KR100545470B1 - Circuit for driving alarming ramp of automobile - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for diagnosing a braking device or an engine and displaying a diagnosis result as a warning light (5), wherein the ECU 1 has a predetermined period in accordance with the diagnosis result, and the first and second are synchronized with each other. Outputs a pulse, and the differential circuit differentiates the first and second pulses and applies them to the AND gate A1, and the AND gate A1 selectively drives the transistor Q2 by combining the outputs of the differential circuit, thereby warning the lamp. The drive of the warning lamp 5 by the drive circuit 20 is controlled.

Description

CIRCUIT FOR DRIVING ALARMING RAMP OF AUTOMOBILE}

The present invention relates to a warning light driving circuit for driving a warning light by diagnosing an abnormality of a braking device, an engine, or the like of a vehicle, and more particularly, to a warning light driving circuit of an automobile capable of displaying an abnormality of a control device for performing diagnosis. It is about.

With the development of automobile technology, automobiles are equipped with a warning function for self-diagnosis of abnormalities in braking devices, engines, etc. and displaying the result. This warning function is configured to display the diagnosis result to the driver by lighting a separate warning light according to the diagnosis result.

1 shows a conventional circuit for turning on a warning light using a relay.

First, since the warning light driving circuit cannot display the diagnosis result by the ECU 1 when a short circuit occurs between the ECU 1 and the warning light driving circuit, a function of driving a warning light to warn the driver is required. The circuit satisfies this requirement.

That is, when the ECU 1 and the relay switch 3 are short-circuited, the power from the ignition switch does not pass through the relay coil 3-1 of the relay switch 3, so no current flows, so the relay The switch 3 is connected to ground, so that the current from the ignition switch is provided to ground via the warning light 5 and the diode D1 so that the warning light 5 lights up. Therefore, it can be seen that the above conditions are satisfied.

On the other hand, in the above-described circuit operation, the ECU 1 should be able to selectively turn on / off the warning light 5. This process is described below.

First, when the driver provides the vehicle with power from the ignition switch with the ignition switch turned on, the ECU 1 connects the relay switch 3 with the battery by passing the power from the terminal P1 to ground. On the other hand, the power from the ignition switch is provided to the warning lamp 5 through the fuse 5-1, but the warning lamp 5 is connected in series with the diode D1, and this diode D1 and the relay switch 2 Are connected in series and the warning lamp 5 is turned off. That is, since the battery voltage is applied to the relay switch 3, the diode D1 is turned off and the warning light 5 is also turned off. However, in the circuit of FIG. 1, the terminal P2 of the ECU 1 is connected in parallel with the diode D1, and the ECU 1 is connected to the terminal (depending on whether the engine or the braking device is abnormal). Optionally connect P2) to ground. When the terminal P2 and the ground are connected in this way, the warning light 5 will be turned on because the warning light 5 is the same as the ground connected, but if the terminal P2 is not connected to the ground and remains shorted, As will be the warning light 5 will be turned off by the battery voltage.

In other words, the ECU 10 turns on the warning lamp 5 by selectively connecting the terminal P2 to ground in accordance with whether the diagnosed device is abnormal.

However, the circuit of FIG. 1 has the following problem.

First, in order to operate the warning lamp driving circuit, the ECU 1 needs two terminals P1 and P2, and there is a problem in that it is not possible to monitor whether the ECU 1 is operating normally. That is, the ECU 1 may be abnormally operated, whereby a case in which the warning lamp 5 is not operated even though the braking device or the engine lamp is in an abnormal state may occur. Such a situation may eventually cause a driver to drive in a state in which the state of the braking device or the engine cannot be accurately understood, and cause a traffic accident.

However, in the circuit of FIG. 1, as mentioned above, no method capable of displaying the abnormal state of the ECU 1 has been devised.

FIG. 2 shows a circuit that solves the problem of the circuit of FIG. 1, that is, the ECU 1 needs two terminals P1 and P2.

If the ECU 1 is ignored in the circuit shown, i.e., the ECU 1 and the warning light drive circuit are shorted together, the power from the ignition switch is charged to the capacitor C1 via the diode D2. A voltage corresponding to the charging voltage of the capacitor C2 is provided to the zener diode ZD1. Here, if it is assumed that the charging voltage of the capacitor C2 is higher than the driving voltage of the zener diode ZD1, the zener diode ZD1 is driven and thus the transistor Q1 is driven. Since the current path is formed in the warning lamp 5 as the transistor Q1 is driven, the warning lamp 5 is turned on.

