Patent Application
20190280464
This description relates to an ignition circuit that can be used in a high-voltage battery system.
Ignition systems can use a variety of high voltage devices such as insulated-gate bipolar transistor (IGBT) devices, ignition coils, and so forth. In some situations, failure of one or more components in an ignition system can cause catastrophic damage to elements of the system and/or a vehicle in which the system is implemented. For instance, a shorted IGBT device may overload a corresponding ignition coil. Such overloading of the ignition coil may result in irreparable damage to the ignition coil and could, in some instances, result in the ignition system causing an engine fire (e.g., due to the ignition coil combusting as a result of excessive current and associated heating in the ignition coil). The likelihood of failures and damage to ignition systems can be increased when using, for example, high-voltage batteries.
In an implementation, a circuit can include a switch circuit configured to be electrically connected to an ignition circuit, a high-side path control circuit electrically connected between the switch circuit and a battery terminal, and a low-side path control circuit electrically connected between the switch circuit and a ground terminal. The circuit can include a control circuit configured to detect an abnormal condition associated with the ignition circuit where the control circuit can be configured to activate the high-side path control circuit in response to the detected abnormal condition.
In another implementation, a circuit can include a switch circuit configured to be electrically connected to an ignition circuit, a high-side path control circuit electrically connected between the switch circuit and a battery terminal, and a low-side path control circuit electrically connected between the switch circuit and a ground terminal. The circuit can also include a control circuit configured to detect an over dwell-time condition associated with the ignition circuit where the control circuit is configured to deactivate the low-side path control circuit in response to the over dwell-time condition such that energy from the ignition circuit is dissipated via the switch circuit.
In yet another implementation, a circuit can include a switch circuit configured to be electrically connected to an ignition circuit, and a high-side path control circuit defining a looped path including the switch circuit, the battery terminal, and terminals configured to be electrically connected with the ignition circuit when the high-side path control circuit is activated. The circuit can include a low-side path control circuit defining a grounded path including the switch circuit, a first ignition circuit terminal, a second ignition circuit terminal, and a ground terminal, when the low-side path control circuit is activated. The first ignition circuit terminal and the second ignition circuit terminal can be configured to be electrically connected with ignition circuit. The circuit can include a control circuit configured to detect an over-current condition associated with the ignition circuit where the control circuit is configured to trigger oscillation between the looped path and the grounded path in response to the detected over-current condition.
In the drawings, like elements are referenced with like reference numerals.
An inductive discharge ignition system, such as the ignition systems described herein, can be used to ignite a fuel mixture in a cylinder of an internal combustion engine. Ignition systems may operate in relatively harsh environments and, therefore, can be subject to failure as a result of these operating conditions, as well as other factors that may cause system failure. These ignition systems can include devices configured to operate at relatively high voltages (e.g., 400 V or more) because the devices can be used as, for example, ignition coil drivers and as protection circuits for the ignition coil drivers. The ignition systems described herein can be configured to operate within and manage these harsh and high-voltage environments.
For example, the ignition systems described herein can be configured to dissipate substantial power, when the ignition systems are used to protect the ignition coil and ignition/battery system in response to an abnormal condition (which can also be referred to as an abnormal mode or failure mode). As a specific example, in response to detecting an abnormal condition, the ignition systems described herein can be configured to activate a protection mode (e.g., a protection strategy), which can include a current-limit protection mode or a soft shutdown protection mode. During a current-limit protection mode or a soft shutdown protection mode, significant levels of power can be managed by the ignition systems described herein.
