JPS60107572A - Direct current level display circuit - Google Patents

Abstract

PURPOSE:To display easily a proper reference position and the direction of variation by providing a lighting-out circuit which turn on part of a display element array only while a DC level is some specific intermediate level. CONSTITUTION:Respective voltage comparing circuits 2-5 output an on signal through lines 2A-5A when a DC control voltage inputted from a line 1A is higher than their comparative reference voltages. Lighting-out circuits 14-16, on the other hand, have the same comparative reference voltages as the comparative voltages set for the voltage comparing circuits 3-5 and input an off signal to display driving circuits 6-8 when the DC control voltage rises above their comparative voltages. Consequently, only one of display elements 10-13 is turned on by the corresponding display driving circuit among circuits 6-9.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a display circuit for blood flow control voltage of a device that performs DC control.

Conventional Structures and Their Problems In recent years, direct current control of devices has become widespread, and the level display has come to be performed not by mechanical positions but by display elements.

Hereinafter, an example of a conventional DC level display circuit will be described with reference to the drawings.

FIG. 1 shows a diagram of a conventional DC level display circuit. In the figure, a DC control voltage used to control the operation of the device is input to voltage comparator circuits 2 to 5 through line 1A, and the output thereof is input to line 2A.
~5A to the display drive circuits 6-9, and the output thereof is input to the display element 10 through lines 6A-9A.
~13.

The operation of the DC level display circuit configured as described above will be explained below. First, a DC control voltage is applied to voltage comparison circuits 2-6 via line 1A, and each voltage comparison circuit 2-5 is configured so that its output changes with respect to different voltages. That is, voltage comparison circuit 2
If the comparison reference voltage at is a, when the DC control voltage is at a higher level than a, an on output is output to line 2A, and when it is at a lower level than a, an off output is output to line 2A. It will be done. Furthermore, if the comparison reference voltage in voltage comparison circuit 3 is b, when the DC control voltage is at a higher level than b, an on output is output to line 3A, and when it is at a lower level than b, an OFF output is output to line 3A. Output is produced. Similarly,
Assuming that the comparison reference voltages of the voltage comparison circuit 4.5 are c and d,
By setting the levels to a (b, (c (d), an on output is output from line 2A to line 5A corresponding to the DC control voltage. Corresponding to the output, display drive circuits 6 to 9 is turned on and display elements 10 to 13 are lit.

In such a display device, when the DC control voltage is at the minimum level, all the display elements 10 to 13 are turned off, and when the DC control voltage is at the maximum level, all the display elements 10 to 13 are turned on.

However, with this configuration, audio balance control,
It is unsuitable for displaying standard positions, such as display devices for fine tuning of channel selection. In other words, the standard position is the center of the variable range of the DC control voltage, and the display needs to indicate whether the change is higher or lower from the standard position, or is it necessary to use the conventional method described above? has the problem that this point cannot be displayed.

Purpose of the Invention The present invention solves the above-mentioned conventional problems.When the DC control voltage is at the standard position, the center of the display element array lights up, and when the DC control voltage is lower than the standard position, the display element array lights up. It is an object of the present invention to provide a DC level display circuit for a DC control device that can perform control such that only one display element lights up, and when the level is high, only the other display element lights up.

Structure of the Invention The DC level display circuit of the DC control device according to the present invention has a voltage comparator circuit and a display drive circuit that have different comparison voltages with respect to the control voltage, and displays information only between some intermediate levels of the DC level. This device is equipped with a turn-off circuit to turn on a part of the element array, and even if the DC control voltage is at its maximum, all the display elements do not turn on, but only some of the display elements turn on. Description of Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows a block diagram of a DC level display circuit according to an embodiment of the present invention. In the figure, parts having the same functions as those in FIG. 1 are given the same numbers, and their explanations will be omitted.

In the figure, 14 to 16 output, via lines 14A to 16A, outputs for turning off the display drive circuits 6 to 9 in response to respective predetermined levels of the DC control voltage input via line 1A. This is a light-off circuit.

