EP3264863B1 - Method for providing power to consumers - Google Patents

Description

The invention relates to a method for supplying power to at least two identical consumers, in particular LEDs or LED arrays, in vehicles with a vehicle electrical system voltage of 12, 24 or 42 volts, comprising at least one input switching element, which is supplied with a supply voltage (U0) and a Switching element controls and a circuit for carrying out the method.

Bulbs in the home or office are normally charged with 230 volts mains voltage. As far as low-voltage lamps are concerned, for example 12-volt halogen lamps, they are generally applied via a transformer with a low output voltage. LED spotlights can be connected directly to the mains voltage of 230 volts, for example via a converter.

As far as the bulbs are to be used for the vehicle sector, the vehicles usually have a vehicle electrical system voltage of 12 or 24 volts DC. In individual cases, higher vehicle voltages of up to 42 volts may be present. The vehicle area here includes power, passenger transport and water vehicles. LED's or LED array require, for example, 12 or 24 volts supply voltage. For this reason, in most cases it is necessary to use a voltage regulator to regulate the voltage down to the desired value and apply this voltage to the LED's or LED arrays. As far as the vehicles are used with different vehicle electrical system voltages, there is the need to use a voltage regulator for each individual voltage, with appropriate storage and administrative costs. In addition, losses occur in each analog circuit, which should be avoided if possible.

From the DE 10 2013 201 766 A1 Lighting device and a method for operating the lighting device is known. In order to supply the semiconductor light sources operated with the device with an electric current of sufficient current intensity, when the threshold falls below a threshold value, the illumination device assigns a first group of semiconductor light sources from a first operating state into a parallel branch of at least one second group of semiconductor light sources and upon reaching or exceeding it Threshold the first and the at least one other group of semiconductor light sources according to a second operating state are connected in series. By using a threshold value, there is a risk that a constant switching process will be triggered when the supply voltage fluctuates by the threshold value, as a result of which premature aging of the semiconductor light sources may occur.

From the DE 43 34 338 A1 is a circuit for monitoring a supply voltage known. For this purpose, a Schmitt trigger is used, but there are no switching operations for end users.

For the above reasons, the invention therefore has the object of demonstrating a method and a circuit which enables the lowest possible power losses and can be used for different voltage ranges.

According to the invention is provided for solving the problem that the input switching element in the form of a Schmitt trigger depending on the level of the input voltage (U0) controls the switching element to convert the load from a series circuit in a parallel circuit or vice versa, with a first switching point at 11 to 16 volts and a second switching point at 20 to 30 volts. Further advantageous embodiments of the method can be found in the dependent claims.

According to the invention, the method provides that a supply voltage in the nominal voltage range is made available for at least two identical consumers, for example LEDs or LED arrays, with the aid of an input switching element which is connected on the input side to the supply voltage via a voltage divider, a switching element being driven optionally controls the admission of the LED's or LED arrays with the required supply voltage. In this case, the input switching element in the form of a Schmitt trigger controls an activation or deactivation of the switching element as a function of the level of the input voltage, which in turn converts the loads from a series connection into a parallel circuit or vice versa. With this method, two identical consumers with and without current control, taking into account the applied input voltage, that is, the vehicle electrical system voltage in series or in parallel. In the case of series connection of two identical consumers is at each consumer half the vehicle electrical system voltage, for example, 12 volts at a vehicle electrical system voltage of 24 volts. As far as a vehicle electrical system voltage of only 12 volts is available, the In contrast, consumers are connected in parallel so that each consumer can be operated with the rated voltage of 12 volts. The switchover between series and parallel connection is carried out by driving the switching element, which may be constructed mechanically or electronically. In this way, the power losses of a conventional analog circuit over the entire voltage range can be significantly reduced. The preferred application of the method is seen in the vehicle sector, both in road vehicles, such as buses, trucks or the like and also in watercraft, which also have their own electrical system voltage with low voltage level. The particular advantage of the present method is that using the method electrical consumers, such as LED lights with different vehicle voltages from 12 to 42 volts can be operated, where otherwise several circuit variants for the power supply of consumers must be produced and stored. In addition, it is possible to use the method even with rectified AC voltage, for example in the low voltage range to improve the efficiency. In this case, the power loss is minimized in all applications and enables a voltage supply to the consumer over a low voltage range of 12 volts to 42 volts.