The ignition systems described herein can include circuits configured to manage protection modes at low power in response to an abnormal condition. The low-power management of protection modes can be particularly advantageous because the ignition systems described herein can then be used in wide variety of applications with a wider range of operating conditions than known ignition systems. For example, the ignition systems described herein can be configured to manage power in ignition systems used in low-voltage or high-voltage battery applications. Without the low-power management modes described herein, the level of power dissipation during protection could be an issue in even relatively low-voltage battery systems (e.g., 14 V battery systems). The ignition systems described herein can be configured to manage power dissipation during activation of protection modes in even relatively high-voltage battery systems (e.g., 24 V battery systems, 36 V battery systems, 48 V battery systems). In addition, the ignition systems described herein can be configured to manage power dissipation during activation of protection modes in response to spikes in battery voltage (e.g., battery voltage spikes from 14 V to 24 V to 48 V) that occur during jump starts, load dump conditions, an/or so forth. Without the low-power management during protection modes, the power dissipation during protection in a relatively high-voltage battery systems application can be, for example, more than 2 times (e.g., 3 times, 5 times, 10 times) the power dissipation in a relatively low-voltage battery applications.
As shown in
The path control circuits P are configured to control energy (e.g., current) along various paths within the ignition control system 150. In some implementations, the high-side path control circuit P1 and the low-side path control circuit P2 are configured to control the routing of energy from the ignition circuit 130 within the ignition control circuit 150.
As shown in
The high-side path control circuit P1 can be referred as a high-side device because of the relative orientation of the high-side path control circuit P1 with respect to the low-side path control circuit P2. The high-side path control circuit P1 is coupled to a high side of the low-side path control circuit P2. The high-side path control circuit P1 can function as a complementary pair with the low-side path control circuit P2.
Activation of a circuit, such as the high-side path control circuit P1, the low-side path control circuit P2, and/or the switch device SW includes, for example, changing to an activation state or on-state, turning on or shorting across the circuit so that energy may flow across the circuit from one side of the circuit to the other side of the circuit. Deactivation of a circuit includes, for example, changing to a deactivation state or off-state, turning off or blocking by the circuit so that energy may not flow (e.g., may be limited) across the circuit from one side of the circuit to the other side of the circuit.
Under normal operation, the control circuit 110 is configured to trigger charging of the ignition coil 132 using a battery (e.g., a high-voltage battery at 48 V) coupled to the battery terminal VBAT by activating the low-side path control circuit P2 and the switch device SW. In some implementations, the low-side path control circuit P2 can be activated by the control circuit 110 before the switch device SW is activated by the control circuit 110.
When a spark is to be generated by the spark plug SP, the switch device SW can be rapidly turned off by the control circuit 110, while the low-side path control circuit P2 is maintained in an activated state by the control circuit 110. In some implementations, when a spark is to be generated by the spark plug SP, the switch device SW can be rapidly turned off by the control circuit 110, while the low-side path control circuit P2 is turned off with a delay time by the control circuit 110. During spark generation, the high-side path control circuit P2 can be controlled by the control circuit 110 to remain in a deactivated state. The ECU 140 can be configured to trigger the timing, via the control circuit 110, of generation of the spark.
In some implementations, the high-side path control circuit P1 and the low-side path control circuit P2 are configured to control (e.g., manage) energy from the ignition circuit 130 in response to detecting an abnormal condition (e.g., a failure). The high-side path control circuit P1 and the low-side path control circuit P2 can be controlled by the control circuit 110 to route energy from the ignition circuit 130 within the ignition control circuit 150 in response to an abnormal condition so that components within the ignition circuit 130 are protected. Specifically, the control circuit 110 can be configured to use the high-side path control circuit P1 and the low-side path control circuit P2 within a protection mode so that components (e.g., switch device SW) within the ignition system 100 are protected.
The control circuit 110 can be configured to control path control circuits P during different protection modes in response to detecting various types of abnormal conditions. The abnormal conditions can include, for example, a short-circuit condition (also can be referred to as a short failure), an over-current condition (can be referred to as a current-limit failure), an over dwell-time condition (can be referred to as a dwell-time failure), an over-voltage condition, an over-temperature condition, and/or so forth.
