Electronic fuse for a power circuit of a vehicle

Abstract

The invention relates to an electronic fuse for a power circuit of a vehicle, comprising an input port and an output port, at least two semiconductor switching devices connected in series or in parallel between the input port and the output port, and a control circuit, the control circuit is configured to provide a control signal for triggering the electronic fuse. The control circuit is adapted to generate the control signal based on voltage and / or current measurements at the input port or at the input port and the output port. In addition, the electronic fuse comprises a driver device for switching on and off the at least two semiconductor switching devices on the basis of the control signal such that the at least two semiconductor switching devices can be switched on and off simultaneously.

Description

Technical Field

[0001] The present invention relates to an electronic fuse for protecting a power circuit from overcurrent or overvoltage.

[0002] The object of the present invention is to provide an electronic fuse which is characterized by small size, fast actuation, longer service life and can be easily configured to meet the required safety requirements.

[0003] The use of the electronic fuse of the present invention is particularly advantageous in vehicles in general, and more particularly in electric or hybrid vehicles. Background Art

[0004] Traditionally, protecting electronic circuits and devices from overcurrent or overvoltage has been accomplished by thermal fuses and electromechanical relays, which are bulky, have short lifespans, and react slowly for certain applications.

[0005] In addition, the traditional thermal fuse is a one-time protection device, and once it blows, it must be manually replaced with a new fuse.

[0006] Electronic fuses have the distinct advantage of being reusable and typically have a faster response than thermal fuses.

[0007] As the demand for smaller devices continues to grow, especially in the automotive industry, the need for electronic fuses with improved features is also growing. Summary of the invention

[0008] The present invention relates to an electronic fuse for a power circuit of a vehicle, preferably for a power circuit having an operating voltage of up to 60 volts and a current of up to 250 amperes.

[0009] The electronic fuse of the present invention comprises: an input port and an output port, and at least two semiconductor switch devices connected in series or in parallel between the input port and the output port, and a control circuit configured to provide a control signal for triggering the electronic fuse, that is, for turning on / off the semiconductor switch device. In the actual implementation of the present invention, the input port and the output port are used to connect the electronic fuse in an electronic circuit.

[0010] The control circuit is adapted to generate a control signal based on voltage and / or current measurements at the input port or at the input port and the output port.

[0011] The electronic fuse further includes a driver device for turning on and off the at least two semiconductor switch devices based on a control signal, so that the at least two semiconductor switch devices can be turned on and off simultaneously.

[0012] In a preferred embodiment, the electronic fuse comprises two, three or more branches connected in parallel between the input port and the output port, each branch comprising at least one semiconductor switch device. Preferably, each branch has two semiconductor switch devices connected in series.

[0013] The two semiconductor switching devices of each branch are connected to allow current to flow in the same direction only in the branch to which they are connected. Alternatively, the two semiconductor switching devices of each branch are connected to allow current to flow in opposite directions in the branch to which they are connected.

[0014] Each semiconductor switching device is a solid state switch, preferably a MOSFET transistor, and is connected with an anti-parallel diode in a known manner.

[0015] In a preferred embodiment, the control circuit comprises a first comparator connected to compare the voltage measurement result at the input port or the output port with the reference voltage, the control signal is the output of the first comparator, and the output is supplied to the driver. The control circuit may comprise a second comparator connected to compare the voltage measurement result at the input port or the output port different from the first comparator with the reference voltage, the control signal is the combination of the outputs of the first comparator and the second comparator, and the combination is supplied to the driver, so that the driver triggers the electronic fuse, that is, if one or both of the voltage measurement results at the input port and the output port are higher than the corresponding threshold voltage, the driver will disconnect the semiconductor switching device.

[0016] The control circuit may include a third comparator connected to compare the current measurement at the input port or the output port with the reference current, the control signal being an output of the third comparator which is supplied to the driver.

[0017] In another preferred embodiment, the control circuit includes the first comparator and the third comparator described above, and the control signal is a combination of the output of the first comparator and the output of the third comparator, which is supplied to the driver so that if one or both of the outputs are positive, the control signal instructs the driver to trigger the electronic fuse.

[0018] In another preferred embodiment, the control circuit includes the aforementioned first comparator, second comparator and third comparator, and the control signal is a combination of the output of the first comparator, the output of the second comparator and the output of the third comparator.

[0019] Optionally, the control circuit may include a fourth comparator connected to compare a current measurement at a different output port or input port than the first comparator with a reference current, wherein the control signal is a combination of the outputs of the first to fourth comparators.

[0020] The control circuit can be implemented with a microcontroller instead of a comparator, in which case the microcontroller is programmed to provide control signals based on voltage and / or current measurements at the input port or at both the input port and the output port. The microcontroller performs the comparison function and provides command signals to the driver to turn the MOSFET on and off.

