A vehicle circuit device for supplying in-vehicle voltage to an electrical load in an overcurrent detection manner

Abstract

The invention relates to a vehicle circuit device (1) for supplying a vehicle voltage (UFB) to an electrical load (2) in an overload detection manner, wherein the electrical load (2) has a preset rated power, and the vehicle circuit device comprises: - a vehicle voltage input terminal (E1); - a control device (3) for controlling vehicle functions, wherein the control device (3) has an integrated semiconductor module (3a), such as a system basis chip (SBC), and the integrated semiconductor module has an integrated high-side switch (S1), the high-side switch being connected to the vehicle voltage input terminal (E1) to connect the vehicle voltage (UFB) applied to the vehicle voltage input terminal (E1) to the high-side switch output terminal (A1), wherein the high-side switch output terminal (A1) has a preset current-carrying capacity, and the control device (3) is configured to detect the output current (IA1) of the high-side switch output terminal (A1), and the rated current consumption of the rated load to be powered is higher than the preset current-carrying capacity of the high-side switch output terminal (A1).

Description

Field of the Invention

[0001] The invention relates to a vehicle circuit device for supplying a vehicle voltage to an electrical load in an overload detection manner, wherein the electrical load has a preset rated power, and the vehicle circuit device includes:

[0002] - a vehicle voltage input terminal,

[0003] - a control device for controlling vehicle functions, wherein the control device has an integrated semiconductor module, such as a system basis chip, and the integrated semiconductor module has an integrated high-side switch, and the integrated high-side switch is connected to the vehicle voltage input terminal to connect the vehicle voltage applied to the vehicle voltage input terminal to the high-side switch output terminal, wherein the high-side switch output terminal has a preset current-carrying capacity, and the control device is configured to detect the output current of the high-side switch output terminal, and the rated current consumption of the rated load to be powered is higher than the preset current-carrying capacity of the high-side switch output terminal. Background Art

[0004] Such a vehicle circuit device is known from the prior art. When powering an electrical load, the problem of the integrated high-side switch is caused by low output power. Therefore, loads that require a relatively high output power usually require more expensive additional components, and with the help of the additional components, a strong power supply to an external load can be ensured. Summary of the Invention

[0005] Therefore, the object of the present invention is to implement a vehicle circuit device that provides a low-cost feasibility for powering relatively power-intensive external loads.

[0006] This object is achieved by a vehicle circuit device of the type mentioned at the beginning, wherein according to the present invention, the vehicle circuit device further has:

[0007] - a Widlar current mirror circuit in a PNP configuration,

[0008] wherein the emitter of the first transistor of the first mirror half of the Widlar current mirror circuit is connected to the output terminal of the high-side switch via a serially connected ohmic scaling resistor, the collector of the first transistor is grounded, and the base of the first transistor is connected to the base of the second transistor, wherein the second transistor is part of the second mirror half, and the second transistor is connected to the vehicle voltage input terminal on the emitter side and to the electrical load to be powered and monitored on the collector side, and the electrical load is grounded, and the scaling resistor is selected such that:

[0009] ·The current consumed on the load side is mapped to the output current of the high-side switch with a conversion ratio on the first mirror half of the Villard current mirror circuit, such that the rated current on the load side causes the following value of the output current on the high-side switch side: the value is lower than the current-carrying capacity of the high-side switch output, and exceeds the rated current on the load side by a preset limit value, causing the current-carrying capacity of the high-side switch output to be exceeded, so that the overload is detected by the control device based on the exceeding of the current-carrying capacity of the high-side switch output.

[0010] By using the said feature, it is feasible to introduce a high-side switch with a small output power into the power supply to the load, which consumes a rated power that is significantly higher than the output power of the high-side switch. Through current mapping, the current consumed from the load side is mapped to the high-side switch output corresponding to the set conversion ratio, such that the output current output by the switch is associated with the load current. If the load consumes an overcurrent or short-circuit current due to a load fault, then this causes the current-carrying capacity of the high-side switch output to be exceeded, thus causing the control device to identify the fault. Based on this, measures for eliminating the fault can be introduced. The fault can be automatically signaled by setting a flag. If necessary, the load can also be automatically disconnected.

