JPS5871467A - Level indicator - Google Patents

Abstract

PURPOSE:To indicate a level by switched and transferred luminescent colors, by a constitution wherein a plural sets of light-emitting diodes having different luminescent colors are provided, cathodes are connected to a driving circuit, and the feeding to anodes different in luminescent colors are switched by a detection level output. CONSTITUTION:A signal at a connecting point between a power amplifier 1 and a speaker 2 is given to resistors (R) 7-11 and transistor (TR) 12-16, both of which are provided for setting an indication level. An LED22 is lighted normally, indicating a zero point. LEDs 36-40 are arranged, with two of (36a, 36b)- (40a, 40b) in a set, on the back surface of a plastic case C. LEDs in green a and red b are set in a pair. A series circuit of R41 and TR42, which adjusts the drive gain of LEDs 36-40 is connected to the common terminal side of Rs 7- 11. Anodes on the sides a and b of LEDs 36-40 are connected a power source +B via a switching circuits comprising TRs 45, 46 and 47, 48. By this constitution, an output of a level detection circuit can be indicated by switched and transferred luminescent colors.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a level display device that displays voltage levels that dynamically change greatly, such as the output level of an amplifier or the recording level of a Teso recorder, by running light emitted from a light emitting diode array.

As shown in Fig. 1, a level display device that uses the running of light emitted from a row of light emitting diodes (hereinafter referred to as LEDs), for example, for stereo equipment, uses an equal number of light emitting diodes (hereinafter referred to as LEDs) to the left and right with the center at zero level. 1.3.10.3 Diodes are arranged in a row, going from the center to the outside.
It is configured with a number representing the level of 0.90.

Conventionally, such a level display device has a display level setting resistor 3, a rectifier diode 4,
The signal output to the terminal 6 via the smoothing capacitor 5 is input to a drive circuit as shown in FIG. 3 and displayed.

In FIG. 3, 7 to 11 are resistors for display level setting, 12 to 16 are switching transistors for driving LEDs, 17 to 22 are LEDs 123 to 28 are LED 1
This is a current limiting resistor for adjusting the current flowing through the terminals 7 to 22.

However, in this case, there is only one level range that can be displayed, and it is very difficult to set the range width to the optimal value using resistor 3. When listening at low volume, the LED will not light up, and if you set it so that an appropriate display is displayed when the volume is low, most LEDs will turn off when listening at high volume.
lights up, and in either case there is no light traveling by the LED, so there is a drawback that the effect of 4-player play is lost.

In order to solve this problem, as shown in Fig. 2 (B), a range changeover switch 29 can be connected to a range adjustment resistor 30 whose one end is grounded, and its drive level can be adjusted. There are some things. In this case, it is possible to select an appropriate display range using the range changeover switch 29, but the changeover is done by manual operation of a mechanical switch, and when the operation is performed, the display effect changes as in the former case. The problem is that the switching operation is cumbersome, and even when the switching operation is performed, the same color light travels, making it difficult to determine which side's Lenz level is currently being displayed. .

SUMMARY OF THE INVENTION In order to solve these problems, an object of the present invention is to provide a level display device that automatically switches display level ranges and emits light in a color that corresponds to the switched range. It is to provide.

Next, the level display device of the present invention will be explained based on an example. First, a means for automatically selecting a display level range will be explained. In FIG. 4, (A) is a pure electronic type in which the output from amplifier f1 is input to the base of transistor 32 via smoothing section 31, and transistor 32 is turned on when the voltage exceeds a certain level, and (B) is a purely electronic type. The transistor 32 is driven by a voltage signal from the dalium 34 that is linked to the volume hilium 33. (C) is a switch 35 that is turned on and off near the midpoint of the volume volume 33.
applying a voltage signal to the transistor 32 by;
etc. What these means have in common is that when the voltage exceeds a set level, the Lenz switching control signal generating transistor 32 is turned on, and an output voltage is obtained at the terminal 32a.

FIG. 5 is a circuit diagram showing an embodiment of the level display device of the present invention, and elements having the same functions and effects as those in FIGS. 2 and 3 are denoted by the same reference numerals. Explanation will be omitted. In the figure, numeral 22 is an LED for displaying the zero point, which is always lit. 36 to 40 are LEDs for level display, respectively (36a, 36b) and (37a, 37b).
.

(:38a, 38b), (39a, 39b), (40a
, 40b) as a set as shown in FIG.

The LEDs are arranged on the back of the case C, and each emit light in a different color. For example, a is a green LED, and b is a red LED.
are paired. The output from the amplifier 1 that displays the level is applied to the common terminal side of the level setting resistors 7 to 11, and a series circuit consisting of a resistor 41 and a transistor 42 is used to adjust the gain of the LED drive circuit. is grounded through.

