JP2021157929A - Abnormality detection device - Google Patents

Abstract

To provide an abnormality detection device capable of highly accurately detecting an abnormality of a lighting device.SOLUTION: An abnormality detection device comprises a first diode, a second diode, and a detection part. The first diode is configured such that an anode is connected to a first terminal which is connected to a power source, and a cathode is connected to a second terminal which is connected to the power source via the lighting device. The second diode is configured such that an anode is connected between the second terminal and the first diode. If the variation in voltage value based on a current flowing through the cathode of the second diode is equal to or higher than a predetermined threshold value, then the detection part detects an abnormality of the lighting device.SELECTED DRAWING: Figure 1

Description

The present invention relates to an abnormality detection device.

Conventionally, for example, there is a lighting device that indicates the operating status of an alternator of a vehicle. Further, in the lighting device, there is a technique for detecting an abnormality such as a disconnection (ball breakage) of the lighting device (see, for example, Patent Document 1).

Jitsuzensho 62-106846

However, in the conventional technique, there is room for further improvement in that an abnormality in the lighting device is detected with high accuracy.

The present invention has been made in view of the above, and an object of the present invention is to provide an abnormality detecting device capable of detecting an abnormality of a lighting device with high accuracy.

In order to solve the above-mentioned problems and achieve the object, the abnormality detection device according to the present invention includes a first diode, a second diode, and a detection unit. The anode of the first diode is connected to the first terminal connected to the power supply, and the cathode is connected to the second terminal connected to the power supply via the lighting device. In the second diode, an anode is connected between the second terminal and the first diode. The detection unit detects an abnormality in the lighting device when the fluctuation of the voltage value based on the current flowing through the cathode of the second diode is equal to or more than a predetermined threshold value.

According to the present invention, it is possible to detect an abnormality of the lighting device with high accuracy.

FIG. 1 is a diagram showing a circuit configuration of an abnormality detection device according to an embodiment. FIG. 2 is a diagram showing a circuit configuration of the abnormality detection device according to the embodiment. FIG. 3 is a diagram showing a circuit configuration of an abnormality detection device according to a modified example. FIG. 4 is a diagram showing a circuit configuration of an abnormality detection device according to a modified example. FIG. 5 is a diagram showing a circuit configuration of an abnormality detection device according to a modified example.

Hereinafter, embodiments of the abnormality detection device disclosed in the present application will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments shown below.

In the following, a case of detecting an abnormality (out of ball) of a lighting device (hereinafter, charge lamp) indicating the operating status of the alternator of the vehicle will be described as an example.

1 and 2 are diagrams showing a circuit configuration of the abnormality detection device 1 according to the embodiment. As shown in FIGS. 1 and 2, the abnormality detection device 1 includes a microcomputer 2 (corresponding to a detection unit), resistors R1 to R8, capacitors C1 to C5, a Zener diode ZD1, and diodes D1 to D3. ..

Further, the abnormality detection device 1 has terminals T1 and T2, and the terminal T1 (corresponding to the first terminal) is connected to the battery 10. The terminal T2 (corresponding to the second terminal) is connected between one end of the charge lamp CR1 and one end of the switch SW1. The other end of the charge lamp CR1 is connected to the battery 10. The other end of the switch SW1 is grounded.

Further, the terminal T1 is connected to the input terminal of the microcomputer 2 via the resistors R1 and R2 connected in series. Further, the cathode of the Zener diode ZD1 is connected between the terminal T1 and the resistor R1, and the anode is grounded.

Further, the capacitor C1 and the capacitor C2 are connected in series, one end of the capacitor C1 is connected between the terminal T1 and the resistor R1, and one end of the capacitor C2 is grounded. The Zener diode ZD1 and the capacitors C1 and C2 function as a surge protection circuit that protects the microcomputer 2 from the surge voltage when a surge voltage is applied to the terminal T1.

Further, one end of the resistor R3 is connected between the resistor R1 and the resistor R2, and the other end is grounded. Further, one end of the capacitor C3 is connected between the resistor R2 and the input terminal of the microcomputer 2, and the other end is grounded.

Further, one end of the resistor R4 is connected between the resistor R1 and the terminal T1, and the other end is connected to one end of the resistor R5 and the anode of the diode D1. The other end of the resistor R5 is connected to the input terminal of the microcomputer 2.

Further, one end of the resistor R6 is connected between the resistor R5 and the input terminal of the microcomputer 2, and the other end is grounded. Further, one end of the capacitor C4 is connected between the resistor R5 and the input terminal of the microcomputer 2, and the other end is grounded.

