JPH0818418A - Control method and electronic equipment - Google Patents

Abstract

PURPOSE:To provide a control method capable of performing ON/OFF control in synchronism with a zero-cross point without receiving the influence of the waveform distortion of an AC power source and noise, etc. CONSTITUTION:In this control method for which this electronic equipment supplied with power from the AC power source 9 is provided with a zero-cross point detection means 77 for detecting the zero-cross point of the AC power source 9 for ON/OFF controlling power supply to an internal or external load in synchronism with the zero-cross point detected by the zero-cross point detection means 77, a frequency discrimination means for discriminating the frequency of the AC power source 9 is provided and the detection operation of the zero- cross point detection means 77 is inhibited during a period excluding the zero- cross point detected by the zero-cross point detection means 77 and a first prescribed period immediately before that based on the cycle of the zero-cross point obtained from the frequency discriminated by the frequency discrimination means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method and electronic equipment for receiving power supply from an AC power supply and synchronizing the zero-cross point of the AC power supply with ON / OFF control of power supply to an internal or external load. And an electronic device that controls on / off of power supply to an internal or external load by a computer.

[0002]

2. Description of the Related Art Conventionally, when ON / OFF control of a load such as a motor and a heater using an AC power source is performed, a zero cross point of the AC power source is detected and matched with the zero cross point in order to prevent generation of noise. , ON / OFF control. Also, in electronic devices that control the power supply on / off by a computer, the computer may run away due to static electricity, external noise, etc., and in devices that use a heater, such as clothes dryers and dishwashers, the heater is turned on. There is a danger such as continuing to drive in the condition. For this reason, Japanese Patent Laid-Open No. 60-170190 proposes that the user is notified of a runaway of the computer.

[0003]

However, when the signal from the zero-cross point is not accurate due to the distortion of the waveform of the AC power supply, noise, etc. Noise is generated by turning on / off the load of the motor, heater, etc.
When the time is counted by the signal of the zero cross point, the measured time may be wrong. In order to remove the effects of AC power supply waveform distortion and noise,
A zero-cross signal detection circuit 115 having a hysteresis as shown in FIG. 14 has been proposed. In FIG. 14, the AC voltage of the AC power supply 111 stepped down by the transformer Tr is full-wave rectified by the bridge rectifier circuit 112, and the smoothing capacitor C1, the constant voltage circuit (for example, 5V), and the smoothing capacitor C2 are passed through the diode D. It is smoothed by passing through the smoothing circuit and is supplied to the microcomputer 110 as a DC power supply Vcc.

The zero-cross signal detection circuit 115 inputs the output of the bridge rectification circuit 112 to the base of a transistor Q1 whose constant-voltage power supply (for example, 5V) is applied to the collector via a resistor R6 and a resistor R6, and the transistor Q1. Is connected to a transistor Q2 whose constant voltage power source (for example, 5V) is applied to the collector through a resistor R4 and a resistor R7, and the collector of the transistor Q2 is connected to an interrupt terminal In of the microcomputer 110 through a resistor R8. It is connected to the base of the transistor Q1 through the resistor R16. Resistors R1 and R
A capacitor C3 whose other end is grounded is connected between the two terminals, and resistors R3 and R5 whose other ends are grounded are connected to the bases of the transistors Q1 and Q2, respectively. Is grounded.

Such a zero-cross signal detection circuit 115.
Then, the full-wave rectified voltage shown in FIG. 15 (b) obtained by stepping down and full-wave rectifying the AC current of the AC power supply 111 shown in FIG. 15 (a) is input to the base of the transistor Q1 through the resistors R1 and R2. Here, when the voltage of the waveform shown in FIG. 15B changes from the H level to the L level, initially the transistor Q1 is on and the transistor Q2 is off, so the collector of the transistor Q2 is at the H level (5 V).
X (R3 + R16) / (R3 + R7 + R16)). Therefore, through the resistor R16, the transistor Q1
Since a current flows into the base of the transistor Q1, the voltage at the time when the transistor Q1 turns off becomes a voltage (V1) lower than the on / off threshold value of the transistor Q1. When the voltage of the waveform shown in FIG. 15B changes from the L level to the H level, initially the transistor Q1 is off and the transistor Q2 is on, so the collector of the transistor Q2 is grounded. Therefore, the current flowing through the resistor R2 is shunted into the base current of the transistor Q1 and the current flowing through the resistor R16. Therefore, the voltage at the time when the transistor Q1 is turned on is higher than the on / off threshold value of the transistor Q1 (V2 )become.

