Control method of GaN power device with vertical structure

Abstract

The invention provides a control method of a GaN power device with a vertical structure. According to the method, when the GaN power device of a vertical structure is in a normal turn-off state, if drain-source voltage of the GaN power device reaches avalanche breakdown voltage, the GaN power device is controlled to enter an avalanche mode, then, in the avalanche mode, the GaN power device clamps the drain-source voltage within an energy consumption voltage range corresponding to the avalanche breakdown voltage, and the energy consumption voltage of the GaN power device is controlled to be within the energy consumption voltage range corresponding to the avalanche breakdown voltage. According to the technical scheme of the invention, the external heat dissipation operation is carried out through the avalanche current generated by the GaN power device within the energy consumption voltage range, and after the external heat dissipation operation is finished, the GaN power device is controlled to exit the avalanche mode and enter the normal turn-off state, so that the overvoltage protection of the device can be realized without an additional external protection circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data processing, in particular to a control method of a vertical structure GaN power device. BACKGROUND

[0002] In the field of power electronics and high-frequency switching circuits, GaN (Gallium Nitride) power devices are gradually becoming an ideal choice to replace traditional silicon-based devices due to their high breakdown field strength, high electron mobility, and excellent thermal conductivity. In particular, in application scenarios with high-density integration, high frequency, and high performance requirements, such as data center power management, electric vehicle charging systems, and radio frequency communication and laser radar, GaN power devices exhibit significant advantages.

[0003] However, as the operating frequency of the circuit increases and the power density increases, the risk of overvoltage faced by GaN power devices during operation also increases. Overvoltage events, especially those caused by overvoltage spikes in external circuits, can cause irreversible damage to GaN power devices, thereby affecting the stability and reliability of the entire system. Therefore, how to effectively protect GaN power devices from overvoltage has become one of the key problems to be solved in the current technical field.

[0004] In the prior art, overvoltage protection for GaN power devices mainly relies on external protection circuits such as RC (resistor-capacitor) buffers, Zener diodes, etc. These external circuits protect the devices from damage by absorbing or shunting overvoltage energy. However, the presence of external protection circuits not only increases the cost and size of the system, but also may not provide timely and effective protection in all cases due to limited response speed. In particular, in high-frequency switching circuits, overvoltage events often occur extremely quickly, and external protection circuits may not respond in time, resulting in device damage. SUMMARY

[0005] The present application provides a control method of a vertical structure GaN power device to achieve overvoltage protection of the device without additional external protection circuits.

[0006] In a first aspect, the present application provides a control method of a vertical structure GaN power device, comprising: When the vertical structure GaN power device is in a normal off state, if the drain-source voltage of the GaN power device reaches an avalanche breakdown voltage, the GaN power device is controlled to enter an avalanche mode; In the avalanche mode, the GaN power device clamps the drain-source voltage within an energy consumption voltage range corresponding to the avalanche breakdown voltage, so as to perform external heat dissipation operation through the avalanche current generated by the GaN power device within the energy consumption voltage range; After the external heat dissipation operation ends, the GaN power device is controlled to exit the avalanche mode and enter the normal off state.

[0007] Optionally, the avalanche breakdown voltage is determined based on a preset safe avalanche working region corresponding to the GaN power device.

[0008] Optionally, the drain-source voltage of the GaN power device reaching the avalanche breakdown voltage is caused by an overvoltage spike occurring in a circuit outside the device.

[0009] Optionally, when the avalanche current of the GaN power device decreases to below a preset current safety value, it is determined that the external heat dissipation operation ends.

[0010] Optionally, when the avalanche current of the GaN power device is maintained below the preset current safety value for a duration exceeding a preset minimum dissipation duration, it is determined that the external heat dissipation operation ends.

[0011] Optionally, the preset minimum dissipation duration is determined according to a load type of a load device in a circuit in which the GaN power device is applied.

[0012] Optionally, the load type includes an inductive load and a capacitive load.

[0013] Optionally, the preset current safety value is determined according to a working current of a load device in a circuit in which the GaN power device is applied and a preset current safety base value.

[0014] Optionally, the avalanche breakdown voltage is determined according to a preset voltage fluctuation range of the GaN power device in an application circuit and a preset safe avalanche working region.

