width modulation signal from the pulse-width modulation controller. Based on the pulse-width modulation signal, the DC voltage modulator supplies an analog DC voltage signal to the heating element. A feedback circuit reports the actual DC voltage applied to the heating element to a microcontroller and, if the actual DC voltage deviates from the DC voltage encoded in the pulse-width modulation signal, the pulse-width modulation controller modulates the pulse-width modulation signal to minimize or eliminate the deviation.

Abstract: To attain a more reliable prevention of an electric shock by checking whether the earth states for two circuit boards are good. There is detected a voltage generated at an anode current sensing resistor 20 inserted into a path where the anode current of a magnetron 8 flows and a signal is transmitted to a microcomputer 27. The microcomputer 27 uses a selector switch 28 to determine the earth states for an inverter circuit board and a control panel circuit board before operation of a device. In case either one or both of the circuit boards are in a floating state, operation of a high-frequency heating device is inhibited. Otherwise, operation of the high-frequency heating device is permitted.

Abstract: A variable-frequency oscillator 1, a semiconductor power amplifier 2 for amplifying the output of the variable-frequency oscillator 1; a radiator 3 for radiating an electromagnetic wave for heating based on the output of the semiconductor power amplifier 2; a reflected wave monitoring circuit 5 for detecting a reflected wave of the electromagnetic wave for heating; and a controller 7 for controlling the oscillation frequency of the variable-frequency oscillator 1 are provided. The controller 7 changes the oscillation frequencies of the variable-frequency oscillator 1 discontinuously, thereby getting a frequency-hopping spread-spectrum radiation done by the radiator 3. The electromagnetic wave radiated by the radiator 3 irradiates an object 9 to be heated (which is usually food) inside a heating chamber 8, thereby heating the object.

Abstract: A radiofrequency ignition device including: a control capable of generating an ignition control signal; a supply circuit controlled by the ignition control signal for applying a supply voltage on an output interface of the supply circuit at a frequency defined by the control signal; at least one plasma generation resonator connected on an output interface of the supply circuit and capable of generating a spark between two ignition electrodes of the resonator upon an ignition control; a mechanism measuring an electric parameter representative of a variation in a supply voltage of the resonator; and a module determining the fouling condition of the electrodes based on the measured electric parameter and on a predetermined reference value.

Abstract: To attain a more reliable prevention of an electric shock by checking whether the earth states for two circuit boards are good. There is detected a voltage generated at an anode current sensing resistor 20 inserted into a path where the anode current of a magnetron 8 flows and a signal is transmitted to a microcomputer 27. The microcomputer 27 uses a selector switch 28 to determine the earth states for an inverter circuit board and a control panel circuit board before operation of a device. In case either one or both of the circuit boards are in a floating state, operation of a high-frequency heating device is inhibited. Otherwise, operation of the high-frequency heating device is permitted.

Abstract: A resonance type high frequency heating apparatus comprising; a direct current power supply; a series connection circuit consisting of a pair of semiconductor switching elements connected in parallel to the direct current power supply; another series connection circuit having a primary coil of a leakage transformer and a capacitor connected to both ends of one of the pair of semiconductor switching elements; and a drive means for driving each of the pair of semiconductor switching elements; wherein a variable dead time preparation circuit is provided in the drive means, and the variable dead time preparation circuit enables dead time to remain constant at below a predetermined frequency and causes the dead time to increase sharply at a point above a predetermined frequency.

Abstract: The invention relates to a high frequency heating apparatus and provides a tracking method of a frequency modulation in order to prevent an extension of the harmonic current component of an oscillation threshold ebm which varies from moment to moment in accordance with a change in the temperature of a magnetron. A driving signal for driving a first semiconductor switching element (3) and a second semiconductor switching element (4) is transmitted to a driving control IC unit (14), and an input reference signal Ref is used to perform an input current fixed control. In this case, a variation amount of the input current of the input reference signal Ref is understood as an accumulation information POW and a constant is optimally configured in a resistor network in an ebm-tracking bias circuit (20).

