JPS63131585A - Drive circuit for light-emitting diode - Google Patents

Abstract

PURPOSE:To display the change of the state in both directions in a drive circuit by connecting one anode and cathode and the other cathode and anode to light- emitting diodes for two elements and connecting a capacitance element in series with a closed circuit consisting of two elements and a current source circuit for drive. CONSTITUTION:The polarity of a current source 4 is shown in the figure, and a second light-emitting diode 2 is lit during a time when charging currents flow through a capacitance element 3 when the current source 4 alters to the state of ON from the state of OFF. When the current source 4 is varied to the state of OFF from the state of ON, a first light-emitting diode 1 is lit during a time when discharge currents from the capacitance element 3 flow. These first and second light-emitting diodes 1, 2 may be discriminated respectively for lighting or putting-out visually, both diodes can also be disposed where separate spatially at a certain distance, and lighting colors such as red, green, yellow, etc. can also be made to differ when the diodes are arranged into the same package. Accordingly, the change of the state in both directions in a circuit can be displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a driving circuit for a light emitting diode.

[Conventional technology]

2. Description of the Related Art Conventionally, light emitting diodes (LEDs) have been used as a display means for electronic devices and the like that consume little power. Second
The figure shows an example of a conventional light emitting diode drive circuit.

Reference numeral 1 denotes a -element light emitting diode, 3 a capacitor 1 element t connected in series with the diode 1, 4 an instantaneous current source, and each element 1, 3.4 forms a closed circuit.

As is well known, the light emitting diode 1 emits light (lights up) by applying a forward current to the pn junction. You can tell by the lighting display.

(Problem to be Solved by the Invention) However, in the conventional drive circuit as described above, only one-way change in the on/off state of the drive direction can be lit/displayed, as shown in the text. However, there was a drawback in that it was not possible to know about state changes in the opposite direction.

The present invention has been made in view of the problems of the prior art described above, and aims to eliminate the above-mentioned drawbacks and to provide a drive circuit capable of displaying state changes in both directions in the drive circuit.

(Means for Solving the Problem) Therefore, in the present invention, the anode and cathode of one of the light emitting diodes of two elements and the cathode and anode of the other are respectively connected, and these two elements and a driving current source are connected to each other. This objective is achieved by configuring a capacitive element to be connected in series to a closed circuit consisting of a circuit.

[Effect]

With the above-described simple configuration, state changes in both directions in the drive circuit can be displayed by lighting the respective light emitting diodes.

〔Example〕

The present invention will be explained below based on examples.

FIG. 1 shows an embodiment of the light emitting diode drive circuit according to the present invention, which is the same as (equivalent to) the conventional example shown in FIG. 2.
Components are represented by the same symbols.

(Structure) In Fig. 1, 1.2 is each light emitting diode of two elements, and the first light emitting diode 1 is opposite to the second light emitting diode.
are connected in parallel with the light emitting diode 2, the anode and cathode of the first light emitting diode 1 being interconnected to the cathode and anode of the second light emitting diode 2, respectively. 3 is a capacitive element connected in series to a closed circuit constituted by each light emitting diode 1.2 and a drive current source 4. The current g4 is driven or cut off by turning on/off the power of the main device or by changing the state of A:3, and is visually indicated by lighting each light emitting diode. This is to learn about the changes.

(Operation) Next, let us explain the operation in the configuration shown below.
'f+. The polarity of the current source 4 is as shown in the figure.

When this current source 4 changes from an off state to an on state, the capacity r'i! , while the charging current flows through the element 3, the second light emitting diode 2 lights up.

Further, when the current source 4 changes from the on state to the off state, while the discharge current from the capacitive element 3 flows, the first
The light emitting diode 1 lights up.

These first/second light emitting diodes 1/2 may be visually distinguished as being on/off, respectively, and both can be separated from each other by distance.
It is also possible to place them in spatially separate locations, and if they are placed in the same package, they can be placed in red, green, yellow, etc.
The lighting color can also be changed.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to display state changes in both directions of a circuit with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of a light emitting diode drive circuit according to the present invention, and FIG. 2 shows an example of the conventional circuit. 1.2---Two-element light emitting diode 3---
--Capacitive element 4---Current source

Claims (1)

[Claims] The anode and cathode of one of the two elements of the light emitting diode and the cathode and anode of the other are interconnected, and a capacitive element is connected in series to a closed circuit consisting of the two elements and the two-element drive current source circuit. A light emitting diode drive circuit characterized by: