JP2000161995A - Warning circuit for cross-coil PWM driven meter - Google Patents

Abstract

(57) Abstract: An inexpensive cross-coil PWM driven meter warning circuit that can omit each warning terminal and each warning drive transistor of a CPU is provided. SOLUTION: Two movement exciting coils L ₁ , L ₂ which are orthogonal to each other, a CPU 1 for calculating an energizing direction and an energizing amount to the two movement exciting coils, and warning light emitting diodes 21, 22, 23, 24 are provided. , The warning circuit of the cross-coil PWM drive meter having a parallel connection circuit of the movement exciting coil and the warning light emitting diode is connected to at least a pair of movement output terminals SIN + and SIN− and a terminal COS + and terminal COS− of the CPU. Connected between.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cross coil type P
The present invention relates to a warning circuit of a WM drive meter, in particular, a cross-coil type PW which calculates a power supply to two coils orthogonal to each other by a CPU and gives a desired angular orientation.
The present invention relates to a warning circuit of an M drive meter.

[0002]

2. Description of the Related Art Cross-coil PWM driven meters are used in tachometers, speedometers, fuel gauges, thermometers and the like for automobiles and the like. As shown in FIG. 8, the driving circuit of the cross-coil type PWM driving meter for each of these signals includes a TM signal from a tachometer, an SP signal from a speedometer, a FUEL signal from a fuel meter, and a TEMP from a thermometer. The CPU 2 receives the signals, the CPU calculates these signals, and outputs a movement output terminal SIN + and a terminal S
IN-, terminal COS +, is flowing from terminal COS- the exciting coil L _1, L ₂ which are orthogonal to each other of the respective boom instrument as pulse width modulation corresponding to each signal (PWM) current (or voltage). The current waveform of this PWM is
It is as shown in FIG. 9, during the period T ₁ in which certain of the one period constant current (this is the H-state.) Flows, during the rest period T ₂ the current does not flow (this To the L state.) By changing the period T ₁ (duty time) for supplying a constant current by the CPU, the current can be changed to an arbitrary magnitude. The PWM current having the predetermined duty ratio is connected to the movement output terminal SIN + of the CPU and the terminal SI.
While the other flows through the movement exciting coil L ₁ to from N-, likewise, PWM current of a predetermined duty ratio C
PU Movement output terminal COS + and from one terminal COS- to the other flows through the exciting coil L ₂ of the movement. The size and the composite magnetic field by the direction of the current flowing through these movements the exciting coil L ₁ and L ₂ are made. A permanent magnet is fixed to the axis supporting the pointer of the meter, and the permanent magnet is arranged in the composite magnetic field, so that the permanent magnet is oriented in the direction of the composite magnetic field, and thus the pointer also swings in the same direction. Different.

[0003] Therefore, as shown in a meter generally shown in FIG. 2, when the dial spans the first to fourth quadrants,
If the meter pointer is in the first quadrant, sin positive (ie,
Movement output terminal SIN + of CPU to terminal SIN
The current flows to-. ), Cos positive (ie, CP
A current flows from the movement output terminal COS + of U toward the terminal COS-. ) And the second quadrant is sin positive, co
s negative (that is, the movement output terminal COS of the CPU)
A current flows from-to the terminal COS +. ) And the third
The quadrant is sin-negative (that is, a current flows from the movement output terminal SIN- of the CPU toward the terminal SIN +) and cos is negative, and the quadrant is determined by sin-negative and cos-positive in the fourth quadrant. the magnitude of the current flowing through the coil L ₁ and L _2, the angle facing is determined.