As described above, the collector voltage of the transistor Q1 shown in FIG. 15C changes from H level to L level and from L level to H level because the voltage of the waveform shown in FIG. To have. The collector voltage of the transistor Q1 is inverted by the transistor Q2 as shown in FIG. 15D, and the interrupt terminal In of the microcomputer 110 is passed through the resistor R8.
Is input to. Here, the transistors Q1 and Q2 are used as switches by using the active region. When the input voltage to the interrupt terminal In changes from the H level to the L level, the microcomputer 110 interrupts and detects the zero-cross point. Here, the hysteresis width can be changed by changing the resistance value of the resistor R16. However, such a zero-cross signal detection circuit 1
15 also has a problem that the circuit configuration becomes complicated and the influence of a large noise cannot be excluded. Also, in the case of notifying the user of a computer runaway, the user notices the notification,
If the power supply is not turned off, the computer will continue to run in a runaway state.

The present invention has been made in view of the above circumstances. In the first invention, the zero-cross points detected by the zero-cross point detecting means and the zero-cross points are detected based on the cycle between the zero-cross points obtained from the determined frequency. By prohibiting the detection operation of the zero-cross point detection means during a period other than the immediately preceding first predetermined period, ON / OFF control can be performed in synchronization with the zero-cross point without being affected by the waveform distortion and noise of the AC power supply. The purpose is to provide a control method. In the second invention, a frequency discriminating means for discriminating the frequency of the AC power supply, a first clocking means for clocking a second predetermined period based on a cycle between zero cross points obtained from the frequency discriminated by the frequency discriminating means, and a first clocking means. By providing a prohibition unit that prohibits the detection operation of the zero-cross point detection unit during the period in which the time-measuring unit measures the second predetermined period from the zero-cross point, without being affected by the waveform distortion and noise of the AC power supply, An object of the present invention is to provide an electronic device that can be on / off controlled in synchronization with a zero-cross point. According to a third aspect of the present invention, a runaway detection circuit that detects a runaway of a computer, and a power supply cutoff circuit that receives a runaway detection signal from the runaway detection circuit when the runaway detection circuit detects a runaway of the computer and turns off power supply. It is an object of the present invention to provide an electronic device that can maintain safety against a computer runaway by providing the.

[0008]

In a control method according to a first aspect of the present invention, an electronic device supplied with electric power from an AC power supply is equipped with a zero-cross point detecting means for detecting a zero-cross point of the AC power supply, and the zero-cross inspection is performed. In a control method of controlling on / off of power supply to an internal or external load in synchronization with a zero-cross point detected by the output means, the frequency of the AC power supply is discriminated, and the cycle between zero-cross points is obtained from the discriminated frequency. Based on this, the detection operation of the zero-cross point detecting means is prohibited during a period other than the zero-cross point detected by the zero-cross point detecting means and the first predetermined period immediately before the zero-cross point.

An electronic device according to a second aspect of the invention is provided with a zero-cross point detecting means for receiving electric power from an alternating-current power source and detecting a zero-cross point of the alternating-current power source, and synchronizing with a zero-cross point detected by the zero-cross point detecting means. In an electronic device that controls ON / OFF of power supply to an internal or external load, a frequency discriminating unit that discriminates the frequency of the AC power supply, and a cycle between zero cross points obtained from the frequency discriminating by the frequency discriminating unit. A first time measuring means for measuring a second predetermined time period based on the first time measuring means, and a prohibiting means for prohibiting the detection operation of the zero cross point detecting means during the time period in which the first time measuring means measures the second predetermined time period from the zero cross point. It is characterized by being provided.

According to a third aspect of the present invention, there is provided an electronic device in which an on-off control of power supply to an internal or external load is performed by a computer, and the runaway detection circuit for detecting runaway of the computer and the runaway detection circuit are provided. When a runaway of the computer is detected, a power supply cutoff circuit for turning off the power supply upon receiving a runaway detection signal from the runaway detection circuit is provided.

[0011]

In the control method according to the first aspect of the present invention, the frequency of the AC power source is discriminated, and the zero-cross point detected by the zero-cross point detecting means and the first predetermined value immediately before the zero-cross point are detected based on the cycle between the zero-cross points obtained from this frequency. The detection operation of the zero-cross point detecting means is prohibited during the period except the period.

In the electronic device according to the second aspect of the present invention, the frequency discriminating means discriminates the frequency of the AC power source, and the second predetermined period based on the cycle between the zero cross points obtained from this frequency,
The prohibiting means prohibits the detection operation of the zero-cross point detecting means during the period in which the first time measuring means measures time from the zero-cross point.

In the electronic device according to the third aspect of the present invention, when the runaway detection circuit detects the runaway of the computer, the power supply cutoff circuit receives the runaway detection signal from the runaway detection circuit without passing through the computer, and the power is cut off. Turn off the supply.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments. FIG. 1 is a vertical cross-sectional view of an electric dryer which is an embodiment of a control method according to the first invention and an electronic device according to the second invention. In the figure, reference numeral 1 denotes the box-shaped frame, and a front portion of the frame 1 is provided with a clothing insertion port 11 for loading and unloading the clothes to be dried. A lid 12 for opening and closing the clothing insertion port 11 is provided outside the clothing insertion port 11. A plurality of air holes 13 for sucking cooling air are provided in the center of the rear wall surface of the frame 1, and air sucked from the air holes 13 is formed in the lower portion of the rear wall surface of the frame 1. An exhaust hole 14 for exhausting is exhausted.

