JPS6149686A - Control circuit of fan - Google Patents

Abstract

PURPOSE:To enable to input a plurality of signals from one input terminal without increasing special part by utilizing a voltage zero cross signal for the signal input of an operation switch. CONSTITUTION:When an operation switch 15 is pressed, an input signal of a terminal 11T varies to H level. A microcomputer recognizes that the switch 15 is pressed when the H level continues stably for a time DELTAt. Then, when an operation switch 17 is pressed, an input signal of the terminal 11T at this time becomes the same as the collector of an NPN type transistor 10, as zero cross signal itself of the power source voltage. The fact that the switch 17 is pressed is recognized by the microcomputer 40 by comparing with the terminal 12T to which the power voltage zero cross signal is input.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a microcomputer-controlled electric fan.
It is related to circuits.

Conventional configurations and their problems In recent years, the application of microcomputers to home appliances has been rapidly progressing, and they are being applied not only to relatively expensive products such as televisions, videos, and air conditioners, but also to washing machines and vacuum cleaners. The scope of its application is expanding to include low-priced products. Furthermore, in recent years, microcomputers have been applied to even low-cost household appliances such as electric fans. However, of course, microcomputers are also cheap.
There are some that are expensive, but generally the ones with fewer pins (number of legs) are cheaper. Generally speaking, the more pins there are, the more complex the microcomputer's architecture is, and the more functionality it has, the higher the degree of integration, and the larger the chip size. However, it cannot be said that fewer bottles are necessarily cheaper. However, in general, the smaller the number of bins, the cheaper the price, and this is especially noticeable in the case of 4-bit, 1-chip microcomputers used in home appliances such as electric fans. The number of pins is 16
Bin, 18 pin.

Most of them are 28-bin or 42-bin, and 22-pin ones are also used in some cases. However, most people have 16 pins, 1
Low pin count of 8 pins, medium pin count of 28 pins,
It is roughly divided into 42-pin high-bin number types. Also, built-in RO
The capacity of M is mostly o, 6KB (kilobyra) for low pin counts, %KB to 1KB for medium pin counts, and 2KB to 4KB for high pin counts. By the way, in the case of an electric fan, as mentioned earlier, it is a low-priced product among home appliances, so of the three types of 4-bit 1-chip microcomputers mentioned above, it is appropriate to use a low-priced one with a low pin count. Not until now. However, the current situation is that this is not the case in general usage, and the reason for this is the method of controlling the electric fan. What is shown in FIG. 1 is a diagram of the operation display board of a microcomputer-controlled electric fan with general specifications, in which 100 is the operation display board, 101, 102, 103 are operation buttons provided therein, and 104 to 11o are Light-emitting diodes for display, 104° to 106 display the air volume, and 107 to 110 display the remaining time of the timer. Next, to explain the operation display board a little differently, reference numeral 101 is an "off" operation button for stopping the electric fan. Reference numeral 102 is an operation button for switching the air volume of the electric fan, and each time this operation button 102 is pressed, the light emitting diodes 104, 105, 106 are activated in this example, 104→106→106→104→... It lights up cyclically and displays the fan's current airflow rate (either low or medium-9 high). The operation button 103 is used to set the time of a timer for delaying the operation of the electric fan.Each time the operation button 103 is pressed, the light emitting diodes 107 to 109 light up in order.
The timer time can be selected from four types: 30 minutes, 1 hour, 2 hours, and 4 hours. As described above, the operation display board in Fig. 1 is an example of microcomputer-controlled functions of a general electric fan, and the number of operation buttons 101 to 103 is three and the number of light emitting diodes 104 to 11o. There are seven, and considering the occupation of input/output terminals, there are ten in total. By the way, in order to operate a microcomputer, a power supply is required, and at least two wires are needed, one each on the positive and negative sides of the power supply.
A book terminal is required. Furthermore, the microcomputer also requires a reset terminal for starting the program written in the ROM more accurately than address 0.

In addition, since a microcomputer must perform various internal operations in a timely manner, it also requires one or two terminals for clock oscillation, which generates the minimum unit of time that serves as a reference for operation. A total of 4 to 5 terminals (bins) including the power supply terminal, reset terminal, and clock oscillation terminal
are necessary for a microcomputer, but from the user's perspective, they cannot be used for any other purpose (hereinafter, for purposes of explanation, such terminals will be referred to as fixed terminals). Furthermore, some microcomputers are often provided with test terminals as fixed terminals for testing the microcomputer itself. Here, the operation of switching the speed of the fan motor of the electric fan in extremely short cycles, which is a condition of the present invention that has not been mentioned in the explanation so far, is to prevent the electrical noise that occurs during this switching. In order to do this, a power supply voltage zero cross signal is almost always input to the microcomputer. This power supply voltage zero cross signal notifies you of the moment when the voltage waveform of the power supply passes the zero point, and by switching the fan motor speed at that time, you can prevent the generation of electrical noise. One input terminal is required to input. To summarize them a bit, in order to control a fan with general specifications with a microcomputer, the microcomputer must have 4 to 5 fixed terminals and 4 input terminals (3 switches, 1 power supply voltage zero cross signal input). ), 11 output terminals ()
(3 for speed switching of the motor, 3 for speed display, 4 for timer display, 1 for buzzer)
Of these, three are required for both fan motor speed switching and speed display light emitting diodes, assuming they can be shared. However, in the method of controlling the electric fan shown in the example of FIG. Since there is no operation switch to select various types of wind (used for control such as blowing air in a state close to natural wind), another operation switch is required.

