High speed fault isolation for vehicle power supply

Abstract

Examples described herein provide a method that includes, in response to determining that a direction of current relative to a power source of a vehicle is a forward current flowing out of the power source; it is determined whether the forward current exceeds a forward current threshold and lasts for a forward overcurrent detection period by comparing the current to the forward current threshold. The method further includes responsive to determining that the direction of the current relative to the power source is a reverse current flowing into the power source, it is determined whether the reverse current exceeds a reverse current threshold and lasts for a reverse overcurrent detection period of the forward overcurrent detection period by comparing the current to the reverse current threshold. The method also includes controlling, using the gate driver, at least one switch associated with the power source to inhibit the current.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to vehicles, and in particular to high speed fault isolation for a vehicle power source. BACKGROUND

[0002] Modern vehicles (e.g., automobiles, motorcycles, boats, or any other type of automobile) can receive power from one or more power sources and can provide power to various systems of the vehicle. For example, an electric vehicle can include one or more batteries to store power and provide power to one or more electric motors that provide propulsion to the vehicle. Such a vehicle configuration is referred to as a battery electric vehicle (BEV). Other types of vehicles can also be equipped with batteries, such as vehicles with internal combustion engines, hybrid electric vehicles, etc., including combinations and / or multiples thereof. Other examples of vehicle components that can use power (e.g., power stored in a battery) include, but are not limited to, pumps, actuators, sensors, processing systems, displays, environmental control systems, infotainment systems, engine control units, etc., including combinations and / or multiples thereof. SUMMARY

[0003] In one embodiment, a method is provided. The method includes receiving a current from a current sensor associated with a power source of a vehicle. The method also includes determining a direction of the current relative to the power source. The method further includes, in response to determining that the direction of the current relative to the power source is a forward current flowing out of the power source, determining, by an overcurrent monitor, whether the forward current exceeds a forward current threshold and for a forward overcurrent detection time period by comparing the current to the forward current threshold. The method further includes, in response to determining that the direction of the current relative to the power source is a reverse current flowing into the power source, determining, by the overcurrent monitor, whether the reverse current exceeds a reverse current threshold and for a reverse overcurrent detection time period that is less than the forward overcurrent detection time period by comparing the current to the reverse current threshold. The method further includes, in response to determining that the forward current exceeds the forward current threshold and for the forward overcurrent detection time period, or in response to determining that the reverse current exceeds the reverse current threshold and for the reverse overcurrent detection time period, controlling at least one switch associated with the power source using a gate driver to suppress the current.

[0004] In addition to one or more features described herein, or as an alternative, further embodiments of the method can include that the current sensor is disposed in the gate driver.

[0005] In addition to one or more of the features described herein, or as an alternative, further embodiments of the method can include that the gate driver includes the current sensor, a temperature sensing block to receive a temperature from a temperature sensor element, an overcurrent detection block, an overtemperature detection block, a gate drive block, and control logic.

[0006] In addition to one or more of the features described herein, or as an alternative, further embodiments of the method can include that the gate drive block of the gate driver controls the at least one switch associated with the power source.

[0007] In addition to one or more of the features described herein, or as an alternative, further embodiments of the method can include that the overcurrent monitor includes a first comparator to detect an overcurrent in the forward current and a second comparator to detect an overcurrent in the reverse current.

[0008] In addition to one or more of the features described herein, or as an alternative, further embodiments of the method can include that the overcurrent monitor further includes a first latch associated with the first comparator to cause a gate drive block of the gate driver to control the at least one switch in response to determining that the forward current exceeds the forward current threshold and for the forward overcurrent detection time period.

[0009] In addition to one or more of the features described herein, or as an alternative, further embodiments of the method can include that the overcurrent monitor further includes a second latch associated with the second comparator to cause the gate drive block of the gate driver to control the at least one switch in response to determining that the reverse current exceeds the reverse current threshold and for the reverse overcurrent detection time period.

[0010] In addition to one or more of the features described herein, or as an alternative, further embodiments of the method can include transmitting a signal to a microprocessor in response to determining that the forward current exceeds the forward current threshold and for the forward overcurrent detection time period, or in response to determining that the reverse current exceeds the reverse current threshold and for the reverse overcurrent detection time period.

[0011] In addition to one or more of the features described herein, or as an alternative, further embodiments of the method can include detecting a gate driver fault of the gate driver, and in response to detecting the gate driver fault of the gate driver, controlling the at least one switch associated with the power source using the gate driver to suppress the current.

[0012] In addition to one or more of the features described herein, or as an alternative, additional embodiments of the method can include that the at least one switch comprises an N-type metal oxide semiconductor.

