JPS62239298A - Trouble display circuit of electronic equipment for vehicle - 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] [Industrial application field] The present invention relates to a failure indicating circuit for vehicular electronic equipment.

[Prior art]

2. Description of the Related Art Conventionally, a circuit having a configuration as shown in FIG. 3 has been proposed as a failure indicating circuit for a vehicle electronic device. Third
In the figure, reference numeral 1 denotes a fail lamp that lights up when a failure occurs in a vehicle electronic device to display and warn of the occurrence of the failure. One terminal of this fail lamp l is connected to a battery 4 via a fuse 2 and an ignition switch 3.
connected to the positive terminal of the 5 is a normally closed relay including a fixed contact 5a, a movable contact 5b, a coil 5c, and a protective diode 5d, and the other terminal of the fail lamp l is grounded via the contact of this relay 5 (i.e., connected to the battery (connected to the negative terminal of 4). Also, Q
For example, l is an NPN type transistor whose emitter is grounded, and the collector of this transistor Q1 is connected to the relay 5.
It is connected to the positive terminal of the battery 4 via the coil 5c, the fuse 2, and the ignition switch 3. In this case, the transistor Q is conductive (on) under normal conditions, that is, when there is no failure in the vehicle electronic equipment.
When a failure occurs, it is configured to be turned off based on a failure signal. 7 is an alternator terminal, and this L terminal 7 is connected via a diode 6 to the terminal of the fail lamp l on the side connected to the relay 5.

In such a conventional circuit configuration, when the ignition switch 3 is turned on, as mentioned above, since the transistor Q is normally on, current from the battery 4 flows to the coil 5c of the relay 5, thereby causing Movable contact 5
b is separated from the fixed contact 5a, the fail lamp 1
is in an off state. In such a state, if a failure occurs in the vehicle electronic equipment, a failure signal is applied to the base of the transistor Q1 as described above, which turns off the transistor Q1 and therefore de-energizes the coil 5C of the relay 5. Since the process is canceled, the contact of the relay 5 is closed, the fail lamp 1 is lit, and a display warning that a failure has occurred is displayed.

However, in the case of a vehicle such as a car, it may be subject to quite severe vibrations and shocks while driving, so if relay 5 breaks down due to this, the fail lamp l will not work even if an electronic device breaks down. There was a problem in that the light was not lit and no warning was given that a failure had occurred.

[Purpose of the invention]

The present invention has been made in view of the problems of the prior art described above, and provides a failure display circuit for vehicle electronic equipment that is capable of reliably displaying and warning when a failure occurs in the vehicle electronic equipment. The purpose is to provide

[Structure of the invention]

In the failure display circuit for a vehicle electronic device according to the present invention, two systems of switch means that are turned on in response to a failure signal when a failure occurs are provided in parallel with each other and connected to a fail lamp.

〔Effect of the invention〕

As described above, in the present invention, two systems of switch means are provided in parallel to each other to turn on the fail lamp in response to a failure in the vehicle electronic equipment, so that even if one system is Even if the electronic device fails due to the action of the other system, the fail lamp can be reliably turned on, thereby effectively solving the problems of the prior art described above. be able to.

〔Example〕

An embodiment of the fault display circuit for a vehicle electronic device according to the present invention shown in FIG. 1 will be described below. Parts in FIG. 1 that correspond to those in FIG. Make it. In Figure 1, 8 is an electronic control circuit (
ECU), and the electronic control circuit 8 includes, in addition to the transistor Q1 described above with reference to FIG. 3, another NPN transistor Q whose emitter is similarly grounded.
2 is provided. The collector of the transistor Q2 is connected to the terminal of the fail lamp 1 on the side connected to the relay 5, and, contrary to the transistor QI, the transistor Q2 has its collector connected to the terminal of the fail lamp 1 on the side connected to the relay 5. It is configured to be in a non-conducting (off) state when no fault occurs, and to be turned on based on a fault signal when a fault occurs. Furthermore, the collector of the transistor Q is connected to a central processing circuit (CPU) (not shown) via a resistor R1 whose one end is grounded and a resistor R2 whose other end is connected to the resistor R1. +B
is the power supply terminal of the electronic control circuit 8, which is connected to the positive terminal of the battery 4 via another fuse 2' and the ignition switch 3.

