JP2012040292A - Electric rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable check of a voltage value of a power supply battery for microcomputer backup when AC power supply recovery from power failure time, and enable suitable rice cooking control according to the check result in a microcomputer control type electric rice cooker.SOLUTION: The electric rice cooker includes: an inner pan; a heating means to heat the inner pan; and a rice cooking control means which includes a microcomputer; and a power supply battery which backs up operation power supply of necessary parts of the rice cooking control means at power failure time. The electric rice cooker is provided with a battery voltage detection means which detects voltage of the power supply battery, detects the voltage of the power supply battery when power supply recovery to the power failure condition from the power failure condition and is enabled suitable rice cooking control according to the detected voltage value.

Description

  The present invention relates to an electric rice cooker having a control unit equipped with a power supply battery for backup.

  In the recent electric rice cooker, the rice cooker efficiently cooks with high heating output, and when the rice cooking is completed, the microcomputer type electric rice cooker that automatically moves to the heat insulation process and maintains the desired heat insulation temperature has become the mainstream. (See Patent Document 1).

  In the case of such a microcomputer-type electric rice cooker, the clock function is maintained and necessary control data is maintained even when a power failure occurs when the power supply plug is removed from the memory unit (RAM) of the control unit centered on the microcomputer. For example, a long-life backup power source made of a power source battery such as a lithium battery is provided (see Patent Document 2).

JP 2000-14541 A (page 1-10 of the specification, FIG. 1-11) Japanese Patent Laid-Open No. 2002-374638 (Specifications, pages 1-7, FIG. 1)

  However, the backup power supply battery with the above configuration is limited in its lifespan and high performance, and its lifespan is finite, and the output voltage is greatly reduced before the lifespan for some reason. It can happen.

  In such a state, the proper backup function at the time of the power failure described above cannot be performed, and the following problem occurs.

  (1) Since a clock circuit such as a real-time clock circuit stops or malfunctions and an accurate clock function cannot be maintained, an accurate timer reservation rice cooking function cannot be realized even after power is restored.

  (2) Even if the backup of the memory unit such as the internal RAM becomes impossible and the power is restored next time, the memory unit will be initialized once. The data of the rice cooking menu used last time is not stored at all.

  Therefore, the user cannot cook rice with a simple operation based on the rice cooking menu data used last time, and there is an inconvenience that the user needs to cook again after performing all necessary setting operations each time. .

  The present invention was made based on such circumstances, so that the voltage of the backup power supply battery can be detected, and when the power is restored from the power failure state, the voltage value of the backup power supply battery is checked, An object of the present invention is to provide an electric rice cooker that solves the above-mentioned conventional problems by making it possible to take an appropriate response according to the voltage value.

  The present invention has been made for the purpose of solving the above problems, and comprises the following effective problem solving means.

(1) 1st subject solution means The 1st subject solution means of this invention is the operation | movement of the required part of this inner rice pot, the heating means which heats an inner pot, the rice cooking control means consisting of a microcomputer, and this rice cooking control means. An electric rice cooker comprising a power supply battery that backs up the power supply in the event of a power failure, provided with battery voltage detection means for detecting the voltage of the power supply battery, and the power supply battery upon power recovery from a power failure state to a power recovery state It is characterized by the fact that it is possible to execute the appropriate rice cooking control according to the detected voltage value.

  According to such a configuration, when the power supply is disconnected from the power failure state where the power plug is removed, the voltage of the backup power source battery is detected by the battery voltage detection means, and the voltage value is When it is too low, for example, it is possible to make a reserved rice with a timekeeping means different from the original clock function, such as a subtraction timer, or the memory data that required backup of the operating power supply such as the internal RAM of the control unit is not used Thus, alternative data stored in an external memory that does not require backup of other operating power sources can be used, or appropriate measures can be taken.

(2) Second Problem Solving Means According to a second problem solving means of the present invention, in the configuration of the first problem solving means, appropriate rice cooking control is a subtraction timer method from the current time point that does not use a clock function. It is the reservation rice cooking control which performs reservation rice cooking.

  According to such a configuration, even if the voltage value of the backup power supply battery drops below a predetermined level and the correct clock function cannot be maintained, the subtraction timer method is used to cook for hours and minutes. Appropriate reserved rice cooking function can be realized in the form of going up.

  Therefore, the user does not feel substantial inconvenience.

(3) Third Problem Solving Means According to a third problem solving means of the present invention, in the configuration of the first problem solving means, an appropriate rice cooking control is performed in an external memory that does not require a backup power supply in advance. It is the rice cooking control performed using the rice cooking menu data memorize | stored.