[0015] In a second aspect, the present application provides a switching power supply circuit, comprising: a GaN power device of vertical structure, which is protected from overvoltage by the control method of the GaN power device of vertical structure in any one of the first aspect.

[0016] In a third aspect, the present application provides an electronic device, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to execute any one of the possible methods in the first aspect by executing the executable instructions.

[0017] In a fourth aspect, the present application provides a computer readable storage medium, which stores computer execution instructions, and the computer execution instructions are used to implement any one of the possible methods in the first aspect when executed by a processor.

[0018] The control method of the vertical structure GaN power device provided in the application is as follows: when the vertical structure GaN power device is in a normal off state, if the drain-source voltage of the GaN power device reaches an avalanche breakdown voltage, the GaN power device is controlled to enter an avalanche mode, then in the avalanche mode, the GaN power device clamps the drain-source voltage in a power consumption voltage range corresponding to the avalanche breakdown voltage, so as to dissipate heat to the outside through the avalanche current generated by the GaN power device in the power consumption voltage range, and after the heat dissipation to the outside is completed, the GaN power device is controlled to exit the avalanche mode and enter the normal off state, thereby realizing overvoltage protection of the device without an additional external protection circuit. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the principles of the application.

[0020] Figure 1 is a flowchart of a control method of a vertical structure GaN power device according to an example embodiment of the application; Figure 2 is a flowchart of a control method of a vertical structure GaN power device according to another example embodiment of the application; Figure 3 is a structural schematic diagram of an electronic device according to an example embodiment of the application.

[0021] The specific embodiments have been shown and described in the above-described drawings, and will be described in more detail hereinafter. The drawings and the written description are not intended to limit the scope of the inventive concept in any way, but to explain the inventive concept to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0022] The example embodiments will be described in detail herein with reference to the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following example embodiments are not meant to represent all implementations consistent with the application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the application as detailed in the appended claims.

[0023] Figure 1 is a flowchart of a control method of a vertical structure GaN power device according to an example embodiment of the application. As shown in Figure 1 The control method of the vertical structure GaN power device provided in the embodiment includes: S101. When the vertical GaN power device is in the normal off state, if the drain-source voltage of the GaN power device reaches the avalanche breakdown voltage, then control the GaN power device to enter the avalanche mode.

[0024] When a vertically oriented GaN power device is in its normal off state, its drain-source voltage can be continuously monitored. Specifically, this can be achieved through a voltage detection circuit to ensure that any abnormal voltage changes can be detected in a timely manner. For example, an analog-to-digital converter can be used to sample the drain-source voltage in real time, and then a comparator can be used to compare the sampled voltage with a preset avalanche breakdown voltage threshold.

[0025] When the drain-source voltage of a GaN power device reaches or exceeds the preset avalanche breakdown voltage, an overvoltage spike in the external circuit can be identified. At this point, the control logic can be immediately triggered, causing the GaN power device to enter avalanche mode. The avalanche breakdown voltage is determined based on the preset safe avalanche operating region of the GaN power device, ensuring operation remains within a safe range. This preset avalanche breakdown voltage should be less than the device's maximum withstand voltage, with a certain safety margin. When the analog-to-digital converter's sampled value exceeds the preset threshold, the microcontroller or dedicated control chip immediately sends a control signal to cause the GaN power device to enter avalanche mode.

[0026] S102. In avalanche mode, the GaN power device clamps the drain-source voltage within the energy dissipation voltage range corresponding to the avalanche breakdown voltage, so as to dissipate external heat through the avalanche current generated by the GaN power device within the energy dissipation voltage range.

[0027] Upon entering avalanche mode, the GaN power device clamps its drain-source voltage within the energy dissipation voltage range corresponding to the avalanche breakdown voltage. Within this voltage range, the GaN power device generates an avalanche current, which is converted into heat energy through the device's internal resistance, thus dissipating heat externally and protecting the device from overvoltage damage.

[0028] In avalanche mode, the internal structure of the GaN power device undergoes avalanche breakdown, forming a conductive channel that clamps the drain-source voltage. Furthermore, the magnitude of the avalanche current is related to the drain-source voltage and device characteristics, allowing the design to ensure that the avalanche current remains within the device's tolerance range.

