JP3484447B2 - Load control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load control device for controlling the operation of a plurality of loads, and is mounted, for example, for displaying a plurality of operation modes in various electric and electronic devices as the load. The present invention relates to a load control device that controls a plurality of mode indicating lamps such as LEDs (light emitting diodes) according to operation modes.

[0002]

2. Description of the Related Art FIG. 9 shows a conventional load control device for controlling a mode display lamp (hereinafter referred to as an LED) as a load. This load control device controls a first LED 81 and a second LED 82 for displaying two operation modes according to the operation mode, and includes a microcomputer (microcomputer) 83 as a control signal output means, A drive control circuit 84 having switching transistors 85 and 86 connected to the LEDs 81 and 82, respectively. The base of the first switching transistor 85 is connected to the output terminal 83a of the microcomputer 83, and the base of the second switching transistor 86 is connected to the other output terminal 83b.

In the first operation mode, the microcomputer 83 outputs an "H" level control signal from its output terminal 83a. As a result, the first switching transistor 8
5 becomes conductive, a current flows from the DC power source + B to the first LED 81 and the first switching transistor 85, and the first LED 81 lights up. At this time, the second LED 8
No. 2 is in a non-lighting state. That is, the first operation mode is indicated by the lighting of the first LED 81.

In the second operation mode, the microcomputer 83 outputs an "H" level control signal from its output terminal 83b. As a result, the second switching transistor 8
6 becomes conductive, current flows from the DC power supply + B to the second LED 82 and the second switching transistor 86, and the second LED 82 lights up. At this time, the first LED 8
1 is in a non-lighting state. That is, the second operation mode is indicated by lighting of the second LED 82.

[0005]

In the above-described conventional load control device, the two LEDs 81 and 82 corresponding to the two operation modes are individually controlled, and the output terminal of the microcomputer 83 is set to each LED individually. 2 corresponding to
Two output terminals 83a and 83b are assigned. When there are three LEDs for operating mode display, each LED
In this configuration, the three output terminals of the microcomputer are assigned individually corresponding to. Generally, there are n
In the case where there are a number, the configuration is such that n output terminals of the microcomputer are assigned.

The number of output terminals of the microcomputer is naturally limited. The output terminal of the microcomputer is valuable for controlling a large number of other controlled parts in electric and electronic devices. The output terminal is one of the LEDs for operating mode display
If they are exclusively assigned to each other, it may hinder the circuit design for controlling other controlled parts.

The present invention was devised in view of the above circumstances, and has an output terminal of a control signal output means such as a microcomputer as a configuration for controlling a load of a mode display lamp for displaying an operation mode. The purpose is to narrow down the number of allocations.

[0008]

According to a first aspect of the present invention, there is provided a load control device for selectively driving and controlling each of the loads between a plurality of loads and an output terminal of a control signal output means. A control circuit is provided, the control signal output is configured to selectively output a plurality of control signals from the output terminal, and the selective drive control circuit applies a load corresponding to each input control signal. a load controller is configured to selectively operate the front
The control signal output means outputs at least the control signal.
The first level output and a plurality of parts with different duty ratios
And a second level output to output the selective output.
The dynamic control circuit changes the level for each control signal.
It generates a voltage and switches each load according to the voltage of each level.
A load control device for selectively driving a ching element , wherein when the control signal output means is, for example, a microcomputer, a plurality of loads are selectively operated by outputting a plurality of types of control signals from an output terminal of the microcomputer. This minimizes the number of output terminals occupied in the microcomputer for controlling multiple loads, and also flattens each pulse output by integration.
By slipping, you can get multiple level output.
Furthermore, the selective drive control circuit is configured to control each control signal.
Generates voltage with different levels for each level, and voltage of each level
Selectively drive the switching elements of each load according to
Is configured.

[0009]

[0010]

[0011]

[0012] The load control device of claim 2 according to the present invention, in the claim 1, to drive the switching element voltage breakdown for each level of voltage generated via different Zener diode It has a simple and rational structure.

[0013]

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a load control device according to the present invention will be described below in detail with reference to the drawings. In the present embodiment, the description will be made by applying an LED (light emitting diode) as a mode display lamp as a load, but the present invention is not limited to this, and the same applies to other loads. Is applicable to.