  As already mentioned, in the case where the voltage of the backup power supply battery has dropped below the predetermined level, if the power plug is unplugged and a power failure occurs, backup becomes impossible, and even if the power is restored next time, Since this is a new reset start, the data of the rice cooking menu used last time is not stored in the memory such as the internal RAM of the rice cooking control means such as the microcomputer.

  Therefore, the user cannot cook rice by simple operation using the rice cooking menu data used last time, and must perform new rice cooking after performing all necessary setting operations each time. There was inconvenience.

  However, as described above, when the power is restored, the voltage value of the backup power supply battery is detected and confirmed, and when the voltage value is lower than the predetermined level, the rice cooking set thereafter is performed. If the menu is stored in, for example, an external memory that does not require a separate backup power source, and then read out as needed and expanded in the internal RAM and cooked, the voltage of the backup power source battery Even when a power failure occurs in a state where the power is low, proper rice cooking can be performed by a simple operation using the previous rice cooking menu at the time of power recovery.

  As a result of the above, according to the present invention, even when the voltage of the backup power supply battery has dropped below a predetermined level at the time of a power failure, the voltage of the power supply battery is accurately determined when power is restored, It becomes possible to take appropriate and appropriate measures.

  As a result, the reliability of the rice cooker can be maintained.

It is a longitudinal cross-sectional view which shows the structure of the whole rice cooker of the electric rice cooker which concerns on embodiment of this invention. It is an enlarged front view which shows the structure of the operation panel part centering on the liquid crystal display part of the same electric rice cooker front. It is a block diagram which shows the structure of the control circuit part of the electric rice cooker. It is a block diagram (connection diagram) which shows the structure of the voltage detection circuit of the backup power supply battery of the microcomputer part of the electric rice cooker. It is a flowchart which shows the content of the rice cooking control at the time of a power recovery corresponding to the detected voltage value of the said backup power supply battery of the electric rice cooker. It is a time chart (when battery voltage is high) corresponding to control of the above-mentioned FIG. 5 in the electric rice cooker. It is a time chart (when battery voltage is low) corresponding to control of the above-mentioned FIG. 5 of the electric rice cooker. It is a block diagram (connection diagram) part which expands and shows the structure of other Embodiment 1 which changed a part of structure of the power supply circuit part for backup of the electric rice cooker. It is a block diagram which shows the structure of the power supply voltage monitoring system of the electric rice cooker which concerns on the other Embodiment 2 of this invention corresponding to the new subject of the electric rice cooker in the structure of the said FIGS. 1-6 and FIG. It is a system block diagram which shows the new subject of the electric rice cooker in the structure of the said FIGS. 1-6 and FIG.

  1 to 4 show the configuration of the rice cooker body and the main part of the electric rice cooker according to the embodiment of the present invention, and FIGS. 5 to 7 show the control contents of the electric rice cooker.

(Configuration of the rice cooker body)
As shown in FIG. 1, the electric rice cooker 1 employs, for example, a hot pot (for example, a ceramic earthen pot) made of a non-metallic material as an inner pot (rice cooker or heat insulation container) 3. The bottom wall 3a of the bottom wall 3a (flat surface) and the curved surface (R surface) of the outer periphery of the bottom wall 3a are capable of self-heating by eddy currents induced therein, such as silver paste The first and second induction heating elements G1 and G2 made of metal are provided.

  The electric rice cooker 1 includes an inner pot 3 having the same configuration, a dish-shaped bottom wall portion 4a made of a lower synthetic resin and an upper side cylinder formed so that the inner pot 3 can be stored and set arbitrarily. An inner case (protective frame) 4 formed of a side wall portion 4b, a bottomed cylindrical outer case 5 which is an outer casing for holding the inner case 4, and a lower portion of the outer case 5 are integrally fitted. A bottom case 13, and a lid unit (lid body) 2 that can be opened and closed at the top of a rice cooker body formed by integrating the outer case 5 and the inner case 4 with a shoulder 10. Yes.

  An operation panel unit 20 is provided above the front surface of the outer case 5. On the operation panel 20 surface, for example, as shown in FIG. 2, a liquid crystal display section 21 having a large display area, a rice cooking reservation switch 22a for timer rice cooking, a rice cooking switch 22b, a heat retention switch 22c, and a cancel switch 22d. , Voice guide switch 22e, rice cooking menu switch 22f for specifying rice cooking menu (for example, white rice, cooking separately, quick cooking, rice cake, rice porridge, brown rice and other course menus), clock and timer time setting switch 22g, clock and timer Various operation switches such as a time setting switch 22h, a rice selection switch 22i, and a fire adjustment level setting switch 22j are provided.

  The timer reservation switch 22a, the rice cooking switch 22b, and the heat retention switch 22c are provided with display LEDs that indicate ON operation states of the switches 22a, 22b, and 22c, respectively.