[0021] Preferably, the electronic fuse comprises a communication port for communicating the electronic fuse with an electronic control unit ECU of the vehicle, the driver being adapted to trigger the electronic fuse further based on a signal received at the communication port.

[0022] Another aspect of the present invention relates to a power distribution unit (PDU) for a vehicle, which includes the above-mentioned electronic fuse.

[0023] Another aspect of the present invention relates to an electronic control unit ECU for a vehicle, which includes the above-mentioned electronic fuse.

[0024] Some advantages of the present invention are as follows:

[0025] -Fast fault protection response (less than 50us) and diagnosis;

[0026] -Controlled overcurrent protection (configurable time and current);

[0027] - Undervoltage and / or overvoltage protection in the main distribution PD unit;

[0028] - define safe states (closed / open switches) in case of a fault;

[0029] -Power electronic switches can perform additional functions such as battery resistance measurement.

[0030] -Bidirectional current monitoring;

[0031] - Communication interface (CAN communication) to send the drive status to other ECUs;

[0032] - Redundancy in measurement;

[0033] - comparative redundancy of open / close switches;

[0034] - Redundancy on the Mosfet to ensure that the safe state can be achieved independently of a Mosfet failure (avoiding single point of failure);

[0035] - Fast MOSFET actuation in the nanosecond range;

[0036] - Resettable protection;

[0037] - Voltage, current and temperature protection;

[0038] -Accurate current protection setting. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to complete this specification and better understand the present invention, a set of drawings is provided. These drawings constitute an integral part of this specification and illustrate the embodiments of the present invention, but should not be interpreted as limiting the scope of the present invention, but only as an example of how to implement the present invention. The drawings include the following figures:

[0040] Figure 1 An electrical diagram of an electronic fuse according to the present invention is shown, using a comparator to generate a control signal.

[0041] Figure 2 An electrical diagram of an electronic fuse according to the present invention is shown, using a microcontroller to generate control signals.

[0042] Figure 3 and Figure 4 Two electrical diagrams showing two alternative embodiments of the electronic fuse of the present invention.

[0043] Figure 5A and Figure 5B Two alternative electrical connections for semiconductor switching devices are shown. Figure 5A In this case, the current can be blocked in both directions, and Figure 5B In a circuit, current can flow in both directions, but is blocked in only one direction.

[0044] Figure 6 An electrical diagram showing the electrical connections between the driver and two semiconductor switching devices. DETAILED DESCRIPTION

[0045] Figure 1 An exemplary embodiment of an electronic fuse 1 according to the present invention is shown, which includes an input port 2 and an output port 3, and three branches 4a, 4b, 4c connected in parallel between the input port 2 and the output port 3, wherein each branch 4a, 4b, 4c includes two semiconductor switching devices 5, 5', 6, 6', 7, 7' connected in series within the corresponding branch - in this example, embodied as MOSFET transistors with anti-parallel diodes connected thereto.

[0046] Each pair of semiconductor switching devices 5, 5', 6, 6', 7, 7' is connected in parallel in sequence, so that the current flowing between the input port 2 and the output port 3 will be divided into three paths. This means that the circulating current and the interrupting current of each branch 4a, 4b, 4c must be calculated, and the circulating current and the interrupting current are 1 / 3 of the rated current expected to flow between the input port and the output port when the specific circuit is operating normally.

[0047] The electronic fuse 1 further includes a driver 8 for simultaneously turning on and off all semiconductor switching devices 5, 5', 6, 6', 7, 7'. For this purpose, the gate terminals of the respective semiconductor switching devices are connected to the output of the driver 8 by means of lines 9. The driver must be able to supply or the required current (I) or voltage (V) to all semiconductors simultaneously, either directly or indirectly (e.g., via one or more capacitors).

[0048] The driver 8 is operated to trigger the electronic fuse based on a control signal supplied by the control circuit 10, which is in turn configured to generate the control signal based on voltage and / or current measurements at the input port or at the input and output ports.

[0049] Preferably, the driver 8 is a high-side driver because the source terminals of the MOSFETs are floating, i.e., not referenced to ground. Additionally, the driver 8 must supply and sink the necessary current to simultaneously turn on / off all the MOSFETs of the electronic fuse within a specified time.