A short condition can occur, for example, when the ignition coil 132 and/or the switch device SW are shorted. An over-current condition can occur, for example, when a current (e.g., a primary current) through the ignition coil 132 exceeds a threshold current limit (e.g., 10 A, 15 A, 20 A). More details regarding the primary current are described in connection with at least
In some implementations, changes in primary current (e.g., bad ignition coil 132, over dwell-time condition, or high battery voltage transients) can indicate deterioration of components in such the ignition circuit 130, which can, result in a current that is above a desired current limit (overcurrent), or can indicate that energy is being dissipated unnecessarily in the ignition coil 132. Such overcurrents, or unnecessary (or undesirable) energy dissipation, can cause damage to the ignition coil 132 (e.g., the primary winding) and/or the switch device SW that is used as a switch to control charging and discharging of the ignition coil 132. Such damage or abnormal conditions (e.g., failure conditions) may cause the ignition system 100 to not function properly and/or could result in hazardous conditions, such as a fire. Accordingly, current-limit protection implemented by the ignition control circuit 150 can be critical.
In response to a short condition, the low-side path control circuit P2 can be deactivated by the control circuit 110 to protect the ignition system 100. In some implementations, in response to a short condition, the switch device SW and/or the high-side path control circuit P1 can be deactivated in addition to the low-side path control circuit P2. For example, in some implementations, in response to a short condition, both the high-side path control circuit P1 and the low-side path control circuit P2 can be deactivated to protect the ignition system 100. In some implementations, in response to a short condition, both the switch device SW and the low-side path control circuit P2 can be deactivated to protect the ignition system 100. In some implementations, in response to a short condition, the switch device SW, the high-side path control circuit P1, and the low-side path control circuit P2 can be deactivated to protect the ignition system 100. In such implementations, the low-side path control circuit P2 can function as a fuse (e.g., a solid-state fuse) for the ignition system 100 (and the ignition control circuit 150).
In response to an over dwell-time condition, a soft shutdown (SSD) protection mode can be activated by the control circuit 110. During the SSD protection mode, the low-side path control circuit P2 can be deactivated by the control circuit 110 and the switch device SW can be used to dissipate energy stored in the ignition coil 132. In some implementations, during the SSD protection mode, the switch device SW can be controlled in, for example, a linear mode to dissipate energy stored in the ignition coil 132. The level of energy dissipated during the SSD protection mode can be managed through the switch device SW in a desirable fashion by deactivating the low-side path control circuit P2 during dissipation of energy using the switch device SW. Accordingly, the switch device SW can be protected in a desirable fashion without damaging the switch device SW.
By controlling the switch device SW and/or the high-side path control circuit P1, power dissipation from the ignition coil 132 can be controlled by the control circuit 110 during the SSD protection mode. In some implementations, the control circuit 110 can regulate (e.g., control) current through the ignition coil 132. Specifically, the control circuit 110 can control power dissipation in a pre-defined profile. In some implementations, the control circuit 110 can regulate (e.g., control) a slew rate of the current through the ignition coil 132. In addition, the control circuit 110 can regulate (e.g., control) current through the ignition coil 132 independent of a voltage of a battery electrically connected to the battery terminal VBAT.
Referring back to
In some implementations, the current-limit protection described herein can prevent damage or hazardous conditions caused as a result of continuing to draw current through the primary winding of the ignition coil 132 (and an associated switch device SW) once the primary winding is fully charged (which can be referred to as charging saturation) and/or when the magnetic core of the ignition coil 132 has been magnetically saturated. The current-limit protection modes described herein also can protect the switch device SW.
In some implementations, the control circuit 110 can be configured to switch (e.g., alternately switch) between the high-side path control circuit P1 and the low-side path control circuit P2 at a specified frequency (e.g., at a frequency greater than 1 kHz (e.g., between 1 kHz and 20 kHz)) when in the current-limit protection mode. In other words, the control circuit 110 can be configured to trigger activation of the high-side path control circuit P1 and/or the low-side path control circuit P2 at a specified frequency (e.g., at a frequency greater than 1 kHz (e.g., between 10-20 kHz)) when in the current-limit protection mode. In some implementations, the frequency can be dynamically adjusted based on the current through the ignition coil 132. In some implementations, the frequency can be a pre-defined frequency.