  The display surface of the liquid crystal display unit 21 displays various rice cooking menus, a set rice cooking menu, a rice cooking reservation state, a rice cooking state, a current time (see “10:30” in FIG. 2), and the like. It is like that. Further, the display state of the current time display unit “10:30” is changed to the cooking time display by the subtraction method at the time of reserved rice cooking by the subtraction timer method to be described later.

  Further, in the inner part (back space) of the operation panel unit 20, the microcomputer board B2 is arranged to descend obliquely forward from the upper end position of the control board B1 provided on the front side of the inner case 4 side wall part 4b. The cover 18 is inclined and installed.

  A room temperature sensor S3 for detecting the indoor temperature is provided at a predetermined position open to the outside air on the microcomputer board B2.

  On the other hand, a coil cover (coil base) 6 having a ferrite core housing portion is provided below the bottom wall portion 4a of the inner case 4, and a ferrite core (reference numeral omitted) is disposed below the coil cover (coil base). Between the induction heating elements G1 and G2 of the first and second sets of the center side flat surface part and the outer peripheral side curved surface part of the bottom wall part 3a of the inner pot 3, respectively. First and second sets of work coils C1 and C2 in which wires are wound concentrically are provided, and the first and second induction heating elements G1 of the inner pot 3 are energized. , G2 is induced to eddy current to heat the inner pot 3 efficiently.

  On the front side of the inner case 4 (side wall part 4b), as described above, rectification is made up of IGBTs, heater drive circuits, and diode bridges for power supply voltage rectification that drive and control the work coils C1, C2, the insulation heater H1, etc. A control board B1 provided with a circuit, a smoothing circuit, and the like and a control board cover 7 are provided in a state of being erected in the vertical direction.

  The control board B1 is provided with a board sensor S2 for detecting the temperature of the same part adjacent to the IGBT side.

  The dish-shaped bottom wall portion 4a of the inner case 4 is formed with a sensor portion fitting port of the bottom sensor S1 in which a thermistor for detecting the temperature of the bottom wall portion 3a of the inner pot 3 is provided at the center of the bottom surface portion. In addition, a donut-shaped heat shield plate 8 is provided on the outer peripheral side upper surface of the sensor part fitting port. Further, a flange-shaped step portion 9 projecting outward in a predetermined width radial direction is provided on the upper end side of the outer peripheral curved surface portion, and the lower end side of the upper cylindrical side wall portion 4b is engaged with the step portion 9 portion. It is placed together.

  On the other hand, the upper end of the upper side cylindrical side wall 4b is connected and fixed to the shoulder member 10 side of the upper end of the rice cooker main body side outer case 5 via an inner frame member (not shown).

  In addition, a side heater H1 that functions as a heating means at the time of rice cooking and warming is provided on the outer periphery of the upper side cylindrical side wall 4b of the inner case 4, and the inner pot 3 is heated at the time of rice cooking and warming. The entire circumference is effectively and uniformly heated.

  Reference numerals 12, 12... Are air inlets for the cooling fan 11 provided in a grill shape at the front portion of the bottom case 13 fitted and integrated with the bottom side of the outer case 5.

(Configuration of lid unit)
Further, reference numeral 2 in FIG. 1 denotes the lid unit. The lid unit 2 includes an outer cover 2a made of a synthetic resin that has an outer peripheral surface and a pressure adjusting unit 14 at the center, and the outer cover 2a. An inner frame 2b made of synthetic resin that is fitted and integrated inside the outer periphery of the metal, a heat sink 2c made of metal fitted in the inner opening of the inner frame 2b, and an upper surface of the heat sink 2c The cover heater H2 is provided, and a metal inner cover 2d provided below the heat radiating plate 2c. Further, packings 19a and 19b are respectively provided below the outer peripheral edge portion of the heat radiating plate 2c and the outer peripheral edge portion of the inner lid 2d, and the inner lid 2d is connected to the opening edge of the inner pot 3 via the packing 19b. It is made to contact the upper surface part of the part 3c. 14d is a pressure regulating valve (sphere) in the pressure regulating pipe 14a fitted to the pressure regulating port 2e of the outer cover 2a, 14c is a valve seat plate having a valve port portion on the lower side, and 14b is a pressure regulating valve. It is the pressure regulation cap fitted by the opening part expanded below the pipe 14a.

  The lid unit 2 is rotatably attached to the shoulder member 10 on the rear end side of the upper portion of the outer case 5 (not shown) via a hinge mechanism. A lock mechanism 17 that engages with a predetermined position on the front end side and opens and closes the lid unit 2 in the vertical direction is provided.