[0029] It is worth noting that when the drain-source voltage reaches the avalanche breakdown threshold, the device automatically enters avalanche mode to clamp the voltage within the safe power dissipation range. This process is based on the inherent characteristics of vertical GaN devices: when the drain-source junction undergoes avalanche breakdown under over-limit voltage, the energy is uniformly dissipated in the drift region through the avalanche current.

[0030] S103. After the external heat dissipation operation is completed, control the GaN power device to exit the avalanche mode and enter the normal shutdown state.

[0031] Then, the magnitude of the avalanche current can be continuously monitored. When the avalanche current decreases below a preset safe current value, or when the avalanche current remains below the preset safe current value for a period exceeding a preset minimum dissipation time, the external heat dissipation operation is considered to have ended. The preset safe current value and preset minimum dissipation time can be determined based on the type of load devices and operating conditions in the circuit.

[0032] When the conditions for ending the external heat dissipation operation are met, a control signal can be sent to cause the GaN power device to exit avalanche mode and re-enter the normal shutdown state, awaiting the next possible overvoltage event. Specifically, this can be achieved by a microcontroller or dedicated control chip immediately changing the control signal state when the exit conditions are detected. Upon receiving the exit signal, the GaN power device quickly shuts down the avalanche channel and returns to the normal shutdown state.

[0033] In the above embodiments, when the vertical GaN power device is in the normal off state, if the drain-source voltage of the GaN power device reaches the avalanche breakdown voltage, the GaN power device is controlled to enter the avalanche mode. Then, in the avalanche mode, the GaN power device clamps the drain-source voltage within the energy dissipation voltage range corresponding to the avalanche breakdown voltage, so as to dissipate external heat through the avalanche current generated by the GaN power device within the energy dissipation voltage range. After the external heat dissipation operation is completed, the GaN power device is controlled to exit the avalanche mode and enter the normal off state, so that the overvoltage protection of the device can be achieved without additional external protection circuitry.

[0034] It is worth noting that in existing technologies, overvoltage protection for GaN power devices typically relies on external circuits (such as RC buffers and Zener diodes) or passive avalanche withstand designs. External circuit protection requires additional components, increasing cost and size, and limiting response speed. Passive avalanche withstand requires GaN power devices to be pre-designed with high avalanche energy tolerance, but the dissipation process cannot be actively controlled, easily leading to localized overheating.

[0035] The aforementioned embodiment uses active control logic to enable the device to autonomously enter avalanche mode during overvoltage, clamping the drain-source voltage within a safe range and utilizing avalanche current for controllable heat dissipation, achieving protection without external components. Furthermore, the control logic response time is faster than external circuits, and since no additional protection components are required, it is suitable for high-density integration scenarios, especially for high-density integrated high-frequency switching circuits. In addition, by controlling heat dissipation to avoid localized overheating, the GaN power device's performance remains undegraded after avalanche cycling.

[0036] In addition, in the prior art, avalanche breakdown is generally regarded as a failure mode that needs to be avoided, while the above embodiment is a reverse use of the avalanche effect, which is converted into a protection mechanism. Specifically, the traditional design considers that avalanche will cause device damage, while the above embodiment makes it a controllable dissipation path by clamping voltage and limiting current.

[0037] Moreover, the method in the above embodiment can be applied to scenarios such as radio frequency communication and laser radar, which have high requirements for the switching speed of devices, and can also be applied to flyback switching power supplies in power electronic systems, such as, in particular, space-limited scenarios such as data centers and electric vehicles.

[0038] In the above flyback switching power supply design, the traditional RCD (resistor-capacitor-diode) absorption circuit is a common solution to suppress the drain-source voltage spike of the switching tube, but it has defects such as large energy loss and limited response speed. The method provided in the above embodiment can achieve effective suppression of the drain-source voltage spike of the switching tube through active avalanche regulation of the vertical structure GaN device, while also improving system reliability and integration.