[First Embodiment] FIG. 1 is a circuit diagram showing a configuration of a load control device according to the first embodiment. In FIG. 1, 1 is a microcomputer (microcomputer) as a control signal output means, 11 is a first LED for displaying an operation mode as an example of a load, 12 is a second LED also as an example of a load, and 2 is This is a selective drive control circuit for driving the two LEDs 11 and 12. The selective drive control circuit 2 includes an integrating circuit 3 including a resistor R ₁ and a capacitor C ₁ , a Zener diode 4 for a selective operation, and a first
And second switching transistors 5 and 6, a switching diode 7 for alternative operation, and a backflow prevention diode 8. The input terminal of the integrator circuit 3 is connected to the output terminal 1a of the microcomputer 1, the output terminal of the integrator circuit 3 is connected to the cathode of the Zener diode 4, and the base resistor R ₃ and the backflow prevention diode 8 are connected.
Is connected to the base of the second switching transistor 6 (hereinafter simply referred to as the second transistor 6) via. The anode of the Zener diode 4 is connected to the base of the first switching transistor 5 (hereinafter simply referred to as the first transistor 5) via the base resistor R ₂ . The first transistor 5 is an NPN type, its emitter is grounded, and its collector is the first LED 11
Connected to the cathode. The second transistor 6 is also NPN type, its emitter is grounded, and its collector is connected to the cathode of the second LED 12. The connection point between the base resistance R ₃ of the second transistor 6 and the backflow prevention diode 8 is connected to the anode of the switching diode 7, and the cathode thereof is connected to the collector of the first transistor 5. First LED 11 and second
The LEDs 12 of the anodes have resistors R for limiting current, respectively.
It is connected to the DC power supply + B via ₄ and R ₅ .

FIG. 2 shows the microcomputer 1 from its output terminal 1a.
3 shows three patterns of output control signals. Figure 2
(A) is, for example, a constant direct current as the first level output.
Pressure V ₁ High level output S₁ And (b) shows the voltage V₁ 
Pulse output S that alternately repeats two values, zero and zero voltage₂ To
(C) shows a second level output such as zero voltage
Low level output S₃ Is shown.

Next, the operation of the load control device of the first embodiment configured as described above will be described.

In the first operation mode, the microcomputer 1 outputs the control signal of the high level output S ₁ from the output terminal 1a as the first level output to the integrating circuit 3 in the preceding stage of the selective drive control circuit 2. . As shown in (a) of FIG. 3, the output voltage Vc ₁ of the integrating circuit 3 at this time becomes the same V ₁ as the high level output S ₁ . Output voltage Vc of this integrating circuit 3
₁ is larger than the Zener voltage V _{ZD of} the Zener diode 4, so that the Zener diode 4 becomes conductive and raises the base voltage of the first transistor 5, so that the first transistor 5 becomes conductive. The output voltage Vc ₁ of the integrating circuit 3 tends to be applied also to the base of the second transistor 6, but the voltage of the collector of the first transistor 5, that is, the switching diode 7 due to the conduction of the first transistor 5. Since the voltage of the cathode is almost at the ground level, the switching diode 7 is driven by the output voltage Vc ₁ of the integrating circuit 3 applied to its anode.
Are turned on, and as a result, the base voltage of the second transistor 6 is pulled down to almost the ground level, so that the second transistor 6 is turned off. The conduction of the first transistor 5 turns on the first LED 11. The second LED 12 is in a non-lighting state.
The first operation mode is indicated by the lighting of the first LED 11.

In the second operation mode, the microcomputer 1 outputs the control signal of the pulse output S ₂ from its output terminal 1a to the integration circuit 3 of the selective drive control circuit 2. Pulse output S
_The output voltage Vc _{1 obtained} by integrating ₂ and smoothing ₂ by the integrating circuit 3 becomes a voltage V ₂ lower than V ₁ as shown in FIG. The duty ratio of the pulse output S ₂ is set so that this voltage V ₂ becomes lower than the Zener voltage V _ZD of the Zener diode 4. Therefore, the Zener diode 4 is not conducting this time, and the first transistor 5 is non-conducting. Since the first transistor 5 is non-conductive, the switching diode 7 is also non-conductive.
As a result, the output voltage Vc ₁ of the voltage V ₂ of the integrating circuit 3
Raises the base voltage of the second transistor 6 via the backflow prevention diode 8, so that the second transistor 6 becomes conductive. The second LED 12 is turned on by the conduction of the second transistor 6. The first LED 11 is in a non-lighting state. The second operation mode is the second
It is indicated by lighting of the LED 12.