  Reference numeral S4 is a lid sensor (steam sensor) for detecting the temperature and boiling state in the inner pot 3, and this lid sensor S4 is a steam pipe 16c having a steam passage 16e in the opening of the inner lid 2d. And the tip of the thermistor 16b attached to the upper heat radiating plate 2c via the attachment holders 16a and 16d is inserted into the steam passage 16e in the steam pipe 16c. In this case, the thermistor 16b is made of a shaft-like one extending long from the upper side to the lower side as shown in the drawing, and the tip side sensor part (temperature detection part) is from the opening edge part 3c of the inner pot 3. Is also provided facing inward (in an intrusive form).

  And thereby, the temperature in the inner pot 3 is detected very accurately from the stage before the generation of steam.

(Configuration of control circuit part)
Next, FIG. 3, FIG. 4 shows the structure of the control circuit part which performs rice cooking and heat retention control of the rice cooker main body comprised as mentioned above.

  In the case of the electric rice cooker of this embodiment, as described above, the control unit is composed of two circuit boards, the microcomputer board B2 and the control board B1, and the microcomputer board B2 is composed of the first and second work coils. Centering on a control microcomputer (rice cooking control unit) 40 for controlling the outputs of C1, C2, the heat retaining heater H1, the lid heater H2, etc., the control board B1 is rectified after the power supply circuit section from the AC power supply 30 side. Smoothing circuit, first and second work coils C1, C2, IGBT, choke coil, IH circuit consisting of resonance circuit, DC power supply circuit, temperature detection circuit using various sensors, input voltage detection circuit, IGBT drive circuit, input A current detection circuit, a zero cross detection circuit for a power supply voltage, a heat retaining heater drive circuit, a lid heater drive circuit, a fan motor drive circuit for the blower fan 11 and the like are provided. And that although, for the details of the control board B1 side of circuit sections are well known and are not shown.

  In FIG. 3, the main clock signal generating circuit (OSC1) 45a for setting the control cycle and the like, and the sub clock signal generating circuit for generating a clock signal for clock display (specifically, as components related to the present invention, are shown. OSC3) 45b, image data for liquid crystal display unit 21, voice guidance data and melody for driving voice circuit 50, external RAM 46 composed of a flash memory that does not require a backup power source storing control data that does not always change, which will be described later, at power failure Microcomputer (RTC circuit 43 and battery backup RAM 42) for backup, a power supply circuit 41 for microcomputer drive control during activation, a reset circuit 48, a voice guidance 50 and a voice circuit 50 for playing a melody are provided. And they are each figure And it is connected to the microcomputer (rice control unit) 40 as.

  In this case, the battery voltage from the backup power supply battery BE is supplied to the battery backup RAM 42 and the RTC circuit 43 via the Zener diode ZD1.

  The battery backup RAM 42 and the RTC circuit 43 are supplied with operating power (3.3 V) from the power circuit 41 for microcomputer drive control via the Zener diode ZD2 when the AC power 30 is energized. The power supply battery BE is configured to have as long a life as possible.

  Further, the microcomputer control unit 40 further includes a liquid crystal display unit 21, a rice cooking reservation switch for timer rice cooking, a rice cooking switch, a heat retention switch, a cancel switch, a voice setting switch, a rice cooking menu (for example, white rice, quick cooking, rice cake, rice porridge, Various operation key switches 22a to 22j such as a rice cooking menu switch for specifying brown rice and other course menus, a time setting switch for clocks and timers, a time setting switch for clocks and timers, a rice selection switch, and a fire level setting switch Are connected to each other, and an electric signal corresponding to the operation content and operation amount is inputted.

  In the microcomputer 40 which is a rice cooking control unit, for example, an internal RAM storing rice cooking menu data as rice cooking control data, an RTC circuit (real time clock circuit) 43 for displaying a clock, a battery backup RAM 42 and the like are provided. In the event of a power failure, the power supply from the backup power source BE to all the parts other than the RTC circuit (real time clock circuit) 43 and the battery backup RAM 42 of the microcomputer (rice cooking control unit) 40 is performed by the battery backup mode of the real time clock circuit 43. Stop (sleep control), reduce the power consumption of the backup power supply battery BE as much as possible, and extend the life.

  The RTC circuit (real-time clock circuit) 43 is operated by the power supply from the backup power supply battery BE instead of the microcomputer drive control power supply circuit 41 in the event of a power failure, and a clock display subclock signal generation circuit having a predetermined oscillation cycle. (OSC3 / 8 MHz) An accurate clock display is performed based on the clock signal from 45b.

  The battery backup RAM 42 has a battery backup area of at least 16 bytes, stores control data that needs to be backed up in the 16-byte backup area in the battery backup mode, and stores the control data when the power is restored. It returns to the control state (for example, standby state, rice cooking reservation state, heat retention state, etc.) before the power failure using the control data, and enables the original control (continuous control from the state before the power failure).