[0039] Specifically, in a flyback power supply, when the main switching tube (such as a MOSFET) is turned off, the leakage energy of the transformer primary coil will be superimposed with the power supply voltage, generating a switching tube drain-source voltage spike voltage. The traditional RCD circuit absorbs part of the energy by charging the capacitor, but its suppression effect is not good due to the limitation of the capacitor capacity and the resistance power consumption, and because the resistance in the RCD circuit continuously consumes energy, the system efficiency is reduced.

[0040] The method of the above embodiment uses the avalanche mode of the vertical structure GaN device to achieve dynamic clamping of the switching tube drain-source voltage spike voltage, and because the avalanche breakdown voltage of the vertical GaN device is determined by the drift layer thickness and the doping concentration, it can be precisely designed by process adjustment (such as stabilizing the avalanche threshold of a 1.2kV rated voltage device at 560V±5V). When the spike voltage reaches the avalanche threshold, the device automatically enters the avalanche mode, and the excess energy is evenly dissipated in the drift region through the avalanche current, avoiding the accumulation of energy in the capacitor leading to secondary overshoot. In addition, the avalanche dissipation process directly uses the device body without the need for a resistance element, eliminating the system efficiency loss caused by resistance heating in the RCD circuit.

[0041] Further, although the RCD circuit can suppress a single VDS spike, in high-frequency switching (such as hundreds of kHz to MHz level) or load mutation scenarios, repeated avalanche impact can cause device parameter drift. For example, after long-term operation, the capacitance value decay of the RCD capacitor can cause the VDS suppression effect to decrease by 10%-15%, and resistance aging can further reduce system stability.

[0042] In comparison, the provided method of the above embodiment can control the triggering and exiting of the avalanche mode through built-in logic, ensure that the energy release of each avalanche is evenly distributed in the drift region, and avoid local overheating. Moreover, the three-dimensional heat dissipation characteristics of the vertical structure can also quickly conduct the heat generated by the avalanche current to the packaging substrate, and the fluctuation amplitude of the junction temperature can also be effectively reduced compared with lateral devices.

[0043] Figure 2 is a flowchart of a control method of a GaN power device with a vertical structure according to another example embodiment of the present application. As shown in Figure 2 the control method of the GaN power device with a vertical structure provided in the present embodiment includes: S201, defining a preset safe avalanche working area of the GaN power device.

[0044] In this step, the static and dynamic avalanche breakdown voltage of the GaN power device with a vertical structure can be tested on an experimental platform. By gradually increasing the drain-source voltage, the voltage value at which the device occurs avalanche breakdown, i.e. the avalanche breakdown voltage, is observed. The measurement results are recorded during the test to evaluate the consistency and stability of the avalanche breakdown voltage.

[0045] Then, under the avalanche breakdown voltage, different current pulses are applied to the device, and the maximum avalanche current that the device can withstand is measured. At the same time, the energy absorbed by the device in a single avalanche event, i.e. the single avalanche energy, is calculated by integration.

[0046] According to the above test results, combined with the design target and actual application scenario of the device, the preset safe avalanche working area of the GaN power device with a vertical structure can be defined. Among them, the preset safe avalanche working area can be designed to include a safe voltage range (for example, it can be slightly lower than the avalanche breakdown voltage), a limit of the maximum avalanche current and a threshold of the single avalanche energy.

[0047] Further, in order to ensure the universality and reliability of the preset safe avalanche working area, the avalanche test of the device can also be carried out under different temperatures and different load conditions to verify its avalanche resistance in various application scenarios. Then, according to the test results, the preset safe avalanche working area is adjusted to optimize the performance of the device.

[0048] In addition, it is worth mentioning that in the actual application of GaN power devices in circuits, the devices are usually purchased externally, therefore, the preset safe avalanche working area of the GaN power device can be determined by checking the device manual, and then the avalanche breakdown voltage can be determined according to the already defined preset safe avalanche working area, for example, the maximum safe working voltage in the preset safe avalanche working area can be determined as the avalanche breakdown voltage.

[0049] S202. Determine the preset minimum dissipation time length according to the load type of the load device in the circuit where the GaN power device is applied.

[0050] Since the load type has a significant impact on the dissipation process, the preset minimum dissipation time length needs to be adjusted according to the load type of the load device (inductive load or capacitive load). It is necessary to identify and classify the load device in the circuit where the GaN power device is applied, and determine whether its load type is inductive load or capacitive load. This step can be completed through circuit design document analysis, actual circuit measurement or load characteristic test.