[0050] In Figure 1 an embodiment, the control circuit 10 includes a first comparator 12 connected to compare the voltage measurement result Vmeas1 obtained at the input port 2 with a reference voltage Vth, and a second comparator 13 connected to compare the voltage measurement result at the output port 3 with the same reference voltage Vth. Additionally, the control circuit 10 includes a third comparator 14 connected to compare the current measurement result Imeas1 at the input port 2 with a reference current Ith, and a fourth comparator 15 connected to compare a second current measurement result Imeas2 also located at the input port 2 with the same reference current Ith. Optionally, the temperature can also be measured.

[0051] The outputs of the first comparator, the second comparator, the third comparator, and the fourth comparator 12 are fed to an AND gate 16, which generates a control signal 11 for the driver 8. Thus, if all the outputs of the comparators are positive, the control signal will instruct the driver 8 to trigger the electronic fuse.

[0052] Alternatively, an OR gate can also be used instead of the AND gate. In this case, if at least one of the comparator outputs is positive, the control signal will activate the driver to trigger the electronic fuse.

[0053] Additionally, the electronic fuse may include a communication port 17 for communicating the electronic fuse with the electronic control unit ECU of the vehicle, and the driver 8 is adapted to trigger the electronic fuse also based on a signal received at the communication port. Figure 1 In a practical example, the communication port 17 is an input of the AND gate 16.

[0054] In Figure 2 In an alternative embodiment, the control circuit is not a comparator but is implemented as a microcontroller 18 which is configured to provide a control signal which is also based on the voltage and / or current measurement results at the input port 2 or at the input port 2 and the output port 3.

[0055] exist Figure 3 In the embodiment of the present invention, the electronic fuse 1 also has three branches 4a, 4b, 4c connected in parallel, but each branch has only one semiconductor switch device 5, 5', 5". The control circuit 10 can be used with respect to Figure 1 described, or using the comparator Figure 2 The described microcontroller is implemented.

[0056] exist Figure 4 In the embodiment of the present invention, the electronic fuse 1 has five branches 4a, 4b, 4c, 4d, 4e connected in parallel, each branch having two semiconductor switch devices 5 connected in series in the branch. The control circuit 10 can be used with respect to Figure 1 described, or using the comparator Figure 2 The described microcontroller is implemented.

[0057] from Figure 3 and Figure 4 As can be seen from the embodiments of the electronic fuse 1, the configuration of the electronic fuse 1 can be easily scaled or adjusted to meet the safety requirements of each specific application.

[0058] In all the above embodiments with two semiconductor switching devices in each branch, the two switches are connected to allow current to flow in the same direction in the branches to which they are connected, such as Figure 5B shown.

[0059] Alternatively, the two switches may be connected to allow current to flow in opposite directions within the branches to which they are connected, such as Figure 5A shown.

[0060] Figure 6 A specific implementation of the driver 8 is shown, which is an Automotive Safety Integrity Level (ASIL) compliant driver with current protection, voltage protection, and temperature protection capabilities, and includes a communication bus to transmit the driver status to other ECUs.

[0061] Preferably, the driver is a high-side driver, since the source terminal of the MOSFET is floating, that is, it is not referenced to the ground of the circuit, in this case, since there is another semiconductor or load that needs to be powered after the source terminal.

[0062] Additionally, the high-side driver must be isolated in order to isolate the circuit feeding the driver itself from the circuit in which the semiconductor is located. The isolation can be, for example, a galvanic isolation or a bootstrap circuit for isolating the two circuits.

[0063] The driver should source and sink the necessary current to turn on / off all the MOSFETs in the system within the specified time. The driver should manage "n" times "I", where "n" is the number of MOSFETs and "I" is the current consumption of each MOSFET. Shunt capacitors can be used to help the driver achieve the peak current to turn the MOSFET on / off.

[0064] Since high currents must be conducted through the printed circuit board (PCB), heavy copper PCBs are used in the implementation of e-fuses, which contain fairly thick copper inserts (inlays) in the internal layers. There are different types of PCBs used for high currents:

[0065] -Metal inlay technology, the minimum thickness of the inlay is 0.5mm (any size);

[0066] - Heavy copper technology, the inlay thickness is at least 100um, preferably higher than 250um, more preferably higher than 500um.

[0067] Any other technology having similar or better performance characteristics and having the above thickness ranges may also be used.

[0068] These thick inlays allow high currents to be conducted without overheating and help dissipate heat by conduction because they have a large surface to exchange heat with the surrounding air.

[0069] Therefore, the top layer of the PCB contains: drivers, logic circuits or microcontrollers, and MOSFETs, and the inner layers contain thick inlays.

[0070] The electronic fuse of the present invention can be implemented in several practical applications, for example:

[0071] - As part of the main power distribution unit, it is responsible for protecting the power from the low voltage battery and distributing it to the various low voltage consumers of the vehicle. This implementation usually consists of a set of electronic fuses, individual current sensors for each auxiliary power line. Typically, these are low voltage - high current applications;

[0072] - As part of the vehicle's low-voltage electronic control unit (ECU), it provides protection at the power supply input of the ECU;

[0073] -As a protection system included in the auxiliary circuit of JBOX. This application is usually high voltage and low current.

