DE102009031040A1 - Vehicle indicator, has switch subjecting LED to input voltage, test circuit testing function of LED, control unit controlling switch, and another switch operated by control unit during malfunction of LED - Google Patents

Abstract

The indicator (2) has an LED (13), and two inputs (E, M) for receiving an input voltage. A switch (15) subjects the LED to the input voltage. A test circuit (100) tests function of the LED. A control unit (10) controls the switch. Another switch (12) is operated by the control unit during malfunction of the LED. The test circuit is provided as a voltage measuring circuit. A power source (11) is provided between the former switch and the LED. A trigger circuit (101) is provided for recognizing a voltage change at the inputs. An independent claim is also included for a method for operating a vehicle indicator controller.

Description

The The invention relates to a vehicle turn signal, a vehicle turn signal control device and a method of operating a vehicle turn signal controller. As a turn signal in vehicles, also referred to as direction indicator be increasingly light emitting diodes are used by a control unit be controlled outside the turn signal. This vehicle turn signal control unit is then preferably for all four turn signals of the vehicle at the same time responsible.

In case of an error message of a light-emitting diode in the turn signal to inform the vehicle turn signal control unit about this error, is in the DE 198 52 351 A1 proposed to modulate the signal consumed by the turn signal pulse width modulated signal to tell the controller, which error is present.

These Device is expensive, since the encoding and decoding a Variety of circuits needed, which in turn reduces the susceptibility of the Systems increased.

It Thus, it is an object of the invention to provide a vehicle turn signal and a Vehicle turn signal control device to provide with the error in the LEDs in a less expensive way to the controller can be reported.

It It is also an object of the invention to provide a corresponding method for To provide driving a vehicle turn signal controller.

These Tasks are solved by the subject-matter of the independent claims solved. Advantageous embodiments emerge from the Objects of the subclaims.

According to the invention a vehicle turn signal with a light emitting diode and two inputs provided for receiving an input voltage. A switch is intended to supply the LED with the input voltage. A measuring circuit is used to check the function the LED. A control unit is for controlling the switch provided, wherein the control unit in case of malfunction of the LED the switch is operated so that the length of time in which the LED lights, shortened.

Of the Vehicle turn signal allows a mistake on as possible inexpensive way to the vehicle turn signal control unit can be reported. This can thus recognize that the control period is shortened for the illumination of the LED. This makes it possible, without elaborate modulation and Demodulating the signal to report the error.

Preferably is a voltage measuring circuit for measuring in the measuring circuit the voltage across the LED provided because the failure a light-emitting diode usually based on the above the light emitting diode occurring voltage is detected quickly.

Preferably is a charge storage device for storing electrical Energy provided for the control device.

In order to it is possible for the control device at least for continue to operate for a certain period of time, even if the input voltage drops to zero.

In an embodiment is between the switch and the LED provides a power source with which the LEDs can be controlled as effectively as possible. The vehicle turn signal is also suitable if several light-emitting diodes are provided in this, the LEDs can thus z. B. individually checked.

In In one embodiment, a trigger circuit is provided to detect a voltage change at the inputs. The control unit is for receiving an output signal of the trigger circuit intended. With the help of the trigger circuit, the control unit recognize when the light-emitting diode should start to shine, from it the time duration can be determined.

The The invention also relates to a vehicle turn signal control unit, a switch for applying an output terminal with has a potential. A current measuring circuit is for measuring the provided by the output terminal flowing current. A control unit is used to switch the switch and to detect an error in the event that the measured current of a predetermined Value deviates. With this vehicle turn signal control unit can be detected, whether the vehicle turn signals consumes less power as expected and conclude that the LED is defective.

Preferably the current measuring circuit contains a current mirror, with In such a case, the measured value for the current can be simple Sorted out.

In In one embodiment, the switch is a power MOSFET formed (metal oxide semiconductor field effect transistor). Such transistors are especially for high currents designed for low power dissipation.

If the control unit with a bus for communication with other control circuits Many messages can be sent to parent Controls are issued as well as commands received from them become.

The The invention also relates to an assembly of an inventive Vehicle turn signals and a vehicle turn signal control device according to the invention. In this case, an output terminal of the vehicle turn signal control unit via a line connected to one of the inputs of the vehicle turn signal. Such an assembly is particularly suitable for a device at the only two lines between the vehicle turn signals and the vehicle turn signal control unit are provided. The one is the above-mentioned line between the output terminal the vehicle turn signal controller and one of the inputs the vehicle turn signal. The other line or connection relates the ground connection, since the mass also each with inputs the two devices is connected.