[0004]

As described above, the CPU signals the TM signal, the SP movement, the FUEL movement, and the TEMP movement respectively.
Terminals SIN + and SIN for supplying current to rotate the pointers of a tachometer, a speedometer, a fuel gauge, and a thermometer according to the SP signal, the FUEL signal, and the TEMP signal.
A movement output terminal of −, terminal COS +, terminal COS− is provided. However, the CPU also has a warning terminal. This warning is issued for each TM signal, SP signal, FUEL signal, TEM
When the P signal exceeds a predetermined value, a warning is issued from the CPU to the driver. Usually, the warning light for each signal is controlled by the CPU each time. In FIG.
An example of a conventional tachometer TM warning and a thermometer TEMP warning by a CPU is shown. That is, the transistor Tr and the TM warning light are connected to the TM warning terminal of the CPU, and the transistor Tr and the TEMP warning light are connected to the TEMP warning terminal. Other SP signals, FUEL
The same applies to signals. When the calculated value exceeds the TM warning value, the CPU turns on the TM warning transistor Tr, turns on the TM warning light, and gives a warning to the driver. Similarly, when the TEMP signal exceeds the TEMP warning value, the CPU turns on the TEMP warning transistor Tr, turns on the TEMP warning light, and gives a warning to the driver. The same applies to other SP signals and FUEL signals. As described above, the transistor Tr and the warning light are connected to the warning terminal of the CPU for the respective signals.
U requires a separate terminal for each warning and a transistor Tr for a warning drive.
There is a problem that the WM drive meter becomes expensive. An object of the present invention is to solve the above problems and to perform a warning drive at low cost.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, two movement exciting coils which are orthogonal to each other, and the direction and amount of current to the two movement exciting coils are provided. In a warning circuit of a cross-coil type PWM drive meter using a CPU for calculating the above, and a warning light emitting diode, a parallel connection circuit of the movement exciting coil and the warning light emitting diode is connected to at least one pair of movement outputs of the CPU. It is characterized by being connected between terminals. Further, according to the second aspect of the present invention, two movement exciting coils orthogonal to each other, and a CPU for calculating the direction and amount of electricity to the two movement exciting coils are provided.
And a warning light emitting diode, a warning circuit of a cross-coil type PWM drive meter using:
A parallel connection circuit of the movement excitation coil and the warning light emitting diode is connected to a DC power supply side and a ground side via switching elements at both ends of the parallel connection circuit, respectively, and a pair of movement output signals from the CPU are used to output the signals. By alternately turning on and off a plurality of switching elements, a current corresponding to a movement output signal from the CPU flows in the parallel connection circuit in one direction and the other direction. According to a third aspect of the present invention, in the warning circuit of the cross-coil PWM drive meter, the warning light-emitting diodes include a plurality of light-emitting diodes connected in anti-parallel. According to a fourth aspect of the present invention, in the warning circuit of the cross-coil type PWM drive meter, the plurality of light emitting diodes are configured with different colors.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a general example of a configuration diagram of a warning circuit of a cross coil type PWM drive meter, which is 360 °.
Can be turned on in the range of. 1 is CPU, L ₁ , L
₂ is an exciting coil, 21 to 22, 23 to 24 are antiparallel light emitting diodes, and 3 is a resistor. Anti-parallel light emitting diode 2
1～22,23～24 is connected to a respective resistor 3 in series, the series circuit is connected in parallel to the exciting coil L _1, L _2. When the characteristics of the anti-parallel light emitting diodes 21 and 22 are different, it is sufficient to stop sharing the resistor 3 and connect a resistor of a desired value to each of the light emitting diodes 21 and 22 in series. The same applies to the anti-parallel light emitting diodes 23 and 24. When the current flowing from the movement output terminal SIN + of the CPU to the terminal SIN− exceeds a predetermined value, the light emitting diode 21 is turned on. Conversely, terminal S
When the current flowing from IN− to the terminal SIN + exceeds a predetermined value, the light emitting diode 22 is turned on. Similarly, CPU
When the current flowing from the movement output terminal COS + to the terminal COS- exceeds a predetermined value, the light emitting diode 23 is turned on, and when the current flowing from the terminal COS- to the terminal COS + exceeds the predetermined value, the light emitting diode 24 is turned on. .
The predetermined value of lighting is determined by the characteristics of the light emitting diode and the value of the resistor 3.