[0013] In another embodiment, a vehicle is provided. The vehicle includes a power source, at least one switch associated with the power source, and a fault detection circuit. The fault detection circuit includes a gate driver and an overcurrent monitor that performs operations. The operations include receiving a current from a current sensor of the gate driver. The operations further include determining a direction of the current relative to the power source. The operations further include, in response to determining that the direction of the current relative to the power source is a forward current flowing out of the power source, determining whether the forward current exceeds a forward current threshold for a forward overcurrent detection time period by comparing the current to the forward current threshold. The operations further include, in response to determining that the direction of the current relative to the power source is a reverse current flowing into the power source, determining whether the reverse current exceeds a reverse current threshold for a reverse overcurrent detection time period that is shorter than the forward overcurrent detection time period by comparing the current to the reverse current threshold. The operations further include, in response to determining that the forward current exceeds the forward current threshold for the forward overcurrent detection time period, or in response to determining that the reverse current exceeds the reverse current threshold for the reverse overcurrent detection time period, causing the gate driver to control the at least one switch associated with the power source to suppress the current.

[0014] In addition to one or more of the features described herein, or as an alternative, additional embodiments of the vehicle can include that the current sensor is disposed in the gate driver.

[0015] In addition to one or more of the features described herein, or as an alternative, additional embodiments of the vehicle can include that the gate driver includes the current sensor, a temperature sensing block to receive a temperature from a temperature sensor element, an overcurrent detection block, an overtemperature detection block, a gate drive block, and control logic.

[0016] In addition to one or more of the features described herein, or as an alternative, additional embodiments of the vehicle can include that the gate drive block of the gate driver controls the at least one switch associated with the power source.

[0017] In addition to one or more of the features described herein, or as an alternative, additional embodiments of the vehicle can include that the overcurrent monitor includes a first comparator to detect an overcurrent in the forward current and a second comparator to detect an overcurrent in the reverse current.

[0018] In addition to one or more of the features described herein, or as an alternative, further embodiments of the vehicle can include that the overcurrent monitor further comprises a first latch associated with the first comparator to cause a gate drive block of the gate driver to control the at least one switch in response to determining that the forward current exceeds the forward current threshold and for the forward overcurrent detection time period.

[0019] In addition to one or more of the features described herein, or as an alternative, further embodiments of the vehicle can include that the overcurrent monitor further comprises a second latch associated with the second comparator to cause the gate drive block of the gate driver to control the at least one switch in response to determining that the reverse current exceeds the reverse current threshold and for the reverse overcurrent detection time period.

[0020] In addition to one or more of the features described herein, or as an alternative, further embodiments of the vehicle can include that the operations further comprise transmitting a signal to a microprocessor in response to determining that the forward current exceeds the forward current threshold and for the forward overcurrent detection time period, or in response to determining that the reverse current exceeds the reverse current threshold and for the overcurrent detection reverse time period.

[0021] In addition to one or more of the features described herein, or as an alternative, further embodiments of the vehicle can include that the operations further comprise detecting a gate driver fault of the gate driver, and controlling the at least one switch associated with the power source using the gate driver to suppress the current in response to detecting the gate driver fault of the gate driver.

[0022] In another embodiment, an overcurrent monitor is provided for determining a forward overcurrent in current flowing out of a vehicle power supply in a forward direction or determining a reverse overcurrent in current flowing into the vehicle power supply in a reverse direction. The overcurrent monitor includes a first comparator for detecting a forward overcurrent by comparing current flowing out of the power supply in the forward direction to a forward current threshold. The overcurrent monitor also includes a second comparator for detecting a reverse overcurrent by comparing current flowing into the power supply in the reverse direction to a reverse current threshold. The overcurrent monitor further includes a first filter to receive a first output of the first comparator and apply a forward current timing threshold to the first output. The overcurrent monitor further includes a second filter to receive a second output of the second comparator and apply a reverse current timing threshold to the second output, the forward current timing threshold being greater than the reverse current timing threshold. The overcurrent monitor further includes a first latching device associated with the first comparator to cause a gate driver to control at least one switch associated with the power supply in response to determining that current flowing out of the power supply in the forward direction exceeds the forward current threshold for the forward current timing threshold. The overcurrent monitor further includes a second latching device associated with the second comparator to cause the gate driver to control the at least one switch associated with the power supply in response to determining that current flowing into the power supply in the reverse direction exceeds the reverse current threshold for the reverse current timing threshold.

[0023] The above features and advantages of the present disclosure, and other features and advantages, are readily apparent from the following detailed description, when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] Other features, aspects, and details are described below with reference to the drawings. The features, aspects, and details are intended to be illustrative and not restrictive.

[0025] Figure 1 is a diagram of a vehicle having a power supply and a fault detection circuit for performing high speed fault isolation on the power supply in accordance with one or more embodiments;

[0026] Figure 2A and 2B is a block diagram of a fault detection circuit for performing high speed fault isolation on a power supply of a vehicle in accordance with one or more embodiments; Figure 1 Figure 1 is a block diagram of a fault detection circuit for performing high speed fault isolation on a power supply of a vehicle in accordance with one or more embodiments;

[0027] Figure 3 is a table of thresholds for performing high speed fault isolation on a power supply of a vehicle in accordance with one or more embodiments;

[0028] Figure 4A and 4B ​is a flowchart of a method for performing high speed fault isolation on a power supply of a vehicle according to one or more embodiments; and

[0029] Figure 5 is a flowchart of a method for performing high speed fault isolation on a power supply of a vehicle according to one or more embodiments. DETAILED DESCRIPTION

[0030] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. As used herein, the term module refers to processing circuitry, which can include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functionality.