When the microcomputer 1 sets its output terminal 1a to the low level output S ₃ of zero voltage as the second level output shown in FIG. 3C, the output voltage Vc of the integrating circuit 3
₁ also becomes zero voltage, both the first transistor 5 and the second transistor 6 are non-conducting, and the first LED 11 and the second LED 12 are non-lighting. This is the normal state.

When the microcomputer 1 switches from the steady state to the first operation mode, only the first LED 11 lights up. When returning to the steady state from the first operation mode,
The first LED 11 is turned off. When the first operation mode is switched to the second operation mode, the first LED 1
At the same time as 1 is turned off, the second LED 12 is turned on. When the microcomputer 1 switches from the steady state to the second operation mode, only the second LED 12 lights up. When the steady state is returned from the second operation mode, the second LED 1
2 goes out. When the second operation mode is switched to the first operation mode, the second LED 12 is turned off and the first LED 11 is turned on at the same time.

In the load control device of the first embodiment, the microcomputer 1 has a configuration for controlling the first LED 11 corresponding to the first operation mode and the second LED 12 corresponding to the second operation mode. As the output terminals, only one output terminal 1a common to both is assigned. Compared with the conventional technology, the output terminal of the microcomputer 1 is 1
It will be over. This surplus output terminal can be assigned to control other controlled parts of the electric device / electronic device, which increases the degree of freedom in circuit design.

[Second Embodiment] FIG. 4 is a circuit diagram showing a configuration of a load control device according to a second embodiment. In FIG. 4, 1 is a microcomputer as a control signal output means, 31
Is a first LE for displaying an operation mode as an example of a load.
D and 32 are second LEDs, which are also examples of loads, and
Reference numeral 1 is a selective drive control circuit for driving the two LEDs 31, 32. The selective drive control circuit 21 is a PNP.
A first switching transistor 22 of the type (hereinafter simply referred to as the first transistor 22) and a second switching transistor 23 of the NPN type (hereinafter simply referred to as the second transistor 23). The base of the first transistor 22 is connected to the output terminal 1a of the microcomputer 1 through the base resistor R ₁₁ , and the second transistor 2
3 has the same output terminal 1a via the base resistor R _12.
It is connected to the. PNP type first transistor 22
Is connected to a DC power source + B, and its collector is grounded via a current limiting resistor R ₁₃ for the first LED 31 and is also connected to the cathode of the first LED 31. The anode of the first LED 31 is connected to the DC power supply + B. The emitter of the NPN-type second transistor 23 is grounded, and its collector is connected to the anode of the second LED 32. Second LED
The cathode of 32 is grounded, and the anode thereof is connected to the DC power source + B via the resistor R ₁₄ for current limiting.

The first transistor 22 is connected to the first LED 3
The second transistor 23 controls the first LED 32 and the second transistor 23 controls the second LED 32. However, both turn off the LED when the transistor conducts,
It is a reversing operation type that lights when it becomes non-conductive.

FIG. 5 shows three patterns of control signals output from the output terminal 1a of the microcomputer 1. First
There are a high level output S ₄ due to a constant DC voltage B ₀ , an open output S ₅ having a high impedance, and a second level output such as a low level output S ₆ due to a ground level zero voltage.

Next, the operation of the load control device of the second embodiment having the above configuration will be described.

In the first operation mode, the microcomputer 1 outputs the control signal of the high level output S ₄ from the output terminal 1a to the selective drive control circuit 21. Since the base voltage of the PNP type first transistor 22 rises, the first transistor 22 becomes non-conductive, and the first LED 31 is not short-circuited by the first transistor 22.
A current flows from the DC power source + B to the first LED 31 and the resistor R ₁₃ , and the first LED 31 lights up. On the other hand, NPN
Since the base voltage of the second LED 32 of the mold rises, the second transistor 23 becomes conductive and shorts the anode and cathode of the second LED 32. That is, DC power supply + B
The current flowing from the resistor R ₁₄ to the second transistor 23 flows into the second transistor 23, so that the second LED 32 is turned off. When the first LED 31 lights up, the first
Represents the operation mode.