The diode D1 and the diode D2 are connected in series, and the cathode of the diode D2 is connected to the anode of the terminal T2 and the diode D3. The cathode of the diode D3 is connected to one end of the resistor R7. The diode D1 and the diode D2 are examples of the first diode, and the diode D3 is an example of the second diode.

The other end of the resistor R7 is connected to the input terminal of the microcomputer 2. Further, one end of the resistor R8 is connected between the resistor R7 and the input terminal of the microcomputer 2, and the other end is grounded. Further, one end of the capacitor C5 is connected between the resistor R7 and the input terminal of the microcomputer 2, and the other end is grounded.

The abnormality detection device 1 according to the embodiment uses the forward voltage of the first diode (diodes D1 and D2) and the second diode (diode D3) to detect the burnout of the charge lamp CR1 during the alternator operation.

Here, the abnormality detection method of the charge lamp CR1 will be described with reference to FIGS. 1 and 2 while explaining an operation example of the abnormality detection device 1. FIG. 1 shows a case where the charge lamp CR1 is normal, and FIG. 2 shows a case where the charge lamp CR1 is abnormal (out of balls).

As shown in FIGS. 1 and 2, the switch SW1 is turned off when the alternator is in operation. Here, as shown in FIG. 1, if the charge lamp CR1 is normal, the voltage of the battery 10 is applied to the terminal T2.

Therefore, the current from the battery 10 does not flow from the terminal T2 to the diode D1 and the diode D2, but flows to the diode D3. Then, when such a current flows from the anode of the diode D3 in the forward direction of the cathode, a forward voltage is generated in the diode D3.

Therefore, at the cathode of the diode D3, the voltage of the battery 10 is added by the forward voltage. Then, the voltage at the cathode of the diode D3 is divided by the resistors R7 and R8, smoothed by the capacitor C5, and input to the microcomputer 2.

Further, as shown in FIG. 1, the current flowing from the terminal T1 through the resistor R4 does not flow to the diode D1 side but flows to the microcomputer 2 through the resistor R5.

On the other hand, as shown in FIG. 2, when the charge lamp CR1 is out of balls, the terminal T2 is in an open state (voltage is substantially zero). Therefore, the current flowing from the terminal T1 through the resistor R4 flows to the microcomputer 2 side and the diode D1 side, respectively.

Then, the current flowing through the diode D1 and the diode D2 flows through the diode D3. Therefore, the forward voltage of each of the diode D1, the diode D2, and the diode D3 is added to the voltage at the cathode of the diode D3.

Then, the voltage at the cathode of the diode D3 is divided by the resistors R7 and R8, smoothed by the capacitor C5, and input to the microcomputer 2.

That is, the voltage at the cathode of the diode D3 is the forward voltage of one diode D3 added when the charge lamp CR1 is normal, whereas the voltage at the cathode of the diode D3 is three diodes when the charge lamp CR1 is abnormal. The forward voltage of D1 to D3 is added.

Therefore, the voltage value input to the microcomputer 2 fluctuates according to the forward voltage of two diodes depending on whether the charge lamp CR1 is abnormal or normal.

Therefore, the abnormality detection device 1 according to the embodiment detects an abnormality (ball breakage) of the charge lamp CR1 when the fluctuation of the voltage value is equal to or more than a predetermined threshold value. In this way, by measuring the fluctuation of the voltage value caused by the forward voltage of the diodes D1 to D3, the abnormality of the charge lamp CR1 can be detected with high accuracy.

The threshold value of the fluctuation of the voltage value is the sum of the forward voltages (first forward voltage) by the first diode (diode D1 and diode D2) and the second diode (diode D3) and the order by the second diode (diode D3). A value is set according to the voltage difference from the voltage (second forward voltage).

That is, the microcomputer 2 sets a threshold value capable of separating the voltage value to which the first forward voltage is added and the voltage value to which the second forward voltage is added. The threshold value can be set by the standard values of the diodes D1 to D3 at the time of circuit design.

By setting the threshold values according to the first forward voltage and the second forward voltage in this way, the abnormality of the charge lamp CR1 can be detected with high accuracy.

Further, as shown in FIGS. 1 and 2, there are a plurality of first diodes, each of which is connected in series. As a result, the voltage difference between the first forward voltage and the second forward voltage can be widened, so that a highly accurate threshold value can be set.

Further, as shown in FIGS. 1 and 2, the microcomputer 2 detects the battery voltage (an example of the power supply voltage) which is the voltage of the battery 10 via the terminal T1. Specifically, the battery voltage applied to the terminal T1 is divided by the resistor R1 and the resistor R3, smoothed by the resistor R2 and the capacitor C3, and input to the microcomputer 2.

