Patent Description:
Solid state devices, such as solid state switches, are used in various applications such as in circuit breakers, e-Fuses, etc. In these types of applications, the solid state devices may remain in the same state for extended periods of time. For example, a solid state device of a circuit breaker may remain in an on state where the solid state device is conducting for years. The solid state device will turn off and close to stop conducting if there is an abnormal condition such as an overload or short circuit. Unfortunately, there is no way to test the solid state device to see if the solid state device is operating correctly and will be able to completely turn off in the event of the abnormal condition. This can result in catastrophic failures and damage.

<CIT> discloses a semiconductor module in a power system of an apparatus. The semiconductor module includes a semiconductor switch, a voltage applying device configured to apply a first voltage to the semiconductor switch in an off-state in a case where the apparatus is not in practical use, and a leak detecting circuit configured to detect a leak current from the semiconductor switch. The first voltage is equal to or higher than a rated voltage of the apparatus. The rated voltage of the apparatus is a rated voltage when the apparatus is in practical use.

One embodiment relates to an apparatus according to claim <NUM>. Another embodiment relates to a method according to claim <NUM>.

To the accomplishment of the foregoing and related ends, the following description and annexed drawings set forth certain illustrative aspects and implementations. These are indicative of but a few of the various ways in which one or more aspects may be employed. Other aspects, advantages, and novel features of the disclosure will become apparent from the following detailed description when considered in conjunction with the annexed drawings.

The claimed subject matter is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. It may be evident, however, that the claimed subject matter may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the claimed subject matter.

Various devices, such as e-Fuses and circuit breakers, may utilize solid state devices that operate in either an on state or an off state. These solid state devices may comprise solid state switches, metal-oxide-semiconductor field-effect transistors (MOSFETs), etc. A solid state device may transition from one of the states to another state based upon a voltage applied to a gate of the solid state device. Once the voltage of the gate reaches a threshold voltage Vth, then the solid state device may change states, such as where the solid state device is turned on and starts conducting. In certain applications, the solid state device may remain in a particular state for an extended period of time. This period of time could be years, such as where a solid state device of a circuit breaker is in an on state until an abnormal condition of an electric supply network occurs such as an overload or short circuit. Because the solid state device remains in one state for such a long period of time, there is no way to verify that the solid state device is operating correctly and will be able to transition states when needed such as to safely turn off when the abnormal condition occurs. This can lead to catastrophic failures and damage.

The health and operability of the solid state device may deteriorate over time due to various reasons such as stress on the solid state device. One issue that can occur is that the threshold voltage Vth of the gate can drift over time, which can lead to excessive leakage current, leakage current due to a drain source on resistance (RDSon) being too low, and/or failure where the solid state device cannot switch states such as to turn off safely. As the threshold voltage Vth drifts towards <NUM>, the solid state device may not even be able to turn off. High leakage currents due to this drift causes health deterioration of the apparatus comprising the solid state device, such as where there is always current flowing through the solid state device to a secondary side of the apparatus. This could lead to a high voltage condition on the secondary side that should otherwise be turned off. If the solid state device cannot completely shut off, then the solid state device will operate similar to a current source and deliver a significant amount of current (e.g., <NUM> to <NUM> milliamps) that can cause overheating and failure due to damage from thermal overstress behavior. The drift of the threshold voltage Vth can occur over a long period of time, and thus the leakage current may slowly increase over time. There is currently no ability to detect this slow drift and leakage current increase in-situ during operation of the apparatus comprising the solid state device.

In order to improve the ability to monitor the health of solid state devices in-situ during operation of apparatuses comprising the solid state devices, a leak detection component and leak detection technique are provided. The leak detection component is capable of testing and monitoring a solid state device of an apparatus during operation of the apparatus in order to detect imminent or future failure of the solid state device. The leak detection component is capable of identifying drift of the threshold voltage Vth of the solid state device based upon a leakage current of the solid state device measured by the leak detection component. The leakage current is detected during operation of the apparatus (e.g., while the circuit breaker or e-Fuse is installed and operational, as opposed to in a test lab environment) by the leak detection component by applying a test voltage to a gate of the solid state device. The leak detection component detects a leakage current resulting from the test voltage being applied to the gate of the solid state device. The test voltage is less than the threshold voltage Vth of the solid state device <NUM> such that increased leakage current will be detected if the solid state device is operating in a degraded operating state (e.g., leakage current larger than a nanoampere range of normal/expected leakage current of a non-degraded device) due to drift of the threshold voltage Vth (e.g., the threshold voltage Vth has drifted down to a smaller value than normal). Otherwise, the test voltage would not be enough voltage to cause the solid state device, operating in a non-degraded operating state, to turn on and conduct current through the solid state device. If the solid state device is operating in the degraded operating state, then various actions can be performed such as generating a warning signal of the degraded operating state (e.g., blinking a light, displaying a message, transmitting a message to a remote device, etc.).