In the second operation mode, the microcomputer 1 outputs the control signal of the low level output S ₆ from its output terminal 1a to the selective drive control circuit 21. Since the base voltage of the PNP type first transistor 22 becomes the ground level, the first transistor 22 becomes conductive and the first LED 3
Short-circuit between the anode and cathode of No.1. That is, the current from the DC power source + B flows through the first transistor 22 and the resistor R ₁₃ and is prevented from flowing into the first LED 31, so that the first LED 31 is in a non-lighting state. On the other hand, N
Since the base voltage of the PN-type second transistor 23 becomes the ground level, the second transistor 23 becomes non-conducting, and the second LE by the second transistor 23 is turned on.
Since a short circuit of D32 does not occur, DC power supply + B to resistor R
_The current passing through ₁₄ flows to the second LED 32, and the second LE
D32 lights up. Illumination of the second LED 32 indicates the second operation mode.

When the microcomputer 1 sets the output terminal 1a to the open output S ₅ , the PNP type first transistor 2
2 and the NPN-type second transistor 23 are connected to each other at their bases, and the first transistor 2
Since the DC power supply + B is applied to the second emitter and the emitter of the second transistor 23 is grounded, the current from the DC power supply + B flows from the emitter of the first transistor 22 to the base, and the current is Flow from the base of the second transistor 23 to the emitter, and as a result, the first transistor 22 also flows into the second transistor 23.
Also conducts. Therefore, the first LED 31 also has the second L
The ED 32 is also short-circuited and both are non-lighted.
This is the normal state. Most of the current from the DC power source + B flows through the series circuit of the first transistor 22 and the resistor R _{13 and} the series circuit of the resistor R ₁₄ and the second transistor 23.

When the microcomputer 1 switches from the steady state to the first operation mode, only the first LED 31 lights up. When returning to the steady state from the first operation mode,
The first LED 31 is turned off. When the first operation mode is switched to the second operation mode, the first LED 3
At the same time that 1 is turned off, the second LED 32 is turned on. When the microcomputer 1 switches from the steady state to the second operation mode, only the second LED 32 lights up. When the steady state is returned from the second operation mode, the second LED 3
2 goes out. When the second operation mode is switched to the first operation mode, the second LED 32 is turned off and the first LED 31 is turned on at the same time.

Also in the load control device of the second embodiment, the microcomputer 1 has a configuration for controlling the first LED 31 corresponding to the first operation mode and the second LED 32 corresponding to the second operation mode. As the output terminals, only one output terminal 1a common to both is assigned.

[Third Embodiment] FIG. 6 is a circuit diagram showing a configuration of a load control device according to a third embodiment. In FIG. 6, 1 is a microcomputer as a control signal output means, 61
Is a first LE for displaying an operation mode as an example of a load.
D and 62 are second LEDs 6 which are also examples of loads.
3 is a third LED as an example of a load, and 41 is 3
This is a selective drive control circuit for driving one LED 61, 62, 63. The selective drive control circuit 41 includes a resistor R
_An integrating circuit 42 including a capacitor ₁₅ and a capacitor C _2, and first and second Zener diodes 43 and 44 for selecting operation
And first, second and third switching transistors 45, 46 and 47, first, second and third switching diodes 48, 49 and 50 for alternative operation, and
And second backflow prevention diodes 52 and 53. The input terminal of the integrating circuit 42 is connected to the output terminal 1a of the microcomputer 1, the output terminal of the integrating circuit 42 is connected to the cathodes of the first and second Zener diodes 43 and 44, and the base resistance R ₁₈ and the second It is connected to the base of the third switching transistor 47 (hereinafter simply referred to as the third transistor 47) via the backflow prevention diode 53. The anode of the first Zener diode 43 is connected to the base of the first switching transistor 45 (hereinafter simply referred to as the first transistor 45) via the base resistor R ₁₆ . The first transistor 45 is an NPN type, its emitter is grounded, and its collector is connected to the cathode of the first LED 61. The anode of the second Zener diode 44 is connected to the second switching transistor 46 via the base resistor R ₁₇ and the second backflow prevention diode 52.
It is connected to the base of (hereinafter simply referred to as the second transistor 46). The second transistor 46 is also an NPN
Type, its emitter is grounded and its collector is connected to the cathode of the second LED 62. The connection point between the base resistance R ₁₇ of the second transistor 46 and the first backflow prevention diode 52 is the first switching diode 4
8 of which the cathode is connected to the collector of the first transistor 45. The third transistor 47 is also NPN type, its emitter is grounded, and its collector is connected to the cathode of the third LED 63. The base resistance R ₁₈ of the third transistor 47 and the second
Is connected to the anodes of the second and third switching diodes 49 and 50, and the cathode of the second switching diode 49 is connected to the collector of the first transistor 45.
The cathode of the switching diode 50 is connected to the collector of the second transistor 46. First LE
The anodes of D61, the second LED 62, and the third LED 63 are connected to the DC power source + B via the current limiting resistors R ₁₉ , R ₂₀ , and R ₂₁ , respectively.