  In this case, as the control data to be stored in the battery backup RAM 42, for example, in addition to the reserved rice cooking menu, specific data that constantly changes with the passage of time, for example, a timer value during rice cooking, a rice cooking process sequence (Water absorption, combined number determination, temperature raising step 1, temperature raising step 2, cooking 1 and cooking 2), uneven time, heat retention time and the like are selected.

  Further, when the stored data of the battery backup RAM 42 is used for control, it is necessary to check whether or not the stored data is correct. Therefore, in this embodiment, for example, of the 16-byte backup area, the 1/16 to 15/16 NO1 to NO15 area is the data storage area, and the remaining 1/16 NO16 area is the data of the NO1 to NO15 area. It is used as a checksum area to put the total value (sum value).

  Then, the sum value of the NO16 area placed before the power failure is compared with the sum of the data values of the NO1-NO15 area after the power recovery, and if they match, the data of the NO1-NO15 area is normal, If they do not match, it is determined as not normal. If not normal, all the data in the NO1 to NO15 areas are initialized and returned to the unset standby state data. This prevents the control from being continued due to erroneous data.

  The external RAM 46 is configured by a flash memory that can be erased and written in predetermined block units, for example, and can store stored data even when power supply is stopped. For example, the main block portion includes the above-described block memory. Various screen data displayed on the liquid crystal display unit 21 and voice data (guidance data, melody data, etc.) necessary for driving the voice circuit 50 are written.

  On the other hand, there are other predetermined empty blocks, and the control data that cannot be stored by the above-mentioned 16-byte backup RAM 42 alone, for example, does not always change with the passage of time. In addition to the voice content and volume level in the voice guidance function whose setting state may be changed at each timing, the reserved time at the time of timer reserved rice cooking and the previous rice cooking menu data are stored.

  However, the backup power supply battery BE in the above configuration has a limited lifespan, no matter how long it has a high performance, and the output voltage becomes large before the life comes for some reason. It can happen that it falls.

  In such a state, the proper backup function at the time of the power failure described above cannot be performed, and the following problem occurs.

  (1) Since the RTC circuit (real-time clock circuit) 43 and the sub-clock signal generation circuit 45b are stopped or malfunctioned and the accurate clock function cannot be maintained, an accurate timer reservation rice cooking function is realized even after the power is restored. Can not do it.

  (2) Even if the memory unit such as the internal RAM 44 cannot be backed up and the power is restored next time, the memory unit will be initialized once. The data of the used rice cooking menu is not stored at all.

  Therefore, the user cannot cook rice with a simple operation based on the rice cooking menu data used last time, and there is an inconvenience that the user needs to cook again after performing all necessary setting operations each time. .

  (3) Since the main clock signal generation circuit (OSC1) 45a requires about 3 seconds (MAX) to wait for oscillation stabilization, the main clock signal generation circuit (OSC1) 45a is stopped (no battery voltage). When the power is restored from, the main clock signal generation circuit (OSC1) 45a must not be switched during the oscillation stabilization wait.

  (4) Whether the main clock signal generation circuit (OSC1) 45a can be switched is determined based on whether or not the content of the battery backup RAM 42 is broken. Since the backup RAM 42 is indefinite, it is considered that it should not be used for such a determination.

  In this embodiment, in order to solve such a problem, a battery voltage detection circuit using an FET 50 capable of detecting the voltage value of the backup power supply battery BE as shown in FIGS. 3 and 4 is provided. When the AC power supply 30 is restored from the power failure state, the voltage value of the backup power supply battery BE is quickly checked so that an appropriate response according to the voltage value can be taken.

  That is, in FIGS. 3 and 4, reference numeral 50 is a MOS FET (N channel) connected internally to the substrate, the drain side is the positive electrode of the backup power supply battery BE, and the source side is the microcomputer 40. Are connected to the A / D conversion input terminal A1N3, and the gate side is connected to the H / L switching signal output terminal PA7 of the microcomputer 40, respectively. When the H (high) signal is output from the L switching signal output terminal PA7, the FET 50 is turned ON and the output voltage (potential) V of the backup power supply battery BE is input to the A / D conversion input terminal A1N3 of the microcomputer 40. And A / D conversion is performed.

  The output signal from the H / L switching signal output terminal PA7 is output at the time of power recovery when the AC power supply 30 is restored from the power failure state as described above, and correspondingly, the A / D conversion input terminal A1N3 as described above. The voltage value V of the backup power supply battery BE is input to the A / D converter and the H signal of the H / L switching signal output terminal PA7 is switched to the L (low) signal output as soon as possible. To turn off FET50.