For example, assuming that the dial of the meter extends from the first quadrant to the fourth quadrant as shown in FIG. 2, the pointer of the meter is at a predetermined angle (for example, 60 °) in the first quadrant. If you want to light up when you come to the place,
The value of the resistance 3 and the light emitting diode 21 to light the size of sin 60 ° of the current flowing through the exciting coil L ₁ it is sufficient to select. In this case, the light emitting diode 21 is 6
The light is turned on in the range of 0 ° to 120 °, and turned off in other than the range. Moreover, if you want to light when the pointer of the meter has come to the place of the first quadrant of 45 °, the rating of the light emitting diode 21 to light the size of sin 45 ° of the current flowing through the exciting coil L ₁ resistance The value 3 may be selected. In this case, the light emitting diode 21 is at 45 ° to 135 °.
It turns on in the range of ° and turns off in the other range. Similarly, for the other light emitting diodes 24, 22, and 23, 13
If it is desired to light at 5 °, 225 °, and 315 °, respectively, the excitation coils L ₂ , si at cos 135 °
The rating of the light emitting diodes 24, 22, and 23 and the value of the resistance value 3 are selected so that the light is lit according to the magnitude of the current flowing through the exciting coil L ₁ at n225 ° and the exciting coil L ₂ at cos 315 °. It is good. In this case, among the four light emitting diodes 21, 22, 23, and 24, the light emitting diode 21 is turned on at 45 ° to 135 °, and the light emitting diode 2 is turned on.
4 lights at 135 ° to 225 °, and the light emitting diode 22
Is turned on at 225 ° to 315 °, the light emitting diode 23 is turned on at 315 ° to 45 °, and any one of them can be always turned on.

Further, the pointer of the meter is set to 30 ° in the first quadrant.
If you want to light up when you come to
_The light emitting diode 21 and the value of the resistance value 3 may be selected so that the light is lit with the current of sin 30 ° flowing through ₁ . In this case, the light emitting diode 21 is 30 ° to 150 °.
It turns on in the range of ° and turns off in the other range. If the other light emitting diodes 22, 23, and 24 are selected in the same manner, a section in which one light emitting diode is turned on and a section in which two light emitting diodes are turned on at the same time can be provided alternately. When two light emitting diodes are turned on at the same time, the color of the light emitting diodes is made different, and the diffusion plate is arranged in front of the light emitting diodes.
(Mixed) colors can also be created. Which of the light emitting diodes 21 to 22 and 23 to 24 should be lit at which angle of the pointer, and in which case, what color should be determined each time in relation to the type of meter and the configuration of the dial. . As described above, according to the present invention, the current CP corresponding to the current flowing through the movement exciting coils L ₁ and L ₂ is used.
Since the U can easily light the warning light emitting diode at an arbitrary position, the CPU does not need each warning terminal and the warning drive transistor Tr.

Hereinafter, a few examples of specific meters will be described. 3 and 4 are configuration diagrams of a warning circuit of a cross-coil type PWM drive speedometer and a scale plate thereof. 4 SP movement, L _1, L ₂ are excitation coil 5 Yellow LED, 6 resistors, 7 red LED 8 is a resistor. Yellow light emitting diode 5
The resistor 6 and the red light emitting diode 7 and the resistor 8 are connected in series. A series circuit of the yellow light emitting diode 5 and the resistor 6 and a series circuit of the red light emitting diode 7 and the resistor 8 are connected to the exciting coils L ₁ and L ₂ at terminals SI and L ₂ , respectively.
N + and the terminal COS + are connected in parallel such that the anode side of each light emitting diode comes to the terminal. It is assumed that the scale of the speedometer comprises only a first quadrant and a second quadrant as shown in FIG. That is, a position at an angle of 180 ° has a speed of 0 km / H, and a position at an angle of 90 ° has a speed of 9 km / H.
0km / H, position at an angle of 0 ° is 180km / H
And And the yellow light emitting diode 5 has a speed of 8
The light emitting diode 7 is set to be lit at a positive sin current value when the speed becomes 0 km / H, and the red light emitting diode 7 is set to be lit at a cos positive current value when the speed becomes 100 km / H. Keep it. Further, a yellow light emitting diode 5 and a red light emitting diode 7 are juxtaposed on the upper part of the scale plate of the speedometer.