The input switching element in the form of a Schmitt trigger here serves the purpose of determining the voltage of the vehicle electrical system voltage and, depending on the vehicle electrical system voltage of 12 volts, 24 volts or optionally 42 volts to cause the closing of the switching contacts. The switching contacts themselves may consist of purely mechanical switches, or electronic switches, such as transistors, field effect transistors (MOSFETs), etc. are used. The method provides in this case that at a supply voltage of 11 to 16 volts, the switching element is driven to close the two contacts, while at a supply voltage of 20 to 30 volts, the switching element is driven to open the two contacts.

To make the switch between a series and parallel connection, the supply voltage is applied to the input switching element via a voltage divider to determine the switching point. On the output side of the input switching element is a direct or indirect control of the switching element, which performs a switch between series connection and parallel connection for the consumer.

For this purpose, a first consumer or a first group of consumers is connected to the positive pole of the supply voltage on the one hand and on the other hand via a diode to a second consumer or a second group of consumers. The second group of consumers is also connected to the negative terminal. The consumers are in this case in series, so that the current from the positive pole on the first consumer and the diode and the second consumer can flow to the negative terminal. Due to the series connection, an almost identical voltage is present at almost identical consumers at both consumers or consumer groups, so that, for example, with a supply of 24 volts, each consumer is only supplied with 12 volts. As far as a network of 42 volts is available, in this case, a supply voltage of about 21 volts would be applied to the consumers, which may be designed either for 12 volts or 24 volts. In the normal case, the voltage is thus reduced in this way to half the value in order to load consumers who are provided for a significantly lower operating voltage.

As far as a lower vehicle electrical system voltage is available, would be at a halving of this voltage, the application of the load in a series connection is not sufficient. The method therefore provides for this purpose that the switchover from a series connection to a parallel connection takes place with the aid of the switching element with at least one first and second switching contact. In this case, the consumers or Consumer groups directly to the supply voltage, for example, a vehicle electrical system voltage of 12 volts and are connected in parallel. For this purpose, a first switching contact is connected directly to the positive pole and is guided on the output side to the cathode of the diode. The second switching contact is on the one hand connected to the negative terminal and on the other hand connected to the anode of the diode, so that the current flows from the positive pole through the first consumer via the second switching contact directly to the negative terminal, while the first switching contact is connected to the positive pole and the current over this the second consumer flows to the negative pole. It is therefore a classic parallel circuit, which is thus used when the vehicle electrical system voltage is, for example, 12 volts and the loads can be applied directly to the vehicle electrical system voltage. The method provides in this case that an adaptation to the respective vehicle electrical system voltage by means of the input switching element and the driven switching element takes place in order to carry out the switching of the consumers described above.

In summary, it can thus be stated that in the series connection of two consumers or consumer groups, a twice as high a vehicle electrical system voltage as the rated voltage of the consumer may be present, while in contrast can be supplied with a low vehicle electrical system voltage of 12 volts consumers due to the parallel circuit directly to the vehicle electrical system voltage.

For applying the method, a circuit for supplying power to at least two identical consumers, in particular LED's or LED arrays, proposed in vehicles with a vehicle electrical system voltage of 12, 24 or 42 volts, wherein the circuit at least one input switching element, which is connected to a supply voltage and a switching element for controlling the consumer has. In this case, the input switching element in the form of a Schmitt trigger controls the switching element as a function of the level of the input voltage in order to supply the loads from a series connection in to transfer a parallel connection or vice versa. About the Schmitt trigger here the vehicle electrical system voltage is determined and carried out depending on the vehicle electrical system voltage of 12 volts, 24 volts or optionally 42 volts closing the switch contacts. The switching points of the Schmitt trigger are on the one hand at 11 to 16 volts, for example, to close the two contacts, while a second switching point at a supply voltage of 20 to 30 volts, for example, to open the two contacts.

For this purpose, the supply voltage is applied via a voltage divider to the input of the input switching element, which controls the downstream switching element via its output. Here, the switching point for the voltage ranges U1 or U2 and U1 plus U2 is set. For this purpose, a Schmitt trigger is used as the input switching element, which has an inverted output for the output signal. If a voltage in the input voltage range of U1 or U2 is available, the output is set to a positive logic signal "1", while at a Einigungsspannung U1 plus U2 a negative logic signal "0" is present.