[0031] One or more embodiments described herein relate to high speed fault isolation for vehicle power supplies. Some modern vehicles with one or more power supplies use semiconductors to control the distribution of power throughout the vehicle. Multiple high power sources (e.g., batteries) can be connected together through power ORing switches. Even in the presence of a fault at one power input, it can be desirable to provide uninterrupted power to certain loads until the vehicle can be safely stopped. This means that a fault at one power input (e.g., a short to ground) should not cause the faultless power input switches to open, and normal operating transients should not cause any of the power input switches to open. Market available gate drivers do not have sufficient overcurrent protection to prevent a single point fault at a power input (e.g., a short to ground fault) from causing multiple power input switches to open due to simultaneous fault detection. Furthermore, market available gate drivers are unable to distinguish between normal operating transients and a legitimate low level overcurrent fault.

[0032] One or more embodiments described herein address these and other shortcomings by providing hardware and software strategies for rationalizing the location of high current faults and quickly isolating the fault from the faultless power supplies so that critical loads of the vehicle can have uninterrupted power from other power inputs until a safe stop of the vehicle or other corrective action can be implemented.

[0033] According to one or more embodiments, three types of faults can latch the gate driver of the fault detection circuit. The first fault type is overcurrent in the forward direction (e.g., current flowing out of the power supply). The second fault type is overcurrent in the reverse direction (e.g., current flowing into the power supply, a fault at the power supply input such as one power supply input shorted to ground, and current provided from the other fault-free power supply). The third fault type is a gate driver fault, which is any serious fault identified by the gate driver. Hardware can detect overcurrent in both forward and reverse directions. Hardware forward and reverse overcurrent detection thresholds can be set at different levels. The reverse overcurrent detection time for a particular power input is set to be less than the forward overcurrent detection time for other power inputs to prevent a hard short to ground from getting a false fault detection (e.g., latching those power inputs) for a fault-free power input. Both hardware forward and reverse overcurrent detection latch the gate driver (e.g., open the switch) for the corresponding power input and indicate a fault detection interrupt to the microprocessor (also referred to as “MCU”). Software can similarly detect overcurrent in both forward and reverse directions for soft short conditions and take action.

[0034] It should be appreciated that functionality of a vehicle implementing one or more embodiments described herein is improved. For example, as described, one or more embodiments can provide: fast isolation of a faulty power input; uninterrupted power supply to vehicle critical loads (e.g., driver output 250 to driver loads) even in the presence of a fault at one power input; improved survivability of high current faults on power distribution inputs, etc., including combinations and / or multiples thereof.

[0035] Figure 1 is an illustration of a vehicle 100 having a power source 102 and a fault detection circuit 104 for performing high speed fault isolation on the power source, according to one or more embodiments. The vehicle 100 can be a car, truck, van, bus, motorcycle, boat, or any other type of automobile. According to an embodiment, the vehicle 100 includes an internal combustion engine (not shown) that is fueled by gasoline, diesel, etc. According to another embodiment, the vehicle 100 is a hybrid electric vehicle that is partially or fully powered by electricity, which can be provided in whole or in part by the power source 102 (e.g., a battery). According to another embodiment, the vehicle 100 is an electric vehicle that is powered by electricity from the power source 102 (e.g., a battery). According to one or more embodiments, the vehicle 100 is an autonomous or semi-autonomous vehicle. An autonomous vehicle is a vehicle that has the capability of autonomous driving.

[0036] According to one or more embodiments, the vehicle 100 includes a power source 102 and a fault detection circuit 104. The power source 102 represents one or more power sources, which can vary in type, capacity, number, etc. Non-limiting examples of power sources include a battery (e.g., one or more batteries and / or a battery system), a power converter module (PCM) (e.g., a direct current (DC) / DC converter that provides current flow between a high voltage DC bus and a low voltage DC bus of the vehicle), another power grid (PG) (e.g., a low voltage (e.g., substantially 12 volt) feed), and / or the like, including combinations and / or multiples thereof.

[0037] The power source 102 provides and / or receives power, which can be used to power systems and / or components of the vehicle 100. More specifically, power can flow into and / or out of the power source 102. Non-limiting examples of systems and / or components of the vehicle 100 that can be powered by the power source 102 include electric motors, pumps, actuators, sensors, processing systems, displays, environmental control systems, infotainment systems, engine control units, etc., including combinations and / or multiples thereof.

[0038] The fault detection circuit 104 can use the collected current information about the power source 102 to perform high speed fault isolation of the power source 102. More specifically, the fault detection circuit 104 can detect overcurrent in the forward direction (e.g., current flowing out of the power source 102), overcurrent in the reverse direction (e.g., current flowing into the power source 102), and / or gate drive faults. For example, the fault detection circuit 104 can use a current sensor to sense a current value flowing out of the power source 102 (forward current) or flowing into the power source 102 (reverse current). That is, the fault detection circuit 104 can sense both the amount of current flowing with respect to the power source 102 and the direction of the current (forward current or reverse current). The fault detection circuit 104 compares the amount of current to a current threshold according to whether the current is a forward current or a reverse current. The forward current can have a current threshold (e.g., a forward current threshold) that is separate from a current threshold (e.g., a reverse current threshold) for the reverse current. The fault detection circuit 104 also uses time information to detect overcurrent faults in the forward and reverse directions. This enables the fault detection circuit 104 to detect overcurrent conditions in the forward direction (forward current) and the reverse direction (reverse current). The fault detection circuit 104 can also detect gate drive faults, which can be any severe fault identified by the gate drive of the fault detection circuit. Other features of the fault detection circuit 104 are now described with reference to FIGS. 2-4.