  The voltage value V of the power supply battery BE input from the A / D conversion input terminal A1N3 is A / D converted by the A / D conversion circuit in the microcomputer 40, and then the battery voltage level is determined by the digital value. It is determined whether or not the voltage drops below a predetermined reference voltage (for example, 2.7 V with respect to the rated 3.3 V).

  And according to the determination result, the suitable rice cooking control method as shown by the flowchart of the following FIG. 5, and the time chart of FIG. 6, FIG. 7 is employ | adopted.

(Power supply voltage monitoring of backup power supply BE and control in case of power failure)
Next, the flowchart of FIG. 5 and the time charts of FIG. 6 and FIG. 7 show the control contents of the backup power supply battery BE and the corresponding reserved rice cooking when the power is restored from the power failure state. .

  The time chart of FIG. 6 shows each operation when the battery voltage V of the backup power supply battery BE is higher than a predetermined reference voltage, and the time chart of FIG. 7 shows each operation when the battery voltage V is lower than the predetermined reference voltage. Is shown.

  This control is started when the AC power supply 30 is unplugged or other power outage described above, and it is determined that the AC power supply 30 has recovered from the power outage state, and necessary power outage handling processing is performed. It shifts to electric processing control.

  That is, first, in step S1, the zero cross signal (Zc in FIGS. 6 and 7) from the zero cross voltage detection circuit for detecting the zero cross voltage of the AC power supply 30 described above is input to the microcomputer 40, and the zero cross signal (H signal) is actually input. It is determined whether or not is input. This determination is repeatedly performed at a predetermined cycle until the zero cross signal (H signal) is input (until determined as YES). When the zero cross signal is input and becomes YES, it is determined that the AC power supply 30 has been restored. Then, the process proceeds to step S2.

  In step S2, the output of the H / L switching signal output terminal PA7 of the microcomputer 40 is set to H output (see the signal waveform of PA7 in FIGS. 6 and 7), and the FET 50 is instantaneously turned on. The port of the A / D conversion input terminal A1N3 is opened (see the signal waveform of A1N3 in FIGS. 6 and 7), and the voltage value V of the power supply battery BE (see the signal level of BE in FIGS. 6 and 7). input. In the subsequent step S3, the AD conversion value of the voltage value V (BE level in FIGS. 6 and 7) of the backup power supply battery BE input from the A / D conversion input terminal A1N3 is input and stored. Correspondingly, in step S4, the output of the H / L switching signal output terminal PA7 is quickly switched to the L (low) output (see the output signal waveform of A1N3 in FIGS. 6 and 7).

  Then, the process proceeds to step S5, and it is determined whether or not the voltage value V of the backup power supply battery BE subjected to the AD conversion is at a level equal to or higher than a predetermined reference voltage value.

  As a result, when the voltage value V of the backup power supply battery BE determined as YES is at an effective level equal to or higher than a predetermined reference voltage value, the sub-clock signal generation circuit (OSC3) 45b operates including the sleep control. As a result, the above-described battery backup RAM 42 is not initialized, and the process immediately proceeds to step S6 without waiting for the oscillation of the main clock signal generation circuit (OSC1) 45a to stabilize. After resetting the power supply battery voltage drop flag indicating that the power supply battery BE has fallen below the predetermined reference value, and when the flag is not set, only the reset process is performed. The process proceeds to the power recovery process in step S13.

  In this case, the power supply battery voltage drop flag is set when the processing steps shown in the following steps S7 to S12 are performed on condition that the actual battery voltage V drops below the reference voltage ( Later).

  On the other hand, when the voltage V of the power supply battery BE determined as NO is lower than the predetermined reference voltage value, first, in step S7, the oscillation state of the main clock signal generation circuit (OSC1) 45a is stabilized. In step S8, the battery backup RAM 42 is always initialized (reset) regardless of the actual memory contents.

  Then, the rice cooking menu is read from the external RAM (flash memory) 46 in step S9, and the read rice cooking menu information (detailed setting data) is expanded in the internal RAM 44 of the microcomputer 40 in step S10.

  Next, the process proceeds to step S11, where the developed current set rice cooking menu is set from the internal RAM 44 so that it can be read out as necessary thereafter. In the next step S12, a flag indicating that the power battery voltage V has dropped below a predetermined reference voltage value is set, and then the process proceeds to the power recovery process control in step S13.

  The power recovery process control corresponding to the power recovery is a process of returning the state of each part of the control unit of the rice cooker to the state before the power failure including the time display state, and when this is executed, the original standby state It is possible to return to the reserved cooking rice state, the cooking rice state, and the like.

  Then, when this power recovery process is completed, whether the rice cooking reservation switch 22a has been pressed down or the rice cooking switch 22b has been pressed down, and in each of these cases, how is the voltage state of the power supply battery BE? Depending on whether or not, the following different processes are performed.

