JP3448434B2 - Cordless iron - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cordless iron.

[0002]

2. Description of the Related Art Conventionally, a cordless iron is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-180800. In this publication, an iron main body having a heater and a mounting table on which the iron main body is mounted and which supplies electric power are provided. The iron body has a DC power supply circuit, a power storage unit (capacitor), and a control unit (a microcomputer, which will be hereinafter referred to as a microcomputer).
And a display unit and a temperature detection unit. The microcomputer has an active operation mode in which it oscillates to perform an instruction operation, and a hold operation mode in which only the internal state before the oscillation is stopped to stop the operation of the system is held with low power consumption. Then, when the iron body is placed, the power storage unit is charged and the DC power supply circuit is transferred to the microcomputer by about 5
Supply a DC voltage of V. Then, the microcomputer controls the temperature and outputs a display control signal to the display means. When the iron body is detached, the power storage unit supplies a discharge voltage to the microcomputer to control the display.

The power supply voltage characteristic of the above cordless iron will be described with reference to FIG. In FIG. 7, the horizontal direction is the elapsed time, and the vertical direction is the power supply voltage (S) supplied to the control unit. When the iron body is placed (a), the power supply voltage (S) is about 5 V, and when the iron body is removed (b), the power supply voltage (S) gradually decreases as the power storage unit discharges. In this way, the power supply voltage (S) is from 5V to 2.5
The period c up to V is the backup time, and the display control is performed. The power supply voltage (S) is 2.5V to 2.1V.
The period d up to V is the hold time, the microcomputer enters the hold operation mode to stop the oscillation, and R in the microcomputer
It holds AM temperature setting information and the like.

[0004]

However, the above-mentioned cordless iron has the first drawback that the backup time c is short (for example, about 80 seconds). Therefore, when the backup time c has passed when the iron body is detached, it becomes impossible to display whether the base temperature is the proper temperature or the non-suitable temperature, which is difficult for the user to use. In order to investigate the cause, the inventor obtained the voltage / current characteristics of the microcomputer as shown in FIG. The horizontal axis in FIG. 8 is the power supply voltage (V) supplied to the microcomputer.
And the vertical axis is the current (mA) flowing through the microcomputer.
It can be seen from FIG. 8 that the current sharply increases as the power supply voltage increases. Therefore, when the power supply voltage of 5V is supplied to the microcomputer, the current is large and the electric charge supplied from the power storage unit is rapidly consumed, so that the backup time c is shortened.

In order to solve this, the present inventor has a structure in which a constant voltage circuit is connected between the microcomputer and the power storage unit to supply a DC voltage of about 3 V to the microcomputer, and also when the iron body is placed. The constant voltage circuit is configured to supply a DC voltage of about 3V to the microcomputer. However, since the above-mentioned 3V power supply voltage is too low, noise is added to the 100V AC voltage from the commercial power supply input to the iron main body (due to external equipment), so the microcomputer is susceptible to noise and malfunctions. There is a second drawback that is easy to do.

In order to increase the backup time c, it is conceivable to increase the capacity of the power storage unit and increase the charging voltage above 5V. However, since the capacity is large, the charging time of the power storage unit becomes longer than the rise time of the base temperature.
Therefore, when the user detaches the iron body and uses it immediately after the base temperature rises, the power storage unit is not sufficiently charged, so the voltage supplied from the power storage unit to the microcomputer is too low, There is a drawback that the microcomputer is reset. Further, when the withstand voltage value of the power storage unit is increased or the capacity is increased, the space occupied by the power storage unit becomes large and the cost becomes high.

Further, in the above cordless iron, a liquid crystal display is used as a display means. However, in order to drive the liquid crystal display, the microcomputer needs a special function. That is, by setting display data in a specific area or register of the RAM, the function of automatically controlling the output terminal connected to the liquid crystal display by the hardware of the microcomputer is used so as to display on the liquid crystal display. Normally, although a small-scale microcomputer with about 28 pins can be used for temperature control and display control of a microcomputer, only microcomputers with more than 64 pins with the above-mentioned special functions are available in the market, so the size of the microcomputer will increase. The third drawback is that the board becomes large and a small cordless iron cannot be obtained. Therefore, in consideration of such conventional drawbacks, the present invention provides a cordless iron which has a long backup time, is less likely to malfunction due to noise, and can be miniaturized.