[0051] Moreover, before identifying the load type, a preset minimum dissipation base time length also needs to be determined. This base time length is an initial value set based on the avalanche characteristics of the GaN power device, thermal design and system safety requirements. It represents the shortest time required for the device to enter avalanche mode and safely exit without the influence of specific load types. The determination of the preset minimum dissipation base time length can be completed through experimental testing, simulation analysis or reference to similar device data. In experimental testing, avalanche events under different conditions can be simulated, the time required for the device to enter avalanche mode and the avalanche current to drop below a safe value is recorded, and the average value of multiple tests is taken as the preset minimum dissipation base time length.

[0052] If the load type is inductive load, the time length is shortened based on the preset minimum dissipation base time length to determine the preset minimum dissipation time length. Inductive load usually contains inductive elements such as motors, transformers, etc. During the off process, inductive load will generate a reverse electromotive force, which may cause voltage spikes.

[0053] For inductive load, since it will generate a reverse electromotive force during the off process, which may cause voltage spikes to last for a short time but with large amplitude. Therefore, the preset minimum dissipation time length can be appropriately shortened based on the preset minimum dissipation base time length. This is because the overvoltage event caused by inductive load usually decays quickly, and a shorter dissipation time length can ensure that the device safely exits the avalanche mode. The specific shortened time length can be determined through experimental testing to ensure that the device can work safely under different inductive load conditions.

[0054] For example, assuming that the preset minimum dissipation base time length is 100 μs, and under inductive load conditions, it is found through experimental testing that when the dissipation time length is shortened to 80 μs, the device can still safely exit the avalanche mode and the performance does not decay. Therefore, the preset minimum dissipation time length under inductive load conditions is set to 80 μs.

[0055] If the load type is a capacitive load, the preset minimum dissipation time length is increased based on a preset minimum dissipation base time length. The capacitive load includes a capacitive element such as a filter capacitor, an energy storage capacitor, etc. During the charging or discharging process, the capacitive load may cause current to suddenly change, and overvoltage may also occur.

[0056] For the capacitive load, it may cause current to suddenly change for a long time and overvoltage to occur during the charging or discharging process. Therefore, the preset minimum dissipation time length needs to be appropriately increased based on the preset minimum dissipation base time length. This is because the overvoltage event caused by the capacitive load may last for a long time, and a longer dissipation time length is needed to ensure that the device fully dissipates the surge energy and safely exits the avalanche mode. The specific time length to be increased also needs to be determined through experimental tests.

[0057] For example, continuing with the preset minimum dissipation base time length of 100 μs as described above, under the condition of a capacitive load, it is found through experimental tests that when the dissipation time length is increased to 120 μs, the device can more fully dissipate the surge energy and safely exit the avalanche mode. Therefore, the preset minimum dissipation time length under the condition of a capacitive load is set to 120 μs. After determining the preset minimum dissipation time length for different load types, experimental verification can also be performed to ensure its effectiveness and reliability. By simulating avalanche events under different load conditions in actual circuits and monitoring changes in parameters such as voltage, current, and temperature of the device, the reasonableness of the preset minimum dissipation time length can be verified. Thus, the preset minimum dissipation time length is optimized and adjusted according to the experimental results. If it is found that the device fails to fully dissipate the surge energy under certain load conditions or that the dissipation time is too long, resulting in a decrease in device performance, the preset minimum dissipation time length needs to be adjusted again and experimental verification needs to be performed again until the optimal preset minimum dissipation time length setting is found.

[0058] In short, in the above steps, for the inductive load, the preset minimum dissipation time length is appropriately shortened because the overvoltage event thereof usually decays quickly, so as to improve the protection efficiency; and for the capacitive load, the preset minimum dissipation time length is increased because the overvoltage event thereof may last for a long time, so as to ensure that the energy is fully dissipated. This dynamic adjustment method can improve the flexibility and effectiveness of overvoltage protection. It can be seen that the above steps solve a specific and practical technical problem, i.e., how to achieve efficient and reliable overvoltage protection under different load conditions. That is, by dynamically adjusting the dissipation time length, damage to the GaN power device caused by overvoltage is effectively avoided, and the stability and reliability of the system are improved.