Inside the frame 1, a horizontal shaft type drum 2 for accommodating clothes and rotating in the circumferential direction is rotatably arranged with its axial center direction being the front-back direction of the frame 1.
The front part of the drum 2 has a circular opening, and the opening is
The clothes inlet 11 is hermetically connected by a cylindrical cylinder cover 15 with a collar. Further, an exhaust port 200 having a plurality of holes is provided at the center of the rear wall surface of the drum 2, and a dust collecting filter 20 is attached so as to cover the exhaust port 200. The dust collecting filter 20 includes a circular lint filter 22 inside a hollow disk-shaped filter cover 21 having a plurality of holes 210, 210 ...

Between the rear wall surface of the frame 1 and the rear wall surface of the drum 2, there is provided a fan housing chamber 30 in which a disk-shaped double-sided fan 3 coaxially arranged with the drum 2 is rotatably housed. Has been formed. A part of the fan storage chamber 30 is opened on the drum 2 side.
The exhaust port 200 on the rear wall surface is airtightly connected by a cylindrical connecting member 33 with a collar.
A round rod-shaped shaft 10 penetrates from the outside of the frame 1 at the center of the filter 20 of the drum 2, the center of the wall surface on the opening side of the fan storage chamber 30, and the center of the rear wall surface of the frame 1. . In the fan storage chamber 30, the double-sided fan 3 is adapted to rotate in the circumferential direction with the shaft 10 as its rotation center. The rear side of the drum 2 is supported by the shaft 10, and the front side of the drum 2 is supported by the cylinder cover 15 to rotate.

The double-sided fan 3 is provided with a plurality of blades (not shown) on each of its front and back surfaces.
The fan storage chamber 30 is used by the double-sided fan 3 for the drum 2
Side first chamber 31 and the second chamber 3 on the rear wall surface side of the frame 1
It is divided into two parts. Fan storage room 30
In the first chamber 31, the air inside the drum 2 is sucked through the filter 20 by the rotation of the double-sided fan 3. On the other hand, in the second chamber 32 of the fan storage chamber 30, the outside air is sucked through the air holes 13, 13 ... By the rotation of the double-sided fan 3.

The lower part of the first chamber 31 of the fan storage chamber 30 is
It is connected to the end of the circulation duct 4, which is an air passage that continues from the bottom of the frame 1 through the front to the cylinder cover 15 below the clothing inlet 11. A first heater 51 and a second heater 52 made of semiconductor heaters are arranged on the front side of the frame 1 in the middle of the circulation duct 4, and on the bottom side of the rear side of the frame 1 in the middle of the circulation duct 4. A drain port 41 for draining the water in the circulation duct 4 to the outside of the machine is provided. In addition, a ventilation hole 42 that connects the circulation duct 4 and the inside of the drum 2 is formed in the end surface of the circulation duct 4 on the cylinder cover 15 side,
The air in the circulation duct 4 is introduced into the drum 2 through the ventilation holes 42.

A motor 6 for rotating the drum 2 and the double-sided fan 3 is arranged on the upper surface of the circulation duct 4 below the frame 1. The motor 6 has rotating shafts 61 and 62 provided in the front-rear direction of the frame 1, and a pulley 63 is attached to the tip of the rotating shaft 61 provided on the front side of the frame 1 to form a drum. 2 and the pulley 63 are interlockingly connected via a V belt 64, and the drum 2 is rotated by the driving force of the motor 6. A fan pulley 65 is attached to the tip of a rotary shaft 62 provided on the rear side of the frame 1, and the double-sided fan 3 and the fan pulley 65 are interlockingly connected via a round belt 66. The double-sided fan 3 is rotated by the driving force of the motor 6.

A first thermosensitive element 71 for detecting the temperature of the air in the first chamber 31 is provided in the first chamber 31 of the fan housing chamber 30, and a first heater in the circulation duct 4 is provided. 51 and the second heater 52, and the drainage port 41,
A second heat sensitive element 72 for detecting the temperature of the air before being heated by the first heater 51 and the second heater 52 is provided, and the first heater 51 and the second heater 5 in the circulation duct 4 are provided.
In front of 2, a third thermosensitive element 73 for detecting the temperature of the air heated by the first heater 51 and the second heater 52.
Is provided.

