JPH0684491U - Two-color LED intermediate color display circuit - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an intermediate color display circuit of a two-color LED, which has a simple structure, is inexpensive, has excellent environmental resistance, and displays an intermediate color whose color tone changes continuously. [Composition] The output terminal of the comparator 2 for comparing the triangular wave voltage ea output from the reference AC generator 1 and the voltage eb whose input voltage from the input power supply terminal 6 is level-adjusted is connected via the current regulator 4 to the output terminal of the comparator 2. , The first and second LEDs 14,
It is connected to a two-color LED light emitter 5 formed by connecting 15 in antiparallel. The comparator 6 outputs a square wave voltage e0 whose pulse width changes according to the input voltage, and the output voltage e0
When is at the H level, the first LED 14 emits light, and when the is at the L level, the second LED 15 emits light.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an intermediate color display circuit of a two-color LED used for level display, polarity display and the like.

[0002]

[Prior art]

 Conventionally, as a method of displaying an intermediate color of the emission colors by using a two-color LED in which LEDs having different emission colors are arranged close to each other, there is a method in which the two-color LEDs are simultaneously turned on and displayed. However, with this method, only one type of fixed intermediate color can be obtained. For example, as in the case of a temperature monitor, if the temperature of a sensor rises above a certain reference temperature, the degree of one color increases and In that case, it could not be used as a visual display for increasing the degree of the other color. Therefore, in order to solve this problem, a method has been proposed in which each of the two-color LEDs is alternately turned on in a time-sharing manner, and the color tone of the intermediate color is varied by changing the light emission time ratio of each LED. The two-color LED intermediate color display circuit used in this method is configured by connecting each two-color LED to each port of the CPU via a resistor for adjusting current. In this two-color LED intermediate color display circuit, since each LED is independently driven by the CPU, the CPU controls the light emission time ratio of each LED to continuously display the intermediate color. Was being done.

[0003]

[Problems to be solved by the device]

 However, in such a two-color LED intermediate color display circuit, although the CPU is used to control the two-color LED, the CPU is expensive due to its complicated structure. The intermediate color display circuit also becomes expensive. Further, in such a two-color LED intermediate color display circuit, it takes a lot of time to set the arithmetic expression in the CPU, and the reliability of the CPU is greatly influenced by the environment, so that it can be used in a relatively bad environment. It was difficult.

Therefore, the present invention solves the drawbacks of the above-mentioned conventional example, has a simple structure, is inexpensive, has excellent environmental resistance, and displays intermediate colors of a two-color LED that continuously displays intermediate colors. The purpose is to provide a circuit.

[0005]

[Means for Solving the Problems]

 To achieve the above object, a two-color LED intermediate color display circuit according to the present invention comprises a reference AC generator 1 and a comparator 2 for comparing an input voltage with a reference AC voltage output from the reference AC generator 1. , A two-color LED light emitter 5 formed by connecting LEDs 16 and 17 having different emission colors in anti-parallel, and a current regulator connected between the output terminal of the comparator 2 and the two-color LED light emitter 5. 4 and is characterized in that the color tone variable display of the intermediate color is performed by changing the light emission time ratio of each of the LEDs 16 and 17 in response to the change of the duty ratio of the output voltage waveform of the comparator 2, and further, The input voltage level adjuster 3 for adjusting the level of the input voltage by the variable resistor 9 is connected to the input terminal of the comparator 2.

[0006]

[Action]

 In such a two-color LED intermediate color display circuit, the input voltage is compared with the reference AC voltage output from the reference AC generator by the comparator. Therefore, the output voltage waveform of the comparator is a square wave whose duty ratio is determined by the level of the input voltage. When this voltage is H level, the forward current flows to the two-color LED light emitter through the current regulator, and the LED connected in the forward direction emits light, and when it is L level, the reverse current is applied to the reverse direction. The connected LED emits light. Therefore, each LED of the two-color LED light emitter emits light alternately. In the intermediate color display circuit of the two-color LED, when the input voltage level changes, the duty ratio of the output voltage waveform changes, and the light emission time ratio of each LED changes, so that the color tone of the intermediate color changes. Therefore, in the intermediate color display circuit of the two-color LED, an intermediate color whose color tone continuously changes according to the level of the input voltage is displayed. Also, in the intermediate color display circuit of a two-color LED in which the input voltage level adjuster is connected to the input terminal of the comparator to which the input voltage is input, the color tone of the intermediate color obtained at a specific input voltage is adjusted by the input voltage level adjuster. It can be set in advance by adjusting the variable resistance of.