[0008]

In order to solve the above-mentioned problems, the first invention comprises an iron main body having a heater for heating a base, and a mounting table for mounting the iron main body and supplying power thereto. The main body includes a power storage unit, a control unit, and a first
It has a constant voltage supply unit and a second constant voltage supply unit, and when the iron is placed, the power storage unit stores electricity, the first constant voltage supply unit supplies the first constant voltage to the control unit, and When leaving,
The second constant voltage supply unit supplies a second constant voltage lower than the first constant voltage to the control unit according to the discharge voltage of the power storage unit.

Further, in the first aspect of the present invention, preferably, the second constant voltage supply section is connected to the first constant voltage supply section via a rectifying element.

According to the first aspect of the present invention, preferably, the second constant voltage supply section is constituted by a MOS type component.

A second aspect of the present invention comprises an iron body having a heater for heating the base, and a mounting table for mounting the iron body and supplying power thereto. The iron body has a power storage unit, a control unit and a liquid crystal display. The control unit outputs a drive signal directly controlled by an output command to the liquid crystal display.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A cordless iron according to an embodiment of the present invention will be described below with reference to the electric circuit diagram of FIG. In FIG. 1, the mounting table 1 has an iron body 2 mounted thereon,
The iron body 2 is energized. A power supply terminal 3 is provided on the mounting table 1, and a commercial power supply 4 is connected to the power supply terminal 3.

The iron body 2 is provided with a power receiving terminal 5 which is connected to the power feeding terminal 3 when the iron body 2 is placed on the placing table 1. A series circuit of the relay contact 6 and the heater 7 is connected between the first lead wire 8 and the second lead wire 9. The heater 7 is embedded in a base (not shown), the base is made of, for example, aluminum die casting, and the heater 7 is configured to heat the base.

A series circuit composed of a Zener diode 10, a resistor 11 and a diode 12 is a first lead wire 8 and a second lead wire.
It is connected between the lead wire 9. The capacitor 13 is connected between the first lead wire 8 and the third lead wire 14,
The third lead wire 14 is a Zener diode 10 and a resistor 11.
It is connected to the midpoint between. The emitter of the transistor 15 is connected to the first lead wire 8, and the collector is connected to the third lead wire 14 via the relay coil 16.
The diode 17 is connected in parallel with the relay coil 16. These Zener diode 10, resistor 11,
Diode 12, capacitor 13, transistor 1
5, the relay coil 16, and the diode 17
The relay drive unit 18 is configured.

A series circuit including a Zener diode 19 and a resistor 20 is connected between the first lead wire 8 and the fourth lead wire 21. The base of the transistor 22 is
It is connected to an intermediate point between the Zener diode 19 and the resistor 20. The collector of the transistor 22 is connected to the second lead wire 9 via a series circuit of a resistor 23 and a diode 24. These Zener diodes 19,
The resistor 20, the transistor 22, the resistor 23, and the diode 24 form a charging unit 25.

The power storage unit 26 is composed of, for example, a capacitor,
It is connected between the first lead wire 8 and the emitter of the transistor 22. The three-terminal regulator 27 is, for example, C-
It is composed of a MOS, and its input terminal (IN) is connected to the emitter of the transistor 22. The resistor 28 is connected to the first lead wire 8 and the ground terminal (GN) of the three-terminal regulator 27.
D). The rectifying element 29 is, for example, a diode, and its cathode is connected to the output terminal (OUT) of the three-terminal regulator 27. Resistance 30
One end of is the ground terminal (GND) of the three-terminal regulator 27.
And a resistor 28, and the other end is connected to a connection point between the output terminal (OUT) of the three-terminal regulator 27 and the rectifying element 29.

The three-terminal regulator 27, the resistor 28, and the resistor 30 constitute a second constant voltage supply section 31. Thus, when the input voltage V1 of the three-terminal regulator 27 is higher than a certain value, the resistance 28 is set so that the output voltage V2 of the three-terminal regulator 27 becomes about 3.3V.
And the size of the resistor 30 is determined.

The capacitor 32 is connected between the first lead wire 8 and the fourth lead wire 21, and the series circuit of the step-down resistor 33 and the diode 34 is connected between the fourth lead wire 21 and the second lead wire 9. It is connected. The series circuit of the Zener diode 35 and the resistor 36 is connected between the first lead wire 8 and the fourth lead wire 21. The capacitor 37 is connected between the first lead wire 8 and the fifth lead wire 38.
The base of the transistor 39 is connected to the midpoint between the Zener diode 35 and the resistor 36, the collector is connected to the fourth lead wire 21, and the emitter is connected to the fifth lead wire 38. The anode of the rectifying element 29 is connected to the emitter of the transistor 39.