[0039] In particular, Figure 2A and 2B is a block diagram of a fault detection circuit 104 for performing high speed fault isolation of a power source 102 of a vehicle 100 according to one or more embodiments.

[0040] The fault detection circuit 104 is connected to the power source 102. In cases where multiple power sources are used, the fault detection circuit 104 can be replicated and connected to each power source. For example, in Figure 2A and 2B the vehicle 100 includes three power sources: a battery source 201, a PCM source 202, and a PG source 203. Each of the sources 201-203 has a fault detection circuit 104 associated with it. A single instance of the fault detection circuit 104 is now described with respect to the battery source 201, but it will be understood that the description applies to the fault detection circuit for each of the sources 201-203.

[0041] The fault detection circuit 104 includes switches 221, 222. According to one or more embodiments, the orientation of the switches 221, 222 can be arranged as shown or swapped. For example, the switches 221, 222 can share a common source (as shown in Figure 2A and 2B ) or can share a common drain between the switches 221, 222 (not shown). The switches 221, 222 can be any suitable type of switching device, such as an n-type metal-oxide-semiconductor (NMOS), which uses n-type metal-oxide-semiconductor field-effect transistors to implement logic gates and other digital circuits. Current can flow out of the battery source 201 through the switches and is referred to as forward current 211. Conversely, current can flow into the battery source 201 through the switches (such as from another one of the sources 202, 203) and is referred to as reverse current 212.

[0042] The fault detection circuit 104 includes a gate driver 220 to control (e.g., open / disable and close / enable) the switches 221, 222. For example, if a fault is detected (e.g., an overcurrent event), the gate driver 220 can open one or both of the switches 221, 222, which can prevent damage, for example, to the battery source 201 or another source (e.g., one of the sources 202, 203), as described herein.

[0043] The gate driver 220 includes a current sense block 223 to sense the direction (e.g., forward current 211 or reverse current 212) and magnitude (e.g., amperage) of current flowing into or out of the battery source 201. At block 226, the current from the current sense block 223 can be used to determine an overcurrent detection. According to one or more embodiments, one of the disconnect switches 221, 222 (depending on the direction of current) is used to protect the fault detection circuit 104 from damage (e.g., NMOS switch and current sensor shunt). Such overcurrent detection is useful for significant overcurrent events (e.g., where the current is significantly above a threshold (e.g., 50% more), but can not be effective in detecting less significant overcurrent events (e.g., 0.01% above a threshold). The gate driver 220 also includes a temperature sense block 224 that receives a temperature from a temperature sensor element 225 of the fault detection circuit 140, and uses the temperature at block 227 to detect an overcurrent temperature fault (e.g., temperature greater than a temperature threshold). The gate driver 220 also contains control logic 228 to control a gate drive block 229 based on blocks 226 and 227 and / or based on signals from an overcurrent monitor 230, as described in more detail herein. The control logic 228 also sends a gate driver fault status to an MCU 252 that is powered by an MCU power supply 254. For example, the MCU can perform software-based processing as described herein with respect to Figure 4A and 4B The MCU 252 generates and / or receives fault isolation control signals for each of the sources 202 and 203 via the respective fault detection circuits 104 of the sources 202 and 203.

[0044] As shown, the gate drive block 229 is connected to the source and gate terminals of the switches 221, 222, and selectively opens / closes the switches 221, 222 based on decisions of the control logic 228. For example, upon detection of an overcurrent or overtemperature event at blocks 226, 227, respectively, the control logic 228 can signal the gate drive block 229 to open one or both of the switches 221, 222, thereby protecting the battery source 201, additional sources (e.g., sources 202, 203), and / or the vehicle 100.

[0045] As described, the control logic 228 of the gate driver 220 can also be controlled by the overcurrent monitor 230 via the illustrated gate driver enable / control signals. The overcurrent monitor 230 detects one or more of overcurrent in the forward direction (forward current 211) and / or overcurrent in the reverse direction (reverse current 212). The overcurrent detection block 226 and / or the overtemperature detection block 227 detect gate driver faults (e.g., faults of the gate driver 220). A gate driver fault can be any server fault identified by the gate driver 220. The overcurrent monitor 230 can detect overcurrent in both the forward direction and the reverse direction. The hardware forward and reverse overcurrent detection thresholds can be set at different levels. According to one or more embodiments, the reverse overcurrent detection time for a particular power input is set to be less than the forward overcurrent detection time for other power inputs to prevent false fault detection (e.g., locking out those power inputs) for a hard short to ground. Both the hardware forward overcurrent detection and the reverse overcurrent detection lock out the gate driver 220 to cause the gate drive block 229 to open one or more of the switches 221, 222 for the corresponding power input (e.g., the battery source 201) and indicate a fault detection interrupt to the MCU 252. Software can similarly detect overcurrent in both the forward and reverse directions for soft short conditions and take action.