Abstract: A microwave oven is provided with an integrated operating unit having an integrated function for power supply, power level control, and inrush current suppression. The integrated operating unit includes a rotary dial, a shaft fixed, at one end thereof, to the rotary dial, a cam mounted about a concentric axis of the shaft to be rotated along with the shaft, and an iron core extending, at one end thereof, from the other end of the shaft away from the shaft beyond the cam. A relay coil is wound around the iron core. The integrated operating unit further includes a power switch attached to a support member extending from the other end of the iron core away from the iron core, an inrush switch for suppressing inrush current, and a power control switch for controlling the power supply time in accordance with a set power level.

Abstract: An apparatus and method for controlling an output of a magnetron of a microwave oven is provided. The method includes setting an initial input current to generate an output higher than rated output. Thereafter, the magnetron is driven using initial input current of the setting. The output of the magnetron is varied within a preset time to prevent overheating caused by driving of the magnetron.

Abstract: A safety apparatus for an output level-adjustable microwave oven includes a fuse disposed in a power supply line that connects a high power relay or a low power relay with a primary coil of a high voltage transformer of the microwave oven. Where a wrong operation occurs due to defects in the relays, such as a melting of any one of the relays, the fuse disposed in the power supply line connected to the primary coil of the high voltage transformer is cut off. Accordingly, a potential fire resulting from the wrong operation is prevented.

Abstract: A microwave oven and a method of controlling the microwave oven recognize a power supply frequency correctly at a time power is supplied by eliminating the influence of noise. A blocking period is set in which generation of interrupts is deferred until a timer count reaches a predetermined set value, and interrupts are generated if the blocking period elapses. Accordingly, the microwave oven and method of the controlling the microwave oven recognize a power supply frequency without the influence of noise at the time of the power supply, thereby improving reliability of the microwave oven.

Abstract: An interactive interpreter of synchronous or asynchronous selective data from an annular indicia. The annular indicia has data contained thereon that is formatted into bit-cells. The bit-cells are angularly positioned about the circumference of the annular indicia. The annular indicia may, if desired, be rotated in the clockwise or counterclockwise direction enabling the interpretation of data encoded as bit-cells. A controller with memory, the memory having stored therein a software program that provides interpretation of the data contained on the annular indicia and the directional rotation of the data. The rotation of the annular indicia may, if desired, be started and stopped at any convenient time without loss of data or reinterpreting of data. The data contained on the annular indicia may, if desired, be selectively disposed about the circumference of the annual indicia.

Abstract: A safety apparatus for an output level-adjustable microwave oven includes a fuse disposed in a power supply line that connects a high power relay or a low power relay with a primary coil of a high voltage transformer of the microwave oven. Where a wrong operation occurs due to defects in the relays, such as a melting of any one of the relays, the fuse disposed in the power supply line connected to the primary coil of the high voltage transformer is cut off. Accordingly, a potential fire resulting from the wrong operation is prevented.

Abstract: An apparatus and method for controlling an output of a magnetron of a microwave oven is provided. The method includes setting an initial input current to generate an output higher than rated output. Thereafter, the magnetron is driven using initial input current of the setting. The output of the magnetron is varied within a preset time to prevent overheating caused by driving of the magnetron.

Abstract: When power supply to a high voltage transformer starts, the phase &thgr; of the voltage of an AC power source when power supply to the high voltage transformer is stopped last time is referred to. In accordance with the value of the phase &thgr;, the phase of the voltage of the AC power source when power supply to the high voltage transformer starts is determined, so that the peak value of the rush current in the high voltage transformer is minimized.

Abstract: A door-monitoring system comprises a power supply electrically connected to an oscillator. The oscillator sends a signal to a junction between a switch to ground and a latch circuit. When the switch to ground is open, current flows from the oscillator to a set input on the latch, thus indicating that connections in the vicinity of the switch have been broken or the door has been opened. A microprocessor is adapted to receive output from the latch circuit and respond appropriately to an indication that the connections have been broken or the door has been opened.