The zener diode 35, the resistor 36, and the transistor 39 make up the first constant voltage supply unit 4
0 is configured. In this way, the first constant voltage supply unit 40 is connected to the second constant voltage supply unit 31 via the rectifying element 29. In addition, the first constant voltage supply unit 40 and the capacitor 32
, Step-down resistor 33, diode 34, and capacitor 3
The power source unit 41 is configured by the components 7 and 7. The voltage applied between the first lead wire 8 and the fifth lead wire 38 is V3.
And

The reset unit 42 is connected between the first lead wire 8 and the fifth lead wire 38, and the voltage detection unit 43a also has the first lead wire.
Connected between the lead wire 8 and the fifth lead wire 38,
The lead wire 38 is grounded.

The temperature detector 43 comprises a thermistor, for example, and is attached to the base. The temperature detection device 44 applies, for example, a predetermined DC voltage to one end of the temperature detector 43 and is grounded to the other end of the temperature detector 43 via a resistor (not shown) to connect the temperature detector 43 and the resistor. The intermediate point is provided as an output terminal (not shown).

The connection detector 45 detects whether or not the power receiving terminal 5 of the iron body 2 is connected to the power feeding terminal 3 of the mounting table 1, and outputs the detection signal to an output terminal (not shown). To do.

The temperature setting section 46 is composed of, for example, a key switch and the like, and is configured to correspond to high temperature operation, medium temperature operation, low temperature operation or stop when pressed once, twice, three times or four times, respectively. One input terminal of the temperature setting unit 46 is connected to the first lead wire 8, and the other input terminal is grounded. The oscillation circuit 47 is connected to the control unit 48, and the control unit 4
A clock signal is supplied to the signal line 8.

Next, the control unit 48 and the liquid crystal display 49 used in this cordless iron will be described with reference to FIG. FIG. 2 is an electric circuit diagram of the controller 48 and the liquid crystal display 49. In FIG. 2, the control unit 48 is, for example, a one-chip microcomputer, and internally has a processing unit CPU and RA.
M, a ROM for storing programs and the like, an analog / digital converter, a plurality of input terminals for receiving each input signal, and a plurality of output terminals for outputting each output signal. The switching element 50 is connected to the output terminal.

The switching element 50 is composed of a plurality of switching elements 50a to 50h (for example, MOS field effect transistors), and each switching element 50a to 50h.
Source is grounded via a terminal P5. The gates of the switching elements 50a to 50h are connected to the CPU via a logic circuit for output control and a bus (none of which is shown), and the drains thereof are connected to the output terminals P11 to P18. Although not shown, the output terminal P1 has the same configuration.

The terminal P1 of the control unit 48 has a resistor 15
via a, to the base of the transistor 15, the terminal P2 to the first lead wire 8, the terminal P3 to the output terminal of the reset unit 42, the terminal P4 to the output terminal of the voltage detection unit 43a, and the terminal P.
5 are connected to the fifth lead wires 38, respectively. Terminal P2
And the terminal P5 are terminals for power supply, and the control section 48 operates by the voltage applied between them.

The terminal P6 of the control section 48 is connected to the temperature detecting device 44, the terminal P7 is connected to the connection detecting section 45, the terminal P8 is one terminal of the oscillation circuit 47, the terminal P9 is the other terminal of the oscillation circuit 47, and the terminal is a terminal. P10 is connected to the output terminal of the temperature setting unit 46.

The output terminals P11 and P1 of the control unit 48 are also provided.
2, P13, P14, P15, P16, and P17 are connected to the respective segment electrodes 52a, 52b, 52c, 5 provided on the liquid crystal display 49 through the respective lead wires 51a to 51g.
2d, 52e, 52f, 52g, respectively.
The output terminal P18 is connected to the common electrode 53 via the lead wire 51h.

One end of the sixth lead wire 54 is connected to the first lead wire 8, and the other end of the sixth lead wire 54 is connected to each resistor 5.
It is connected to the lead wires 51a to 51h via 5a to 55h.

Next, the liquid crystal display 49 will be described with reference to FIGS. 3 is a sectional view of the liquid crystal display 49, FIG. 4 is a plan view of a segment electrode used in the liquid crystal display 49,
FIG. 5 is a plan view of a printing unit used in the liquid crystal display 49.