FIG. 7 shows four patterns of control signals output from the output terminal 1a of the microcomputer 1. Figure 7
(A) shows a high level output S ₁₁ of a constant DC voltage V ₁₁ , for example, as a first level output, and (b) shows a voltage V ₁₁
Shows a first pulse output S ₁₂ with a large on-duty that alternately repeats two values of zero voltage and zero voltage, and (c) shows a similar second pulse output S ₁₃ with a small on-duty,
(D) shows the low level output S ₁₄ of zero voltage, for example, as the second level output.

As shown in FIG. 8, the output voltage V of the integrating circuit 42 when the high level output S ₁₁ passes through the integrating circuit 42.
The voltage V ₁₁ which is c ₂ , the voltage V ₁₂ when the first pulse output S ₁₂ is smoothed by the integrating circuit 42, and the voltage V ₁₂ when the second pulse output S ₁₃ is also smoothed
₁₃ and the Zener voltage V of the first Zener diode 43
The magnitude relationship between _{ZD 1} and the Zener voltage V _{ZD2 of} the second Zener diode 44 is that the base-emitter voltage for making the first transistor 45 conductive is α ₁ , and the second transistor 46 is conductive. The duty ratio of the first pulse output S ₁₂ and the second pulse output S ₁₃ such that V ₁₃ <V _ZD2 + α ₂ <V ₁₂ <V _ZD1 + α ₁ <V ₁₁ with the base-emitter voltage α _2. Is set.

Next, the operation of the load control system according to the third embodiment having the above configuration will be described.

In the first operation mode, the microcomputer 1 outputs the control signal of the high level output S ₁₁ from its output terminal 1a to the integrating circuit 42 in the preceding stage of the selective drive control circuit 41. As shown in FIG. 8A, the integration circuit 4 at this time
The output voltage Vc ₂ of ₂ becomes V ₁₁ which is the same as the high level output S ₁₁ . Since the output voltage Vc ₂ (= V ₁₁ ) of the integrating circuit 42 is larger than the Zener voltage V _{ZD1 of} the first Zener diode 43, the first Zener diode 43 becomes conductive and the base voltage of the first transistor 45 rises. As a result, the first transistor 45 becomes conductive. Integrating circuit 4
Since the output voltage Vc ₂ (= V ₁₁ ) of the second Zener diode 44 is larger than the Zener voltage V _{ZD2 of} the second Zener diode 44, the second Zener diode 44 is also conductive, and the output voltage Vc ₂ of the integrating circuit 42 is the second transistor. The voltage of the collector of the first transistor 45, that is, the voltage of the cathode of the first switching diode 48 becomes almost the ground level because the first transistor 45 is turned on. , By the output voltage Vc ₂ of the integrating circuit 42 applied to its anode
The switching diode 48 of will become conductive,
As a result, the base voltage of the second transistor 46 is pulled down to almost the ground level, so that the second transistor 46 becomes non-conductive. The output voltage Vc ₂ of the integrating circuit 42 tries to be applied to the base of the third transistor 47, but the second switching diode 49 becomes conductive for the same reason as described above, and as a result, the third transistor 47 is turned on. The base voltage of the third transistor 47 is pulled down to almost the ground level.
Becomes non-conductive. The conduction of the first transistor 45 turns on the first LED 61. The second LED 62 and the third LED 63 are turned off. The first operation mode is indicated by the lighting of the first LED 61.