  That is, first in step S14, it is determined whether or not the rice cooking reservation switch 22a is pressed.

  As a result, when YES, the rice cooking reservation switch 22a is pressed, the process proceeds to step S17 to determine whether the power battery voltage drop flag is reset or set. I do.

  As a result, when the voltage value V of the power supply battery BE in which the flag is in a reset state is higher than a predetermined reference voltage value and an effective operating voltage level, the clock function should be accurately maintained, so that Proceeding to step S18, the reserved rice cooking mode is switched to the reservation setting mode based on the current time by the clock function, and the cooking time is set by the clock function in the subsequent step S19.

  Then, after that, it is determined whether or not the rice cooking switch 22b is pressed in step S20, and when the rice cooking switch 22b is pressed, the timer reservation time based on the clock function based on the current time is determined and the reservation rice cooking mode is entered To do.

  On the other hand, it is determined that the backup function of the internal RAM 44, the battery backup RAM 42, and the RTC circuit 43 is not performed effectively because the voltage value V of the power supply battery BE in which the power supply voltage drop flag is set is equal to or lower than a predetermined reference voltage value. In this case, since the accurate clock function cannot be maintained and the accurate current time is unknown, the process proceeds to step S21 to switch to the reserved time setting mode by the subtraction timer, and in step S22 following the subtraction timer method. Set the calculation time until cooking.

  Then, after that, it is determined whether or not the rice cooking switch 22b has been pressed, and when the rice cooking switch 22b is pressed, the setting of the reservation time by the subtraction timer is confirmed and the reservation rice cooking mode is entered.

  According to such a configuration, the voltage value V of the backup power supply battery BE such as the internal RAM 44, the battery backup RAM 42, and the RTC circuit 43 of the microcomputer 40 is lowered below a necessary reference voltage level, and an accurate clock function is maintained. Even if it becomes impossible, the reserved rice cooking function can be realized in the form of cooking after hours and minutes by the subtraction timer method.

  On the other hand, when it is determined NO in the above-described determination of depressing the reservation switch 22a in step S14, the process proceeds to step S15, where it is determined whether or not the rice cooking switch 22b is pressed down.

  As a result, when the rice cooking switch 22b is pushed after the power recovery process of YES, the process proceeds to step S24, where the above-mentioned power battery voltage drop flag is set or reset. It is determined whether or not.

  As a result, when the voltage value V of the power supply battery BE in the reset state is higher than a predetermined reference voltage value and an effective operating voltage level, the memory data in the internal RAM 44 of the microcomputer 40 should be accurately maintained. Because there is, proceed to the rice cooking mode as it is and cook rice.

  On the other hand, when the voltage value V of the power supply battery BE in which the power supply voltage drop flag is in the set state is a voltage level lower than the predetermined reference voltage value, the process proceeds to step S25, and the rice cooking menu to be cooked this time is already set. It is determined whether or not it is the same as the previous one.

  As a result, in the case of YES, the rice cooking menu stored in the external memory 46 as described above is expanded in the internal RAM 44 and can be read out. On the other hand, when it is another menu of NO, it progresses to step S26 and memorize | stores the present rice cooking menu which should be set to internal RAM44 of the said microcomputer 40 not in the said internal RAM44 but in the empty block part of the above-mentioned external memory 46 Then, go to the rice cooking mode and execute the rice cooking function using the menu.

  On the other hand, when it is determined NO in step S15 described above, the process further proceeds to step S16 to determine whether or not the menu switch 22f has been pressed.

  As a result, when the NO menu switch 22f is not pressed, that is, when a new menu setting is not made, the process directly returns to step S14, and the above-described control operations of steps S14 to S26 are repeated.

  On the other hand, when the menu switch 22f of YES is pressed and a new menu is set, the process proceeds to step S27, and the currently set menu (for example, white rice) is changed to the next new menu (for example, cooking). After changing to (new memory in the internal RAM 44), the process returns to steps S14 to S26.

  Thereby, in the same case, the processes of steps S25 and S26 described above are also changed corresponding to the process of step S27, and the new menu (for example, cooking) is stored in the external memory 46. The menu stored in 46 is used in steps S9, S10, S25, and S26 as described above.

  As described above, when the voltage V of the backup power supply battery BE is lowered to a predetermined reference voltage value (e.g., 2.7 V when the rating is 3.3 V) or less, the power plug is unplugged. Then (when the AC power supply 30 is in a power failure state), the backup becomes impossible, and even if the power supply plug is connected and the AC power supply 30 is restored next time, a new reset start is started and the previously used rice cooking menu in the internal RAM 44 is restored. Data is not stored.