In these figures, the first glass 57 is arranged under the first polarizing plate 56, and the common electrode 53 is arranged on the back surface of the first glass 57. The first alignment film 58 is arranged below the common electrode 53. A second glass 59 is arranged below the first glass 57, and these glasses 57,
A seal portion 60 is arranged around 59.

The segment electrode 5 is formed on the surface of the second glass 59.
2 are arranged. As shown in FIG. 4, the segment electrode 52 includes a first segment electrode 52a, a second segment electrode 52b, a third segment electrode 52c, a fourth segment electrode 52d, a fifth segment electrode 52e, a sixth segment electrode 52f and a seventh segment electrode. Separately arranged on the electrode 52g. The second alignment film 6 is formed on the segment electrode 52.
1 is arranged. First alignment film 58 and second alignment film 61
The liquid crystal 62 is arranged so as to be located between the and and surrounded by the seal portion 60.

The printing portion 63 is arranged on the back surface of the second glass 59. As shown in FIG. 5, the printing unit 63 includes a first printing unit 63a, a second printing unit 63b, a third printing unit 63c, a fourth printing unit 63d, a fifth printing unit 63e, a sixth printing unit 63f, and a seventh printing unit. The parts 63g are separately arranged. In this way, the printing units 63a to 63g are connected to the segment electrodes 52a.
It is arranged so that it may be located under each of ~ 52g.

The second polarizing plate 64 is arranged below the printing section 63, and the reflection plate 65 is arranged below the second polarizing plate 64 to form the liquid crystal display 49. With the above parts, this cordless iron 6
6 are configured. In the above description, the control unit 48
Although the resistors 55a to 55h are connected to the output terminals P11 to P18 of the C-MOS output port, the output on the P channel side of the C-MOS output port can be used instead of the external resistors 55a to 55h.

Next, the operation of the cordless iron 66 will be described with reference to FIGS. FIG. 6 shows the voltage characteristics of the voltages V1, V2, and V3 in the cordless iron 66. The horizontal direction shows the elapsed time, and the vertical direction shows the value of each voltage.

First, the user mounts the iron body 2 on the mounting table 1
(E in FIG. 6) and insert the plug into an outlet (neither is shown). As a result, an AC voltage is applied from the commercial power source 4 to the first lead wire 8 and the second lead wire 9 via the power feeding terminal 3 and the power receiving terminal 5. Then, the rectified current flows through the Zener diode 35, the resistor 36, the step-down resistor 33, and the diode 34. Further, the transistor 39 is turned on. As a result, the first constant voltage (power supply voltage composed of DC 5V) is started to be supplied between the terminals P2 and P5 of the control unit 48 (see FIG. 6). In addition, the charging unit 25
Is energized, the transistor 22 is turned on, and the power storage unit 26 starts charging.

Then, the control unit 48 receives the output from the oscillation circuit 47, starts oscillation, and starts "control operation". At this time, the control unit 48 alternately executes an instruction to turn on the output port, which is one of the instruction operations of the control unit 48, and an instruction to turn it off to the output terminal P18 by the program of the built-in ROM. As a result, the "Hi" signal and the "Lo" signal are repeatedly output to the gate of the switching element 50h to turn the switching element 50h on and off, and the drive signal is output to the common electrode 53 of the liquid crystal display 49 via the output terminal P18. (64 Hz rectangular wave) is output.

Similarly, the control unit 48 alternately executes an instruction to turn off the output port and an instruction to turn it on to the output terminal P11 in synchronization with the output timing of the output terminal P18. That is, the control unit 48 controls the switching element 5
The “Lo” signal and the “Hi” signal are repeatedly output to the gate of 0a, and the drive signal (rectangular wave) that is the inverted rectangular wave is output to the segment electrode 52a of the liquid crystal display 49.

Further, the controller 48 outputs the output terminals P12 to P17.
, An instruction to turn on the output port and an instruction to turn off the output port are alternately executed in synchronization with the output timing to P18,
The same signal as that of the gate of the switching element 50h is supplied to the gates of the switching elements 50b to 50g.

As a result, a predetermined voltage (a positive / negative alternating rectangular wave of 64 Hz) is applied to the liquid crystal 62 located between the first segment electrode 52a and the common electrode 53, and the display corresponding to the first segment electrode 52a lights up. However, it is displayed together with the "OFF" character of the first printing portion 63a located below the liquid crystal 62 in this portion. At this time, the segment electrode 52b
No voltage is applied between ~ 52g and the common electrode 53, and the display is turned off.