Next, the operation of the thus constructed electric dryer will be described. When the motor 6 is driven, the drum 2 and the double-sided fan 3 rotate simultaneously. Double-sided fan 3
When is rotated, the air in the circulation duct 4 heated by the first heater 51 and the second heater 52 is introduced as hot air into the drum 2 through the ventilation holes 42, and the introduced hot air is transferred to the drum 2 Inside, heat is exchanged with clothes to become hot and humid air, which is sucked into the first chamber 31 of the fan storage chamber through the filter 20.

On the other hand, in the second chamber 32 of the fan housing chamber 30, the cooling air is sucked through the air holes 13, 13 ... By the rotation of the double-sided fan 3, and the sucked cooling air is The double-sided fan 3 in the second chamber 32 is cooled, and after cooling, it is exhausted to the outside of the machine through the exhaust holes 14. With the cooling of the double-sided fan 3 as described above, the hot and humid air in the first chamber 31 is also cooled, and the moisture in the air in the first chamber 31 is condensed to generate water droplets. This water drop is shaken off by the double-sided fan 3 in the first chamber 31 and sent into the circulation duct 4,
It is drained out of the machine through the drainage port 41 at the bottom. The air from which the moisture has been removed in this way passes through the circulation duct 4 and is heated by the first heater 51 and the second heater 52,
It is again sucked into the drum 2.

FIG. 2 is a plan view of a keyboard having various operation keys which are operated to operate the electric dryer. The board surface of the keyboard is a horizontally long rectangle, and the first heater 51 and the second heater 5 are arranged on the front side from left to right.
Heater switching key 81 for switching between strong and weak modes of the heater output by selecting the use of both two or one of the two, a plurality of predetermined drying courses (60 minutes course, ironing course, ... standard course ), A course switching key 82 for switching the drying course to select a desired drying course, a start key 85 for instructing start and stop of operation, and a power switch 86 are provided in this order. Further, behind the heater switching key 81,
A heater LED for lighting up and displaying either the mode of strong or weak of the heater output selected by the heater switching key 81.
810 is provided. Behind the course switching key 82, a course LED 820 that lights up and displays the dry course selected by the course switching key 82 is provided.

Next, the structure of the control system of the electric dryer will be described. FIG. 3 is a block diagram showing the basic configuration of the control system of the electric dryer. The microcomputer 100 that performs various controls of the electric dryer is adapted to operate by the power supplied from the power supply circuit 9, and is interrupted by the zero-cross signal detection circuit 77 that detects the zero-cross point of the AC power supply from the power supply circuit 9. A signal is input. The microcomputer 100 is supplied with a clock from a clock oscillating circuit 76, a door switch 74 for detecting opening and closing of a door, an input key circuit 101 including various operation keys as described above, and a first thermosensitive element 7.
The signals from the first, second, and third thermosensitive elements 72, 73 are input.

The microcomputer 100 includes an LED lighting circuit 102 including various LEDs as described above.
Is connected to the heater LED 810 and the course switching key 82 from the microcomputer 100 to the LED lighting circuit 102 according to the input signal from the input key circuit 101.
The data for lighting etc. is given. In addition, the microcomputer 100 is connected with a load driving circuit 103 which is a circuit for driving the motor 6, the first heater 51, the second heater 52, and an automatic power-off device 104 for automatically turning off the power. The load drive circuit 103 includes an input key circuit 10
A control signal for driving the device is given based on the signals input from the first, first heat-sensitive element 71, the second heat-sensitive element 72, and the third heat-sensitive element 73. Further, the microcomputer 100 is connected to a reset circuit 75 for resetting the various settings described above.

When performing the drying operation, the heater output can be selected to either "strong" or "weak" mode as described above. When the heater output is selected to "strong", Both the first heater 51 and the second heater 52 are operated, and when the heater output is selected as "weak", one of the first heater 51 and the second heater 52 is operated. .

FIG. 4 is a circuit diagram showing a configuration example of the zero-cross signal detection circuit 77 (FIG. 3). Power supply circuit 9 (Fig. 3)
Is a smoothing circuit including a smoothing capacitor C1, a constant voltage circuit (for example, 5V), and a smoothing capacitor C2, which are full-wave rectified by a bridge rectification circuit 112, the AC voltage of the AC power supply 111 being stepped down by a transformer Tr, and via a diode D. Is passed through to be smoothed and supplied to the microcomputer 100 as a DC power supply Vcc.

The zero-cross signal detection circuit 77 inputs the output of the bridge rectification circuit 112 to the base of the transistor Q1 whose constant-voltage power supply (for example, 5V) is applied to the collector through the resistors R1 and R2 and the resistor R9, and the transistor Q1. The collector of is connected to the interrupt terminal In of the microcomputer 100 via the resistor R10.
Between the resistors R1 and R2, a capacitor C whose other end is grounded
3 is connected, and the base of the transistor Q1 is connected to the resistor R3 whose other end is grounded, and the base of the transistor Q1 is grounded.