In some implementations, the timing ratio (e.g., duty ratio) of activation/deactivation of the high-side path control circuit P1 and the low-side path control circuit P2 can be pre-defined based on the current through the ignition coil 132 (e.g., during current-limit protection mode). In some implementations, the timing ratio (e.g., duty ratio) of activation/deactivation of the high-side path control circuit P1 and the low-side path control circuit P2 can be dynamically (e.g., periodically) adjusted based on the current through the ignition coil 132 (e.g., during current-limit protection mode). In some implementations, the timing ratio (e.g., duty ratio) of activation/deactivation of the high-side path control circuit P1 and the low-side path control circuit P2 can be increased or decreased based on the current through the ignition coil 132. For example, a duration (e.g., time period) of activation of the high-side path control circuit P1 and the low-side path control circuit P2 can be longer than a duration of deactivation of the high-side path control circuit P1 and of the low-side path control circuit P2 based on the current through the ignition coil 132. As another example, a duration of activation of the high-side path control circuit P1 and the low-side path control circuit P2 can be shorter than a duration of deactivation of the high-side path control circuit P1 and of the low-side path control circuit P2 based on the current through the ignition coil 132.
When in the looped path configuration, the ignition coil 132 may be discharging (small conduction loss), and when in the grounded path configuration, the ignition coil 132 may be charging (e.g., charging via the battery electrically connected to the battery terminal VBAT). Thus, by switching between these path configurations, the current through the ignition coil 132 may be limited or maintained at a specified current limit. The current can be maintained about a current set point (or below a current limit) within a relatively tight range by switching between charging (grounded path) and discharging (looped path). The current can oscillate within a range about a current set point (or below a current limit) when switching between charging (grounded path) and discharging (looped path). In some implementations, some conduction loss may occur when switching between the looped path and the grounded path. Switching at a relatively high frequency (e.g., greater than 1 kHz) can help to maintain a tight range around a current limit set point.
As shown in
As shown in
In some implementations, the switching between the grounded path configuration and the looped path can be performed with a symmetric timing (e.g., even timing). For example, alternating between the grounded path and the looped path can be performed with symmetric timing during cycles (e.g., same time period for grounded path and the looped path). In some implementations, the switching between the grounded path configuration and looped path can be performed with asymmetric timing (e.g., uneven timing). For example, alternating between the grounded path and the looped path can be performed with asymmetric timing during cycles (e.g., grounded path using for longer periods of time than the looped path). In some implementations, the symmetric or asymmetric handling of the switching between the grounded path and looped path can depend on the elements included in each of the paths (e.g., sizes of MOSFET devices, battery voltage, and/or ignition coil 132 primary inductance). In other words, in some implementations, the timing ratio (e.g., duty ratio) of activation/deactivation of the high-side path control circuit P1 and the low-side path control circuit P2 can be asymmetric. For example, a duration of activation of the high-side path control circuit P1 can be greater than a duration of activation of the low-side path control circuit P2 based on the current through the ignition coil 132. In such situations, the duration of deactivation of the high-side path control circuit P1 can be less than the duration of deactivation of the low-side path control circuit P2. As another example, a duration of activation of the high-side path control circuit P1 can be less than a duration of activation of the low-side path control circuit P2 based on the current through the ignition coil 132. In such situations, the duration of deactivation of the high-side path control circuit P1 can be greater than the duration of deactivation of the low-side path control circuit P2.
Referring back to
In some implementations, the control circuit can be configured to switch between the SSD protection mode and the current-limit protection mode (e.g., from the current-limit mode to SSD protection mode). For example, if during implementation of a current-limit protection mode a dwell-time limit is exceeded, the ignition control circuit 150 can be configured to implement (e.g., commence implementation of) a SSD protection mode.
The switch circuit 120 includes as a switch device (e.g., switch device SW) an IGBT device IGBT1. Because the IGBT device IGBT1 can have a high input impedance, low conduction loss, relatively high switching speed, and/or robustness, the IGBT device IGBT1 can operate (e.g., integrate) well with the ECU 140 and integrated circuits (ICs), which are often implemented using complementary metal-oxide semiconductor processes. The switch circuit 120 also includes a resistor-diode network (network) R1. In some implementations, the resistor-diode network R1 can be excluded. The network R1, and specifically the Zener diodes between ICT2 and the IGBT device IGBT1 gate terminal, can be configured to define a high-voltage clamp for the ignition control circuit 150.