In this way, the output terminals P11 to P11 of the control unit 48 are
P18 is connected to each electrode (52a to 52g and 53) of the liquid crystal display 49. Then, at each timing of the output waveform by the program stored in the built-in ROM,
Switching elements 50a of output terminals P11 to P18 one by one
Directly control ~ 50h. As a result, the output terminals P11 to P11
A predetermined voltage is applied to each of the electrodes (52a to 52g and 53) by the drive signal output from P18, and the turning on / off of the liquid crystal display 49 is controlled.

Next, when the user presses a key (not shown) of the temperature setting section 46 once, for example, the "high" temperature set value is stored in the RAM in the control section 48. At the same time, the control unit 48 controls the same common electrode 5 as in the case of the above "off" display.
In the state where the drive signal to 3 is output, the instruction to turn off the output port and the instruction to turn on the output port are alternately executed to the output terminal P14. That is, the control unit 48 controls the switching element 5
The “Lo” signal and the “Hi” signal are repeatedly output to the gate of 0d, and the drive signal of the inverted form of the drive signal to the common electrode 53 is applied to the fourth segment electrode 52d.

Further, the control unit 48 outputs to the output terminals P11 to P13 an instruction to turn on the output port in synchronization with the output timing of P18 so that the same drive signal as that of the common electrode 53 is applied to the segment electrodes 52a to 52c. , The instructions to turn off are alternately executed to switch elements 50a to 50c.
To control.

As a result, a positive / negative alternating rectangular wave having a predetermined voltage value is applied to the liquid crystal 62 located between the fourth segment electrode 52d and the common electrode 53, and the liquid crystal display 49
"High" is displayed on. Further, the switching elements 50e-
By supplying a predetermined rectangular wave to the gate of 50 g, the liquid crystal display 49 displays “appropriate temperature”, that is, the fifth printing unit 63.
e to blink the level display of the seventh printing unit 63g.

As described above, the control unit 48 outputs the drive signal directly controlled by the output command to the liquid crystal display 49. As a result, the control unit 48 does not need the special function (described in the section of the problem to be solved by the invention) as in the conventional case. Therefore, the control unit 48 can use a small 28-pin microcomputer (in the present cordless iron 66, 18-pin terminals are used).

Then, the temperature detector 43 and the temperature detector 44
The analog value of the temperature information output from and is input to the terminal P6 and converted into a digital value in the control unit 48. When the control unit 48 determines that the above digital value is lower than the temperature setting value of the temperature setting unit 46, “Lo” is applied to the terminal P1.
A signal is output (the output of the terminal P1 is turned on).

As a result, the transistor 15 is turned on, the relay coil 16 of the relay drive section 18 is energized, the relay contact 6 is closed, the energization of the heater 7 is started, and the temperature of the base rises. When the temperature information detected by the temperature detector 43 reaches the temperature set value of the temperature setting unit 47, the control unit 4
8 outputs a "Hi" signal to the terminal P1 (turns off the output of the terminal P1). As a result, the transistor 15 is turned off, the energization of the relay coil 16 is stopped, the relay contact 6 is opened, the energization of the heater 7 is stopped, and the temperature of the base is lowered.

In this way, based on the comparison between the temperature information and the temperature set value, the control unit 48 sends the "Lo" signal and the "H" signal to the terminal P1.
By alternately outputting the "i" signal, the heater 7 repeats energization and stop, and the control unit 48 performs "temperature control" so that the temperature information of the temperature detector 43 substantially matches the temperature set value.

When the control unit 48 outputs the "Hi" signal to the terminal P1, the liquid crystal display 49 displays "appropriate temperature" via the output terminals P15 to P17 (fifth printing unit 63e to seventh printing unit 63g). (Level display of) lights up. In this way, when the temperature information of the temperature detector 43 is less than or higher than the temperature set value, the control unit 48 causes the liquid crystal display 49 to blink or light the "appropriate temperature" display, respectively, so that the user is in the optimum temperature state. Let me know. In this way, the control unit 48 performs "display control".