[0011] The control device can be a conventional control device that already exists in the vehicle, for example, in order to control vehicle functions. Here, for example, it can relate to the function of vehicle headlights and / or can also relate to a simple fan function. Currently, in the case of passenger cars, the on-vehicle voltage is usually a rated voltage of 12V, and conversely, in the case of trucks, the voltage is usually 24V. In principle, the on-vehicle voltage can be freely selected - then only the components used are designed corresponding to the expected voltage. This also applies to the expected power. The vehicle circuit device can be optimized to supply a specific rating to the load. Correspondingly, then the individual values, especially the conversion ratio of the current mirror circuit, can be optimized by a person skilled in the art for the corresponding application.

[0012] Furthermore, it can be proposed that the vehicle circuit device includes an automated overload protection device in such a way that the control device is connected to a microcontroller, and the value of the current detected at the high-side switch output is fed to the microcontroller, where the microcontroller is configured to control a cut-off device such that the load is automatically cut off in the case of the current-carrying capacity of the high-side switch output being exceeded. Specifically, it can be proposed here that the cut-off device is connected to the base of the transistor supplying power to the load and reduces the base-emitter voltage of the transistor in order to effect the cut-off, thereby cutting off the transistor. Such a device is shown in Figure 2 For example, if a short circuit occurs at the powered fan, then the current through Q2 increases (see Figure 1 and Figure 2), whereby, via reflection, the current at Q1 increases. This increase is detected at the output A1 of the high-side switch, and a flag can be set which is continuously queried by the microprocessor such that the microprocessor can introduce the measure for switching off Q2 when the set flag is determined.

[0013] Furthermore, it can be provided that the mirror ratio of the Villard current mirror circuit is selected such that the current on the load side of the second current mirror half is reflected onto the first current mirror half with a ratio of at least 10:1. According to Figure 1 , this means that the current I A1 is at most 1 / 10 of the I L value.

[0014] In particular, it can be provided that the conversion ratio of the current mirror circuit is selected such that the rated current consumption of the load causes the following output current at the output of the high-side switch: the output current is lower than at least 50% of the maximum current-carrying capacity of the output of the high-side switch. The ratio can be in the range of 1:10 to 1:20, for example. In this case, this means that the current consumption on the load side must exceed the rated current by at least twice the value in order to trigger an overload at the output of the high-side switch. Thereby, for example, the power reserve required for the permitted operating states can be achieved, which operating states have an increased current demand above the rated current during this time - for example when starting a fan. Thus, conventional current peaks can be taken into account. The selection of the conversion ratio can be optimally set according to the load to be supplied. Instead of the proposed ratio, larger intervals can also be selected, for example, three times, four times or even ten times the rated current can be set as the limit.

[0015] Furthermore, it can be provided that the current-carrying capacity of the output of the high-side switch is at most 100 mA.

[0016] In particular, it can be provided that the vehicle electrical system includes a load to be supplied, wherein the load has a fan.

[0017] Furthermore, it can be provided that the vehicle electrical system includes a load to be supplied, wherein the load has an optical module, in particular an LED optical module.

[0018] In particular, it can be provided that the high-side switch is configured as part of a system basis chip.

[0019] Furthermore, the invention relates to an electrical vehicle system which includes a vehicle electrical system according to the invention and a vehicle battery for outputting on-vehicle voltage, wherein the vehicle battery is electrically connected to the on-vehicle voltage input of the vehicle electrical system.

[0020] The invention also relates to a vehicle headlight, which includes a vehicle electrical circuit device according to the invention. The invention further relates to a vehicle, which includes a vehicle electrical circuit device according to the invention and / or a vehicle system according to the invention and / or a vehicle headlight according to the invention. Description of the Drawings

[0021] In the following, the invention will be explained in detail on the basis of exemplary and non - restrictive embodiments illustrated in the drawings. Shown in the drawings are:

[0022] Figure 1 A schematic diagram showing a first embodiment of the invention, and

[0023] Figure 2 A schematic diagram showing an improvement of the first embodiment.