Then, the microcomputer 2 detects the fluctuation of the battery voltage, and corrects the threshold value for detecting the abnormality of the charge lamp CR1 according to the fluctuation. Specifically, when the battery voltage fluctuates high with respect to the reference voltage, the threshold value is corrected high, and when the battery voltage fluctuates low with respect to the reference voltage, the threshold value is corrected low.

As a result, even when the voltage fluctuation is relatively large as in a vehicle-mounted battery, the voltage is changed when the voltage of the battery 10 fluctuates and the voltage value for detecting an abnormality of the charge lamp CR1 fluctuates. By correcting the threshold value according to the fluctuation, stable abnormality detection can be performed.

Next, FIG. 3 is a diagram showing a circuit configuration of the abnormality detection device 1 according to the modified example. Compared with the circuit configuration of the abnormality detection device 1 shown in FIG. 1 or 2, the circuit configuration of the abnormality detection device 1 shown in FIG. 3 has only the diode D1 and no diode D2, that is, the first diode is one. It differs in some respects.

As a result, the number of circuit parts can be reduced, which can contribute to the reduction of parts cost and the reduction of installation man-hours.

Next, FIG. 4 is a diagram showing a circuit configuration of the abnormality detection device 1 according to the modified example. The circuit configuration of the abnormality detection device 1 shown in FIG. 4 differs from the circuit configuration of the abnormality detection device 1 shown in FIG. 1 or 2 in that it further includes a Zener diode ZD2 and capacitors C6 and C7.

The cathode of the Zener diode ZD2 is connected between the terminal T2 and the diode D2, and the anode is grounded.

Further, the capacitor C6 and the capacitor C7 are connected in series, one end of the capacitor C6 is connected between the terminal T2 and the diode D2, and one end of the capacitor C7 is grounded. The Zener diode ZD2 and the capacitors C6 and C7 function as a surge protection circuit that protects the microcomputer 2 from the surge voltage when a surge voltage is applied to the terminal T2.

That is, the abnormality detection device 1 shown in FIG. 4 is provided with a surge protection circuit at each of the terminals T1 and T2.

Further, FIG. 5 is a diagram showing a circuit configuration of the abnormality detection device 1 according to the modified example. As shown in FIG. 5, a surge protection circuit may not be provided at each of the terminals T1 and T2. Alternatively, although not shown, a surge protection circuit may be provided only at the terminal T2 of the terminals T1 and T2.

That is, in the abnormality detection device 1, a surge protection circuit is connected to at least one of the terminal T1 and the terminal T2. As a result, each element and the microcomputer 2 can be protected from the surge voltage of the battery 10.

As described above, the abnormality detection device 1 according to the embodiment includes a first diode (diode D1 and diode D2), a second diode (diode D3), and a detection unit (microcomputer 2). The anode of the first diode is connected to the first terminal T1 connected to the power supply (battery 10), and the cathode is connected to the second terminal T2 connected to the power supply via the lighting device (charge lamp CR1). In the second diode, the anode is connected between the second terminal T2 and the first diode. The detection unit detects an abnormality in the lighting device when the fluctuation of the voltage value based on the current flowing through the cathode of the second diode is equal to or more than a predetermined threshold value. As a result, it is possible to detect an abnormality in the lighting device with high accuracy.

Further effects and variations can be easily derived by those skilled in the art. For this reason, the broader aspects of the invention are not limited to the particular details and representative embodiments expressed and described above. Therefore, various modifications can be made without departing from the spirit or scope of the general concept of the invention as defined by the appended claims and their equivalents.

1 Anomaly detection device 2 Microcomputer 10 Battery

Claims (5)

A first diode in which the anode is connected to the first terminal connected to the power supply and the cathode is connected to the second terminal connected to the power supply via the lighting device.
A second diode with an anode connected between the second terminal and the first diode,
An abnormality detection device including a detection unit that detects an abnormality in the lighting device when the fluctuation of the voltage value based on the current flowing through the cathode of the second diode is equal to or greater than a predetermined threshold value. The predetermined threshold is
The abnormality detection device according to claim 1, wherein the value corresponds to a voltage difference between the first forward voltage of the first diode and the second diode and the second forward voltage of the second diode. The first diode is
The abnormality detection device according to claim 1 or 2, wherein there are a plurality of anomaly detection devices, each of which is connected in series. The detection unit
The abnormality detection device according to any one of claims 1 to 3, further detecting a power supply voltage indicating the voltage of the power supply and correcting the threshold value according to fluctuations in the power supply voltage. The invention according to any one of claims 1 to 4, further comprising a protection circuit connected to at least one of the first terminal and the second terminal and protecting a surge voltage input from the power supply. Anomaly detector.

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