As shown in
In this implementation, the high-side path control circuit P1 is a transistor device M1, and the low-side path control circuit P2 is a transistor device M2. Specifically, in this implementation, the high-side path control circuit P1 is an N-type MOSFET (NMOS) device M1, and the low-side path control circuit P2 is an NMOS device M2. In some implementations, the high-side path control circuit P1 can be, or can include, a diode.
In some implementations, the transistor device M1 and the transistor device M2 can be the same size (e.g., same width and/or same length). In some implementations, the transistor device M1 and the transistor device M2 can be different sizes (e.g., different width and/or different length).
As shown in
In an implementation, terminal T1 can be used to communicate one or more signals, from the ignition control circuit 150 to the ECU 140, that indicate occurrence of an abnormal condition, such as those discussed herein, and/or to indicate that the ignition control circuit 150 is operating normally or as expected. In some implementations, the terminal T1 could be a single bi-directional terminal configured to both send and receive signals, such as the signals described herein.
In
As shown in
The terminals T4 and T5 can be terminals through which the high-side path control circuit P1 (e.g., NMOS device M1) and the low-side path control circuit P2 (e.g., NMOS device M2) are controlled (e.g., driven, triggered). The terminal T6 of the control circuit 110 can be a ground terminal that is connected with an electrical ground for the control circuit 110.
The ignition coil 132 has a primary coil electrically coupled to the ignition circuit terminals ICT1 and ICT2, and the ignition coil 132 has a secondary coil electrically coupled to the switch circuit S3 and the spark plug SP. In ignition circuit implementations, a ratio of a number of windings in the primary coil to a number of windings in the secondary coil can vary. For example, the number of windings in the primary coil can be less than the number of windings in the secondary coil (e.g., step-up). In still some implementations, the number of windings in the primary coil can be equal to (e.g., substantially equal to) the number of windings in the secondary coil.
A current in a primary winding (e.g., an inductor) of the ignition coil 132 (e.g., a magnetic core transformer), which can be referred to as a primary current, can be dependent on a variety of components and factors. In the ignition control circuit 150, changes in the primary current (as compared to the primary current expected during normal operation) can indicate improper operation of the ignition system 100. This improper operation can be caused by failure of one or more components in the ignition circuit 130, the ECU 140, the ignition control circuit 150, and/or so forth.
The ignition control circuit 150 of
The control handling circuit 210 includes a low-side path control driver 217 and a high-side path control driver 218 that are configured to, for example, control (e.g., drive, trigger), respectively, the low-side path control circuit P1 and the low-side path control circuit P2 shown in at least
The control handling circuit 210 can be configured to detect one or more abnormal conditions (e.g., failure modes) such as an over-current condition, an over dwell-time condition, a short condition, an over-voltage condition, an over-temperature condition, and/or so forth. The control handling circuit 210 can be configured to detect one or more of these abnormal conditions based on one or more abnormal conditions 211. For example, the control handling circuit 210 can be configured to detect an over dwell-time condition based on a dwell-time threshold stored as or implemented by the abnormal conditions 211. In some implementations, the control handling circuit 210 can be configured to detect a failure using the resistor R2. In some implementations, one or more of the abnormal conditions 211 can be implemented at least in part as a hardware circuit.
The control handling circuit 210 includes a limit controller 213, an SSD controller 214, and a short controller 215. These controllers are configured to implement various protection modes by triggering control of, for example, the switch device SW, the high-side path control circuit P1, and/or the low-side path control circuit P2 using, respectively, the switch driver 216, the high-side path control driver 218, and/or the low-side path control driver 217. In some implementations, the control handling circuit 210 can include other controllers (not shown) that can be used to trigger control of the switch device SW, the high-side path control circuit P1, and/or the low-side path control circuit P2 in response to a variety of abnormal conditions.