[0007]

【Example】

 Referring to FIGS. 1 and 2, the embodiment of the present invention will be described in detail. FIG. 1 is a circuit diagram of an intermediate color display circuit of a two-color LED in the embodiment of the present invention, and FIG. It is a figure explaining each voltage waveform of the intermediate color display circuit of LED.

In the figure, reference numeral 1 is a reference AC generator, which generates a triangular wave. Reference numeral 2 is a comparator, the inverting input terminal of which is connected to the reference AC generator 1, the non-inverting input terminal of which is connected to the input power supply terminal 6 via the resistor R1 and the input level adjuster 4 via the resistor R2. ing. The input level adjuster 4 is configured by connecting the variable resistor 7, the first and second DC power supplies 8 and 9 in series, and grounding the connection point of the first and second DC power supplies 8 and 9. The movable contact of the variable resistor 7 is connected to the non-inverting input terminal of the comparator 2 via the resistor R2. Reference numeral 4 denotes a current regulator configured by connecting a series circuit of the first resistor 10 and the first diode 12 and a series circuit of the second resistor 11 and the second diode 13 in parallel. Yes, it is connected to the output terminal of the comparator 2. Reference numeral 5 is a two-color LED light emitter that is configured by connecting the first LED 14 that emits red light and the second LED 15 that emits green light in anti-parallel, and is connected to the current regulator 4. Has been done.

In the two-color LED intermediate color display circuit of this embodiment, the voltage level of the input voltage from the input power supply terminal 6 is adjusted, and the DC voltage eb is applied to the non-inverting input terminal of the comparator 2. The comparator 2 compares this voltage eb with the triangular wave voltage ea from the reference AC generator 1. When the voltage eb is zero voltage, the voltage waveforms are as shown in FIG. 2A, and the waveform of the output voltage e0 from the comparator 2 is the L level voltage value VL at the time T1 and the H level voltage value VH. Becomes a square wave that is repeated (at a duty ratio of 0.5). When the voltage eb is a positive voltage, the voltage waveforms are as shown in FIG. 2B, and the waveform of the output voltage e0 from the comparator 2 is the H level when the time T1 at the L level voltage value VL is H level. It becomes a square wave (duty ratio less than 0.5) shorter than the time T2 which is the voltage value VH. In this way, the output voltage e0 from the comparator 2 becomes a voltage eb, that is, a pulse width modulated wave corresponding to the input voltage from the input power supply terminal 6. When the output voltage e0 from the comparator 2 is the H level voltage value VH, the forward current flows through the current regulator 4 to the two-color LED light emitter 4 and the first LED 14 turns red. When it emits light and has the L level voltage value VL, a reverse current flows, and the second LED 15 emits green light. By repeating the voltage values VH and VL, the first LED 14 and the second LED 15 alternately emit light. Therefore, by setting the times T2 and T1 at which the voltage values VH and VL become sufficiently fast with respect to the sensitivity of the human eye, an arbitrary intermediate color can be obtained by repeating the light emission of the LEDs 14 and 15. For example, when the voltage eb is zero voltage, the waveform of the output voltage e0 from the comparator 2 is as shown in FIG. 2 (a), so that the orange light is displayed by the repeated light emission of the LEDs 14 and 15. When the voltage eb is a positive voltage, the waveform of the output voltage e0 from the comparator 2 is as shown in FIG. 2 (b), so that the emission time (T2) of the first LED 14 is equal to that of the second LED 15. It becomes longer than the time (T1), and a reddish orange color is displayed.