Such a control method is almost always added to a simple microcomputer version of a conventional electric fan, which consists of mechanical switches and timers, as shown in the example in Figure 1. Currently, this is one of the major features of electric fans controlled by microcomputers. By the way, summarizing what has been explained so far,
When controlling a fan with a micro core computer, there are 4 to 6 fixed terminals (5 to 6 at most) and 5 input terminals (
1 switch added) Output terminals - 8 terminals total 17 to 18 (18 to 19 at most), and the 1e pin, which is said to have the lowest number of pins in a 1-chip microcomputer, goes to the fan. This application becomes impossible due to a slight shortage of pins, and even if it has 18 bins, it is similarly impossible to use it with a micro core computer that has many fixed terminals. By the way, there is a method called the 17x method (in the case of lighting of light emitting diodes, it is called Guinaminoku lighting) that allows more input/output with a smaller number of pins than before, and output terminals and input terminals are arranged in a matrix. Light-emitting diodes that serve as switches or loads are inserted at the intersections, and the switches are scanned one after another at high speed, or the light-emitting diodes are turned on one after the other. less 1
It has no effect on chip microcomputers, and it is necessary to take into account short circuits between terminals due to double-pressing of switches (pressing one or more switches at the same time), reverse voltage application to light-emitting diodes, etc. , the number of parts increases, and in this case, the cheap 1 with a small number of pins is used.
There is no effect of using a chip microcomputer.

OBJECTS OF THE INVENTION The present invention eliminates these conventional problems, allows more input signals to be input from fewer input terminals in an inexpensive manner, and provides a cost-effective 16.18 bin class. This allows a one-chip microcomputer to be used to control an electric fan.

Structure of the Invention To achieve this object, the electric fan control circuit of the present invention comprises a fan motor and a microcomputer having a function of switching the speed of the fan motor in extremely short cycles. lj control circuit and a plurality of operation switch parts for operating this microcomputer, and by utilizing the zero cross signal for inputting the microcomputer, a plurality of different operation signals of the operation switches can be input to the microcomputer from one input terminal. This is a configuration for inputting signals to a computer, and has the effect of allowing the use of a microcomputer with a small number of pins that can input a plurality of signals from one input terminal.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on factors 2 to 4.

FIG. 2 is an example of an implementation circuit of the electric fan control device of the present invention. 1 is an AC power supply, 2 is a fuse, 3 is a surge absorber, 4 is a dropper resistor for creating a power supply for the microcomputer, 5 is a rectifier diode for the same purpose,
6 is an electrolytic capacitor having the same purpose, T is a constant voltage diode having the same purpose, and these components 4 to 7 create a DC power source with a lower voltage than the AC power source. 8 is a resistor, 9 is a diode, 1o is an NPN l-transistor, and 11 is a resistor.
.

The so-called power supply voltage is inputted by components 8 to 11. Figure 3 shows this situation.
, ' is a microcomputer that generates zero-cross signals. FIG. As shown in b, N
PN) The transistor 1o is turned on because the pace current is supplied to a.
During the negative half-wave of the AC power supply 1 shown, the collector voltage becomes 0 (V) through the resistor 8. Also, in the case of a positive half wave, since it is bypassed by diode 9, NPN) transistor 10
is in the off state, and the collector voltage becomes v(v). In the time chart, the boundary between the changes in o(V) and v(V) is the zero-crossing point of the voltage of the AC power source 1.

In other words, the zero-crossing signal of this example is intended to determine the zero-crossing point of the AC power supply 1 at the boundary between changes of 0(v) and v(v), and this signal is sent to the terminal of the microcomputer 40 (described later) as T. is input and recognized and judged by the software of the microcomputer 4o, but the details of this software will be omitted. 12 is a resistor, and 13 is a capacitor. These two parts constitute a time constant circuit that ensures that the program starts from address 0 when the microcomputer is powered on. This signal is sent to the terminal 4o of the microcomputer. 1.3 It is input to T. In other words, terminal 13T is the so-called reset terminal.
In the case of the microcomputer 40 of this example, the H level (V
(V)), the reset is canceled and actual execution of the program is started. 14 is resistance, 15, 16, 1
7 and 18 are operation switches for setting the operating state of the electric fan. In the example of the operation panel shown in Fig. 1, each corresponds to "off", "air volume adjustment", and "timer", and the remaining one corresponds to "timer". This is an operation switch for selecting a mode in which the speed of the fan motor of the electric fan is changed in extremely short cycles.The signal input to the microcomputer by these switches 15 to 18 will be described in detail later.19, 20
21 is a resistor, 21 is a piezoelectric buzzer, 22.23 is a resistor, 24 is a capacitor, and 25 is a resistor. The two components 24.25 constitute a time constant circuit for clock oscillation of the microcomputer 40. 26 is resistance, 27.2B,
29 and 30 are light emitting diodes, and in this example, each serves to display the remaining time of a timer of 30 minutes, 1 hour, 2 hours, and 4 hours. 31°32.33 is the resistance,
The current of the light emitting diode 34, 35, 36 and the gate current of the try book 37, 38, 39 for driving the fan motor 41 are limited. 4o is the microcomputer mentioned earlier, and the terminals t- from 1T to 16T
It is a 16-pin microcomputer.