<FIG> illustrates a leak detection component <NUM> configured to dynamically monitor the operating state and health of a solid state device <NUM> (e.g., a device under test (DUT)) of an apparatus <NUM>. The apparatus <NUM> comprises a voltage source <NUM> that is connected to a switch <NUM>. In some embodiments where the apparatus <NUM> is an e-Fuse being used for a DC breaker application, the switch <NUM> is a battery main switch that electrically connects and disconnects the voltage source <NUM> from other components of the apparatus <NUM> such as the solid state device <NUM>. In some embodiments, the switch <NUM> may be connected in series with the solid state device <NUM> so that power from the voltage source <NUM> is supplied to the solid state device <NUM> (e.g., to a source of the solid state device <NUM>) when the switch <NUM> is on (closed).

The apparatus <NUM> comprises a load <NUM> connected in series to the switch <NUM> and the solid state device <NUM>. It may be appreciated that in some embodiments, the load <NUM> is represented by a resistance Rdisc and capacitance Cbyp for simplicity, but may comprise various components, circuitry, hardware, and/or software. When the load <NUM> is on and in an operating state, an auxiliary current laux <NUM> and a voltage <NUM> (e.g., Vfuse) may be applied to the source of the solid state device <NUM> that is connected in series to the load <NUM>. The load <NUM> may be in an operational state (on) or a non-operational (off) based upon a load enable signal <NUM> (e.g., a signal generated by software to turn on or off the load <NUM>). The signal <NUM> may be used to control a controllable portion <NUM> of the load <NUM>, such as an inverter circuit. In some embodiments, a discharge circuit of the load <NUM> (e.g., Rdisc and Cbyp) may be permanently connected. In some embodiments, the load <NUM> may generate the auxiliary current laux <NUM> and the voltage <NUM> when the load enable signal <NUM> is enabled to turn on the load <NUM> and the switch <NUM> is closed so that the load <NUM> is connected to the voltage source <NUM>.

A gate driver <NUM> (GDU) may be connected to the gate of the solid state device <NUM>. The gate driver <NUM> may be configured to drive the gate of the solid state device <NUM> by applying a voltage to the solid state device <NUM> in order to operate the solid state device <NUM>. When the gate driver <NUM> applies a voltage equal to or greater than the threshold voltage Vth of the solid state device <NUM>, then the solid state device <NUM> will turn on into an operational state. A device enable signal <NUM> may be used to control the gate driver <NUM> to turn on or off the solid state device <NUM>. When the solid state device <NUM> is to be turned on, the device enable signal <NUM> causes the gate driver <NUM> to apply the voltage, equal to or greater than the threshold voltage Vth of the solid state device <NUM>, to the gate of the solid state device <NUM>. When the solid state device <NUM> is to be turned off, the device enable signal <NUM> is disabled to cause the gate driver <NUM> to stop applying the voltage to the gate of the solid state device <NUM>.

If the threshold voltage Vth of the solid state device <NUM> drifts over time to lower voltage values, then the solid state device <NUM> will produce significant leakage current when the solid state device <NUM> is supposed to be in an off state even to the point of where the solid state device <NUM> is not able to fully turn off by applying a normally applied off-level voltage via the gate driver <NUM>. This can cause catastrophic failure and damage to the apparatus <NUM>, such as where a circuit breaker is unable to turn off in the event of a short circuit or other abnormal condition. In order to detect drift of the threshold voltage Vth and/or leakage current of the solid state device <NUM> during operation of the apparatus <NUM>, the leak detection component <NUM> in combination with a dedicated gate stimulus circuit (e.g., test circuitry <NUM>) is used to detect these indicators of degraded performance and potential failure of the solid state device <NUM>.