[0046] The overcurrent monitor 230 is now described in more detail. The overcurrent monitor 230 includes a first comparator 231 to detect overcurrent in the forward direction and a second comparator 232 to detect overcurrent in the reverse direction. The first comparator 231 compares the current (I monitor ) (from the current sense block 223 of the gate driver 220) to a forward current threshold (OVC_FWD_Threshold) and the output of the first comparator 231 is fed into an OR gate 233 along with the reverse of the current direction (I direction ). The OR gate 233 generates an output that is fed into a filter 237 that applies a forward overcurrent detection time period (e.g., on the order of hundreds of microseconds (ps)). If the output of the OR gate 233 exceeds the forward overcurrent detection time period determined at the filter 237 (e.g., a forward current positive time threshold), a locker 239 generates an interrupt signal to the control logic 228 of the gate driver 220 and the MCU 252 indicating a forward overcurrent event.

[0047] The second comparator 232 compares the current (I monitor ) (from the current sense block 223 of the gate driver 220) to a reverse current threshold (OVC_SCG_Threshold) and the output of the second comparator 232 is fed into an OR gate 234 along with the forward of the current direction (I direction) together into OR gate 234. OR gate 234 produces an output that is fed into filter 238 that applies a reverse overcurrent detection time period that is significantly smaller than the forward overcurrent detection time period. If the output of OR gate 234 exceeds the reverse overcurrent detection time period determined at filter 238 (e.g., a reverse current timing threshold), latch 240 generates an interrupt signal to the control logic 228 of gate driver 220 and MCU 252 that indicates a reverse overcurrent event.

[0048] According to one or more embodiments, a comparator positive feedback for either or both of the first comparator 231 and the second comparator 232 can be added for hysteresis phenomena. It should be appreciated that the Figure 2A and 2B The current thresholds and time periods described are merely examples, and other threshold and / or time period values can be used in other embodiments. It should also be appreciated that either or both of latches 239, 240 can be an SR latch or a D-flop with a set and reset.

[0049] According to one or more embodiments, fault detection circuit 104 can include additional components, such as shunts, resistors, capacitors, inductors, and / or the like, including combinations and / or multiples thereof. Assuming that steady state and transient loading / charging operations have been specified, one possible configuration of components that implement the desired hardware operations is now described. For example, the following hardware design specifications can be implemented for fault detection circuit 104.

[0050] Consider the following assumptions / constraints:

[0051] I NORMAL_FWD = normal operating steady state / transient load current in forward direction

[0052] I NORMAL_REV = normal operating steady state / transient charging current in reverse direction

[0053] I OVC_FWD_SW = required software forward overcurrent threshold > I NORMAL_FWD

[0054] I OVC_REV_SW = required software reverse overcurrent threshold > I NORMAL_REV

[0055] I OVC_FWD_HW = required hardware forward overcurrent threshold > I OVC_FWD_SW

[0056] I OVC_REV_HW = required hardware reverse overcurrent threshold > I OVC_REV_SW

[0057] IOVC_FWD_SW ≥I OVC_REV_SW

[0058] I OVC_FWD_HW ≥I OVC_REV_HW

[0059] I OVC_GD_HW = Gate Driver Overcurrent Threshold (Bi-directional) >I OVC_FWD_HW

[0060] T FILTER_GD = Gate Driver Overcurrent Shutdown Detection Filter Time (~10us)

[0061] T FILTER_FWD = Required Hardware Forward Overcurrent Detection Filter Time > T FILTER_GD

[0062] T FILTER_REV = Required Hardware Reverse Overcurrent Detection Filter Time < T FILTER_FWD & > T FILTER_GD

[0063] T DETECT_SW = Software Forward / Reverse Overcurrent Detection Time (~50ms) >> T FILTER_FWD

[0064] Temp SDN_threshold = Hardware Overtemperature Shutdown Threshold < Rated Temperature of FET

[0065] T TEMP_SDN = Hardware Overtemperature Shutdown Time

[0066] It should be appreciated that, in accordance with one or more embodiments, T FILTER_GD is significantly less than T FILTER_REV . For example, T FILTER_GD may be substantially 50% of T FILTER_REV , substantially 20% of T FILTER_REV , substantially 10% of T FILTER_REV , or less.

[0067] The shunt resistor (R SHUNT ) is selected and verified not to exceed rated power under normal steady state and transient load / charge conditions. The shunt resistor can be one or more shunt resistors in parallel to reduce power dissipation of individual components.

[0068] The MOSFETs (e.g., switches 221, 222) are selected and verified not to exceed rated power and heat under normal steady state and transient load / charge conditions. One or more field effect transistors can be injected in parallel to reduce power dissipation of individual components.

[0069] The current amplifier gain (GAIN CSProvides monitoring up to I OVC_REV_HW Reverse current and up to I OVC_FWD_HW The software for positive current.