[0010] In speedometer of the above configuration, if the pointer is pointing to speed 0 km / H, the second quadrant of the exciting coil L ₂ a Cos180 ° of the current flowing is the maximum value, but the red light emitting diode 7 is blocked The yellow light-emitting diode 5 is not lit because it is in the direction, the yellow light-emitting diode 5 is also not lit because the sine positive is less than the predetermined value, and both the red light-emitting diode 7 and the yellow light-emitting diode 5 are turned off. As speed increases, cos negative decreases and sin positive increases. Now, when the speed becomes 80 km / H, the yellow light emitting diode 5 is turned on with the sin positive signal value at that time, and the driver can be alerted to that. As the speed further increases, the brightness of the yellow light emitting diode 5 increases, and at a speed of 90 km / H, sin
It becomes the positive maximum value and the brightness of the yellow light emitting diode 5 becomes the maximum. When the speed further increases, the brightness of the yellow light emitting diode 5 slightly decreases, but conversely, the positive cos increases, and when the speed becomes 100 km / H, the red light emitting diode 7 is turned on by a predetermined current of the positive cos when the speed becomes 100 km / H. . As the speed further increases, the positive cos increases, so that the brightness of the red light emitting diode 7 increases. The above configuration can be applied to a tachometer as long as the tachometer is composed of a first quadrant and a second quadrant as shown in FIG. 4, and the same applies to other meters.
Thus, according to the present invention, the movement exciting coil L
_1, since L ₂ a CPU with a current value corresponding to the value of the current flowing through it can be easily turned two types of warning light emitting diode warnings and cautions, the CPU transistor terminals and warning drive for warning Tr becomes unnecessary.

FIG. 5 is a configuration diagram of a cross-coil type PWM driven fuel gauge. 9 is a FUEL movement, L ₁ , L ₂
Is an exciting coil, 10 is a red light emitting diode, and 11 is a resistor. The red light emitting diode 10 and the resistor 11 are connected in series. Red series circuit of the light emitting diode 10 and the resistor 11 is connected to the anode of the light emitting diode 10 is at the terminal COS- side in parallel to the exciting coil L _2. The scale of the fuel gauge is about half of the first quadrant (45 ° or more)
And about half (135 ° or less) of the second quadrant. The red diode 10 is selected so as to emit light with a predetermined cos negative current value (for example, a current value of cos 130 °).

In the fuel gauge having the above configuration, the fuel is full.
In the case of “F”, cos positive and sin
Movement excitation coil with PWM current of the same positive value
L₁, L _TwoIt is flowing to. As fuel is consumed
The pointer moves counterclockwise toward "E". Pointer is 1
Move into the second quadrant across the / 2 scale,
G excitation coil L₁, L_TwoHas cos negative and sin positive PW
The M current flows, and the cos negative current value increases. this
Therefore, according to the configuration diagram of the fuel meter shown in FIG.
And red diode under cos negative predetermined current value
Although 10 is off, a predetermined current value of cos negative (here,
In this case, the current value of cos 130 °)
10 lights up, and as fuel approaches "E"
Thus, the light amount of the red diode 10 increases. in this way
According to the present invention, the red diode 10 has a simple
The warning of the charge can be issued, and the CPU warning
Terminal for warning and transistor Tr for warning drive
Becomes unnecessary.