In such a zero-cross signal detection circuit 77, the full-wave rectified voltage shown in FIG. 10 (b) obtained by stepping down and full-wave rectifying the AC current of the AC power supply 111 shown in FIG. It is input to the base of the transistor Q1 through R2, and from the collector of the transistor Q1 shown in FIG.
The inverted and amplified voltage shown in 0 (c) is output. This voltage is applied to the microcomputer 100 through the resistor R10.
Is input to the interrupt terminal In. When the input voltage to the interrupt terminal In exceeds the threshold voltage V3 from the L level to the H level, the microcomputer 100 interrupts and detects the zero-cross point. In the electronic device according to the present invention, ON / OFF control can be performed in synchronization with the zero-cross point without being affected by the waveform distortion of the AC power supply, noise, etc., so that the simple zero-cross signal detection circuit 77 as described above is used.
Can be used.

The operation of the control method and the electronic apparatus according to the present invention for on / off control in synchronization with the zero-cross point will be described below with reference to the flowcharts of FIGS. Here, in the above-mentioned electric dryer, the phase of the motor is controlled in synchronization with the zero-cross point.
When the electric dryer is turned on, first, all the RAM of the microcomputer 100 is cleared (see FIG. 5S1).
0), all outputs are turned off (S11 in FIG. 5). Next, when the frequency is discriminated by the frequency discriminating operation described later (FIG. 5S12), LED output control (FIG. 5S13), keyboard operation key input control (FIG. 5S14), drying control (FIG. 5S15), etc. (S16 in FIG. 5) is repeatedly executed until the power of the electric dryer is cut off.

Whenever the electric dryer is turned on and the zero-cross point of the AC power source is detected, an external interrupt is executed (S19 in FIG. 6). At first, since the frequency has not been determined, the frequency OK flag is 0 (FIG. 6S20), the Hz preparation flag is 0 (FIG. 7S35), the Hz determination flag is also 0 (FIG. 7S40), and the Hz counter is incremented by +1 ( 7S37). Since the Hz counter is not 16 (FIG. 7S38), the Hz preparation flag is reset to 0 (FIG. 7S43), and the timer 1 is set to 9.088 msec (FIG. 7S44). 9.088 msec corresponds to the time between zero cross points when the frequency of the AC power supply is 55 Hz, and it is determined that the time until the external interrupt by the next zero cross point is longer than this, 50 Hz, and when it is shorter than this, 60 Hz. It is supposed to do.

The timer 1 starts counting time of 9.088 msec (S45 in FIG. 7), and the timer 1 completes timing until the external interrupt by the next zero cross point is executed (the time between the zero cross points of the AC power supply is 9 If it is longer than 0.088 msec), the timer 1 interrupt (FIG. 7, 8S55) is executed. Since the frequency OK flag is 0 (S56 in FIG. 8),
The Hz preparation flag is set to 1 (FIG. 8S59), the routine returns (FIG. 8S58), and the external interrupt also returns (FIG. 7S48). When an external interrupt by the next zero-cross point is executed (FIG. 6S19), the frequency OK flag is 0 (FIG. 6S20), and the Hz preparation flag is 1 (FIG. 7S3).
5), the Hz determination flag is 0 (S36 in FIG. 7), and the Hz
The counter is reset to 0 (FIG. 7S41), and the Hz determination flag is inverted to 1 (FIG. 7S42). Next, the Hz preparation flag is reset to 0 (FIG. 7S43), and timer 1 is set to 9.088 msec (FIG. 7S44).

The timer 1 starts counting time of 9.088 msec (S45 in FIG. 7), and the timer 1 finishes timing until the external interrupt by the next zero cross point is executed (the time between the zero cross points of the AC power supply is 9 If it is longer than 0.088 msec), the timer 1 interrupt (FIG. 7, 8S55) is executed. Since the frequency OK flag is 0 (S56 in FIG. 8),
The Hz preparation flag is set to 1 (FIG. 8S59), the routine returns (FIG. 8S58), and the external interrupt also returns (FIG. 7S48). When the external interrupt by the next zero cross point is executed, the frequency OK flag is set to 0 (S2 in FIG. 6).
0), the Hz preparation flag is 1 (FIG. 7S35), the Hz determination flag is 1 (FIG. 7S36), and the Hz counter is incremented by +1 (FIG. 7S37). Hz counter ≠ 16
(FIG. 7S38), the Hz preparation flag is reset to 0 (FIG. 7S43), and timer 1 has 9.088 msec.
Is set (S44 in FIG. 7).