[0070] Select the overcurrent detection comparator threshold voltage (resistive divider or precision-tuned reference voltage source) to set the hardware forward and reverse overcurrent thresholds. Hysteresis can be incorporated into the comparator threshold by adding a feedback resistor between the comparator output and the comparator positive input.

[0071] V OVC_FWD_HW =(I OVC_FWD_HW *R SHUNT )*GAIN CS

[0072] V OVC_REV_HW =(I OVC_REV_HW *R SHUNT )*GAIN CS

[0073] Design the hardware forward and reverse overcurrent filtering time (such as the time constant of a first-order resistor and capacitor low-pass filter).

[0074] Minimum T FILTER_FWD Greater than the maximum value T for the designed power input FILTER_REV This prevents simultaneous overcurrent detection / shutdown across multiple power inputs in the event of a short circuit to ground at the power input. The T... FILTER_FWD It can be set to be basically greater than T FILTER_REV Twice as big.

[0075] Verify hardware survivability under high-current fault conditions:

[0076] A very hard short-fault causes a problem in T. FILTER_GD Flowed through Gundam I OVC_GD_HW +margin forward / reverse current.

[0077] A hard ground short circuit fault caused T FILTER_REV Flowed through Gundam I OVC_GD_HW The reverse current.

[0078] Hard internal / load short circuit fault caused in T FILTER_FWD Flowed through Gundam I OVC_GD_HW The positive current.

[0079] A soft ground short circuit fault caused T DETECT_SW Flowed through Gundam I OVC_REV_HW The reverse current.

[0080] A soft internal / load short circuit fault caused in T DETECT_SW Flowed through Gundam IOVC_FWD_HW The positive current.

[0081] If the shunt resistor or FET cannot survive under any fault conditions, perform one or more of the following actions: tune the overcurrent threshold to a lower value without falling below the minimum system operability requirements; add a parallel element (shunt or FET) to reduce individual power consumption; change the value of the shunt or FET to reduce power consumption; and replace the shunt or FET with a better quality element with a higher transient operating rating.

[0082] Figure 3 Table 300 shows thresholds for performing high-speed fault isolation of the vehicle's power supply according to one or more embodiments. Table 300 illustrates... Figure 2A and 2B Thresholds for each power source (e.g., battery source 201 (also referred to as "Power Source 1"), PCM source 202 (also referred to as "Power Source 2"), and PG source 203 (also referred to as "Power Source 3")). As shown, different thresholds and detection times (as further described herein) can be set for hardware overcurrent and software overcurrent detection. For example, for hardware overcurrent detection, a forward overcurrent threshold, a reverse overcurrent threshold, a gate driver overcurrent threshold, and a gate driver overtemperature threshold can be set. For software overcurrent detection, forward and reverse thresholds can be set. Similarly, detection times can be set separately for forward and reverse overcurrent detection for hardware and software overcurrent detection, and gate driver overcurrent and gate driver overtemperature detection times can be set for hardware overcurrent detection, as shown in the figure. It should be understood that other thresholds and detection times can be implemented in other embodiments. According to one or more embodiments, the overtemperature turn-off time (T) TEMP_SDN This is a preset and not configurable threshold. The over-temperature shutdown threshold (Temp) is... SDN_threshold This limits the NMOS junction temperature within the NMOS's rated values. According to one or more embodiments, the hardware reverse overcurrent detection time can be filled in a range of essentially 75 μs to 150 μs to account for inter-component differences. Within the range of inter-component differences, the hardware forward overcurrent detection time is greater than 150 μs.

[0083] This article is aimed at Figure 4A and 4B Method 400 and Figure 5 Method 500 describes other aspects and features of the fault detection circuit 104.

[0084] Figure 4A and 4B This is a flowchart of a method 400 for performing high-speed fault isolation of a vehicle's power supply according to one or more embodiments. Method 400 can be implemented using any suitable system or device. For example, it can be implemented using... Figure 1and the fault detection circuit 104 of FIG. 2 to implement the method 400.

[0085] For example, the method 400 can be implemented using a combination of hardware and software. According to one or more embodiments, the method 400 includes a hardware portion (e.g., blocks 402, 404, 406, 408, 410, 418, 420, 422, 424) performed by some of the components shown in Figure 2A and 2B (e.g., one or more of the gate driver 220, the overcurrent monitor 230, the switches 221, 222, and / or the like), including combinations and / or multiples thereof. According to one or more embodiments, the method 400 also includes a software portion (e.g., blocks 412, 414, 416, 426, 428, 430, 432, 434, 436, 438) performed by some components shown in Figure 2A and 2B (e.g., the MCU 252). It should be understood that in other embodiments, some or all of the blocks performed by hardware in Figure 4A and Figure 4B may instead be performed by software, and / or that some or all of the blocks performed by software in Figure 4A and Figure 4B may instead be performed by hardware. The method 400 is now described with reference to Figure 1 and FIG. 2, but is not limited thereto.

[0086] At block 402, a power source is connected. For example, the power source 102 (which can be one or more of the battery source 201, the PCM source 202, and / or the PG source 203) is connected to the vehicle 100. At block 404, a switch (e.g., one of the switches 221, 222) is enabled (closed) and the fault detection circuit 104 is enabled.