FIG. 6 is a configuration diagram of a cross-coil type PWM driving thermometer. 12 is a TEMP movement, L ₁ ,
L ₂ is the exciting coil 13 is blue light emitting diode, 14 is a red light emitting diode, 15 resistors. The blue light emitting diode 13 and the red light emitting diode 14 are connected in anti-parallel, and are connected in series to the resistor 15. The terminal CO in parallel to the blue light emitting diode 13 and the red light emitting diode circuit consisting of 14 and the resistor 15 is the exciting coil L ₂
S + is connected so as to come to the anode side of the red light emitting diode 14. The blue light emitting diode 13 is set so that the pointer of the thermometer is turned on at a cos negative value of an angle of 100 ° or more, and the red light emitting diode 14 is selected so that the pointer of the thermometer is turned on at a cos positive value of an angle of 40 ° or more. Keep it. The scale of the thermometer consists of about half of the first quadrant (45 ° or more) and about half of the second quadrant (135 ° or less), and the pointer changes from a low temperature to a high temperature (unlike FIG. 5). (From the second quadrant to the first quadrant).

In the thermometer having the above structure, when the temperature is the lowest and the pointer is at the position indicating "C" in the second quadrant,
Exciting the coil L ₂ given lighting current or the PWM current of the blue light-emitting diode 13 from terminal COS- to the terminal COS + is already flowing. Therefore, the blue light emitting diode 1
3 emits blue light. The blue light is the brightest when the pointer indicates "C", gradually diminishes as the pointer moves clockwise, and has a negative cos predetermined value (here, an angle of 100).
Turns off at the current value of °). Furthermore as the temperature increases pointer enters the first quadrant, is to flow the PWM current from the terminal COS + to terminal COS- to the exciting coil L _2. For this reason, a PWM current flows through the red light emitting diode 18 and c
The red light-emitting diode 14 is turned on at a current value of os positive predetermined (here, an angle of 40 °). The red light gradually increases in brightness, and becomes brightest when the pointer indicates "H". As described above, according to the present invention, the light emitting diodes 13 and 14 can be turned on with a simple configuration, and can emit not only warning light (red light) but also safety light (blue light). The scale plate of each of the cross coil meters described above has half each of the first quadrant and the second quadrant. However, the scale plate is not limited to those, and as described above, the first quadrant is used. , A second quadrant, a third quadrant, and a fourth quadrant.

Further, in the above embodiment, two reverse
The lighting energy of the row-connected light emitting diodes is CPU
In this way, the current capacity of the CPU is increased.
I needed something kinky. The solution to this point is shown in FIG.
FIG. 3 is a configuration diagram of a learning circuit. That is, two antiparallel
The connected light emitting diodes 95 and 96 are connected to the exciting coil L. ₁
Are connected in parallel, but this parallel circuit
It is connected between the terminal SIN + and the terminal SIN- of the PU.
Instead, a series connection of two switching elements Tr1 and Tr2
Two connection circuits (Tr1-Tr2, Tr3-Tr4) in parallel
Connect between the DC power supply + DC and the ground,
This parallel circuit is connected between the connecting points C1 and C2 of the switching element.
Has been continued. And one series connection of this parallel circuit
Inverting element is connected to the control terminal of one of the switching elements Tr1
91 to control the other switching element Tr2.
CPUs are connected to the control terminals via two inverting elements 92, respectively.
Terminal SIN +. Similarly, the other of the parallel circuits
Control terminal of one switching element Tr3 connected in series
Through one of the inverting elements 93 to the other switching element.
It is connected to the control terminal of the child Tr4 via two inverting elements 94.
Each is connected to the terminal SIN- of the CPU.