In the second operation mode, the microcomputer 1 outputs the control signal of the first pulse output S ₁₂ from the output terminal 1a to the integration circuit 42 of the selective drive control circuit 41. The output voltage Vc _{2 obtained} by integrating and smoothing the first pulse output S ₁₂ by the integrating circuit 42 is V ₁₁ as shown in FIG. 8B.
This results in a lower voltage V ₁₂ . This voltage V ₁₂ is lower than the Zener voltage V _ZD1 of the first Zener diode 43 (however, higher than the Zener voltage V _{ZD2 of} the second Zener diode 44), so that the first pulse output S ₁₂ duty ratios are set. Therefore, the first Zener diode 43 is not conducting this time,
The first transistor 45 is turned off. Since the output voltage Vc ₂ (= V ₁₂ ) of the integrating circuit 42 is larger than the Zener voltage V _ZD2 of the second Zener diode 44,
, The first transistor 45 is non-conductive and the first switching diode 48 is also non-conductive. Therefore, the second transistor 46 of FIG.
The base voltage of the second transistor 4
6 becomes conductive. The output voltage Vc ₂ of the integrating circuit 42 is about to be applied to the base of the third transistor 47,
Since the second transistor 46 becomes conductive, the collector voltage of the second transistor 46, that is, the cathode voltage of the third switching diode 50 becomes substantially at the ground level, so that the output of the integrating circuit 42 applied to the anode thereof. The voltage Vc ₂ causes the third switching diode 50 to become conductive, and as a result, the base voltage of the third transistor 47 is pulled down to approximately the ground level, so that the third transistor 47 becomes non-conductive. The conduction of the second transistor 46 causes the second
LED 62 lights up. First LED 61 and third
The LED 63 of is turned off. The second operation mode is indicated by the lighting of the second LED 62.

In the third operation mode, the microcomputer 1 outputs the control signal of the second pulse output S ₁₃ from the output terminal 1a to the integration circuit 42 of the selective drive control circuit 41. The output voltage Vc _{2 obtained} by integrating and smoothing the second pulse output S ₁₃ by the integrating circuit 42 is V ₁₂ as shown in (c) of FIG.
This results in a lower voltage V ₁₃ . The duty ratio of the second pulse output S ₁₃ is set so that this voltage V ₁₃ becomes lower than the Zener voltage V _ZD2 of the second Zener diode 44. Therefore, the first Zener diode 43
Neither the second Zener diode 44 is conductive at this time, and the first transistor 45 and the second transistor 46 are non-conductive. First and second transistor 4
Since 5 and 46 are non-conductive, the third switching diode 50 is also non-conductive. As a result, the output voltage Vc ₂ of the voltage V ₁₃ of the integrating circuit 42 raises the base voltage of the third transistor 47 via the second backflow prevention diode 53, so that the third transistor 47 becomes conductive. The conduction of the third transistor 47 turns on the third LED 63. The first LED 61 and the second LED 62 are turned off. Lighting of the third LED 63 indicates that the operation mode is the second operation mode.

When the microcomputer 1 sets its output terminal 1a to the low level output S ₁₄ of zero voltage shown in FIG. 8D, the output voltage Vc ₂ of the integrating circuit 42 also becomes zero voltage,
Neither the first transistor 45, the second transistor 46, nor the third transistor 47 is in the non-conducting state, and the first LE
Neither D11, the second LED 12, nor the third LED 63 is in a non-lighting state. This is the normal state.

When the microcomputer 1 switches from the steady state to the first operation mode, only the first LED 61 lights up. When returning to the steady state from the first operation mode,
The first LED 61 goes out. When the first operation mode is switched to the second operation mode, the first LED 6
At the same time that 1 is turned off, the second LED 62 is turned on. When the first operation mode is switched to the third operation mode, the first LED 61 is turned off and at the same time the third LE is turned on.
D63 lights up. When the microcomputer 1 switches from the steady state to the second operation mode, only the second LED 62 lights up. When the steady state is returned from the second operation mode, the second LED 62 is turned off. When the second operation mode is switched to the first operation mode, the second L
At the same time when the ED 62 is turned off, the first LED 61 is turned on. When the second operation mode is switched to the third operation mode, the second LED 62 is turned off and at the same time the third operation mode is set.
LED 63 of turns on. When the microcomputer 1 switches from the steady state to the third operation mode, the third LED 6
Only 3 lights up. When the steady state is returned from the third operation mode, the third LED 63 is turned off. When the third operation mode is switched to the first operation mode, the third LED 63 is turned off and at the same time the first LED 61 is turned on. When the third operation mode is switched to the second operation mode, the third LED 63 is turned off and at the same time the second LED 62 is turned on.

