JP2014140506A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice cooker capable of reducing the size of a backup battery and, for a commercial power supply, capable of acquiring a clear liquid crystal display by the best contrast.SOLUTION: A rice cooker includes: an operation display part including a liquid crystal display 14 for setting the heating of an inner pot; and control means. The control means includes: a power supply voltage determination circuit 7 for determining the power supply of a DC5V power supply 3 and a backup battery 4; a liquid crystal drive circuit 9; an internal voltage dividing resistor 11 in which the liquid crystal display 14 becomes a display of a clear contrast; a voltage dividing resistor 13 in which the liquid crystal display 14 can acquire a display of a minimum contrast; an internal change-over switch 10 for turning ON/OFF the liquid crystal drive circuit 9 and the internal voltage dividing resistor 11; and an external change-over switch 12 for turning ON/OFF the liquid crystal drive circuit 9 and the voltage dividing resistor 13. When the DC5V power supply 3 is used, the internal change-over switch 10 is turned ON and the external change-over switch 12 is turned OFF. When the backup battery 4 is used, the external change-over switch 12 is turned ON and the internal change-over switch 10 is turned OFF.

Description

  The present invention relates to a rice cooker that can switch the contrast of a liquid crystal display.

  As background art of this technical field, Patent Document 1 discloses a voltage dividing resistor (about 200 kΩ) constituting a liquid crystal power supply means for generating a driving voltage for a liquid crystal display device of a rice cooker, a resistance (about 1-2 kΩ) and a photo. While the circuit connected to the coupler output terminal is connected in parallel and power is supplied from the commercial power supply, it becomes the combined resistance of the resistor connected in parallel by the photocoupler to the voltage dividing resistor, and the voltage from the backup power supply such as a battery is When the power supply from the commercial power supply is cut off, the resistor is not connected in parallel to the voltage dividing resistor by the photocoupler, and the voltage from the battery is By using the resistance value of the voltage dividing resistor, when power is supplied from a backup power source such as a battery, the consumption is reduced, the battery life is extended, the resistance value of the voltage dividing resistor is reduced, and uneven display is suppressed. Are listed.

JP 2006-326142 A

  In recent years, liquid crystals such as portable devices are widely used, and liquid crystal and batteries are also used in rice cookers. In addition, awareness of the environment and energy savings is increasing, and it is desired to extend the life of batteries installed as backup power supplies.

  However, in Patent Document 1, since the resistor (about 1 to 2 kΩ) and the output terminal of the photocoupler are connected to the voltage dividing resistor (about 200 kΩ) to switch between parallel connection and no parallel connection, the current flowing through the voltage resistor There was a problem that the contrast of the liquid crystal display deteriorated.

  In order to solve the above problem, a heating unit that heats the accommodated inner pot, an operation unit that sets the heating of the heating unit, a display unit that displays the heating set by the operation unit, and a set heating Power is supplied from either the control means for controlling the heating means according to the power supply, the main power supply for supplying power from a commercial power supply, the backup battery for supplying power from the battery, the main power supply, or the backup battery. A power supply voltage determination circuit that determines whether the liquid crystal display is high, a first voltage dividing resistor used to increase the contrast of the liquid crystal display, and a second voltage dividing resistor used to decrease the contrast of the liquid crystal display The first voltage dividing resistor is connected when electric power is supplied from the main power source, and the second voltage dividing resistor is connected when electric power is supplied from the backup battery, and the liquid crystal display A liquid crystal driving circuit for driving the, those having a.

  ADVANTAGE OF THE INVENTION According to this invention, a backup battery can be reduced in size and a rice cooker provided with a clear liquid crystal display device with the best contrast with a commercial power supply can be obtained.

The schematic sectional drawing of the rice cooker of one Example. The block part containing the liquid crystal drive circuit of the rice cooker of one Example.

  Hereinafter, an embodiment of the rice cooker of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of the rice cooker of this embodiment, and FIG. 2 is a block unit including a liquid crystal driving circuit of the rice cooker.

  As shown in FIG. 1, an inner pot 32 is detachably inserted into a main body 31 of the rice cooker, and an outer lid 33 that covers an upper portion of the main body 31 is attached to be openable and closable. The outer lid 33 is provided with an inner lid 34 that covers the upper opening of the inner hook 32, and the temperature detection means 36 is provided in the steam discharge path 35 of the outer lid 33, so that the steam is boiled and the steam is discharged from the inner pot 32. 35 is detected by temperature. The main body 31 is provided with heating means 37 for heating the inner pot 32.

