JPS61114433A - Overcurrent protection element operation display circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an overcurrent protection element operation display circuit, and is particularly applicable to wiring short-circuits in large equipment such as automatic analyzers with a large number of wirings, winding short-circuits of components, etc. This invention relates to an overcurrent protection element operation display circuit suitable for those who require protection against local overcurrent.

[Background of the invention]

In promoting the miniaturization and high-density packaging of printed circuit boards, ensuring circuit reliability and maintainability is one of the design conditions. Furthermore, protection against excessive current that flows when some kind of abnormality occurs in mounted components is also an important item in protecting circuits. In this case, the fuse is generally mounted on a printed circuit board in a removable manner as a combination of a cylindrical fuse and a socket, but this poses the problem of increasing the area of the printed circuit board. Furthermore, if there are multiple fuses, it is not easy to determine which fuse has worked. For these reasons, there has been a decline in practicality, especially in terms of maintainability.

[Purpose of the invention]

The present invention has been made in view of the above, and its purpose is to protect against overcurrent! It is an object of the present invention to provide an overcurrent protection element operation display circuit capable of displaying the operating state of a g-element by emitting light and outputting an operation signal to an external circuit.

[Summary of the invention]

The first feature of the present invention is that the present invention has a structure different from that of a visually visible display element means connected in parallel with an overcurrent protection element of a power supply voltage supply circuit, and a current limiting means for limiting the current flowing through the display element means. That's the point.

A second feature is that an output means for outputting an operation signal synchronized with the operation of the overcurrent protection element, which is electrically insulated from the overcurrent protection element, is connected in parallel to the circuit of the display element means. be.

[Embodiments of the invention]

The present invention will be explained in detail below using the embodiments shown in FIGS. 1 to 3.

FIG. 1 is a basic circuit configuration diagram showing an embodiment of the overcurrent protection element operation display circuit of the present invention. In FIG. 1, reference numeral 1 denotes an overcurrent protection element, which is composed of a fuse or an element having a function equivalent to a fuse. 2 is a display element such as an LED, and 3 is a current limiting means for limiting the current flowing through the display element 2 to within the rated current of the display element 2 when the fuse blows out, and usually uses a resistor.

In the configuration shown in FIG. 1, when the fuse operates and blows, the power supply voltage (direct current) of the circuit is applied to both ends of the fuse, and current flows through the display element 2, lighting it up and indicating that the fuse has blown.

Some of the recent overcurrent protection devices 1, such as ROHM's IC protector ICP series, are built into a plastic package, and when they are not in operation, the function cannot be checked from the outside without a measuring device such as a tester. There are some elements for which it is impossible to determine whether or not the display element 2 is the same, but if a large number of them are used, maintenance will be complicated and practical use will be difficult unless the display element 2 according to the present invention is used together.C - As shown in FIG. The configuration is usually mounted on a set of circuit boards and used as a circuit function module having two lead frames.

Furthermore, when mounting each individual component on a printed circuit board, it is also possible to use a cylindrical general-purpose fuse with a socket, and to mount the display element 2 and resistor 3 on the printed circuit board as desired. be.

The most efficient mounting method on a printed circuit board is to integrally form these circuits on a ceramic substrate. In this way, when the fuse is activated, it is determined that the circuit has failed, the complete module is cut out, the cause of the failure is eliminated, and a replacement is re-soldered to allow the module to be put to new use.

According to the embodiments of the present invention described above, (1) The operation result of the overcurrent protection element 1 such as a fuse can be visually observed even without a measuring means.

(2) By integrating the overcurrent protection element 1, display element 2, and resistor 3 into a mechanical module and cutting off the functional module terminals, the operating parts can be easily replaced.

There are effects such as

FIG. 2 is a circuit configuration diagram showing another embodiment of the present invention.
Components that are the same as those in the figures are designated by the same reference numerals, and their explanation will be omitted here. Figure 2 shows a circuit that can be used for multiple direct and dual voltage circuits, and is equipped with a voltage selection resistor 4 and a voltage selection terminal ■, so that it can also be used for the lowest voltage, e.g., 5V circuit. This is so that it can be done. Terminal ■ is
The value of the resistor 4 is selected so that it can be used at an intermediate value between t-12 and 24Vt+Ill, and is provided so that it can be used at a voltage between these values.This arrangement is effective when used with a plurality of DC voltages. For example, resistor 4 is 150Ω for a 5■ circuit.
Then, a current of about 20 mA is caused to flow through the display element 2,
When using a 5V circuit, short-circuit terminals ■ and ■ with an external circuit. When used in a 12V or 24V circuit, select the value of resistor 3 to be an intermediate value between the two. That is, resistor 3t
If 1KΩ is selected, when 12V is applied to terminal ■, display element 2 will receive approximately 10mA, and when 24V is applied, approximately 20mA will be applied to display element 2.
A current of mA can flow, and the same terminal can be used for the voltage between them. In other words, in a module with a 3-terminal configuration, 5,
Can be used in common with various voltage circuits such as 12, 15.24V.

FIG. 3 is a circuit diagram showing still another embodiment of the present invention, in which the same parts as in FIG. 2 are designated by the same reference numerals. FIG. 3 shows the circuit of FIG. 2 with a fuse operation signal output element added. That is, a general-purpose photocoupler 5 is used as the operation signal output element. Since the photocoupler 5 has almost the same rating as the display element 2, it is connected in parallel with the display element 20 circuit as shown in the figure, the operating current is limited by the resistor 6, and the operating signal is sent to the terminals ■ and ■. Since the 4 operation signals taken out from between are taken out through optical means, they are electrically insulated from the overcurrent protection element (fuse) 1, and are connected to the load side circuit with good electrical connection. It can be used not only as a simple alarm but also as a remote control or remote display signal.

According to FIG. 3, the operation result of the overcurrent image Wjt element 1 can be visually observed, and an operation signal synchronized with the operation can be output to an external circuit.

〔Effect of the invention〕

As described above, according to the present invention, the operating state of the overcurrent protection element can be displayed by light emission, and an operating signal can be output to an external circuit.

[Brief explanation of drawings]

FIG. 1 is a basic circuit configuration diagram showing one embodiment of the overcurrent protection element operation display circuit of the present invention, FIG. 2 is a circuit configuration diagram showing another embodiment of the present invention, and FIG. FIG. 7 is a circuit configuration diagram showing still another embodiment. 1... Overcurrent protection element, 2... Display element, 3...
Current limiting resistor, 4... Voltage selection resistor, 5...
Photocoupler, 6...Resistor.

Claims (1)

[Scope of Claims] 1. The display device is characterized by comprising: a visually visible display element means connected in parallel with an overcurrent protection element of a power supply voltage supply circuit; and a current limiting means for limiting the current flowing through the display element means. Overcurrent protection element operation display circuit. 2. The overcurrent protection element operation display circuit according to claim 1, wherein a plurality of said current limiting means are provided so that they can be used for various types of power supplies. 3. Visually visible display element means connected in parallel with the overcurrent protection element of the power supply voltage supply circuit, current limiting means for limiting the current flowing through the display element means, and connected in parallel with the circuit of the display element means. An overcurrent protection element operation display circuit comprising an output means for outputting an operation signal synchronized with the operation of the overcurrent protection element electrically insulated from the overcurrent protection element.