When the plug is inserted into the outlet, the power storage unit 26 starts to be charged, and after about 60 seconds, the saturation voltage (the charging voltage, which is indicated by the voltage V1 in FIG. 6) is about 5.3.
It becomes V. Thus, when the charging voltage V1 is applied to the input terminal (IN) of the three-terminal regulator 27, the output terminal (O
The output voltage V2 is about 3.3V. However, at this time, the voltage V3 is about 5V, which is higher than the voltage V2, so that the voltage V3 (about 5V) is applied between the terminals P2 and P5 of the control unit 49.

The three-terminal regulator 27 is a negative power supply regulator, and normally, a current flows from the output terminal (OUT) to the input terminal (IN). In addition, as described above, the power storage unit 26
At the rising edge (immediately after the start of charging), electric charge is slowly accumulated in power storage unit 26, and the voltage between first lead wire 8 and IN of three-terminal regulator 27 becomes V1 = -2V, for example. On the other hand, the voltage V3 = -5V is applied instantaneously. As a result, in the three-terminal regulator 27, from IN to OUT
An electric current is about to flow. However, the first constant voltage supply unit 4
Since the rectifying element 29 is provided so that the current flows from 0 to the second constant voltage supply unit 31, no current flows from IN to OUT of the three-terminal regulator 27.

Since the three-terminal regulator 27 is a negative power supply regulator as described above, if a current flows from IN to OUT, it may be destroyed. In order to avoid this, the rectifying element 29 is provided between the first constant voltage supply unit 40 and the second constant voltage supply unit 31. This prevents backflow of current and prevents the destruction of the three-terminal regulator 27.

Next, when the user removes the iron body 2 from the mounting table 1 for ironing (f in FIG. 6), the iron body 2 is connected to the first lead wire 8 and the second lead wire 9. Supply of alternating voltage is stopped. At this time, the power supply unit 41
The power supply to the power source is stopped instantaneously, and the first constant voltage supply unit 40 stops the voltage supply to the control unit 48.

Then, as shown in FIG. 6, discharge voltage V1 of power storage unit 26 gradually decreases. Even if the voltage V1 changes in this way, the output voltage V2 of the three-terminal regulator 27 is about 3.3 due to the regulator characteristic of the three-terminal regulator 27.
Maintained at V. This voltage V2 is reduced by 0.3V by the rectifying element 29, and the power supply voltage V3 to the control unit 48 is about 3V.
Be maintained. In this way, when the iron body 2 is detached,
The second constant voltage supply unit 31 uses the discharge voltage of the power storage unit 26 to
The second constant voltage V3 (about 3 V) lower than the first constant voltage (about 5 V)
V) is supplied to the control unit 48.

However, when the voltage V1 further decreases and the voltage V1 becomes lower than about 3.3 V (illustrated at the point g), the regulator function of the three-terminal regulator 27 no longer works, and the voltage V2 also gradually decreases. As a result, the voltage V
3 also begins to decline.

The decrease in the power supply voltage V3 to the control unit 48 is detected by the voltage detection unit 43a, and when the power supply voltage V3 becomes about 2.5 V or less, the voltage detection unit 43a controls the control unit 49a.
A specific signal is output to the terminal P4 of, and the control unit 48 stops the oscillation. Then, only the temperature setting information of the RAM is held and the hold operation mode for stopping the operation is entered.

As described above, the period h from when the iron body 2 is detached from the mounting table 1 until the control unit 48 stops the oscillation is the backup time, which is, for example, about 180 seconds. During this backup time h, the controller 48 continues to oscillate and performs the "control operation".

The "control operation" at the time of disengagement means that the control unit 48 compares the temperature information of the temperature detector 43 with the non-suitable temperature determination temperature corresponding to the temperature set value of the temperature setting unit 46, and the temperature information is the above-mentioned. When the temperature is equal to or higher than the determination temperature, the control unit 48 causes the liquid crystal display 49.
When the temperature information is less than the determination temperature, the control unit 48 causes the liquid crystal display 49 to blink or turn off the "suitable temperature" display. When the iron body 2 is detached, the liquid crystal display 4
The "high" display of 9 is turned off.

In this way, when the iron body 2 is detached, the power supply voltage to the control unit 48 is set to the second constant voltage (5V) lower than the second constant voltage.
By supplying a constant voltage (3V), the current flowing through the control unit 48 is small as shown in FIG. Therefore, the power storage unit 2
Discharge current from 6 is also small, backup time h
Becomes longer. Therefore, when the user irons with the iron main body 2, the time for which "display control" can be performed becomes long,
Usability is improved.