Abstract: A wall-mounted microwave oven and a method for controlling the same, wherein the microwave oven and a hood unit are prevented from being operated at maximum power at the same time in the initial operation state. The microwave oven comprises a hood unit driver for controlling an operation of the hood unit, power output switching means for controlling the level of a voltage to be supplied to a transformer, and a controller for controlling the hood unit driver and power output switching means to prevent the hood unit and a magnetron from being operated at the maximum power at the same time in the initial operation state. In the initial operation state, the hood motor and microwave oven are prevented from being operated at the maximum power at the same time for a certain period of time. Then, the hood motor and microwave oven are normally operated at the maximum power after the lapse of the certain time period.

Abstract: When power supply to a high voltage transformer starts, the phase &thgr; of the voltage of an AC power source when power supply to the high voltage transformer is stopped last time is referred to. In accordance with the value of the phase &thgr;, the phase of the voltage of the AC power source when power supply to the high voltage transformer starts is determined, so that the peak value of the rush current in the high voltage transformer is minimized.

Abstract: Disclosed is a microwave oven comprising a power supply part supplying a commercial alternating current (AC) power, a rectifying and filtering part rectifying and filtering the commercial AC power, a high voltage transformer generating a high voltage by means of direct current (DC) power from the rectifying and filtering part; and a magnetron generating electromagnetic waves based on the high voltage from the high voltage transformer, further comprising a control signal generator part generating a control signal; an inverter part converting the DC power from the rectifying and filtering part into a high voltage AC power based on the control signal from the control signal generator part, and a control part blocking the control signal converted through the inverter part from being applied to the magnetron if the converted control signal is not within a predetermined range.

Abstract: In the microwave oven having a high voltage driving part with a high voltage transformer, a switching unit applies electric power to the high voltage driving part. In the switching unit, when switched on, an operational contact firstly comes in contact with a first contact coupled with a PTC thermistor and secondly with a second contact after a given time period, and a driving unit generates driving force and turns on/off the switching unit. Since the switching unit and driving unit may be simply installed to effectively eliminate the inrush current, assembly and work efficiencies are improved according to a simpler wiring process, and also, the total manufacturing cost for the microwave oven is reduced.

Abstract: A surge current prevention circuit of a microwave oven, where a surge relay is turned on or turned off by a predetermined DC voltage supplied by rectification of a predetermined low voltage, such that cost of parts of the surge current prevention circuit becomes low to thereby reduce the manufacturing cost, and electricity can be decreased and operation of the microwave oven can be stabilized by the constant switching operation time of the surge relay.

Abstract: A power supply circuit of a microwave oven includes a door switch connected between an AC power supply and a magnetron driving circuit for switching in accordance with a door opening/closing operation, and a power supply control switch connected between the AC power supply and door switch for switching by a power supply command. Also included as parts are a current limit resistor connected between the door switch and magnetron driving circuit, and a relay having a contact point connected in parallel with the current limit resistor to be driven by a low AC voltage supplied from a motor driven by being supplied with the AC power supply when the door switch is on. By using the low AC voltage relay with the small number of coil turns the relay manufacturing time is shortened while improving reliability.

Abstract: An improved method for controlling a power relay of a microwave oven which is capable of reducing the generation of sparking which occurs when the contact points of the power relay are separated, by turning off the power relay at a time (2n-1) .pi.+3/4.pi.during the "+" cycle and at a time 2n.pi.+3/4.pi. during the "-" cycle in the voltage phase or the current phase, for separating the contact points when the flow of the current is decreased, thus extending the life span of the relay. The method includes judging whether the power relay was previously turned off during the "+" cycle of the power voltage or during the "-" cycle of the power voltage when a clock signal of 50 Hz/60 Hz is inputted, and turning off the power relay after an apex of the "+" or "-" cycle of the power voltage after delaying the output time of a relay driving signal for a predetermined time in accordance with the judgement.

Abstract: In a relay driving apparatus and method for a microwave oven, a high relay driving voltage is applied at an initial relay driving time to reduce the operating time deviation between relay parts and the high relay driving voltage is lowered to a normal relay driving voltage through a damp resistance if contact points of a relay switch are coupled, thereby implementing a fix crossing. Therefore, rush current is minimized during relay operation, thereby preventing the fixation of the contact points of a relay switch and the generation of noises due to vibration.