As described above, in the two-color LED intermediate color display circuit of the embodiment, since the pulse width of the output voltage waveform of the comparator 2 changes according to the level of the input voltage from the input power supply terminal 6, the level of the input voltage is changed. Correspondingly, an intermediate color whose color tone changes continuously is displayed.

In the intermediate color display circuit of the two-color LED of this embodiment, the first and second resistors 10 and 11 of the current regulator 4 are respectively used when the first LED and the second LEDs 14 and 15 emit light independently. The brightness is adjusted, and further, by adjusting the respective resistance values, it is possible to set the color tone of the intermediate color displayed at the reference voltage eb.

Further, by adjusting the variable resistor 7 of the input voltage level adjuster 3, the voltage eb at an arbitrary input voltage from the input power supply terminal 6 is adjusted and the pulse width of the output voltage waveform of the comparator 2 is adjusted. Therefore, it is possible to set the color tone of the intermediate color displayed at the reference input voltage. When the color tone of the intermediate color is set with respect to the reference input voltage only by the input voltage level adjuster 3, the first and second resistors 10 and 11 can be made one resistor, and The second diode 12, 13 can be deleted.

The two-color LED intermediate color display circuit according to the present invention has been described above in detail based on an example considered to be typical. The embodiment of the two-color LED intermediate color display circuit according to the present invention is, for example, The output voltage from the reference AC generator is not limited to the structure of the above embodiment, such as a triangular wave or a sawtooth wave is appropriate, but other AC voltage may be used. The present invention is intended to be modified as appropriate as long as it has the constituent requirements described in 1), exhibits the action of the present invention, and has the effects described below.

[0014]

【effect】

 In the two-color LED intermediate color display circuit according to the present invention, by comparing the input voltage with the reference AC voltage by the comparator, the duty ratio of the output waveform of the comparator is changed according to the input voltage, and the two-color LED is changed. Since the light emission time ratio of each LED of the light emitter changes, and an intermediate color whose color tone changes continuously according to the input voltage can be displayed, the circuit configuration is simple and inexpensive. Further, unlike the CPU, the comparator can withstand use in a relatively bad environment, so that the intermediate color display circuit of the two-color LED has excellent environment resistance. Also, in the intermediate color display circuit of a 2-color LED in which the input voltage level adjuster is connected to the input terminal of the comparator to which the input voltage is input, by adjusting the variable resistance of the input voltage level adjuster, the reference input It is possible to easily set the color tone of the intermediate color obtained by the voltage.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a two-color LED intermediate color display circuit according to an embodiment of the present invention.

FIG. 2 is a view for explaining each voltage waveform of the intermediate color display circuit of the two-color LED of the same embodiment.

[Explanation of symbols]

 1 Reference AC Generator 2 Comparator 3 Input Level Adjuster 4 Current Adjuster 5 Two-Color LED Light Emitter 6 Input Power Supply Terminal 7 Variable Resistor 8 First DC Power Supply 9 Second DC Power Supply 10 First Resistance 11 Second Resistor 12 First diode 13 Second diode 14 First LED 15 Second LED

Claims (2)

[Scope of utility model registration request] 1. A reference AC generator (1), a comparator (2) for comparing an input voltage with a reference AC voltage output from the reference AC generator (1), and an LED (emission color different from each other). 16 and 17) are connected in anti-parallel to form a two-color LED light emitter (5) and a comparator (2)
Current regulator (4) connected between the output terminal of the LED and the two-color LED light emitter (5), and each LED (1) corresponding to the duty ratio change of the output voltage waveform of the comparator (2).
6. The intermediate color display circuit of a two-color LED, wherein the color tone variable display of the intermediate color is performed by changing the emission time ratio of 6, 17). 2. An input voltage level adjuster (3) for adjusting the level of an input voltage by a variable resistor (9) is connected to an input terminal of a comparator (2). Two-color LED intermediate color display circuit.