Next, the voltage V3 further decreases, and the hold time i is from 2.5V to 2.1V, for example, about 30 minutes. At this hold time i, the control unit 4
No. 8 stops oscillation, but stores data such as temperature setting values in the RAM of the control unit 48. Therefore, after the iron body 2 is mounted on the mounting table 1 again, the temperature is controlled according to the "high" temperature set value, so that the user sets the temperature setting unit 46.
There is no need to re-key, which improves usability.
This is the end of the description of the operation of the cordless iron 66.

[0061]

As described above, according to the first aspect of the present invention, when the iron body is placed, the first constant voltage supply section outputs a relatively high first constant voltage to the control section. Since the power supply voltage (first constant voltage) to the control unit is relatively high as described above, the control unit is less likely to malfunction with respect to noise from the commercial power supply input to the iron body.

Then, when the iron body is detached, the second constant voltage supply unit outputs a second constant voltage lower than the first constant voltage to the control unit according to the discharge voltage of the power storage unit. In this way, the power supply voltage (second constant voltage) to the control unit is relatively low, so the current flowing through the control unit is low. As a result, the backup time (oscillation allowable time) of the control unit becomes longer, and the usability is improved.

In the first aspect of the present invention, preferably, the second constant voltage supply section and the first constant voltage supply section are connected via a rectifying element. If there is no rectifying element, the electricity storage unit will slowly store electricity for a while after the iron body is placed.
In the constant voltage supply unit, the potential of the input terminal becomes higher than the potential of the output terminal, and current flows from the input terminal to the output terminal. However, due to the rectifying element, no current flows from the input terminal to the output terminal. Therefore, there is no danger of the second constant voltage supply section being destroyed.

Furthermore, in the first aspect of the present invention, it is desirable that the second constant voltage supply section be composed of a MOS type component to reduce the current flowing through the second constant voltage supply section itself when the iron body is detached. Can be done. As a result, the discharge current from the power storage unit is supplied to the control unit without loss, so that the backup time of the control unit is further extended.

Further, in the second aspect of the present invention, the control section outputs a drive signal for direct control to the liquid crystal display through the output terminal according to the output command of the CPU. In this way, the control unit
By controlling the switching element of the output terminal directly at each timing of the output waveform of the drive signal by the program stored in, the predetermined voltage is output to the liquid crystal display and the turning on / off is controlled. . As a result, the control unit does not need a special function as in the conventional case, and a small 28-pin microcomputer can be used. Therefore,
The control unit becomes smaller, the board becomes smaller, and the size can be reduced, and the cost can be reduced. Further, since the liquid crystal display of low power consumption is used, the displayable time becomes long when the iron is removed.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of a cordless iron according to an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of a control unit and a liquid crystal display used in the cordless iron.

FIG. 3 is a cross-sectional view of the liquid crystal display.

FIG. 4 is a plan view of a segment electrode used in the liquid crystal display.

FIG. 5 is a plan view of a printing unit used in the liquid crystal display.

FIG. 6 is a characteristic diagram of each voltage in the cordless iron.

FIG. 7 is a voltage characteristic diagram of a conventional cordless iron.

FIG. 8 is a voltage / current characteristic diagram in the control unit.

[Explanation of symbols]

1 table 2 Iron body 7 heater 26 Power storage unit 31 Second constant voltage supply unit 40 First constant voltage supply unit 48 control unit

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) D06F 75/26

Claims (4)

(57) [Claims] 1. An iron main body having a heater for heating a base, and a mounting table for mounting the iron main body and supplying power thereto, the iron main body including a power storage unit, a control unit, and a first constant voltage supply unit. A second constant voltage supply unit, the power storage unit stores electricity when the iron is placed, the first constant voltage supply unit supplies a first constant voltage to the control unit, and The cordless iron according to claim 2, wherein the second constant voltage supply unit supplies a second constant voltage, which is lower than the first constant voltage, to the control unit according to a discharge voltage of the power storage unit at the time of disconnection. 2. The cordless iron according to claim 1, wherein the second constant voltage supply unit is connected to the first constant voltage supply unit via a rectifying element. 3. The cordless iron according to claim 1, wherein the second constant voltage supply unit is formed of a MOS type component. 4. An iron main body having a heater for heating a base, and a mounting table for mounting the iron main body and supplying power thereto, the iron main body having a power storage unit, a control unit, and a liquid crystal display. The control unit outputs a drive signal directly controlled by an output command to the liquid crystal display, the cordless iron.