In the load control device of the third embodiment, the first LED 61 corresponding to the first operation mode, the second LED 62 corresponding to the second operation mode, and the first LED 61 corresponding to the third operation mode. As a configuration for controlling the three LEDs 63, only one output terminal 1a common to the three output terminals of the microcomputer 1 is assigned. Compared with the conventional technique, two output terminals of the microcomputer 1 are left over. These two remaining output terminals can be assigned to control other controlled parts of the electric device / electronic device, increasing the degree of freedom in circuit design.

In the above embodiment, the number of LEDs for operation mode display is further increased, and the number of switching transistors, zener diodes, and switching diodes in the selective drive control circuit is increased.
By increasing the level classification of the Zener voltage and increasing the type of duty ratio of the pulse output corresponding to it, an arbitrary number of LEDs can be selectively selected by changing the pattern of the control signal from the common single output terminal 1a of the microcomputer 1. Can be configured to control.

In each of the above-described embodiments, the microcomputer 1 outputs a high level as a first level output, a low level as a second level output, and a pulse output and a high impedance which alternately repeat the both levels. Open output, pulse output with different duty is output, and these combinations are used.
Alternatively, a combination of other forms of pulse output can be used.

[0044]

As described above, according to the load control device of the present invention, the microcomputer supplies the control signal necessary for selectively operating the load such as the mode display lamps such as the plurality of LEDs. Since it is possible to output from the minimum number of output terminals of control signal output means such as, only one output terminal is occupied in the microcomputer for controlling multiple loads, and the output that is left as a result By allocating the terminal to control other controlled parts of the electric device / electronic device, the degree of freedom in circuit design can be increased.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a load control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a pattern of a control signal output from a microcomputer in the first embodiment.

FIG. 3 is a waveform diagram for explaining the operation of the first embodiment.

FIG. 4 is a circuit diagram of a load control device according to a second embodiment.

FIG. 5 is a diagram showing a pattern of a control signal output from a microcomputer in the second embodiment.

FIG. 6 is a circuit diagram of a load control device according to a third embodiment.

FIG. 7 is a diagram showing a pattern of control signals output from a microcomputer in the third embodiment.

FIG. 8 is a waveform diagram for explaining the operation of the third embodiment.

FIG. 9 is a circuit diagram of a conventional load control device.

[Explanation of symbols]

1 ... Microcomputer (control signal output means) 1a ... Microcomputer output terminals 2, 21, 41 ... Selective drive control circuit 3, 42 ... Integrating circuit 4, 43, 44 ... Zener diode 5, 22, 45 ...... First switching transistor 6, 23, 46 ...... Second switching transistor 47 ...... Third switching transistor 7,48,49,50 ...... Switching diode 11, 31, 61 for alternative operation ...... 1st LED (mode display lamp) 12, 32, 62 ... 2nd LED (mode display lamp) 63 ... 3rd LED (mode display lamp)

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G08B 1/00-31/00 G05B 23/00-23/02

Claims (2)

(57) [Claims] 1. A selective drive control circuit for selectively driving and controlling each load is provided between a plurality of loads and an output terminal of a control signal output means, and the control signal output selects a plurality of control signals. configured to output the to the output terminal, said selective drive control circuit is a load controller configured to selectively operate the corresponding load according to each of the control signal input , The control signal output means, at least as the control signal
Also has a plurality of different first level outputs and different duty ratios.
A pulse output and a second level output are output, and the selective drive control circuit outputs a level for each control signal.
Generate different voltages, and adjust each voltage according to the voltage of each level.
A load control device characterized by selectively driving a load switching element . 2. A breakdown for each generated voltage level.
The switch is connected through Zener diodes with different voltages.
The load control device according to claim 1, wherein the load control device drives a switching element .