[0024] In the following drawings - unless otherwise stated - the same reference numerals denote the same features. Detailed Description of the Invention

[0025] Figure 1 A schematic diagram showing a first embodiment of a vehicle electrical circuit device 1 for supplying a vehicle voltage U to an electrical load 2 in an overload - detection manner, where the electrical load 2 has a preset rated power. The vehicle electrical circuit device 1 includes a vehicle - voltage input terminal E1, a control device 3 for controlling vehicle functions, where the control device 3 has an integrated semiconductor module 3a, such as a system - basis chip SBC, and the integrated semiconductor module 3a has an integrated high - side switch S1. The switch S1 is connected to the vehicle - voltage input terminal E1 to connect the vehicle voltage U applied to the vehicle - voltage input terminal E1 FB to a high - side - switch output terminal A1. Here, the high - side - switch output terminal A1 has a preset current - carrying capacity. The control device 3 is configured to detect the output current I FB at the high - side - switch output terminal A1, and the load 2 or the current - carrying capacity is selected such that the rated - current consumption of the load 2 to be powered is higher than the preset current - carrying capacity of the high - side - switch output terminal A1. A1

[0026] The vehicle electrical circuit device 1 also has a Villard current - mirror circuit 4 in a PNP configuration. For better illustration, the Villard current - mirror circuit 4 is shown in Figure 1is surrounded by a rectangle of thin dashed lines. The emitter of the first transistor Q1 of the first mirror half of the Villard current mirror circuit is connected to the output terminal A1 of the high-side switch S1 via the ohmic scaling resistor R2 connected in series. The collector of the first transistor Q1 is grounded, and the base of the first transistor Q1 is connected to the base of the second transistor Q2. The second transistor Q2 is part of the second mirror half. The second transistor Q2 is connected to the vehicle voltage input terminal E1 on the emitter side and to the electrical load 2 to be powered and monitored on the collector side, where the electrical load 2 is grounded. Here, the scaling resistor R2 is selected such that the current I L is mapped to the output current I A1 of the high-side switch S1 with a conversion ratio on the first mirror half of the Villard current mirror circuit, such that the rated current I LN (not shown in the drawing but can be obtained, for example, from the data sheet of the corresponding load 2) causes the following value of the output current I A1 on the high-side switch side: The value is lower than the current-carrying capacity of the high-side switch output terminal A1 and exceeds the rated current I LN on the load side by a preset limit value, causing an overload to be detected by the control device 3 based on exceeding the current-carrying capacity of the high-side switch output terminal A1. Here, the mapping is performed in an effective manner by: when the switch S1 is turned on, the base-emitter voltage at Q1 is reduced by the voltage drop across R2 compared to the base-emitter voltage at Q2. The voltage drop is derived from the product of the current I A1 and the resistor R2. Therefore, the voltage drop is proportional to R2, whereby the conversion ratio of the current mirror circuit can be set purposefully by appropriately selecting R2. It can be advantageous that the two transistors Q1 and Q2 are identical to each other. In this way, it can be ensured that not only the amplification factors of the transistors but also the internal body resistances are largely the same as each other, whereby a particularly precise and sensitive mapping can be achieved. In addition, in the current circuit, the resistor R1 is only used as an auxiliary resistor and can also be omitted.

[0027] Figure 2 shows a schematic diagram of an improvement of the first embodiment. An automated overload protection device is integrated therein by connecting the control device 3 to a microcontroller 5, and the microcontroller is supplied with the current I A1Value. The microcontroller 5 is provided for controlling the disconnecting device 6 such that in the case of exceeding the current-carrying capacity of the high-side switch output A1, the load 2 is automatically disconnected. Specifically, the transistor Q3 controlled by the microcontroller can prevent the base current from flowing through the transistor Q2, thereby turning off Q2. As long as Q4 is turned on, for example, also via the microcontroller GPIO pin, Q3 can be turned on. A voltage causing the turn-on occurs at the BE section of Q3 via the voltage divider R5 and R4. C1 is used for attenuation in order to achieve a slow rise of the output current and the measured current.

[0028] The invention is not limited to the embodiments shown, but is defined by the entire scope of protection of the claims. It is also possible to consider and combine with each other the individual aspects of the invention or the embodiments. The possible reference signs in the claims are exemplary and are only for easier readability of the claims and do not limit the claims.