[0059] S203, determining a preset current safety value according to a working current of a load device in a circuit to which the GaN power device is applied and a preset current safety base value.

[0060] Since the working current of the load device directly affects the size of the avalanche current generated in the avalanche process, the current safety value needs to be reasonably preset according to the working current of the load device and the preset current safety base value.

[0061] Firstly, the working current of the load device in the circuit to which the GaN power device is applied can be monitored and obtained in real time. This step can be realized by means of series connection of a current sampling resistor, use of a current transformer or a Hall effect sensor, etc. in the circuit. Among them, the current sampling resistor method is to connect a small resistance sampling resistor in series in the load loop, and the working current is calculated by measuring the voltage drop across the resistor. The current transformer method is to use a current transformer to convert the load current into a smaller secondary current in proportion, and then measure it. The Hall effect sensor method is to use the Hall effect principle to convert the magnetic field change into a voltage signal to measure the current.

[0062] Then, the preset current safety base value is an initial reference value set based on the avalanche characteristics, thermal design and system safety requirements of the GaN power device. It represents the maximum current value that the device can safely withstand in the avalanche mode without the influence of the specific load current. The setting of the preset current safety base value can be completed by experimental test, simulation analysis or reference to the data of similar devices. In the experimental test, the avalanche events under different conditions can be simulated, the maximum avalanche current value of the device before it safely exits the avalanche mode is recorded, and the average value of multiple tests or appropriate adjustment according to the safety margin requirement is taken as the preset current safety base value.

[0063] After the working current of the load device is determined and the preset current safety base value is set, the preset current safety value needs to be adjusted according to the actual working current of the load device. Since there is a positive correlation between the working current and the preset current safety value, i.e. the larger the working current, the preset current safety value should also be increased accordingly to ensure the safety of the device.

[0064] The specific adjustment method can adopt the proportional coefficient method or the table lookup method: Proportional coefficient method: set a proportional coefficient k (0 < k ≤ 1), and the product of the preset current safety base value and the working current of the load device is taken as the adjusted preset current safety value. That is: preset current safety value = k × preset current safety base value × load device working current / rated working current (or reference working current). Among them, the rated working current or the reference working current is a reference value for standardization, which can be set according to the actual situation.

[0065] For example, assuming that the preset current safety base value is 10A, the proportional coefficient k is 0.8, the rated operating current of the load device is 5A, and the actual operating current is 7A. The adjusted preset current safety value is: 0.8 x 10A x (7A / 5A) = 11.2A.

[0066] Table lookup method: The corresponding preset current safety values are set in advance according to different operating current ranges of the load device and stored in the lookup table of the controller. In actual operation, the controller obtains the corresponding preset current safety value from the lookup table according to the real-time monitored operating current of the load device.

[0067] For example, a lookup table is set in advance as shown in the following table. In actual operation, when the operating current of the load device is monitored to be 7A, the controller obtains the corresponding preset current safety value of 11A from the lookup table. After determining the preset current safety values for different operating currents of the load device, experimental verification is needed to ensure its effectiveness and reliability. The rationality of the preset current safety value can be verified by simulating avalanche events under different load current conditions in the actual circuit and monitoring the changes in parameters such as voltage, current, and temperature of the device. Then, the preset current safety value is optimized and adjusted according to the experimental results.

[0068] If it is found that the device fails to safely exit or prematurely exits the avalanche mode under certain load current conditions, resulting in insufficient protection, the preset current safety value needs to be adjusted again and experimental verification needs to be performed again until the optimal preset current safety value setting is found.

[0069] In the above steps, in the case of high load current, increasing the preset current safety value can ensure that the device has sufficient current bearing capacity in the avalanche mode and avoid insufficient protection caused by premature exit from the avalanche mode; in the case of low load current, reducing the preset current safety value can reduce unnecessary energy dissipation and improve system efficiency. The technical problem solved is how to achieve accurate and reliable overvoltage protection under different load current conditions. That is, by dynamically adjusting the preset current safety value, the damage of overvoltage to the GaN power device is effectively avoided, and the stability and reliability of the system are improved.