The The invention also relates to a method for operating a vehicle turn signal controller, wherein a period of time for turning on the light emitting diode through the Control unit of the vehicle turn signal control unit specified becomes. The switch of the vehicle turn signal controller is turned on for a first period of time. Subsequently the current is measured through the output terminal. If the measured Current history before the expiration of the time under a predetermined Value drops, an error is displayed. Such a procedure allows a fast and less error prone Operating the controller.

Various Error types can help with different duration shortenings be reported. For example, if a first light emitting diode is defective, if the time is shortened by 10%, this is a second LED defective, the duration is shortened by 15%.

The The invention will now be described with reference to the accompanying drawings an embodiment explained. Show

1 an inventive vehicle turn signal control unit;

2 a turn signal according to the invention;

3 Signal curves of the voltages and the current through the connection terminal between the vehicle turn signals and vehicle turn signal control unit.

1 shows a vehicle turn signal control unit, which is a control unit 3 , a resistance 4 , a first current mirror transistor 5 , a second current mirror transistor 6 and a circuit breaker 7 having. The vehicle turn signal control unit 1 receives at a first input a first potential V, for example of 12 V above ground. This first potential is connected to a first terminal of the resistor 4 and to the collector of the npn transistor 6 connected. The collector and the base of the transistors 5 and 6 are connected. The collector of the first current mirror transistor 5 is with the second terminal of the resistor 4 connected. The emitters of the first current mirror transistor 5 and the second current mirror transistor 6 are connected to the source of the self-blocking p-channel MOSFET transistor circuit breaker 7 connected. The source of this transistor is connected to the first output terminal A of the vehicle turn signal controller 1 connected.

The control unit 3 receives at its inputs for their power supply the potential V and the potential of the ground 35 , It also receives from a bus 20 Control signals via which the control unit is controlled by a higher-level control unit. About the bus 20 can the control unit 3 also news, z. B. error messages, output to the parent control unit. In addition, an input of the control unit 3 with the second terminal of the resistor 4 connected and the output of the control unit 3 is connected to the gate of the transistor designed as a circuit breaker 7 connected. Gives the control unit 3 a low potential, opens the circuit breaker 7 , allowing a current from the first input of the vehicle turn signal controller 1 through the second current mirror transistor 6 as well as in parallel by the resistance 4 and the first current mirror transistor 5 to the source of the circuit breaker 7 , through the load path of the circuit breaker 7 to its drain and the output terminal A of the vehicle turn signal controller 1 flows.

The transistors 5 and 6 are dimensioned and interconnected so that they work as a current mirror, ie, the respective collector-emitter currents are proportional to each other. The largest part of the current flows through the transistor 6 , so not too many heat losses in the resistor 4 arise. The above the resistance 4 Falling voltage is a measure of the current through the transistor 5 and thus also for the current through the transistors 6 and 7 , The voltage across the resistor 4 is proportional to the current through the circuit breaker 7 , The control unit 3 is with an input to the second terminal of the resistor 4 connected. The control unit thus receives a measure of the current through the circuit breaker 7 ,

The control unit 3 controls the circuit breaker 7 as follows:
The control unit 3 receives over the bus 20 a command to periodically turn the turn signal on and off. The circuit breaker is turned on and off with a period of, for example, 600 ms. In the time in which the circuit breaker 7 is switched on, the current flow is measured periodically. If the current is above a predetermined threshold during the time in which the circuit breaker 7 is activated, the vehicle turn signal control unit goes off 1 assume that the turn signal is working without errors.

If the circuit breaker 7 is turned on and the control unit 3 detects that the current flow is not above a predetermined threshold, this control unit goes 3 assume the turn signal is not working properly due to a malfunction. Then inform the vehicle turn signal control unit 3 over the bus 20 the higher-level control unit of the vehicle via this error condition. Based on this status, the higher-level control unit carries out various measures. This may be the notification of the driver, increasing the frequency of the turn signal, saving the error type, a central error notification via a WLAN to a workshop or the like. To achieve this, a turn signal with specific features is provided.