The feature of this circuit is that such a light-off circuit is provided.

The operation of the DC level display device of the DC control device configured as described above will be described below. First, the first
By making the comparison reference voltage of the light-off output of the light-off circuit 14 the same as the comparison voltage of the first voltage comparison circuit 3,
The display drive circuit 6 turns on only when the DC control voltage is above level a and below level b, and the display drive circuit 6 turns on only when the DC control voltage is above level a and below level b.
0 lights up. Similarly, if the comparison reference voltage of the second light-off circuit 15 is 01, and the comparison reference voltage of the third light-off circuit 16 is d, then when the DC control voltage is a - b...the display element 10 is Lit b -
When c...When the display element 11 is lit c-d...When the display element 12 is lit 6 or more...
- The display element 13 is turned on, and only one of the display elements can be turned on.

A specific example of this is shown in FIG. 17-1 in the diagram
Reference numeral 9 constitutes the voltage comparison circuits 2 to 5 shown in FIG. 2, resistors 17 and 18 are used for setting comparison voltages, and 19 is a comparator. 20 to 23 are light extinguishing circuits 14 to 16 in Fig. 2.
The resistors 20 and 21 are used to set the extinguishing voltage, and 22 is a comparator. 23 is a transistor for turning off the light. Further, 24 is a transistor constituting a display drive circuit, and 25 is a light emitting diode used as a display element.

According to this embodiment, by appropriately setting the extinguishing voltage using the resistors 20 and 21, it is possible to turn on only a specific display element between some levels of the DC control voltage.

In addition, in the above explanation, voltage comparison circuits 2 to 6 and light extinguishing circuit 1 are
4 to 16 are configured using comparators, but as shown in FIG. 4, the voltage comparison circuit 2 in FIG.
．． 31 and 31 respectively, and by using the base bias voltage (1 diode with respect to ground) when the display drive transistors 34 and 36 are turned on, the 3rd
It is possible to have the same effect as 17 to 19 in the figure.

Furthermore, the resistor 28.29 and the transistor 35 have the same effect as 20-23 in FIG. The same applies to the resistor 32 and 33 and the transistor 37.

Effects of the Invention As described above, according to the present invention, by having the light-off circuit, it is possible to turn on the display element at a fixed time between some levels of the DC control voltage, and to display the balance of the audio signal and fine signal. For displaying tuning, an excellent effect can be obtained in that an appropriate standard position and direction of change can be easily displayed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional DC level display circuit, FIG. 2 is a block diagram of a DC level display circuit according to an embodiment of the present invention, and FIG. 3 is a specific circuit diagram of the main parts of the circuit.
FIG. 4 is a circuit diagram of another example of the main part of the circuit. 1A...DC control voltage line, 2 to 5...
・Voltage comparison circuit, 6 to 9...Display drive circuit, 1
0-13... Display element, 14-16... Light-off circuit, 17°18.20, 21.26-33... Resistor,
19°22... Comparator, 23, 24.3
4-37...Transistor, 38.39...
display element. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A first voltage comparison circuit having a first comparison reference voltage, a second voltage comparison circuit having a second comparison reference voltage larger than the first comparison reference voltage, and the first voltage comparison circuit. a first display element connected to the output end of the circuit via a first drive circuit; and a second display element connected to the output end of the second voltage comparison circuit via a second drive circuit. and the above-mentioned No. 1. A comparison DC control voltage is commonly applied to the second voltage comparison circuit, and when this DC control voltage exceeds the first comparison reference voltage, the first display element is driven to turn on, and the DC control voltage is When the second comparison reference voltage is exceeded, the second display element is driven to turn on, and when the DC control voltage reaches the second comparison reference voltage, the second display element is operated and the first display element is activated. Canceling the operation of the drive circuit or the first display element, the voltage comparison circuit constitutes a drive circuit with first and second resistors that divide the DC control voltage. Amplification times (
3) The light-off circuit turns off the amplifier circuit of the drive circuit.