  The main body 31 is provided with an operation display unit 38, and the user can select an arbitrary menu from a plurality of rice cooking menus. The operation display unit 38 includes a liquid crystal display 14 and displays a user's selection and the status of the main body 31. The main body 31 is provided with a control means 39, and the control means 39 heats the heating means 37 according to a rice cooking heating procedure determined in advance based on the temperature information of the temperature detection means 36 according to the rice cooking menu selected by the operation display unit 38. Control the behavior.

  FIG. 2 shows a block unit including various components required for driving the liquid crystal display of this embodiment. Reference numeral 8 denotes a microcomputer, and a liquid crystal driving circuit 9 for driving the liquid crystal display 14 is included therein.

  The plug 2 of the main body 31 is connected to and disconnected from the commercial power source 1. When the plug 2 is connected to the commercial power source 1, the commercial power source 1 is supplied to the DC 5 V power source 3 (main power source). Then, it is supplied as VDD to the microcomputer 8 via the diode 5.

  A backup battery 4 is connected as VDD of the microcomputer 8 via the diode 6. Therefore, when the plug 2 is not connected to the commercial power source 1, power is supplied from the backup battery 4 via the diode 6 as VDD of the microcomputer 8 and the microcomputer 8 is driven.

  Reference numeral 7 denotes a power supply voltage determination circuit which is connected to the diode 5 and the diode 6 and determines whether power is supplied from the DC5V power supply 3 via the diode 5 or whether power is supplied from the backup battery 4 via the diode 6. Is transmitted to the microcomputer 8.

  The microcomputer 8 includes a liquid crystal drive circuit 9 that drives the liquid crystal display 14 to display. An external changeover switch 12 is connected to the liquid crystal drive circuit 9 inside the microcomputer 8. The external changeover switch 12 is connected to a voltage dividing resistor 13 that creates a liquid crystal driving voltage provided outside the microcomputer 8. The voltage dividing resistor 13 is provided with a high resistance (for example, 300 kΩ) so as to ensure a minimum contrast, and a current flowing through the resistor is lowered.

  An internal changeover switch 10 is connected to the liquid crystal drive circuit 9 inside the microcomputer 8. The internal changeover switch 10 is connected to an internal partial pressure resistor 11 that creates a liquid crystal drive voltage provided inside the microcomputer 8. The internal voltage dividing resistor 11 is provided with a low resistance (for example, 10 kΩ) so as to display a clear contrast, and the current flowing through the internal voltage dividing resistor 11 is higher than the current flowing through the voltage dividing resistor 13.

  The microcomputer 8 is connected to a RAM 15 and a ROM 16.

  The microcomputer 8 controls the RAM 15 and the liquid crystal drive circuit 9 by a program written in the ROM 16 and displays on the liquid crystal display 14.

The microcomputer 8 determines whether the power is supplied from either the DC5V power supply 3 or the backup battery 4 from the power supply voltage determination circuit 7.
Perform different actions.

  When the battery power supply is determined to be driven by the backup battery 4, the external changeover switch 12 is turned on to connect only the voltage dividing resistor 13 to the liquid crystal drive circuit 9. The other internal changeover switch 10 is turned off and the internal partial pressure resistor 11 is not connected to the liquid crystal drive circuit 9. And since the electric current which flows into the voltage dividing resistance 13 is made low, the consumption current of the backup battery 4 can be restrained low.

  On the other hand, when the commercial power source is determined to be connected to the commercial power source 1 and driven by the DC 5 V power source 3, the internal changeover switch 10 is turned on to connect only the internal partial resistance 11 to the liquid crystal drive circuit 9. The other external changeover switch 12 is turned off and the voltage dividing resistor 13 is not connected to the liquid crystal drive circuit 9. Since the current flowing through the inner partial resistance 11 is increased, a clear display can be made on the liquid crystal display (LCD) 14.

  The operation of the above configuration will be described. The user connects the plug 2 to the commercial power source 1, attaches the sharpened white rice and the inner pot 32 filled with water to the main body 31, closes the outer lid 33 including the inner lid 34, and cooks rice with the operation display unit 38. When the selection is made and the display on the liquid crystal display 14 is confirmed and the rice cooking start operation is performed, the rice cooking is started.