The timer 1 starts counting time of 9.088 msec (S45 in FIG. 7), and the timer 1 completes counting by the time when the external interrupt by the next zero cross point is executed (the time between the zero cross points of the AC power supply is 9 If it is longer than 0.088 msec), the timer 1 interrupt (FIG. 7, 8S55) is executed. Since the frequency OK flag is 0 (S56 in FIG. 8),
The Hz preparation flag is set to 1 (FIG. 8S59), the routine returns (FIG. 8S58), and the external interrupt also returns (FIG. 7S48). When the external interrupt by the next zero cross point is executed, the frequency OK flag is set to 0 (S2 in FIG. 6).
0), the Hz preparation flag is 1 (FIG. 7S35), the Hz determination flag is 1 (FIG. 7S36), and the Hz counter is incremented by +1 (FIG. 7S37). Hz counter ≠ 16
(S38 in FIG. 7), the Hz preparation flag is reset to 0 (S43 in FIG. 7), and the timer 1 is set to 9.088 msec.
Is set (S44 in FIG. 7).

The timer 1 starts counting time of 9.088 msec (S45 in FIG. 7), and the timer 1 completes timing until the external interrupt by the next zero cross point is executed (time between the zero cross points of the AC power supply). When the external interrupt is repeated 16 times (longer than 9.088 msec) (when Hz counter = 16 (FIG. 7S38)), the frequency OK flag is set to 1 (FIG. 7S39).

On the other hand, when the time between the zero-cross points of the AC power supply is shorter than 9.088 msec, the timer 1 of 9.08
After starting the time measurement of 8 msec (S45 in FIG. 7), the external interrupt at the next zero-cross point is executed in the state where the time measurement of the timer 1 is not completed. At the next external interrupt due to the zero-cross point, the frequency OK flag is 0 (see S2 in FIG. 6).
0), the Hz preparation flag is 0 (FIG. 7S35), the Hz determination flag is 0 (FIG. 7S40), and the Hz counter is incremented by +1 (FIG. 7S37). Hz counter ≠ 16
(S38 in FIG. 7), the Hz preparation flag is reset to 0 (S43 in FIG. 7), and the timer 1 is set to 9.088 msec.
Is set (S44 in FIG. 7). Then, the timer 1 starts counting (FIG. 7S45) and returns (FIG. 7S4).
8).

The time between zero cross points of the AC power supply is 9.0.
When it is longer than 88 msec, timer 1's 9.088 ms
After starting the timing of ec (S45 in FIG. 7), the timer 1 interrupt (FIG. 8) is executed, the Hz preparation flag is set to 1 (S59 in FIG. 8), and the process returns to execute the external interrupt (FIG. 6). When the time between the zero-cross points of the AC power supply is shorter than 9.088 msec, the Hz preparation flag is 0 (timer 1 interrupt is not executed), and the external interrupt continues 16 times (when Hz counter = 16 (Fig. 7S38)), and sets the frequency OK flag to 1 (FIG. 7S39).

Here, when the Hz determination flag is 1, it can be determined that the AC power source is 50 Hz, and when the Hz determination flag is 0, the AC power source is 60 Hz. Thereafter, each time an external interrupt is started at the zero-cross point, when the frequency OK flag is 1 (FIG. 6S20), when the Hz determination flag is 1 (FIG. 6S21), when the Hz determination flag is 0 ( In FIG. 6S21), 8.2 msec is set in the timer 1 (FIGS. 6S22 and S23), and at the same time the timer 1 starts counting (FIG. 6S24), the external interrupt is prohibited (FIG. 6S25). While the external interrupt is prohibited, the external interrupt is not executed even if an erroneous zero-cross signal due to the waveform distortion of the AC power supply, noise, etc. is input.

When the motor output is instructed in the drying control (FIG. 5S15) (FIG. 6S26), the motor flag is set to 0 (FIG. 6S27) and the timer 2 is set to 4.0 msec (FIG. 6S28). 2 interrupts are enabled (Fig. 6S
29), the timer 2 starts counting time of 4.0 msec (S30 in FIG. 6). Next, the outputs other than the motor are controlled (S32 in FIG. 6). On the other hand, when the timer 2 starts measuring time of 4.0 msec (S30 in FIG. 6) and finishes measuring time,
The timer 2 interrupt (S65 in FIG. 9) is executed. Since the motor flag is 0 (Fig. 9S66), the motor flag is set to 1 (Fig. 9S70), the motor output signal is turned on (Fig. 9S71), and at the same time, 2.0 msec is set to the timer 2 (Fig. 9S72). (Fig. 9 S73). When the timer 2 finishes measuring the time, the motor output signal is turned off (S67 in FIG. 9) and, at the same time, the timer 2 interrupt is prohibited (S68 in FIG. 9) and the process returns (S69 in FIG. 9). When the motor output is not instructed in the drying control (FIG. 5S15) (FIG. 6S26), external interrupt is prohibited (FIG. 6S25)
Immediately after that, the outputs other than the motor are controlled (Fig. 6 S3).
2).