The leak detection component <NUM> may be connected to the solid state device <NUM>. In some embodiments, the leak detection component <NUM> is connected in parallel with the solid state device <NUM>. In some embodiments, the leak detection component <NUM> is connected to a source and a drain of the solid state device <NUM>. In some embodiments, a leak detection component may be implemented as a current measurement device in series with the solid state device <NUM>. The leak detection component <NUM> is configured to measure a leakage current of the solid state device <NUM> when a test voltage is applied to the gate of the solid state device <NUM> during a test sequence. The test sequence is used to test the health of the solid state device <NUM> for determining whether the solid state device <NUM> is operating in a non-degraded operating state or degraded operating state. Details of the test sequence are further described in conjunction with the method <NUM> of <FIG>.

As part of performing the test sequence, the apparatus <NUM> includes test circuitry <NUM> configured to apply a test voltage <NUM> to the gate of the solid state device <NUM>. In some embodiments, the test circuitry <NUM> is integrated into the gate driver <NUM>. The test circuitry <NUM> is controlled by a test enable signal <NUM>. In response to the test enable signal <NUM> indicating that the test sequence is to be initiated (e.g., a threshold amount of time has occurred since a prior test sequence was performed), the test circuitry <NUM> closes a series switch <NUM> that is in series between a test voltage source <NUM> and the gate of the solid state device <NUM>. Closing the series switch <NUM> connects the test voltage source <NUM> to the gate of the solid state device <NUM> so that that the test voltage <NUM> is applied to the gate of the solid state device <NUM>. The test voltage <NUM> is less than the threshold voltage Vth. In this way, the solid state device <NUM> will not turn on from the test voltage <NUM> being applied to the gate of the solid state device <NUM> if the solid state device <NUM> is operating in a non-degraded operating state and has not experienced significant drift of the threshold voltage Vth. In some embodiments, the test voltage <NUM> is applied to the gate of the solid state device <NUM> while the solid state device <NUM> is in an off state where the gate driver <NUM> is not applying a voltage to the gate of the solid state device <NUM>.

As part of performing the test sequence, the leak detection component <NUM> measures the leakage current output through the solid state device <NUM> while the test voltage <NUM> is applied to the gate of the solid state device <NUM>. In some embodiments, the leak detection component <NUM> may measure the leakage current utilizing a capacitor <NUM>, as illustrated by <FIG>. The capacitor <NUM> is connected to the solid state device <NUM> in parallel. As part of starting the test sequence, switch <NUM> is closed (e.g., switch <NUM> is normally closed), the load <NUM> is disabled, and the device <NUM> is opened. In this way, the capacitor <NUM> is charged up to Vbattery. Then, the switch <NUM> is opened and the test voltage <NUM> is applied to the gate of the solid state device <NUM>. Because there is no current feed from Vbattery due to the switch <NUM> being opened, a discharge rate of the capacitor <NUM> is proportional to the leakage current of the solid state device <NUM>. In some embodiments, an external source is used to charge the capacitor <NUM> or a current source may feed into a pin (e.g., pin Vfuse associated with voltage <NUM>) while the load <NUM> is disabled and the switch <NUM> is opened. As the test voltage <NUM> is applied to the gate of the solid state device <NUM>, the leak detection component <NUM> measures a rate of change of a charge of the capacitor <NUM> over time to determine whether the rate of change of the charge of the capacitor <NUM> exceeds a threshold. The larger the rate of change of the charge of the capacitor <NUM>, the larger the leakage current of the solid state device <NUM>. The larger the leakage current of the solid state device <NUM>, the larger the drift of the threshold voltage Vth. The larger the rate of change of the charge of the capacitor <NUM> (e.g., the rate of change of the charge of the capacitor <NUM> exceeding the threshold) and the larger the leakage current and the larger the drift of the threshold voltage Vth, then the more the solid state device <NUM> is operating in a degraded operating state. In some embodiments of performing the test sequence, the test sequence may include charging the capacitor <NUM>, turning on the switch <NUM>, and then measuring the voltage <NUM> across the switch <NUM> to identify the rate of change of the charged of the capacitor <NUM> over time.