2 shows a vehicle turn signal according to the invention 2 as mounted in the vehicle to mark a direction indicator of the vehicle.

The vehicle turn signal 2 contains a control unit 10 , a measuring circuit 100 , a trigger circuit 101 , a diode 8th , a capacitor 9 , a first power source 11 , a second power source 12 , a first light emitting diode 13 , a second LED 14 as well as a switch 15 , The vehicle turn signal 2 receives a potential at its input E. The input E is connected to the output terminal A of the vehicle turn signal controller 1 connected via a one-wire line.

The desk 15 is with its load path between the input E and each first terminals of the power source 11 and 12 connected. The second connection of the power source 11 is with the anode of the LED 13 connected, whose cathode with the mass 35 connected is. The second connection of the power source 12 is with the anode of the LED 14 connected, whose cathode with the mass 35 connected is. The control unit 10 has the supply inputs S and M and the output A. The trigger circuit 101 has an input T and the measuring circuit 100 the inputs D1 and D2 on.

The diode 8th is with its anode to the first input E and with its cathode to a first plate of the capacitor 9 connected. The second plate of the capacitor 9 is with the crowd 35 connected. The cathode of the diode 8th is in addition to the input S of the control unit 10 connected. The first input E is connected to the input T. The input D1 is connected to the anode of the LED 13 and the input D2 to the anode of the light emitting diode 14 connected.

The control unit 10 is with its output A to the switching input of the switch 15 connected. Is the switch 15 closed, set the constant current sources 11 and 12 each have a constant current available through each of the light emitting diodes 13 respectively. 14 flows. The voltage across the LEDs 13 and 14 is measured in the control circuit. The control circuit 10 is through the circuit of diode 8th and capacitor 9 provided. At the first input E, a potential of 0 V and 12 V is periodically provided. These fluctuations are caused by the smoothing circuit of diode 8th and capacitor 9 smoothed, so the control unit 10 is supplied by a substantially constant voltage SU.

The desk 15 is closed in the normal state. Thus, the voltage applied to the inputs supplies the LEDs 13 and 14 directly via the power sources 11 and 12 , The signal at the input T of the control unit 10 indicates when a potential change occurs at input E. The supply voltage for the control unit 10 can still use the control unit 10 supply when the potential at the first input E is zero.

It is understood that instead of the capacitor 9 also other energy storage devices can be provided. If the turn signal 10 is turned on, ie a high potential is provided at the input E, the control unit 10 supplied with voltage SU and the carrier signal at the input T notified via the trigger circuit 101 the control unit 10 that the light emitting diodes 13 and 14 through the vehicle turn signal control unit 1 be turned on.

Because the switch 15 is closed, a constant current flows through the LEDs 13 and 14 , causing a voltage drop across each of the light emitting diodes 13 and 14 causes. This voltage drop is from the measuring circuit 100 detected this information to the control unit 10 forwards. If the detected voltages are within predetermined limits indicative of the functioning of the LED, the LEDs remain on as long as there is a positive potential on input E.

If, on the other hand, that of the measuring circuit 100 measured voltages across the LEDs 13 and 14 outside these limits are the desk 15 is actively switched off by the control unit before the cycle is completed. In this case, the cycle is the time in which a high potential is present at the first input E. The switching frequency is normally around 1.5 Hz according to the legal requirements. For example, while the duration of an error is reduced from 333 ms to 300 ms. This shortening is not perceived by the human eye.

If the switch 15 active from the control unit 10 due to a malfunction of the LEDs has been opened, this is from the vehicle turn signal control unit 1 detected. This measures that power consumption through the circuit breaker 7 decreases. Accordingly, the control unit 3 of the vehicle turn signal controller made one of the measures described above.

3 illustrates waveforms at the entrance E of the vehicle turn signal 2 , The circuit breaker 7 of the vehicle turn signal controller 1 switches on and off periodically. Accordingly, the potential O at the input E of the vehicle turn signal 2 alternating for each 300 ms at high potential and at 0 V.

The second waveform shows the current flow through the circuit breaker 7 in the case that the light emitting diodes 13 and 14 are not broken. In this case, after increasing the potential due to the charge storage device, the power consumption first steeply increases, falls exponentially to a low level, and then decreases to 0A when the potential goes to 0V.