As a switching element is either a mechanical two-pole switch in question or an electronic switch, which are used in both cases for switching from the series connection for parallel connection. As far as it can be mechanical switches, they can either be configured bipolar or consist of two individual simultaneously controlled switches.

To enable the switching process is provided for this purpose that the anode of the diode is connected to a first switching contact of a two-pole switching element, the first switching contact is connected on the output side to the negative terminal and the cathode of the diode with a second switching contact of a two-pole switching element is connected, wherein the second switching contact is connected on the input side to the positive pole. In this way, the operating voltage can be applied to the first and second consumers or the first and second load groups when the switch contacts are closed, so that the current of the first consumer group can flow to the negative pole via the second switch contact, while the second consumer group is connected to current via the first switch contact is supplied, which can flow from the positive terminal via the switching contact through the second consumer to the negative terminal.

Preferably, the circuit is used for lamps of vehicles, which have a vehicle electrical system voltage of 12 or 24 volts or higher.

The particular advantage of the present circuit and of the disclosed method is that a single circuit can be used to take into account a plurality of on-board voltages of vehicles that are used to load LED's or LED arrays. For this purpose, the consumers are connected directly to the plus and minus poles, if necessary, so that several consumers are connected in parallel, while at a higher vehicle electrical system voltage consumers are connected in series and thus in consequence of the voltage division at each consumer or each Consumer group only half the rated voltage is applied. By this circuit thus a costly storage is avoided and also created the possibility that when changing the vehicle electrical system voltage, the same circuit can be used. A particular advantage arises from a much lower power dissipation, as they arise, for example, in analog circuits with different vehicle electrical system voltages.

The invention will be explained again with reference to two embodiments.

Fig. 1

einen Schaltplan einer ersten Ausführungsform mit zwei mechanischen Schaltkontakten und

Fig. 2

einen Schaltplan einer zweiten Ausführungsform mit Transistoren als Schaltelemente.

It shows

Fig. 1

a circuit diagram of a first embodiment with two mechanical switching contacts and

Fig. 2

a circuit diagram of a second embodiment with transistors as switching elements.

FIG. 1 shows a first embodiment of a circuit which is equipped with conventional switch contacts. The inventive circuit comprises a Schmitt trigger 1 and a first switching contact 2 and a second switching contact 3. The Schmitt trigger 1 is acted on the input side via a voltage divider 4, 5 and is designed as an inventing Schmitt trigger 1 to the two mechanical switching contacts. 2 , 3 so that they are either open or closed. The mechanical switching contacts 2, 3 are further connected to the consumers 6, 7, and indeed the first consumer 6 is connected to a first input directly to the supply voltage U +, while the output of the consumer 6 via a diode 8 to the second consumer. 7 is connected, which in turn is connected to its second output to the supply voltage U-. The cathode of the diode 8 is connected to the output of the first switching contact 2, while the anode is connected to the second switching contact 3. The first switching contact 2 is in this case connected to U +, while the second switching contact 3 is connected to U-.

If the input voltage U ₀ does not fall below the voltage range of U1 plus U2, the switching contacts 2, 3 remain open. Thus, the two consumers 6, 7 are connected in series to the input voltage U ₀ . As far as the two Consumers 6, 7 are almost identical, is thus at each consumer 6, 7 to half of the supply voltage U1 and U2. In this case, the current flows from U + through the first load 6 via the diode 8 to the second load 7 to U-. Taking into account the rated voltage of the two consumers 6, 7 U ₀ can thus reach a value which corresponds to twice the rated voltage. As a consumer 6, 7, for example, LEDs or LED arrays are used, which are usually applied with 12 volts. Thus, at a voltage U ₀ of 24 volts halving the supply voltage through the series circuit can be reduced to the rated voltage of the load.