If the rate of change of the charge of the capacitor <NUM> does not exceed the threshold, then the leak detection component <NUM> determines that the solid state device <NUM> is operating in a non-degraded operating state. If the rate of change of the charge of the capacitor <NUM> exceeds the threshold, then the leak detection component <NUM> determines that the solid state device <NUM> is operating in a degraded operating state. If the leak detection component <NUM> determines that the solid state device <NUM> is operating in a degraded operating state, then the leak detection component <NUM> may generate a signal, such as a warning signal that the solid state device <NUM> is unhealthy, operating in the degraded operating state, and/or should be replaced (e.g., the signal may cause a light on the apparatus <NUM> to turn on, a message to be displayed on the apparatus <NUM>, or a message to be transmitted to a remote device over a communication network).

It may be appreciated that the leak detection component <NUM> may utilize other components and/or functionality than the capacitor <NUM> for measuring the leakage current of the solid state device <NUM>. In some embodiments, the leak detection component <NUM> utilizes a voltage source <NUM> as part of the test sequence for measuring the leakage current, as illustrated by <FIG>. The voltage source <NUM> may be an independent voltage source from other voltage sources of the apparatus <NUM> such as the voltage source <NUM>. In some embodiments, the leak detection component <NUM> utilizes a current source <NUM> as part of the test sequence for measuring the leakage current, as illustrated by <FIG>. The current source <NUM> may apply a current to a drain potential of a drain of the solid state device <NUM>. Instead of applying the test voltage <NUM> as part of the test sequence, a current through the solid state device <NUM> is measured to determine the leakage current of the solid state device <NUM>. In some embodiments, a leak detection component may be implemented as a current measurement device in series with the solid state device <NUM>.

<FIG> illustrates a method <NUM> for detecting leakage current of the solid state device <NUM>. During operation <NUM> of method <NUM>, the solid state device <NUM> is turned on using the device enable signal <NUM>. In some embodiments, the device enable signal <NUM> causes the gate driver <NUM> to apply a voltage to the gate of the solid state device <NUM>. The voltage is equal to or greater than the threshold voltage Vth of the solid state device <NUM>. This causes the solid state device <NUM> to turn on. In some embodiments, the solid state device <NUM> is turned on while the switch <NUM> is on (e.g., closed so that the voltage source <NUM> is connected to the load <NUM> and/or the solid state device <NUM>). In some embodiments, the load <NUM> is turned on using the load enable signal <NUM>. In this way, the switch <NUM> is closed, and the solid state device <NUM> and the load <NUM> are turned on into an operational state.

The leak detection component <NUM> may determine that a test sequence is to be initiated to determine whether the solid state device <NUM> is operating in a non-degraded operating state or a degraded operating state (e.g., a threshold amount of time has passed since a prior test sequence was performed). Accordingly, during operation <NUM> of method <NUM>, the load enable signal <NUM> is disabled in order to turn off the load <NUM>. In this way, the load <NUM> is not drawing power, such as from the voltage source <NUM>, while off. In some embodiments, the load <NUM> is turned off while the switch <NUM> is still on (closed).

During operation <NUM> of method <NUM>, the device enable signal <NUM> is disabled to turn off the solid state device <NUM>. In particular, the device enable signal <NUM> is an input into the gate driver <NUM> in order to control the gate driver <NUM>. Disabling the device enable signal <NUM> triggers the gate driver <NUM> to stop applying the voltage, greater than the threshold voltage Vth, to the gate of the solid state device <NUM>, thus turning off the solid state device <NUM>. In particular, the gate driver <NUM> provides an off-level gate driver signal to the solid state device <NUM>.

During operation <NUM> of method <NUM>, the switch <NUM> is turned off to interrupt the supply of power to the solid state device <NUM>. In some embodiments, the switch is turned off (opened) in order to interrupt the supply of power from the voltage source <NUM> through the load <NUM> to the source of the solid state device <NUM>. Once the switch is turned off, and the load <NUM> and the solid state device <NUM> are turned off, the test sequence triggers the test circuitry <NUM> to apply the test voltage <NUM> to the gate of the solid state device <NUM>.