Next, the operation of the circuit according to the invention shown in FIG. 1 will be explained with reference to FIG. In the state shown in FIG. 1, the ignition switch 3 is in the OFF state, that is, in the OFF position in FIG. 2(A). In the same figure, ACC is the accessory position, ON is the ignition-on position, and ST is the starter-on position.The engine starts at time T1, a while after the starter is turned on, but the ignition switch 3 is in the ON position. At the point in time, transistor Q1 conducts (turns on) as shown by ON in FIG. 2(E), and at the same time,
As shown in FIG. 2(B), a voltage appears at the alternator terminal 7, but if the terminal voltage of the battery 4 is, for example, 12 to 16 V, this voltage is, for example, about 2 V. , the fail lamp 1 lights up. However, when the engine starting point T is reached, the voltage at the alternator's negative terminal becomes approximately equal to the battery's terminal voltage, so the fail lamp l goes out, and in that case, the transistor Q1 is turned on as described above. The coil 5C of the relay 5 is energized from the batch U4 and the movable contact 5b is separated from the fixed contact 5a, so that the contact is in the OFF state. Note that the other transistor Q2 is turned off as described above.

In such a state, if a failure occurs in the vehicle electronic equipment and is detected at time T2 shown in FIG.
At that point, a fail signal, indicated as ON in FIG.
1 and Qt, thereby turning off one transistor Q1 and turning on the other transistor Q2, as shown in FIGS. 2(E) and (F). When the transistor Q1 is turned off in this way, the energization to the coil 5C of the relay 5 is interrupted, so the movable contact 5b of the normally closed relay 5 is engaged with the fixed contact 5a to close the contact, and as a result, fail. The lamp L is lit to warn you that a failure has occurred in the vehicle electronic equipment, but in this case, the transistor Q and the switch system driven by the coil 5C of the relay 5 are Since the switch system using the provided transistor Q2 is also turned on, even if, for example, relay 5 were to fail for some reason and its contacts would no longer close, the switch system using the transistor Q2 would remain on regardless. Therefore, the fail lamp 1 is reliably lit, and the initial failure display warning function can be ensured.

Furthermore, in the embodiment described above, the collector of the transistor Q8 is connected to the CPU via the resistors R, R2, so if the fail lamp 1 is disconnected, the collector voltage of the transistor Q2 is It can be detected based on the

Furthermore, in the embodiment described above, by applying a check pulse signal to the base of the transistor Q1 or Q2, the transistor Q1 fail lamp l,
It is possible to check whether there is a failure in the fuse 2, the transistor Qz, the fail lamp 1, or the fuse 2. In this case, the pulse signal may be applied to either one of the transistors Q1 and Q2, or to both.

In the above-described embodiment, the present invention is applied to a failure display circuit related to an alternator, but the present invention is not limited thereto, and can be applied to, for example, an anti-skid system or any other desired vehicle electronic equipment. It will be appreciated that this also applies to fault indicating circuits.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a failure display circuit of a vehicle electronic device according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of a tenth circuit, and FIG. 3 is a circuit diagram of a conventional vehicle electronic device. FIG. 2 is a circuit diagram showing a failure indicating circuit of the device. In the drawing, 1 is a fail lamp, 4 is a battery, and 5 is a fail lamp.
represents a relay, and Q, ,Q represent a transistor, respectively.

Claims (1)

[Claims] 1. a fail lamp having one terminal connectable to one electrode of a battery; a first switch means connected between the other terminal of the fail lamp and the other electrode of the battery; Failure of a vehicle electronic device comprising a drive means configured to normally hold the first switch means in an open state and close the first switch means in response to a failure signal when a failure occurs. In the display circuit, it is normally held in an open state, and when a failure occurs, it is composed of a movable contact 5b, and the driving means is a transistor Q.
_1 and the coil 5c of the relay 5, and the second switch means is composed of a transistor Q_2.