In such a circuit, the CPU terminal S
When a current flows from IN + to the terminal SIN−, the switching elements Tr1 and Tr4 are turned off, and the switching elements Tr2 and Tr3 are turned off.
It is turned on, in this case, the exciting coil L ₁ current flows in the direction of the C1 from the connecting point C2, therefore, it is possible to light emitting diode 96 of the two light-emitting diodes are turned on at the predetermined current value . Conversely, when a current flows from the terminal SIN- of the CPU to the terminal SIN +, the light emitting diode 95 can be turned on with a predetermined current value according to the same principle. FIG. 7 shows a terminal SIN + and a terminal SI of the CPU.
Has been described for an example of the exciting coil L ₁ between N-, similar circuit terminals COS +, excitation coil between terminals COS- L ₂
Can be applied, and another light emitting diode can be turned on by a current flowing between the terminal COS + and the terminal COS−. With the above-described warning circuit, the number of transistors used is slightly increased as compared with the conventional one, but the number of warning terminals for each signal can be reduced. Further, since the CPU only needs to supply the signal energy, a small-capacity CPU is sufficient as compared with the circuit of the first embodiment, so that the cost can be further reduced.

[0017]

As described above, in the warning circuit of the cross-coil type PWM drive meter according to the present invention, the warning light emitting diode is connected in parallel to the excitation coil of the movement, so that each warning terminal and each warning drive are provided. And a low-cost cross-coil type PWM driving meter warning circuit can be provided.

[Brief description of the drawings]

FIG. 1 is a general configuration diagram in which a warning circuit of a cross coil type PWM drive meter according to the present invention can be turned on within a range of 360 °.

FIG. 2 is a diagram showing a scale plate of a meter capable of indicating 360 °.

FIG. 3 is a configuration diagram of a warning circuit of the speedometer according to the present invention.

FIG. 4 is a diagram showing a scale plate of the speedometer according to the present invention.

FIG. 5 is a configuration diagram of a warning circuit of the fuel meter according to the present invention.

FIG. 6 is a configuration diagram of a warning circuit of the thermometer according to the present invention.

FIG. 7 is another configuration diagram of a warning circuit according to the present invention.

FIG. 8 is a configuration diagram of a warning circuit of a conventional cross coil type PWM drive meter.

FIG. 9 is a view for explaining a PWM output waveform.

[Explanation of symbols]

1: CPU 4, 9, 12: Movement. 2, 5, 7, 10, 13, 14, 21, 22, 23, 2
4: Light emitting diode. 3, 6, 8, 11, 15: resistance. L _1, L _2: excitation coil. 91, 92, 93, 94: inverting elements. 95, 96: light emitting diodes. Tr1, Tr2, Tr3, Tr4: switching element

Claims (4)

[Claims] 1. A cross-coil type PWM drive meter using two movement exciting coils orthogonal to each other, a CPU for calculating an energizing direction and an energizing amount to the two movement exciting coils, and a warning light emitting diode. A warning circuit for a cross-coil PWM drive meter, wherein a parallel connection circuit of the movement exciting coil and the warning light emitting diode is connected between at least a pair of movement output terminals of the CPU. 2. A cross-coil PWM drive meter using two movement exciting coils orthogonal to each other, a CPU for calculating a direction and amount of current to the two movement exciting coils, and a warning light emitting diode. In the warning circuit, a parallel connection circuit of the movement excitation coil and the warning light emitting diode is connected to a DC power supply side and a ground side via switching elements at both ends of the parallel connection circuit, respectively, and a pair of movements from the CPU is provided. A cross-coil type PWM characterized in that a current corresponding to a movement output signal from a CPU is caused to flow in one direction and the other direction to the parallel connection circuit by alternately turning on and off the plurality of switching elements with an output signal. Warning circuit for drive meter. 3. A cross-coil P-type warning device according to claim 1, wherein said warning light-emitting diode comprises a plurality of light-emitting diodes connected in anti-parallel.
Warning circuit of WM drive meter. 4. The cross-coil PWM according to claim 1, wherein in the warning circuit of the cross-coil PWM drive meter, the plurality of light emitting diodes are configured in different colors. Warning circuit for drive meter.