When the timing of the timer 1 ends (S3 in FIG. 6)
3), the timer 1 interrupt is executed (Fig. 6, 8S5
5), since the frequency OK flag is 1 (S56 in FIG. 8), the external interrupt is enabled (S57 in FIG. 8) and the process returns (FIG. 8).
S58), the external interrupt also returns (S3 in FIG. 6).
4). In this state, when a zero-cross signal is input to the interrupt terminal of the microcomputer 100, an external interrupt is executed. At this time, the frequency OK flag is 1 (FIG. 6S20), and the frequency discrimination operation (FIG. 7S35).
The processing after the operation of checking the Hz determination flag (S21 in FIG. 6) is executed without passing through.

FIG. 11 is a block diagram showing the basic construction of a control system of an electric dryer which is an embodiment of the electronic apparatus according to the third invention. The electric dryer and the keyboard for operating the electric dryer are one embodiment of the control method according to the first invention and the electronic device according to the second invention described above (FIG. 1). Since it is the same as the keyboard (FIG. 2), the description thereof will be omitted. The block diagram of the control system shown in FIG. 11 is a block diagram of the control system of the electric dryer which is one embodiment of the control method according to the first invention and the electronic device according to the second invention shown in FIG. 10
When the runaway detection circuit 78 detects the runaway of the microcomputer 100a, the auto power off circuit 104a (power supply that cuts off the power supply without the intervention of the microcomputer 100a) is added. A signal (runaway detection signal) for turning off the power supply to the load drive circuit 1
03 and the power supply circuit 9a are turned off. Other configurations are the same as the block diagram of the control system of the electric dryer that is one embodiment of the electronic device according to the first aspect of the invention and the control method according to the second aspect of the invention described above, and thus the description thereof is omitted.

FIG. 12 is a circuit diagram showing a configuration example of the runaway detection circuit 78, the auto power off circuit 104a and the power supply circuit 9a. The power supply circuit 9a performs full-wave rectification on the AC voltage of the AC power supply, which has been stepped down by the transformer Tr, by the bridge rectification circuit 112, and through the smoothing capacitor C4 and the constant voltage circuit (for example, 7V) 114, the smoothing capacitor C1 and the constant voltage circuit. (For example, 5V) and a smoothing capacitor C2 to pass through a smoothing circuit to smooth the DC power supply V
It is supplied to the microcomputer 100a as cc. The constant voltage from the constant voltage circuit 114 is supplied to the auto power off circuit 104a.

In the runaway detecting circuit 78, a differential circuit 116 composed of a capacitor C5 and a resistor R15 is connected to an output terminal Px of a pulse which is periodically output by a program of the microcomputer 100a, and the output of the differential circuit 116 is a power supply. It is applied to a grounded emitter NPN transistor Q3 having a collector connected to (for example, 5V) via a resistor R11 and a diode D1 connected between the base and the emitter. The collector voltage of the NPN transistor Q3 is given to the retriggerable monostable multivibrator 117, and the monostable multivibrator 1 is supplied.
The output of 17 is supplied to an emitter-grounded NPN transistor Q4 having a base and an emitter connected to a resistor R13 through an inverter 118 and a resistor R12. NP
The collector voltage of N transistor Q4 is applied to auto power off circuit 104a.

In the auto power off circuit 104a, the NP
The collector voltage of the N-transistor Q4 is given to the gate of the triac Trc to which the capacitor C6 is connected between the gate and the trigger through the resistor R14. A constant voltage from the constant voltage circuit 114 is applied to the trigger capacitor C6 side of the triac Trc, and the other of the triggers is connected to the excitation circuit of the power supply switch circuit 119.

Below, the runaway detection circuit 7 having such a configuration will be described.
8 and the operation of the auto power-off circuit 104a will be described with reference to a waveform diagram (FIG. 13) showing voltage waveforms of respective portions. A pulse waveform as shown in FIG. 13A is output from the output terminal Px of the microcomputer 100a. An edge of this waveform is detected by the differentiating circuit 116, and this edge (FIG. 13B) is amplified by the NPN transistor Q3, and the monostable multivibrator 1
Given to 17. Monostable multivibrator 117
Oscillates due to this edge to generate an H level signal (see FIG.
(C)) is output. This H level signal is inverted to the L level (FIG. 13D) by the inverter 118,
It is input to the PN transistor Q4. At this time, NPN
The transistor Q4 does not turn on.

Here, the monostable multivibrator 117 is used.
The width ΔT of the output pulse (H level signal) is set to a value (ΔT >> Δt) sufficiently larger than the width Δt of the pulse (FIG. 13A) from the microcomputer 100a. Therefore, while the pulse (FIG. 13A) from the microcomputer 100a is normally output, NP
N transistor Q4 does not turn on.