The third waveform shows that through the circuit breaker 7 flowing current in the event of a defect of one of the LEDs 13 or 14 , After about 100 ms, the control unit detects 10 the vehicle turn signal 2 that the voltage across the light emitting diode 14 has risen sharply. It can be concluded that the light emitting diode 14 is broken and no electricity flows through them. Accordingly, the switch opens 10 the switch 15 , so no more power in the vehicle turn signal 2 flows. Thus, no current flows through the circuit breaker 7 , what about the controller 3 is detected. The current flow through the circuit breaker thus initially increases steeply as in the second waveform, then decreases exponentially to an intermediate level and then drops to zero after only 100 ms. From the difference between the voltage pulse according to the first waveform and the current pulse according to the third waveform recognizes the control unit 3 in that there is an error and accordingly reports an error to a higher-level control unit.

The bus 20 For example, it may be a local area network (LAN) or a controller area network (CAN) bus. The vehicle turn signal control unit 1 can also be part of a higher-level vehicle control unit and then no longer needs it with a bus 20 to communicate.

LIST OF REFERENCE NUMBERS

1

Vehicle winker controller

2

Vehicle turn signals

3

control unit

4

resistance

5

transistor

6

transistor

7

breakers

8th

diode

9

capacitor

10

control unit

11

power source

12

power source

13

led

14

led

15

switch

20

bus

35

Dimensions

100

measuring circuit

101

trigger circuit

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19852351 A1 [0002]

Claims (12)

Vehicle turn signals having the following features: - a light-emitting diode ( 13 ), - two inputs (E, M) to receive an input voltage, - a switch ( 15 ) for applying the LED ( 13 ) with the input voltage, - a measuring circuit ( 100 ) for checking the function of the light-emitting diode ( 13 ), - a control unit ( 10 ) for controlling the switch ( 15 ), characterized in that the control unit ( 10 ) in case of malfunction of the LED ( 13 ) the switch ( 12 ) is actuated so that the time duration in which the light-emitting diode ( 13 ) is lit, shortened. Vehicle turn signal according to claim 1, characterized in that the measuring circuit ( 100 ) is a voltage measuring circuit. Vehicle turn signal according to one of claims 1 to 2, characterized in that a charge storage device ( 9 ) for storing electrical charge for the control unit ( 10 ) is provided. Vehicle turn signal according to one of claims 1 to 3, characterized in that between switch ( 15 ) and light emitting diode ( 13 ) a power source ( 11 ) is provided. Vehicle turn signal according to one of claims 1 to 4, characterized in that a plurality of light emitting diodes ( 13 . 14 ) are provided. Vehicle turn signal according to one of claims 1 to 5, characterized in that a trigger circuit ( 101 ) is provided for detecting a voltage change at the inputs (E, M) and that the control unit ( 10 ) is provided for receiving an output signal of the trigger circuit. Vehicle turn signal control unit, comprising: - a switch ( 7 ) for applying an output terminal (A) to a potential (V), - an ammeter ( 4 . 5 . 6 ) for measuring the current flowing through the output terminal (A) (Iout), - a control unit ( 3 . 10 ) for switching the switch ( 4 ) and for detecting an error in the event that the measured current deviates from a predetermined value. Vehicle turn signal control unit according to claim 7, characterized in that the current measuring circuit comprises a current mirror ( 5 . 6 ) contains. Vehicle turn signal control device according to one of claims 7 and 8, characterized in that the switch ( 7 ) is formed as a power MOSFET. Vehicle turn signal control device according to one of claims 7 to 9, characterized in that the control unit ( 3 ) with a bus ( 20 ) is designed for communication with another control device. An assembly of a vehicle turn signal according to one of claims 1 to 6 and a vehicle turn signal control device according to any one of claims 7 to 10, characterized in that the output terminal (A) of the vehicle turn signal control device ( 1 ) via a line with one of the inputs (E) of the vehicle turn signal ( 2 ) connected is. Method for operating a vehicle turn signal control unit ( 1 ) according to one of claims 7 to 10, comprising the following steps: - predetermining a time duration for switching on the light-emitting diode ( 13 ) by the control unit ( 3 ) of the vehicle turn signal controller ( 1 ), - switching on the switch ( 7 ) of the vehicle turn signal controller for the first period of time, - measuring the current through the output terminal (A), - if the measured current waveform falls below a predetermined value before the lapse of the first period of time, indicating an error.

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