Claims

1. An electronic fuse (1) for a power circuit of a vehicle, the electronic fuse comprising: Input port (2) and output port (3), at least two semiconductor switch devices (5, 5') connected in series or in parallel between the input port (2) and the output port (3), a control circuit (10) configured to provide a control signal (11) for triggering the electronic fuse, wherein the control circuit (10) is adapted to generate the control signal based on a voltage and / or current measurement result at the input port (2) or at the input port (2) and the output port (3), A driver (8) is used to switch on and off the at least two semiconductor switch devices (5, 5') based on the control signal (11), so that the at least two semiconductor switch devices (5, 5') can be switched on and off at the same time.

2. The electronic fuse according to claim 1 further comprises two, three or more branches (4a, 4b, 4c) connected in parallel between the input port (2) and the output port (3), each branch comprising at least one semiconductor switching device (5, 5').

3. The electronic fuse according to claim 2, wherein: Each branch (4a, 4b, 4c) has two semiconductor switching devices (5, 5') connected in series.

4. The electronic fuse according to claim 3, wherein: The two semiconductor switching devices (5, 5') of each branch (4a, 4b, 4c) are connected to allow current to flow in the same direction within the branch to which they are connected.

5. The electronic fuse according to claim 3, wherein: The two semiconductor switching devices (5, 5') of each branch (4a, 4b, 4c) are connected to allow current to flow in opposite directions within the branch to which they are connected.

6. The electronic fuse according to claim 1, wherein: Each semiconductor switching device (5, 5') is formed by a MOSFET transistor having an anti-parallel diode connected to the MOSFET transistor.

7. The electronic fuse according to claim 1, wherein: The control circuit (10) comprises a first comparator (12) connected to compare a voltage measurement result at the input port (2) or the output port (3) with a reference voltage, wherein the control signal (11) is an output of the first comparator, which is supplied to the driver (8).

8. The electronic fuse according to claim 7, wherein: The control circuit (10) comprises a second comparator (13) connected to compare a voltage measurement at the input port (2) or the output port (3) different from the first comparator (12) with a reference voltage, wherein the control signal (11) is a combination of the outputs of the first comparator (12) and the second comparator (13), which is supplied to the driver (8) so that if one output is positive or both outputs are positive, the control signal (11) instructs the driver (8) to trigger the electronic fuse.

9. The electronic fuse according to claim 1, wherein: The control circuit (10) comprises a third comparator (14) connected to compare a current measurement result at the input port (2) or the output port (3) with a reference current, wherein the control signal (11) is an output of the third comparator (14) which is supplied to the driver (8).

10. The electronic fuse according to claim 7, wherein: The control circuit (10) comprises a third comparator (14) connected to compare the current measurement result at the input port (2) or the output port (3) with a reference current, wherein the control signal (11) is a combination of the output of the first comparator (12) and the output of the third comparator (14), which is supplied to the driver (8) so that if both outputs are positive or one of the two outputs is positive, the control signal (11) instructs the driver (8) to trigger the electronic fuse.

11. The electronic fuse according to claim 8, wherein: The control circuit (10) comprises a third comparator (14) connected to compare a current measurement result at the input port (2) or the output port (3) with a reference current, the control signal (11) being a combination of an output of the first comparator (12), an output of the second comparator (13) and an output of the third comparator (14), wherein the control signal (11) is supplied to the driver (8) such that if one of the outputs is positive, the control signal (11) instructs the driver (8) to trigger the electronic fuse.

12. The electronic fuse according to claim 1 comprises a communication port (17) for communicating the electronic fuse with an electronic control unit ECU of a vehicle, the driver (8) being adapted to trigger the electronic fuse also based on a signal received at the communication port (17).

13. The electronic fuse according to claim 1, wherein: The control circuit (10) comprises a microcontroller (18) configured to provide the control signal (11) based on voltage and / or current measurements at the input port (2) or at the input port (2) and the output port (3).

14. The electronic fuse of claim 1, comprising a printed circuit board (PCB), the PCB comprising thick copper inlays in various layers inside the PCB, wherein: The semiconductor switching devices (5, 5') are connected by means of these thick copper inlays, and wherein the thickness of the thick copper inlays is at least 100um, preferably higher than 250um, and more preferably higher than 500um.

15. An electronic control unit ECU for a vehicle, the ECU comprising the electronic fuse (1) according to any one of claims 1 to 14.

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