During operation <NUM> of method <NUM>, the test sequence is initiated by applying the test voltage <NUM> to the gate of the solid state device <NUM> using the test circuitry <NUM>. The test voltage <NUM> is less than the threshold voltage Vth such that if the solid state device <NUM> is operating in a non-degraded operating state (e.g., experiencing little to no threshold voltage Vth drift), then the solid state device <NUM> will not turn on and will not generate a large leakage current. In some embodiments, the test sequence of the test voltage <NUM> being applied to the gate of the solid state device <NUM> and the leak detection component <NUM> determining a leakage current inducted by the test voltage <NUM> is performed in-situ when the apparatus <NUM> is deployed and operational (e.g., during a power up/down sequence of a vehicle boardnet of a vehicle). In some embodiments, the test voltage <NUM> is applied to the gate of the solid state device <NUM> while the solid state device <NUM> is in an off state where the gate driver <NUM> is not applying the voltage greater than the threshold voltage Vth to the gate of the solid state device <NUM>.

During operation <NUM> of method <NUM>, the leak detection component <NUM> measures the leakage current from the solid state device <NUM>. The leakage current may be induced by the test voltage <NUM> being applied to the gate of the solid state device <NUM>. Various techniques may be used to measure the leakage current or other operational properties of the solid state device <NUM>, such as through the use of the capacitor <NUM> of <FIG>, the voltage source <NUM> of <FIG>, the current source <NUM> of <FIG>, etc. In some embodiments of using the capacitor <NUM>, the leak detection component <NUM> measures a rate of change of a charge of the capacitor <NUM> over time. The leakage detection components determines the leakage current based upon the rate of change of the charge of the capacitor <NUM> over time.

During operation <NUM> of method <NUM>, the leak detection component <NUM> determines whether the solid state device <NUM> is operating in a degraded operating state or a non-degraded operation state based upon the leakage current of the solid state device <NUM> and/or the rate of change of the charge of the capacitor <NUM> over time. If the leak detection component <NUM> determines that the solid state device is in the degraded operating state (e.g., the leakage current exceeds a threshold; the threshold voltage Vth has drifted by 1V, 2V, or some other voltage such as where a <NUM>. 5V drift that would be catastrophic if the threshold voltage Vth is <NUM>. 5V), then the leak detection component <NUM> may generate a warning signal (e.g., turn on or blink a warning light of the apparatus <NUM>, display an alert on a display of the apparatus <NUM>, transmit the warning signal to a remote device or computer to notify a user, etc.).

<FIG> illustrates a timing diagram <NUM> associated with solid state device leak detection. The x-axis represents time during which the test sequence may be performed. The load enable signal <NUM> is initially enabled (high) so that the load <NUM> is on and operational. The device enable signal <NUM> is also initially enabled (high) so that the gate driver <NUM> applies a voltage to the gate of the solid state device <NUM>. The voltage applied to the gate of the solid state device <NUM> is equal to or larger than the threshold voltage Vth <NUM> of the solid state device <NUM> (e.g., greater than <NUM>. 5V, or some other threshold voltage), and thus the solid state device <NUM> is on and operational. A switch enable signal <NUM>, used to control the switch <NUM>, is initially enabled (high) so that the switch <NUM> is on (closed).

A determination is made that the test sequence is to be performed. Accordingly, the load enable signal <NUM> is disabled (low) at a first point in time <NUM> to turn off the load <NUM>. The device enable signal <NUM> is disabled (low) at a second point in time <NUM> to turn off the solid state device <NUM> by controlling the gate driver <NUM> to stop applying the voltage to the gate of the solid state device <NUM>. The switch enable signal <NUM> is disabled (low) at a third point in time <NUM> so that the switch <NUM> is off (opened). The switch <NUM> may be turned off once the voltage <NUM> has reached a battery voltage <NUM> of the voltage source <NUM>.

At a fourth point in time <NUM>, the test enable signal <NUM> is enabled (high) to cause the test circuitry <NUM> to apply the test voltage <NUM> to the gate of the solid state device <NUM>, which has a gate voltage <NUM>. A rate of change <NUM> of a charge of the capacitor <NUM> is measured while the test voltage <NUM> is applied to the gate of the solid state device <NUM> in order to determine an increase in leakage current of the solid state device <NUM> from the test voltage <NUM> being applied to the gate of the solid state device <NUM>. Once the leakage current and/or a drift of the threshold voltage Vth is determined, the test enable signal <NUM> is disabled (low) at a fifth point in time <NUM> to complete the test sequence.