On the other hand, should the applied voltage U _{0 be} only about 12 volts, consequently, each consumer 6, 7 would only be charged with 6 volts when the switching contacts 2, 3 were open. In order to ensure the operation of the consumer 6, 7, in particular the intended LED's or LED arrays using the Schmitt trigger 1 falls below a preset voltage level by the voltage divider 4, 5, a closing of the switching contacts 2, 3. By closing the previously existing series connection of the two consumers 6, 7 transferred to a parallel circuit. In this case, the current flows through the second consumer 7 of U + starting via the first switching contact 2 directly to the consumer 7 and from there to U-. The current for the first consumer 6 also flows from U +, starting from the consumer 6 via the second switching contact 3 to U-. Thus, the two consumers 6, 7 are parallel, so that both are applied to the applied voltage U ₀ = 12 volts.

By switching using the Schmitt trigger 1 can thus take place depending on the applied supply voltage U ₀ with the same circuit, a loading of the two consumers 6, 7 both at 12 volts and at 24 volts. For this purpose, the output of the inverting Schmitt trigger 1 at output "1" is when the voltage is in the input voltage range of U1 and U2, respectively, and "0" if the voltage has the higher input voltage range on U1 plus U2.

A first switch point is in this case at 11 to 16 volts and a second switching point at 20 to 30 volts to make the control of the switching element of a switch from a series connection in a parallel circuit and vice versa.

FIG. 2 shows a further embodiment of a circuit, which also starts from a supply voltage U ₀ , wherein the Schmitt trigger 10 via a voltage divider 11, 12 is applied to the input side. Also in this case, it is an inverted Schmitt trigger 10, which is provided for driving three transistors 13, 14, 15. The transistors 14, 15 are used analogously to the mechanical switching contacts according to the first embodiment and in turn serve to convert the connected loads 16, 17 of a series circuit in a parallel circuit. In the exemplary embodiment shown, the loads are designed as LED arrays, with a diode 18 again being arranged between the two loads 16, 17, as in the preceding example.

In the non-conductive state of the two transistors 14, 15 is a series circuit of the two consumers 16, 17 before, so that the applied voltage U ₀ generates a current which of U + via the first consumer 16 and the diode 18 to the second consumer 17 and from this to U-flows. As far as the two transistors 14, 15 are acted upon at their base, the conductive state is reached, so that the current for the second load 17 via the first transistor 15 from U + to U-flow, while the current for the first load 16 of U + via the load and the second transistor 14 to U flows.

The two transistors 14, 15 are in this case driven once by a series resistor 19 directly from the inverting Schmitt trigger 10 and once via a series resistor 20 and a first transistor 13 and a further voltage divider 21, 22nd

The second embodiment by means of electronic switches in the form of transistors 13, 14, 15 fulfills the same purpose as the first circuit example, namely the switching of the adjacent loads 16, 17 from a series circuit to a parallel circuit, so taking into account the applied voltage at the respective consumers 16, 17 again either in the series circuit half the supply voltage U ₀ is applied or in the parallel circuit, the entire supply voltage U ₀ . As in the first embodiment, a first switching point is at 11 to 16 volts and a second switching point at 20 to 30 volts to make a switch from a series circuit to a parallel circuit and vice versa.

The particular advantage of the two embodiments is that in an existing vehicle electrical system voltage in the automotive sector on the different circumstances can be taken and switching the consumers using the Schmitt trigger, so on the one hand a series circuit and on the other hand, a parallel circuit is present, so either at lower Vehicle electrical system voltage, the supply voltage is applied directly to each consumer or at a higher supply voltage, the load can be applied in an identical design approximately half the supply voltage of the vehicle electrical system voltage. By this measure it is achieved that one and the same circuit can be used for different vehicle electrical system voltages and thus storage can be significantly reduced. In addition, the power loss compared to analog circuits is significantly reduced, because possible voltage drops over series resistors, etc. can be avoided.