That is, in the circuit of FIG. 2, the short circuit between the ECU 1 and the warning light driving circuit can be displayed by driving the warning light 5.

On the other hand, when the ECU 1 and the warning light drive circuit are connected, the ECU 1 can selectively drive the warning light 5 by selectively connecting the terminal P1 to ground. That is, even when the power is supplied from the ignition switch, when the ECU 1 connects the terminal P1 to the ground, a low level voltage is applied to the zener diode ZD1, and thus, the transistor Q1 and the warning lamp are eventually supplied. (5) is turned off. However, when the ECU 1 shorts the terminal P1, the voltage of the ignition switch is provided to the zener diode ZD1, so that the transistor Q1 and the warning lamp 6 are turned on.

That is, in the circuit of FIG. 2, the warning lamp 5 can be selectively driven by one terminal P1.

However, even in the circuit of FIG. 2, there is a problem in that the circuit of FIG. 1 cannot be monitored as to whether the ECU 1 is operating normally.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide an apparatus capable of displaying an abnormality of an ECU that controls the driving of a warning lamp driving circuit.

In order to achieve the above object, the present invention provides a charging / discharging capacitor for charging and discharging a power supply voltage from an ignition switch applied through a diode, a zener diode for driving according to the voltage of the charging / discharging capacitor, and driving according to the operation of the zener diode And a warning lamp configured between the switching first transistor and the ignition switch and the first transistor to drive in accordance with the driving of the first transistor, and self-diagnosing whether the braking device is normal and displaying the diagnosis result as the warning lamp driving. An apparatus comprising: an ECU for diagnosing a braking device and outputting first and second pulses having a predetermined period and having mutual synchronization coincident; A differential circuit for differentiating the first and second pulses of the ECU; An AND gate for combining the output of the differential circuit; And a switching second transistor connected to the capacitor and switched according to the output of the AND gate to control the potential of the capacitor.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic block diagram of a device according to the invention, with the warning light drive circuit 10 of FIG. 2 as shown.

The ECU 1 is for selectively driving a warning light as described later. When the warning light is to be driven, the ECU 1 outputs square wave pulses P11 and P12 as shown in FIG. 4 through the terminals P1 and P2, respectively. It is configured to. Here, the pulses P11 and P12 must be synchronized with each other.

Pulses P11 and P12 from the ECU 1 are provided to the ECU monitoring circuit 20, which is composed of resistors R4 and R5 and capacitors C2 and C3 as shown. It is composed of a differential circuit and configured to provide the AND gate A1 after differentiating the pulses P11 and P12. Here, reference numeral (R6-R9) is a bias resistor.

The combined signal at the AND gate 1 is provided to the switching transistor Q2, and the switching transistor Q2 controls the potential of the capacitor C1 of the warning lamp driving circuit 10.

The warning light driving circuit 10 includes a reverse current prevention diode D2, and a capacitor C1 for charge and discharge is connected in series with the diode D2, and a zener diode ZD1 is connected in parallel with the capacitor C1. It is.

Zener diode ZD1 is selectively turned on / off according to the output voltage of capacitor C1. The switching transistor Q1 is connected to the zener diode ZD1, and the warning light 5, the fuse 5-1 and the ignition switch are connected in series to the collector of the transistor Q1. The warning lamp 5 is configured to drive in accordance with the driving.

In this configuration, the warning light driving circuit 10 for driving the warning light 5 is the same as the circuit shown in FIG. 2, but the ECU detecting circuit 20 is further configured between the warning light driving circuit 10 and the ECU 1. It can be seen that the ECU 1 differs from the circuit of FIG. 2 having two terminals P1 and P2.

In this configuration, when the ECU 1 and the ECU monitoring circuit 20 are shorted, the AND gate A1 is provided with a low level logic, so the AND gate A1 outputs a low level, and accordingly, the transistor Q2 Will be off. Therefore, the power supply voltage from the ignition switch turns on the zener diode ZD1, and the transistor Q1 is turned on by the turn-on of the zener diode ZD1 to drive the warning lamp 5.