<FIG> illustrates a diagram <NUM> depicting various voltage threshold drifts of the solid state device <NUM>. The x-axis <NUM> represents voltage, such as the threshold voltage Vth <NUM> of the solid state device <NUM> and a gate-source voltage bias <NUM> of the solid state device <NUM>. The y-axis <NUM> represents current from the solid state device <NUM>, such as leakage current produced before a voltage applied to the gate of the solid state device <NUM> reaches the threshold voltage Vth <NUM>. A current curve <NUM> represents current from the solid state device <NUM> if the solid state device is operating in a non-degraded operating state. The current curve <NUM> shows that there is little to no leakage current before the voltage applied to the gate reaches the threshold voltage Vth <NUM>. Once the threshold voltage Vth <NUM> is reached, then current from the solid state device <NUM> increases because the solid state device <NUM> is on and operational.

As the solid state device <NUM> experiences voltage threshold drift, leakage current from the solid state device <NUM> will occur before the threshold voltage Vth <NUM> is reached. The current curve <NUM> illustrates how leakage current from the solid state device <NUM> occurs before the threshold voltage Vth <NUM> is reached, which is indicative of a leakage current due to drift in the threshold voltage Vth <NUM>. Current curve <NUM> illustrates critical drift in the threshold voltage Vth <NUM> where there is leakage current well before the threshold voltage Vth <NUM> is reached. Current curve <NUM> illustrates very critical drift in the threshold voltage Vth <NUM> where the solid state device <NUM> may not even be able to turn off and there is significant leakage current while the solid state device <NUM> is supposed to be off. As previously discussed, the techniques described herein are capable of detecting these leakage currents and voltage threshold drifts during operation of the solid state device <NUM> in order to provide early detection and warning of imminent or potential future failures.

As used in this application, the terms "component," "module," "system", "interface", and the like are generally intended to refer to a computer-related entity, either hardware, a combination of hardware and software, software, or software in execution. One or more components may be localized on one computer and/or distributed between two or more computers.

Furthermore, the claimed subject matter may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques to produce software, firmware, hardware, or any combination thereof to control a computer to implement the disclosed subject matter. The term "article of manufacture" as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. Of course, those skilled in the art will recognize many modifications may be made to this configuration without departing from the scope of the claimed subject matter.

Various operations of embodiments are provided herein. In one embodiment, one or more of the operations described may constitute computer readable instructions stored on one or more computer readable media, which if executed by a computing device, will cause the computing device to perform the operations described. The order in which some or all of the operations are described should not be construed as to imply that these operations are necessarily order dependent. Alternative ordering will be appreciated by one skilled in the art having the benefit of this description. Further, it will be understood that not all operations are necessarily present in each embodiment provided herein.

Any aspect or design described herein as an "example" is not necessarily to be construed as advantageous over other aspects or designs. Rather, use of the word "example" is intended to present one possible aspect and/or implementation that may pertain to the techniques presented herein. Such examples are not necessary for such techniques or intended to be limiting. Various embodiments of such techniques may include such an example, alone or in combination with other features, and/or may vary and/or omit the illustrated example.

As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless specified otherwise, or clear from context, "X employs A or B" is intended to mean any of the natural inclusive permutations. In addition, the articles "a" and "an" as used in this application and the appended claims may generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form. Also, unless specified otherwise, "first," "second," or the like are not intended to imply a temporal aspect, a spatial aspect, an ordering, etc. Rather, such terms are merely used as identifiers, names, etc. for features, elements, items, etc. For example, a first element and a second element generally correspond to element A and element B or two different or two identical elements or the same element.

Claim 1:
An apparatus, comprising:
a solid state device (<NUM>);
a switch (<NUM>) in series with the solid state device (<NUM>);
a leak detection component (<NUM>) connected to the solid state device (<NUM>) and comprising a capacitor (<NUM>) connected in parallel to the solid state device(<NUM>); and
a gate driver (<NUM>) configured to drive a gate of the solid state device (<NUM>) and comprising test circuitry (<NUM>) configured to apply a test voltage (<NUM>) to the gate of the solid state device (<NUM>),
wherein the test voltage (<NUM>) is less than a threshold voltage of the solid state device (<NUM>), and
wherein the leak detection component (<NUM>) is configured to detect a leakage current of the solid state device (<NUM>),
wherein the capacitor (<NUM>) of the leakage detection component is configured to be charged when the switch (<NUM>) is closed, and
wherein the leak detection component (<NUM>) is configured to detect the leakage current based upon a rate of a change of a charge of the capacitor (<NUM>) over a period of time exceeding a threshold when the switch (<NUM>) is open.