[0087] At blocks 406-416, various determinations are made using the fault detection circuit 104, which are now described in more detail.

[0088] Blocks 406-410 are now described, which relate to hardware-based overcurrent detection. At block 406, it is determined whether the current is a forward current (e.g., I_direction = forward) and whether the current is greater than a hardware current threshold for a forward overcurrent detection time period (T filter_fwd ). At block 408, it is determined whether the current is a reverse current (e.g., I_direction = reverse) and whether the current is greater than a hardware reverse current threshold for a reverse overcurrent detection time period (T filter_rev ). At block 410, it is determined whether the gate driver 220 is experiencing an overcurrent fault or an overcurrent temperature fault.

[0089] Blocks 412-416 are now described, which relate to software-based overcurrent detection. At block 412, it is determined whether the current is a forward current (e.g., I direction = forward) and whether the current is greater than a software current threshold. At block 414, it is determined whether the current is a reverse current (e.g., I direction = reverse) and whether the current is greater than a software reverse current threshold. At block 416, it is determined whether disabling (opening) a switch (e.g., one of switches 221, 222) is desired.

[0090] If any of blocks 406-416 results in a negative response (any of blocks 406-416 is “No”), it is determined that no fault has occurred. In this case, method 400 returns to block 404 as shown to continue fault detection.

[0091] However, if any of blocks 406-416 results in a positive response (any of blocks 406-416 is “Yes”), a fault condition is detected, and method 400 continues to take action (e.g., disabling (opening) a switch (e.g., one of switches 221, 222)), as described.

[0092] 0070If block 406 results in a positive response (block 406 is “Yes”), then method 400 proceeds to block 418, and a locker 239 of overcurrent monitor 230 locks forward overcurrent detection. This can occur, for example, when an internal short or load current exceeds the capacity of an electronic control unit (ECU) of vehicle 100. If block 408 results in a positive response (block 408 is “Yes”), then method 400 proceeds to block 420, and a locker 240 of overcurrent monitor 230 locks reverse overcurrent detection. This can occur, for example, in the presence of a hard short to ground. If block 410 results in a positive response (block 410 is “Yes”), then method 400 proceeds to block 422, and gate driver 220 locks gate driver fault detection (i.e., 226 or 227) via control logic 228. This can occur, for example, when there is a hard short to ground, there is an internal short, load current significantly exceeds ECU capacity, temperature of one or more of switches 221, 222 exceeds a threshold, etc., including combinations and / or multiples thereof. After either of blocks 418, 420, or 422 is executed, method 400 proceeds to block 424, in which overcurrent monitor 230 locks gate driver 220 to de-energize (open) one or more of switches 221, 222. Also at block 424, overcurrent monitor 230 generates an interrupt to MCU 252 to indicate that a hardware fault was detected, as described above. Figure 2A and 2BAt block 426, the method 400 includes software operations to rationalize which hardware fault has occurred (forward overcurrent, reverse overcurrent, gate driver overcurrent / overtemperature) by reading the hardware latched signals from the overcurrent monitor 230.

[0093] If block 412 results in a positive response (block 412 is "Yes"), the method 400 proceeds to block 428, which includes software operations to rationalize a forward overcurrent due to an internal short or a load current exceeding the capacity of the ECU of the vehicle 100. If block 414 results in a positive response (block 414 is "Yes"), the method 400 proceeds to block 430, which includes software operations to rationalize the presence of a soft short to ground.

[0094] After either of blocks 428 or 430 is executed, or if block 416 results in a positive response (block 416 is "Yes"), the method 400 proceeds to block 432, which includes software operations to latch the gate drive block 229 as disabled (off), thereby opening one or both of the switches 221, 222.

[0095] After either of blocks 426 and / or 432 is executed, the method 400 then proceeds to block 434, which includes software operations to determine whether to attempt a retry. If not (block 434 is "No"), at block 436 the software causes the gate drive block 229 to be latched as disabled (off). If it is determined to attempt a retry (block 434 is "Yes"), then the method 400 proceeds to block 438, which includes software operations to hold the reset of the overcurrent monitor 230 and the gate driver 220 for a short duration (e.g., 100 ms), and then release the reset. The method 400 then returns to block 404, and the method 400 can be repeated.

[0096] Additional procedures can also be included, and it should be understood that Figure 4A and 4B The procedures depicted in the figures are representative of example procedures, and other procedures can be added or existing procedures can be removed, modified, or rearranged, without departing from the scope of the present disclosure. It should be understood that Figure 4A and 4B The procedures depicted in the figures can be implemented as program instructions stored on a non-transitory computer-readable storage medium that when executed by a processor of a computing system, cause the processor to perform the procedures described herein.

[0097] Figure 5 is a flowchart of a method 500 for performing high speed fault isolation on a power supply of a vehicle, in accordance with one or more embodiments. The method 500 can be implemented using any suitable system or device. For example, the method 500 can be implemented using the system 200 of FIG. 2. Figure 1The method 500 can be implemented with the fault detection circuit 104 of FIG. 2. Referring now to FIG. 5, a method 500 for detecting a fault in an electrical system of a vehicle is depicted and described. The method 500 can be implemented with the fault detection circuit 104 of FIG. 2. Referring now to FIG. 5, Figure 1 The method 500 is described with respect to FIG. 2, but is not limited thereto.