Abstract: A microwave oven has a food-receiving cavity and a magnetron for delivering microwave power to the cavity. The magnetron is supplied with a high voltage through a transformer, and a variable impedance is connected in series with the primary winding of the transformer. The resistive heating effect produced by primary current is utilized to heat the air in the oven cavity, and the magnitude of the impedance is variable to vary the output of the magnetron.

Abstract: An improved controller for a microwave oven capable of preventing it from an undesired heating caused by an erroneous operation thereof, which includes a heating member for generating heating energy; a power switch for controlling electric power supply to the heating member; a switch module including a plurality of switches for selecting a desired function; a microcomputer for outputting scanning signals having predetermined time differences to the switch module and for outputting a predetermined control signal in accordance with a key input signal outputted from the switch module; and a controller for controlling the power switch in accordance with control signals outputted from the microcomputer and a signal applied from the switch module, wherein the control signals includes a latch signal maintaining a predetermined state after the output signal of a switch is detected, while having the same level as a scanning signal outputted from a switch which is selected by an operation mode corresponding to scanning

Abstract: A microwave oven has a cooking time selecting unit and a cooking power selecting unit. The cooking time selecting unit has a first shaft which extends through a control panel and a first knob is mounted on the first shaft. The cooking power selecting unit has a second shaft which is disposed parallel to the first shaft and extends through the control panel. A second knob is mounted on the first shaft and has an outwardly open recess in which the first knob is freely rotatably disposed. A rotary power transmitter such as an idler gear or a timing belt interconnects the second knob and second shaft.

Abstract: A microwave output stabilizing apparatus for a microwave oven comprises a rectifier circuit for rectifying power from an AC power supply into a constant DC voltage; an invertor circuit for generating a high frequency power supply by controlling the DC voltage at an intermittent output state; a high voltage transformer for stepping up the high frequency power supply; and magnetron drive circuit for rectifying the high frequency power supply and oscillating a magnetron. Also, an inverter control circuit detects the current flowing into the primary winding of the high voltage transformer, converts the detected current into a corresponding voltage, the corresponding voltage with a reference voltage, and controls the inverter circuit according to the results of the comparison.

Abstract: The present invention provides a method and system for performing a delay start regardless of the open/close state of the microwave oven door, where the present time Tp is continually counted after a warning signal telling a user to close the door is produced, even if the door is opened during the pre-cooking start time stage or the door is opened during the post-cooking time stage, whereby further cooking is interrupted after the warning signal is produced until the door is closed. Therefore, cooking can be started at a pre-determined time even if the door is opened during the execution of the delay start.

Abstract: A cooking appliance has several sensors to detect which attachment has been placed in a cooking compartment. When a door to the compartment is closed and a start switch is operated within ten seconds, the appliance automatically starts cooking in a mode determined by the attachment detected by the sensors. After the door has been closed for ten seconds, even though the start switch is operated by accident, the appliance will not start cooking.

Abstract: A method for controlling a power relay for actuating a magnetron of a microwave oven in which contacts thereof are closed at various points of time or phase of an AC sinusoidal waveform input thereto with an equal probability, thereby preventing a transfer of the contacts of the power relay. According to the present invention, a count number of a relay counter is incremented periodically upon application of power, until a start key signal is inputted. The count number of the relay counter is then incremented by 1 whenever the start key signal is inputted and the power relay is toggled from its off state to its on state. An interrupt number is incremented periodically as the count number of the relay counter whenever an internal or external interrupt routine is performed. When the count number of the relay counter and the interrupt number are the same, the contacts of the power relay are closed at a phase or a point of time corresponding to the same number, so as to actuate the magnetron.

Abstract: A microwave oven having microwave source and a power unit associated therewith which is supplied with mains voltage via a relay. A microprocessor device comprised in the oven is used for controlling switch-on and switch-off of the relay, eliminating thereby the influence by varying switch-on/switch-off times of the one and same relay and between different relays, and allowing for a connection and respectively disconnection of the mains voltage at a desirable phase thereof.