[0070] S204, when the GaN power device in the vertical structure is in a normal off state, if the drain-source voltage of the GaN power device reaches the avalanche breakdown voltage, the GaN power device is controlled to enter the avalanche mode.

[0071] When the GaN power device is in a normal off state, its drain-source voltage can be continuously monitored, specifically, by a voltage detection circuit to ensure that any abnormal changes in the voltage can be captured in a timely manner. For example, an analog-to-digital converter can be used to sample the drain-source voltage in real time, and then a comparator can be used to compare the sampled voltage with a preset avalanche breakdown voltage threshold.

[0072] When the drain-source voltage of the GaN power device reaches or exceeds the preset avalanche breakdown voltage, it can be determined that an overvoltage spike has occurred in the external circuit. At this time, the control logic can be triggered immediately to cause the GaN power device to enter an avalanche mode. The avalanche breakdown voltage is determined based on a preset safe avalanche operating region of the GaN power device to ensure that the operation is within a safe range. The above-mentioned preset avalanche breakdown voltage should be less than the maximum withstand voltage of the device, and a certain safety margin should be left. When the analog-to-digital converter sampling value exceeds the preset threshold, the microcontroller or dedicated control chip immediately sends a control signal to cause the GaN power device to enter the avalanche mode.

[0073] It is worth noting that the drain-source voltage of the GaN power device reaching the avalanche breakdown voltage is caused by an overvoltage spike in the external circuit of the device. In high-density integrated, high-frequency, and high-performance application scenarios, such as data center power management and electric vehicle charging systems, overvoltage spikes in the external circuit are common problems. Through the above steps, the GaN power device can be effectively protected from overvoltage damage, improving the stability and reliability of the system, while reducing the system cost and size.

[0074] The determination of the avalanche breakdown voltage can be based on the preset voltage fluctuation range and the preset safe avalanche operating region of the GaN power device in the application circuit. GaN power device samples with different structure parameters and doping concentrations can be prepared, and different voltages can be applied to the samples in a simulated application circuit environment. The voltage value at which the avalanche breakdown phenomenon occurs is observed and recorded, which is the actual measured avalanche breakdown voltage. Then, the experimentally measured avalanche breakdown voltage data is compared with the theoretical results. Based on the experimental comparison and analysis results, the parameters in the model are corrected, and the avalanche breakdown voltage is further optimized in combination with the requirements of the preset voltage fluctuation range and the preset safe avalanche operating region to determine the final avalanche breakdown voltage value. This value should ensure that within the preset voltage fluctuation range of the application circuit, when the device enters the avalanche mode, its working state falls within the preset safe avalanche operating region, ensuring safe and reliable operation of the device.

[0075] S205、In the avalanche mode, the GaN power device clamps the drain-source voltage within the energy consumption voltage range corresponding to the avalanche breakdown voltage, so as to dissipate heat externally through the avalanche current generated by the GaN power device within the energy consumption voltage range.

[0076] After entering the avalanche mode, the GaN power device clamps its drain-source voltage in the energy consumption voltage range corresponding to the avalanche breakdown voltage. In this voltage range, the GaN power device generates an avalanche current, which is converted into heat energy by the internal resistance of the device, achieving external heat dissipation and protecting the device from overvoltage damage.

[0077] In the avalanche mode, the internal structure of the GaN power device undergoes avalanche breakdown, forming a conductive channel and clamping the drain-source voltage. The size of the avalanche current is related to the drain-source voltage and the characteristics of the device, and can be ensured to be within the range that the device can withstand during design.

[0078] It is worth noting that when the drain-source voltage reaches the avalanche breakdown threshold, the device automatically enters the avalanche mode and clamps the voltage in the safe energy consumption range. This process is based on the inherent characteristics of the vertical structure GaN device: when the drain-source junction undergoes avalanche breakdown under an overvoltage, the energy is uniformly dissipated in the drift region through the avalanche current.

[0079] S206、In the time when the avalanche current of the GaN power device is maintained below the preset current safety value for a time period longer than the preset minimum dissipation time period, it is determined that the external heat dissipation operation is completed.