On the other hand, when the ECU 1 and the ECU monitoring circuit 20 are connected, the ECU 1 should detect the abnormal state of the braking device or the engine lamp and selectively turn on / off the warning lamp 5. In this case, when the warning lamp 5 is to be turned off, the potential of the terminals P1 and P2 is assumed to be at a low level, and the AND gate A1 is the same as when the ECU 1 and the ECU monitoring circuit 20 are short-circuited. ) Outputs a low, so the warning lamp 5 lights up.

However, when the warning lamp 5 is to be turned off, the ECU 1 outputs pulses P11 and P12 via the terminals P1 and P2 as described above. Here, the pulses P11 and P12 must coincide with each other. That is, the pulses P11 and P12 are differentiated through the differential circuits of the resistors R4 and R5 and the capacitors C2 and C3 in the ECU monitoring circuit 20, and the pulses P11 and P12 are brought into the state of the pulses P13 and P14 as shown in FIG. Since the gate A1 is provided, the AND gate A1 temporarily outputs a high level pulse P15 when the synchronization of the pulses P11 and P12 coincides, but the pulses P11 and P12 as shown in FIG. If the synchronization of the?) Does not match, the AND gate A1 outputs a low-level pulse P16.

The transistor Q2 is turned on and off by the pulse P15 of the AND gate A1, and thus the potential of the capacitor C1 is lowered. Therefore, if the capacitance of the capacitor C1 is set so that the potential of the capacitor C1 becomes equal to or less than a predetermined level (a voltage capable of turning off the zener diode ZD1) according to the on / off time of the transistor Q2. Zener diode ZD1 is turned off by pulse P15 of gate A1. When the Zener diode ZD1 is turned off, the transistor Q1 is turned off accordingly, and the warning lamp 5 is turned off because the current path from the ignition switch is blocked in the warning lamp 5 by the off state of the transistor Q1.

In other words, when the ECU 1 operates normally and the pulses P11 and P12 having the same synchronization are applied to the terminals P1 and P2, the warning lamp 5 is turned off.

On the other hand, when the ECU 1 operates abnormally, the synchronization does not coincide between the pulses P11 and P12 as described above. In this case, as shown in FIG. 5, the AND gate A1 continuously outputs low-level logic, so that the warning lamp 5 is turned on. That is, the user can know that the state of one of the abnormalities of the braking device (or the engine lamp) or the abnormality of the ECU 1 or the short circuit with the ECU 1 is caused by the lighting of the warning light 5.

As described above, the present invention has an effect that it is possible to display the abnormality of the ECU, the short circuit of the ECU, and whether the ECU operates normally by using the warning lamp.

1 is a warning light driving circuit diagram of a conventional vehicle,

2 is another warning driving circuit diagram of a conventional vehicle;

3 is a warning light driving circuit diagram of a vehicle according to the present invention;

4 and 5 are main part waveform diagrams of a warning light driving circuit of a motor vehicle according to the present invention;

<Description of the symbols for the main parts of the drawings>

1: ECU 10: warning light drive circuit

20: ECU monitoring circuit

Claims (1)

Charge and discharge capacitors for charging a power supply voltage from an ignition switch applied through a diode, a zener diode driven according to the voltage of the charge and discharge capacitor, a switching first transistor driven in accordance with the drive of the zener diode, and the ignition A warning light is provided between the switch and the first transistor to drive in accordance with the driving of the first transistor, and self-diagnoses whether a predetermined device is normal, and displays the diagnosis result as whether the warning light is driven. Diagnosing the predetermined device and outputting first and second pulses having a predetermined period, but outputting first and second pulses having mutual synchronization coinciding only in a normal operating state, and mutual synchronization not coinciding in an abnormal operating state. An ECU for outputting a second pulse; A differential circuit for differentiating the first and second pulses of the ECU; An AND gate which combines the outputs of the differential circuits and outputs pulses having different levels depending on whether the first and second pulses are synchronized with each other; And a switching second transistor connected to the AND gate and the capacitor to be controlled according to the output of the AND gate to selectively turn on the warning lamp through the potential control of the capacitor. Warning light drive circuit of car.