  When the power supply voltage determination circuit 7 of the control means 39 determines that the power supply voltage determination circuit 7 is connected to the commercial power supply 1 and is driven by the DC 5 V power supply 3, the microcomputer 80 indicates that the power supply voltage determination circuit 7 is connected to the commercial power supply 1. The internal partial pressure resistor 11 is connected to the liquid crystal driving circuit 9 by the internal changeover switch 10, and the liquid crystal display 14 displays a clear contrast.

  For example, after cooking rice, if the plug 2 is disconnected from the commercial power source 1 by putting the rice in a separate container or the like, the power source voltage determination circuit of the control means 39 determines that the battery is being driven by the backup battery 4, and the microcomputer 80 The internal partial pressure resistor 11 connected to the liquid crystal driving circuit 9 is disconnected by the internal changeover switch 10 and the voltage dividing resistor 13 is connected by the external changeover switch 12, so that the liquid crystal display 14 has a minimum contrast. Will be displayed. At the same time, keep current consumption low.

  2 shows an example in which the internal partial pressure resistor 11, the internal changeover switch 10, and the external changeover switch 12 are built in the microcomputer 8, these may be provided outside the microcomputer.

  According to the above-described embodiment, the control means 39 is supplied with two types of power sources, ie, the DC5V power source 3 connected to the commercial power source 1 and the backup battery 4, and either the backup battery 4 or the DC5V power source 3. A liquid crystal driving circuit 9 for driving the liquid crystal display 14 to the microcomputer 8, and the voltage dividing resistor 13 for the liquid crystal driving circuit 9. And an internal partial pressure resistor 11 provided in the microcomputer 8, and an internal changeover switch 10 when the internal partial pressure resistor 11 is connected to the liquid crystal drive circuit 9. If it is determined that power is supplied from the battery 4, the microcomputer 8 turns off the internal changeover switch 10 and turns on the external changeover switch 12 to connect the voltage dividing resistor 13 to the liquid crystal drive circuit 9. When the power supply voltage determination circuit 7 determines that the power is supplied from the DC5V power supply 3, the microcomputer 8 turns off the external changeover switch 12 and turns on the internal changeover switch 10 so that the internal partial resistance 11 is liquid crystal. Since switching is performed so as to connect to the drive circuit 9, when driven by the backup battery 4, the liquid crystal display 14 can obtain a minimum contrast and can keep current consumption low, thereby reducing the size. The backup battery 4 can be used. Further, when the product is operated by being connected to the commercial power source 1, the liquid crystal display 14 can obtain a clear display with the best contrast.

DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Plug 3 DC5V power supply 4 Backup battery 5 Diode 6 Diode 7 Power supply voltage determination circuit 8 Microcomputer 9 Liquid crystal drive circuit 10 Internal changeover switch 11 Internal partial pressure resistance 12 External changeover switch 13 Voltage division resistance 14 Liquid crystal display 15 RAM
16 ROM
31 Main body 32 Inner hook 33 Outer lid 34 Inner lid 37 Heating means 38 Operation display section 39 Control means

Claims (2)

Heating means for heating the contained inner pot;
An operation unit for setting heating of the heating means;
A display unit for displaying heating set in the operation unit;
Control means for controlling the heating means in accordance with the set heating;
A main power source for supplying power from a commercial power source;
A backup battery that supplies power from the battery;
A power supply voltage determination circuit for determining whether power is supplied from the main power supply or the backup battery;
A first voltage dividing resistor used for increasing the contrast of the liquid crystal display;
A second voltage dividing resistor used to lower the contrast of the liquid crystal display;
The first voltage dividing resistor is connected when electric power is supplied from the main power source, and the second voltage dividing resistor is connected when electric power is supplied from the backup battery, and the liquid crystal that drives the liquid crystal display A drive circuit;
The rice cooker characterized by comprising. The rice cooker according to claim 1, further comprising:
A first changeover switch provided between the liquid crystal driving circuit and the first voltage dividing resistor;
A second changeover switch provided between the liquid crystal driving circuit and the second voltage dividing resistor;
When power is supplied from the main power source, the first changeover switch is turned on and the second changeover switch is turned off.
When the electric power is supplied from the backup battery, the first changeover switch is turned off and the second changeover switch is turned on.