[0098] At block 502, the overcurrent monitor 230 receives a current from a current sensor (e.g., the current sense block 223) associated with a power source (e.g., the power source 102) of a vehicle (e.g., the vehicle 100). At block 504, the overcurrent monitor 230 determines a direction of the current with respect to the power source. That is, a determination is made as to whether the current is a forward current (e.g., the forward current 211) flowing out of the power source or a reverse current (e.g., the reverse current 212) flowing into the power source. At block 506, in response to determining that the direction of the current with respect to the power source is a forward current flowing out of the power source, the overcurrent monitor 230 determines whether the forward current exceeds a forward current threshold for a forward overcurrent detection time period by comparing the current to the forward current threshold. At block 508, in response to determining that the direction of the current with respect to the power source is a reverse current flowing into the power source, the overcurrent monitor 230 determines whether the reverse current exceeds a reverse current threshold for a reverse overcurrent detection time period that is shorter than the forward overcurrent detection time period by comparing the current to the reverse current threshold. At block 510, in response to determining that the forward current exceeds the forward overcurrent detection current threshold for the forward overcurrent detection time period, or in response to determining that the reverse current exceeds the reverse current threshold for the reverse overcurrent detection time period, the gate driver 220 causes at least one switch (e.g., at least one of the switches 221, 222) associated with the power source to suppress the current.

[0099] Additional processes can also be included, and it should be understood that Figure 5 The processes depicted in the figures represent illustrative stages that can be added, omitted, modified, rearranged, or combined, and in which other processes can be added, without departing from the scope of the disclosure. It should be understood that Figure 5 The processes depicted in the figures can be implemented as program instructions stored on a non-transitory computer-readable storage medium that when executed by a processor of a computing system, cause the processor to perform the processes described herein.

[0100] The term “a” does not denote a limitation of quantity, but rather is used to mean that “at least one” of the referenced item is present. Unless otherwise clearly indicated, the term “or” means “and / or.” Reference throughout this specification to “an aspect” means that a particular element described in connection with the aspect is included in at least one aspect described herein and can be present or can not be present in other aspects. Additionally, it is to be appreciated that described elements can be combined in a variety of ways without departing from the scope of the disclosure.

[0101] When an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0102] Unless otherwise indicated herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

[0103] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0104] While the foregoing disclosure has been described in reference to exemplary embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the disclosure without departing from the central scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed, but will include all embodiments falling within the scope of the disclosure.

Claims

1. A method comprising: receiving a current from a current sensor associated with a power source of a vehicle; determining a direction of the current relative to the power source; in response to determining that the direction of the current relative to the power source is a forward current flowing out of the power source, determining, by an overcurrent monitor, whether the forward current exceeds a forward current threshold and persists for a forward overcurrent detection time period by comparing the current to the forward current threshold; in response to determining that the direction of the current relative to the power source is a reverse current flowing into the power source, determining, by the overcurrent monitor, whether the reverse current exceeds a reverse current threshold and persists for a reverse overcurrent detection time period that is shorter than the forward overcurrent detection time period by comparing the current to the reverse current threshold; and in response to determining that the forward current exceeds the forward current threshold and persists for the forward overcurrent detection time period, or in response to determining that the reverse current exceeds the reverse current threshold and persists for the reverse overcurrent detection time period, controlling at least one switch associated with the power source using a gate driver to suppress the current.

2. The method of claim 1, wherein, the current sensor is disposed in the gate driver.

3. The method of claim 2, wherein, the gate driver includes the current sensor, a temperature sensing block to receive a temperature from a temperature sensor element, an overcurrent detection block, an overtemperature detection block, a gate drive block, and control logic.

4. The method of claim 3, wherein, the gate drive block of the gate driver controls the at least one switch associated with the power source.

5. The method of claim 1, wherein the overcurrent monitor includes a first comparator to detect an overcurrent in the forward current and a second comparator to detect an overcurrent in the reverse current.

6. The method of claim 5, wherein the overcurrent monitor further includes a first latched associated with the first comparator to cause a gate drive block of the gate driver to control the at least one switch in response to determining that the forward current exceeds the forward current threshold and persists for the forward overcurrent detection time period.

7. The method of claim 6, wherein the overcurrent monitor further includes a second latched associated with the second comparator to cause the gate drive block of the gate driver to control the at least one switch in response to determining that the reverse current exceeds the reverse current threshold and persists for the reverse overcurrent detection time period.

8. The method of claim 1, further comprising transmitting a signal to a microprocessor in response to determining that the forward current exceeds the forward current threshold and persists for the forward overcurrent detection time period, or in response to determining that the reverse current exceeds the reverse current threshold and persists for the reverse overcurrent detection time period.

9. The method of claim 1, further comprising: detecting a gate driver fault of the gate driver; and In response to detecting the gate driver failure of the gate driver, the at least one switch associated with the power source is controlled using the gate driver to suppress the current.

10. The method of claim 1, wherein, The at least one switch comprises an N-type metal oxide semiconductor.

Images