Claims

1. A vehicle circuit device (1) for supplying a vehicle voltage (UFB) to an electrical load (2) in an overload detection manner, wherein the electrical load (2) has a preset rated power, and the vehicle circuit device comprises: - A vehicle voltage input terminal (E1), - A control device (3) for controlling vehicle functions, wherein the control device (3) has an integrated semiconductor module (3a), and the integrated semiconductor module has an integrated high-side switch (S1), and the high-side switch is connected to the vehicle voltage input terminal (E1) to connect the vehicle voltage (UFB) applied to the vehicle voltage input terminal (E1) to a high-side switch output terminal (A1), wherein the high-side switch output terminal (A1) has a preset current-carrying capacity, and the control device (3) is configured to detect an output current (IA1) of the high-side switch output terminal (A1), and the rated current consumption of the rated load to be powered is higher than the preset current-carrying capacity of the high-side switch output terminal (A1), It is characterized in that the vehicle circuit device further has: - A Villard current mirror circuit (4) in a PNP configuration, wherein the emitter of a first transistor (Q1) of a first mirror half of the Villard current mirror circuit is connected to the high-side switch output terminal (A1) of the high-side switch (S1) via a serially connected ohmic scaling resistor (R2), the collector of the first transistor (Q1) is connected to ground, and the base of the first transistor (Q1) is connected to the base of a second transistor (Q2), wherein the second transistor (Q2) is part of a second mirror half, and the second transistor (Q2) is connected to the vehicle voltage input terminal (E1) on the emitter side and to the electrical load (2) to be powered and monitored on the collector side, and the electrical load (2) is grounded, and mirroring is achieved by the fact that when the high-side switch (S1) is turned on, compared with the base-emitter voltage of the second transistor (Q2), the base-emitter voltage at the first transistor (Q1) is reduced by the voltage drop across the ohmic scaling resistor (R2), and the ohmic scaling resistor (R2) is selected such that: · The current (IL) consumed on the load side is mirrored to the output current (IA1) of the high-side switch (S1) with a conversion ratio on the first mirror half of the Villard current mirror circuit, such that the rated current (ILN) on the load side causes an output current (IA1) on the high-side switch side with a value: the value is lower than the current-carrying capacity of the high-side switch output terminal (A1), and exceeding the rated current (ILN) on the load side with a preset limit value causes exceeding the current-carrying capacity of the high-side switch output terminal (A1), so that the control device (3) detects an overload according to exceeding the current-carrying capacity of the high-side switch output terminal (A1), The vehicle circuit device further includes an automated overload protection device in such a way that the control device (3) is connected to a microcontroller (5) and conveys the value of the output current (IA1) detected at the high-side switch output (A1) to the microcontroller, wherein the microcontroller (5) is configured to control a cut-off device (6) such that in the case of exceeding the current-carrying capacity of the high-side switch output (A1), the electrical load (2) is automatically cut off. In this way, the cut-off device (6) has a transistor (Q3) controlled by the microcontroller (5), and by means of this transistor, the base current can be prevented from flowing through the second transistor (Q2), thereby enabling the second transistor (Q2) to be turned off.

2. The vehicle circuit device (1) according to claim 1, wherein the integrated semiconductor module (3a) is a system basis chip.

3. The vehicle circuit device (1) according to claim 1 or 2, wherein the mirror ratio of the Willard current mirror circuit (4) is selected such that the current (IL) on the load side of the second mirror half is reflected onto the first mirror half in a ratio of at least 10:

1.

4. The vehicle circuit device (1) according to claim 1 or 2, wherein the conversion ratio of the current mirror circuit is selected such that the rated current consumption of the electrical load (2) causes the output current (IA1) at the high-side switch output (A1), and this output current is at least 50% lower than the maximum current-carrying capacity of the high-side switch output (A1).

5. The vehicle circuit device (1) according to claim 1 or 2, wherein the current-carrying capacity of the high-side switch output (A1) is at most 100 mA.

6. The vehicle circuit device (1) according to claim 1 or 2, wherein the vehicle circuit device (1) includes the electrical load (2) to be powered, and the electrical load (2) has a fan.

7. The vehicle circuit device (1) according to claim 1 or 2, wherein the vehicle circuit device (1) includes the electrical load (2) to be powered, and the electrical load (2) has an optical module.

8. The vehicle circuit device (1) according to claim 7, wherein the electrical load (2) has an LED optical module.

9. The vehicle circuit device (1) according to claim 1 or 2, wherein the high-side switch (S1) is configured as part of a system basis chip.

10. An electrical vehicle system, the electrical vehicle system includes the vehicle circuit device according to any one of claims 1 to 9 and a vehicle battery for outputting the vehicle voltage, wherein the vehicle battery is electrically connected to the vehicle voltage input (E1) of the vehicle circuit device (1).

11. A vehicle headlight, the vehicle headlight includes the vehicle circuit device (1) according to any one of claims 1 to 9.

12. A vehicle, the vehicle includes the vehicle circuit device (1) according to any one of claims 1 to 9, the vehicle system according to claim 10, and / or the vehicle headlight according to claim 11.

Images