A range switching control signal from the transistor 32 shown in FIG. 4 is input to the base of the transistor 42 via a buffer resistor 44.

The cathodes of the a side and b side LEDs of the LEDs 36 to 40 forming each set are commonly connected, and a current limiting resistor 23
A drive signal is input through 27, and one of the other terminals (a side) is connected to a switching transistor 45.4.
The other side (b side) is connected to the power supply element B via a first switching circuit composed of switching transistors 47 and 48. It is connected to the. In addition, 4
9.50 is a buffer resistor, and 51 and 52 are bias resistors. A control signal for level switching is input to the base of the transistor 46 of the first switching circuit, and a transistor 48 of the second switching circuit is inputted with a control signal for level switching.
The emitter of the first switching transistor 45 is connected to the base of the first switching transistor 45 via a buffer resistor 50.

Next, the operation of the level display device configured in this way will be explained. Now, if you turn down the volume for adjusting the volume of your audio equipment and the level is on the low side,
Since the transistor 32 in the range switching means shown in FIG. 4 is in the OFF state, the transistor 42 and the transistor 46 are also in the OFF state, and the transistor 4
5 is in the ON state. That is, since the gain of the LEI) drive circuit is large and the first switching circuit is in a conductive state, the LED 36 a * on the a side of each set of LEDs
3.7 a *38 a + 39 a r 40
A power supply voltage is applied to a. Therefore, the display color on the low range side, in this example green, changes depending on the level. Note that, as described above, the transistor 45
is in the ON state, the transistor 48 is in the ON state and the transistor 47 is in the OFF state, and the second switching circuit is in the closed state, so the LE on the b side of each group
D 36 b to 40 b are not lit.

Next, when the volume volume is increased and the level reaches or exceeds the range switching setting level, transistor 32 is turned on, so transistors 42 and 46 are turned on.
In this state, the transistor 45 is in the OFF state, so the transistor 48 is in the OFF state, and the transistor 47 is in the ON state.
state. That is, since the input side of the LED drive circuit is grounded via the resistor 41, its gain is low, and the first switching circuit is in the OFF state and the second switching circuit is in the ON state. Therefore, even though a high level signal is input to the LED drive circuit,
Since the LED drive circuit is switched to an appropriate display level and the second switching circuit is turned on, the color indicating that the range has been switched to the high range side, in this example, the t, ED of each set. 36-40 red side L
Since the power supply voltage is applied to ED 36 b to 40 b,
At an appropriate display level, the red light will run according to the level.

Note that since the first switching circuit is in the OFF state, the green LED 36 that displays the level on the low range side
A to 40a are not lit.

As explained above, in the present invention, the display range is automatically selected depending on the level of the signal to be displayed, and any signal from low level to high level can be displayed on the LED at an appropriate display level. In addition, when the range is changed, the color of the light emitted from the LED displaying the driving is also changed, so that the display range can be easily identified and the De1Ssolley effect can be further enhanced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an arrangement form of LEDs in a level display device based on the running of light emission from the LEDs, and FIG. 2(A). (B) is a diagram showing an input signal section to a conventional level display device when displaying the level of audio equipment, FIG. 3 is a circuit diagram showing an LED drive circuit in the conventional level display device, and FIG. (A), (B), and (C) are diagrams showing an example of the range switching means of the level display device;
The figure is a circuit diagram showing an embodiment of the level display device of the present invention, and FIG. 6 is a diagram showing the configuration of two LEDs forming a set. 1... Amplifier, 4... Rectifier diode, 7 to 11
...Display level setting resistor, 12 to 16...LED
Drive switching transistors, 23-28... Current limiting resistors, 32... Range switching control signal generation transistors, 22... LEDs, 36-40... Each set of -J" LEDs, 42 .45~48...Switching transistor. Fig. 1 power 1evel (W/8fl) Fig. 4 (A) i-3° (C)

Claims (1)

[Claims] A plurality of sets of two light emitting diodes with different light emitting colors are arranged on one display surface, and the cathodes of the light emitting diodes of each set are commonly connected and connected to a light emitting diode drive circuit, and the first light emitting color of each set is All the anodes of the light emitting diodes of each set are connected in common and connected to a power supply via the first switching circuit, and all the anodes of the light emitting diodes of the second light emitting color of each set are connected in common to form a second switching circuit. and controlling the first switching circuit and the second switching circuit so that only one of them is in a conductive state by the output of a level detection circuit that detects the level of the signal to be displayed; A level display device characterized in that the gain of the light emitting diode drive circuit is switched.