When the microcomputer 100a runs out of control, no pulse is output from the output terminal Px of the microcomputer 100a. As a result, the voltage of the output terminal Px is fixed to H level or L level (see FIG.
3 (e)), the output of the differentiating circuit 116 is also fixed at the L level (FIG. 13 (f)). Therefore, the monostable multivibrator 117 does not oscillate, and its output is fixed at the L level (FIG. 13 (g)). Therefore, the output of the inverter 118 becomes H level (FIG. 13 (h)), and the NPN transistor Q4 is turned on. When the NPN transistor Q4 turns on, the triac Trc of the auto power off circuit 104a becomes conductive, the exciting circuit of the switch circuit 119 is excited, and the switch circuit 119 turns off. In the above-mentioned embodiments, the electric dryer is described, but the present invention can be applied not only to ordinary electronic equipment, but also to a controller and a timer having no load such as a motor and a heater therein. .

[0048]

According to the control method of the first aspect of the present invention, it is possible to realize a control method capable of performing on / off control in synchronization with a zero cross point without being affected by waveform distortion and noise of an AC power supply.

According to the electronic device of the second aspect of the present invention, a simple and inexpensive zero-cross signal detection circuit is used, and it is turned on / off in synchronization with the zero-cross point without being affected by the waveform distortion and noise of the AC power supply. An electronic device that can be turned off can be realized.

According to the electronic device of the third aspect of the present invention, even when a microcomputer using a heater, such as a clothes dryer, runs out of control, the operation is continued in the heating state of the heater to keep the clothes heated. You can avoid
You can keep safety.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an electric dryer that is an embodiment of a control method according to a first invention and an electronic device according to a second invention.

FIG. 2 is a plan view of a keyboard including various operation keys that are operated to operate the electric dryer.

FIG. 3 is a block diagram showing a basic configuration of a control system of the electric dryer.

FIG. 4 is a circuit diagram showing a configuration example of a zero-cross signal detection circuit.

FIG. 5 is a flowchart showing an operation of the control method according to the first invention and the electronic device according to the second invention.

FIG. 6 is a flowchart showing the operation of the control method according to the first invention and the electronic device according to the second invention.

FIG. 7 is a flowchart showing operations of the control method according to the first invention and the electronic device according to the second invention.

FIG. 8 is a flowchart showing an operation of the control method according to the first invention and the electronic device according to the second invention.

FIG. 9 is a flowchart showing operations of the control method according to the first invention and the electronic device according to the second invention.

FIG. 10 is a waveform diagram showing output waveforms of respective portions of an AC power supply, a power supply circuit, and a zero-cross signal detection circuit.

FIG. 11 is a block diagram showing a basic configuration of a control system of an electric dryer that is an embodiment of an electronic apparatus according to the third invention.

FIG. 12 is a circuit diagram showing a configuration example of a runaway detection circuit, an auto power-off circuit, and a power supply circuit.

FIG. 13 is a waveform diagram showing voltage waveforms at various parts of the runaway detection circuit.

FIG. 14 is a circuit diagram showing a configuration example of a conventional zero-cross signal detection circuit.

FIG. 15 is a waveform diagram showing output waveforms of respective parts of a conventional AC power supply, a power supply circuit, and a zero-cross signal detection circuit.

[Explanation of symbols]

 6 Motor 77 Zero Cross Signal Detection Circuit 78 Runaway Detection Circuit 104a Auto Power Off Circuit (Power Supply Cutoff Circuit) 100, 100a Microcomputer

Claims (3)

[Claims] 1. An electronic device, which is supplied with electric power from an AC power supply, is provided with a zero-cross point detection means for detecting a zero-cross point of the AC power supply, and is synchronized with a zero-cross point detected by the zero-cross point detection means. In a control method for controlling on / off of power supply to an external load, a frequency of the AC power supply is discriminated, and a zero-cross point detected by the zero-cross point detection means is determined based on a cycle between zero-cross points obtained from the discriminated frequency. A control method characterized in that the detection operation of the zero-cross point detection means is prohibited during a period other than the first predetermined period immediately before that. 2. An internal or external load, which is provided with a zero-cross point detecting means for receiving a power supply from an alternating-current power source and detecting a zero-cross point of the alternating-current power source, in synchronization with the zero-cross point detected by the zero-cross point detecting means. In an electronic device for controlling on / off of power supply to a power source, a frequency discriminating means for discriminating a frequency of the AC power source, and a second predetermined period based on a cycle between zero cross points obtained from the frequency discriminated by the frequency discriminating means. An electronic device comprising: a first timing means for timing; and a prohibiting means for inhibiting the detection operation of the zero-cross point detecting means during a period in which the first timing means measures a second predetermined period from the zero-cross point. machine. 3. In an electronic device for controlling on / off of power supply to an internal or external load by a computer, a runaway detection circuit for detecting runaway of the computer, and the runaway detection circuit detected runaway of the computer. An electronic device comprising: a power supply cutoff circuit that turns off the power supply in response to a runaway detection signal from the runaway detection circuit.