LIST OF REFERENCE NUMBERS

1

Schmitt trigger

2

switching contact

3

switching contact

4

voltage divider

5

voltage divider

6

consumer

7

consumer

8th

diode

10

Schmitt trigger

11

voltage divider

12

voltage divider

13

transistor

14

transistor

15

transistor

16

consumer

17

consumer

18

diode

19

dropping resistor

20

dropping resistor

21

voltage divider

22

voltage divider

Claims (15)

1. Method for the voltage supply of at least two identical consumers (6, 7, 16, 17), in particular LEDs or LED arrays, in vehicles with an on-board supply voltage of 12, 24 or 42 Volt, comprising at least one input switching element which is provided with a supply voltage (U₀) and controls a switching element,
   characterized in that
   the input switching element in the form of a Schmitt trigger controls the switching element in response to the level of the input voltage (U₀) to transfer the consumers (6, 7, 16, 17) from a series connection to a parallel connection or vice-versa, wherein a first switch point is 11 to 16 Volt and a second switch point is 20 to 30 Volt.
2. Method according to claim 1,
   characterized in that
   the supply voltage (U₀) is applied to the input switching element via a voltage divider (4, 5, 21, 22).
3. Method according to claim 1 or 2,
   characterized in that
   a first consumer (6, 7, 16, 17) or a first group of consumers (6, 7,16, 17) is connected on the one hand to the positive pole of the supply voltage (U₀) and on the other hand via a diode (8, 18) to a second consumer (6, 7, 16, 17) or a second group of consumers (6, 7,16, 17) which is furthermore connected to the negative pole.
4. Method according to one of claims 1, 2 or 3,
   characterized in that
   a changeover from the parallel connection to the series connection and vice-versa is effected via controllable switching contacts (2, 3), in particular two switching contacts (2, 3).
5. Method according to one of claims 1 to 4,
   characterized in that
   during the closing of the first and second switching contacts (2, 3), the first and second consumers (6, 7, 16, 17) or groups of consumers (6, 7, 16, 17) are directly applied to the supply voltage (U₀) and are connected in parallel.
6. Method according to one of claims 1 to 5,
   characterized in that
   during the opening of the first and second switching contacts (2, 3), the first and second consumers (6, 7, 16, 17) or groups of consumers (6, 7, 16, 17) are connected in series.
7. Method according to one of claims 1 to 6,
   characterized in that
   the input switching element controls, at a supply voltage of 11 to 16 Volt, the switching element for closing the two switching contacts (2, 3).
8. Method according to one of claims 1 to 7,
   characterized in that
   the input switching element controls, at a supply voltage of 20 to 30 Volt, the switching element for opening the two switching contacts (2, 3).
9. Circuit for the voltage supply of at least two identical consumers (6, 7, 16, 17), in particular LEDs or LED arrays, in vehicles with an on-board supply voltage of 12, 24 or 42 Volt, comprising at least one input switching element which is provided with a supply voltage (U₀) and controls a switching element,
   characterized in that
   the input switching element in the form of a Schmitt trigger controls the switching element in response to the level of the input voltage (U₀) to transfer the consumers (6, 7, 16, 17) from a series connection to a parallel connection or vice-versa, wherein a first switch point is 11 to 16 Volt and a second switch point is 20 to 30 Volt.
10. Circuit according to claim 9,
    characterized in that
    the supply voltage (U₀) is applied to the input switching element via a voltage divider (4, 5, 21, 22).
11. Circuit according to claim 9 or 10,
    characterized in that
    the switching element has a two-pole design or consists of two individual, simultaneously controlled switching elements, in particular switching contacts (2, 3).
12. Circuit according to claim 9, 10 or 11,
    characterized in that
    the anode of the diode (8, 18) is connected to a first switching contact (2, 3) of a two-pole switching element, wherein the first switching contact (2, 3) is connected, on the output side, to the negative pole, and the cathode of the diode (8, 18) is connected to a second switching contact (2, 3) of a two-pole switching element, wherein the second switching contact (2, 3) is connected, on the input side, to the positive pole.
13. Circuit according to one of claims 9 to 12,
    characterized in that
    the diode (8, 18) is switched from the positive pole to the negative pole in the flow direction.
14. Circuit according to one of claims 9 to 13,
    characterized in that
    a first consumer (6, 7, 16, 17) or a first group of consumers (6, 7, 16, 17) is on the one hand connected to the positive pole of the supply voltage (U₀) and on the other hand via a diode (8, 18) to a second consumer (6, 7, 16, 17) or a second group of consumers (6, 7,16, 17) which is furthermore connected to the negative pole.
15. Circuit according to one of claims 9 to 14,
    characterized in that
    the input switching element comprises an inverting output for the output signal, and/or that the switching element consists of a mechanical or electronic switch.

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