41 is a fan motor of the electric fan, and 42 is its phase advancing capacitor. Next, the basic operation will be explained mainly around the operation switch according to the present invention.

As mentioned above, the switches 15, 16, 17, and 18 are operation switches for setting various operations of the electric fan.
．． The signal of 17 is the Z:5 child 1 of the microcomputer 40.
The signals from the operation switches 16 and 18 are input from the terminal 10T. By the way, since the terminals 10 and 11T have exactly the same signal type and output, only the terminal 11T will be explained. No trenches,
Even when both the operation switches 15 and 160 are not pressed, the terminal 11T is pulled down by the resistor 20, so it is always at o(V) (hereinafter referred to as L level). Next, when the operation switch 15 is pressed, the state of the terminal 11T at this time is at time t, as shown in the time chart d in FIG. If the operation switch is pressed at , the input signal at the terminal 11T changes to H level. And in the microcomputer, this H level is for a time of Δt,
It is recognized that the operation switch 16 has been pressed when the operation continues stably. During this recognition period, there is a phenomenon in which the contacts of the operation switch 16 chatter and turn on and off many times, so abnormal inputs due to this are prevented. It is generally provided for a specific purpose. Next, when operating switch 1 is pressed, the state of the input signal of terminal 11T at this time is 4th.
This is shown in the time chart in figure b. In other words, operation switch 1
Since one end of 7 is connected to the collector of the NPN resistor 10, pressing the operation switch 17 means that the state of the input signal at the terminal 11T is the same as that of the collector of the NPN resistor 10, and the power supply voltage This is the zero cross signal itself. Figure 4b explains this. When the operation switch 17 is pressed at time 0, the signal input to the 11 terminals continues to be at L level until time t1 when the power supply voltage zero cross signal rises, and the microcomputer At 4o, it is not known at all whether the operation switch 17 is pressed from time t0 to time tl. The signal input becomes H level for the first time at time t1, but at this point the microcomputer 4Q cannot yet distinguish whether the operation switch 15 or 17 has been pressed. However, at time t2, the signal input to the terminal 11T changes from the H level to the L level. This phenomenon occurs when Kr, to which the power supply voltage zero cross signal is input inside the microcomputer 40,
It is easy to see that the operating switch 17 is pressed by comparing it with the terminal 12T, but even if the operating switch 16 is pressed quickly, it may coincidentally synchronize with the zero cross signal, so in Fig. 4b, Comparison with the zero cross signal is performed at each of the rising edge at time t3 and the falling edge at time t4, and if these match the terminal 12T, it is determined that the operation switch 17 has been pressed. However, even if this is done, the response speed Δt will be less than 50 m5, which is extremely fast and satisfactory as the response time of the operation switch.

Effects of the Invention As described above, according to the present invention, the power supply voltage zero cross signal, which is provided for the purpose of preventing the generation of electrical noise that occurs when the speed of the electric fan is changed in an extremely short period, is used as the signal of the operation switch. J5 used for input allows multiple signals to be input from one input terminal without adding special parts, and allows the use of a low-cost microcomputer with a small number of pins required for microcomputer control of the electric fan. It has the effect of making it possible.

[Brief explanation of the drawing]

FIG. 1 is a front view of an operation display board explaining the general control contents of an electric fan controlled by a microcomputer, FIG. 2 is a control circuit diagram of an electric fan according to an embodiment of the present invention, and FIG. A waveform time chart showing the state of the power supply voltage zero cross signal in the circuit diagram of Figure 2, and Figure 4 shows the input waveform when multiple signals are input from one input terminal using the power supply voltage zero cross signal. This is a time chart showing the situation. 41...Fan motor, 4o...Microcomputer, 16-18...Operation switch, 12T...Power zero cross terminal. Name of agent: Patent attorney Toshi Nakao, male and 1 other person
figure

Claims (1)

[Claims] a fan motor; a microcomputer having a function of switching the speed of the fan motor in short cycles;
A fan comprising a plurality of operation switches for operating the microcomputer, and inputting a plurality of different operation signals of the operation switches to the microcomputer from one input terminal by using the microcomputer input zero-cross signal. control circuit.