  Therefore, the user cannot cook rice by a simple operation using the previously used rice cooking menu, and there is an inconvenience that the user has to perform rice cooking after performing all necessary setting operations each time.

  However, as described above, when the power is restored, the value of the voltage V of the backup power supply battery BE is confirmed, and when the value of the voltage V is reduced to the reference voltage (2.7 V) or less. Then, the rice cooking menu set thereafter is stored in an external RAM (flash memory that does not require a backup power source) 46, and then read out as needed to be developed in the internal RAM (internal memory) 44 to cook rice. Thus, even when a power failure occurs in the state where the voltage of the backup power supply battery BE is low, rice can be cooked by a simple operation using the previous rice cooking menu at the time of power recovery.

(Other embodiment 1)
Next, FIG. 8 shows a configuration of a backup power supply circuit according to another embodiment 1 of the present invention.

  In the case of this embodiment, as shown in the circuits of FIGS. 3 and 4 described above, the backup power supply battery BE functions as an operating power supply (3.3 V) for the battery backup RAM 42 and the RTC circuit 43 in the event of a power failure. Yes.

  However, if the voltage V of the power supply battery BE drops below a predetermined level as it is, not only the clock function is lost as described above, but also there is a possibility that it cannot be returned from the sleep mode (energy saving mode).

  Therefore, as shown in FIG. 3, the control power supply line (3.3 V) from the power supply circuit 41 for driving the microcomputer 40 is connected to the output line of the backup power supply battery BE through the Zener diode ZD2. In this way, even when the voltage of the backup power supply battery BE is lowered, the necessary operation can be ensured as long as at least the AC power is present. Further, since the current consumption of the power supply battery BE for non-power failure state backup itself can be reduced, the life of the power supply battery BE itself can be extended.

  In this case, in the configuration of the present embodiment in FIG. 3, the control power supply line from the microcomputer drive power supply circuit 41 is connected to the output side of the power supply battery BE through the Zener diode ZD2. ZD2 may be a normal diode D as shown in FIG.

(Other embodiment 2)
Next, FIG. 9 shows a configuration of a microcomputer backup system during a power failure according to another embodiment 2 of the present invention.

  For example, as shown in FIG. 10, while the control power can be supplied from the driving power supply circuit 41 of the microcomputer 40 as shown in FIGS. 3 and 8, the main memory system centering on the internal RAM 44 of the microcomputer 40. If a sub memory system 52 is provided separately from 51 and the sub memory system 52 holds necessary control data in the event of a power failure, backup by the backup power supply battery BE of the main memory system 51 can be made unnecessary, thereby saving energy. Function can be improved.

  However, in this case, at least the sub memory system 52 needs to be backed up by the power supply battery BE. Therefore, if the backup power supply battery BE reaches the end of its life, the power supply voltage necessary for operation cannot be obtained at the time of a power failure, and necessary control data cannot be retained.

  Therefore, in the case of such a circuit, it is necessary to provide power supply voltage monitoring circuits 53 and 54 for each of the main memory system 51 and the sub memory system 52 to monitor the power supply voltage.

  However, even in this case, for example, as shown in the circuit of FIG. 9, the operation input voltage on the sub memory system 52 side is detected by the AD conversion circuit provided on the main memory system 51 side on the condition that the power is restored. However, if it is below a predetermined reference voltage, the sub memory system 52 can be initialized to prevent erroneous control and to generate an alarm.

  In this case, as can be understood from the circuit configuration of FIG. 9, at least the power supply voltage monitoring circuit 54 on the sub memory system 52 side can be eliminated. As a result, the circuit configuration can be simplified.

  Reference numeral 40 denotes a microcomputer, 41 a power supply circuit, 42 a battery backup RAM, 43 an RTC circuit, 44 an internal RAM, 45 a a main clock signal generation circuit (OSC 1), and 45 b a sub clock signal generation circuit (OSC 1).

Claims (3)

  An electric rice cooker comprising an inner pot, a heating means for heating the inner pot, a rice cooking control means composed of a microcomputer, and a power supply battery that backs up the operating power of the required part of the rice cooking control means in the event of a power failure The battery voltage detecting means for detecting the voltage of the power battery is provided, the voltage of the power battery is detected when the power is restored from the power failure state to the power recovery state, and appropriate rice cooking control according to the detected voltage value can be executed. An electric rice cooker characterized by doing so.   2. The electric rice cooker according to claim 1, wherein the appropriate rice cooking control is reservation rice cooking control in which reservation rice cooking is performed by a subtraction timer method from a current time point without using a clock function.   2. The electric rice cooker according to claim 1, wherein the appropriate rice cooking control is rice cooking control performed using rice cooking menu data stored in an external memory that does not require a backup power source in advance.

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