In response to detection of a over-current condition using the control handling circuit 210, the limit controller 213 can be configured to implement a current-limit protection mode by, for example, triggering switching between the high-side path control circuit P1 and the low-side path control circuit P2 using, respectively, the low-side path control driver 217 and the high-side path control driver 218. In response to detection of an over dwell-time condition using the control handling circuit 210, the SSD controller 214 can be configured to implement an SSD protection mode by controlling, for example, the switch device SW, the high-side path control circuit P1, the low-side path control circuit P2 using, respectively, the switch driver 216, the high-side path control driver 218, and the low-side path control driver 217. In response to detection of a short failure using the control handling circuit 210, the short controller 215 can be configured to implement short protection mode by controlling, for example, the low-side path control circuit P2 using the low-side path control driver 217.
As shown in
The input buffer 220 of the ignition control circuit 110 in
The voltage regulator 230, when implemented in the ignition control circuit 110, can receive the battery voltage VBAT and, based on that battery voltage, provide reference voltages, direct-current voltages, etc. used in the ignition control circuit 110 of
In some implementations, in response to detecting an abnormal condition (e.g., a failure mode in the ignition coil 132 and/or magnetic saturation of the ignition coil 132) the control handling circuit 210 can be configured to send a signal to the ECU 140 to indicate the detected condition. In some implementations, the ECU 140 can be configured to adjust the command signal to control operation of the switch device SW, the high-side path control circuit P1, the low-side path control circuit P2 to protect the ignition system 100 from damage (e.g., prevent a dangerous condition, such as a fire from occurring).
A low-side path control circuit is deactivated in response to the over dwell-time condition (block 620). The low-side path control circuit can be, for example, the low-side path control circuit P2 shown in
A high-side path control circuit is activated or deactivated in response to the over dwell-time condition (block 630). The high-side path control circuit can be, for example, the high-side path control circuit P1 shown in
A switch device is operated in linear mode in response to the over dwell-time condition to dissipate energy from the ignition circuit (block 640). The switch device can be, for example, the switch device SW shown in
Oscillation between a looped path and a grounded path is performed in response to the detected over-current condition (block 720). An example looped path is shown in
As shown in
In some implementations, the current could be limited, during different times periods, to different current limits. For example, the current could be limited to a first current limit between times Q1 to Q2 and a second (and different (e.g., higher, lower)) current limit between times Q3 to Q4.
The table below illustrates a comparison of values from a known ignition control system (system B) and the ignition control system operation illustrated in
As shown in
It will be understood that, in the foregoing description, when an element is referred to as being on, connected to, electrically connected to, coupled to, or electrically coupled to another element, it may be directly on, connected or coupled to the other element, or one or more intervening elements may be present. In contrast, when an element is referred to as being directly on, directly connected to or directly coupled to another element, there are no intervening elements present. Although the terms directly on, directly connected to, or directly coupled to may not be used throughout the detailed description, elements that are shown as being directly on, directly connected or directly coupled can be referred to as such. The claims of the application, if any, may be amended to recite exemplary relationships described in the specification or shown in the figures.
As used in this specification, a singular form may, unless definitely indicating a particular case in terms of the context, include a plural form. Spatially relative terms (e.g., over, above, upper, under, beneath, below, lower, and so forth) are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. In some implementations, the relative terms above and below can, respectively, include vertically above and vertically below. In some implementations, the term adjacent can include laterally adjacent to or horizontally adjacent to.
Implementations of the various techniques described herein may be implemented in (e.g., included in) digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Portions of methods also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).
Some implementations may be implemented using various semiconductor processing and/or packaging techniques. Some implementations may be implemented using various types of semiconductor processing techniques associated with semiconductor substrates including, but not limited to, for example, Silicon (Si), Gallium Arsenide (GaAs), Gallium Nitride (GaN), Silicon Carbide (SiC) and/or so forth.
While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the scope of the implementations. It should be understood that they have been presented by way of example only, not limitation, and various changes in form and details may be made. Any portion of the apparatus and/or methods described herein may be combined in any combination, except mutually exclusive combinations. The implementations described herein can include various combinations and/or sub-combinations of the functions, components and/or features of the different implementations described.