[0080] As described in the previous step S203, the preset current safety value should be determined according to the working current of the load device and the preset current safety base value, ensuring that the maximum current that the device can withstand in the avalanche mode does not exceed the safety value, thereby avoiding damage to the device.

[0081] The preset minimum dissipation time period should be set according to the avalanche characteristics of the device, thermal design, and system safety requirements, as described in the previous step S202. It represents the shortest time required for the device to enter the dissipation state and safely exit the avalanche mode, ensuring that the device has enough time to dissipate the heat generated during the avalanche process and avoid overheating damage.

[0082] The preset current safety value and the preset minimum dissipation time period can be stored in the non-volatile memory such as the flash memory or EEPROM of the controller. Then, based on real-time monitoring of the avalanche current, it needs to be compared with the preset current safety value in real time to determine whether the avalanche current has fallen within the safe range.

[0083] Specifically, the comparison logic can be implemented in the software program of the controller to compare the real-time collected avalanche current value with the preset current safety value. If the avalanche current value is less than or equal to the preset current safety value, it is considered that the avalanche current has fallen within the safe range; otherwise, it is considered that the avalanche current is still in a dangerous state.

[0084] And, the result of each comparison is recorded, including the comparison time, the avalanche current value, and the comparison result (whether lower than the preset current safety value), and these recorded data can also be used for subsequent analysis and troubleshooting.

[0085] In addition, after confirming that the avalanche current has fallen below the preset current safety value, a dissipation time length timer needs to be started to time the length of time that the avalanche current is maintained within the safety range. When the timing length exceeds the preset minimum dissipation time length, it is determined that the external heat dissipation operation is completed. And, the dissipation time length timer is started or reset each time the avalanche current is confirmed to be lower than the preset current safety value.

[0086] During the timing process, the timing length is compared with the preset minimum dissipation time length in real time. If the timing length exceeds the preset minimum dissipation time length, it is considered that the device has sufficiently dissipated the heat generated in the avalanche process, and the dissipation state can be safely exited; otherwise, the dissipation state is continued until the timing length meets the requirement.

[0087] When it is determined that the dissipation time length meets the requirement, a dissipation operation completion signal is generated to notify the controller to perform subsequent operations, such as turning off the dissipation circuit, restoring the device to the normal working state, and the like.

[0088] In addition, it is worth mentioning that during the external heat dissipation operation, abnormal situations may occur due to various reasons, such as the avalanche current continuously being higher than the preset current safety value, the dissipation time length being too long, and the like. In order to ensure the safety of the device, these abnormal situations need to be handled and protected in a timely manner. Optionally, the key parameters such as the avalanche current and the dissipation time length can be monitored and identified in real time to monitor and identify abnormal situations. For example, an upper threshold of the avalanche current and an upper threshold of the dissipation time length are set, and when the parameters exceed the thresholds, it is considered that an abnormal situation occurs. For the situation that the avalanche current continuously exceeds the preset current safety value, measures such as increasing the dissipation power and reducing the device working voltage can be taken; for the situation that the dissipation time length is too long, it can be checked whether the dissipation circuit is working normally and whether the device has a fault, and the like. While implementing the abnormal handling strategy, a safety protection mechanism can also be started, such as triggering a protection circuit to cut off the power supply of the device, sending an alarm signal to notify the user, and the like, to ensure the safety of the device and the system.

[0089] It is worth mentioning that relying only on the current instantaneous value may not accurately reflect the sufficiency of heat dissipation. For example, a temporary drop in current followed by a rebound can cause the device to exit the protection mode before it is completely cooled, triggering repeated overloads. Under noise or transient interference, current fluctuations can mistakenly trigger the protection mechanism to terminate, reducing system stability. The above combination of current threshold and time threshold can filter out current instantaneous fluctuations or noise interference, avoid misoperation, and through the time dimension verification, it can also solve the problem of insufficient protection caused by too fast current drop speed, and improve the stability of the device under extreme working conditions S207, after the external heat dissipation operation ends, the GaN power device exits the avalanche mode and enters a normal off state.

[0090] When the external heat dissipation operation end condition is met, a control signal can be sent to make the GaN power device exit the avalanche mode and re-enter the normal off state, and wait for the next possible overvoltage event. Specifically, the microcontroller or dedicated control chip can change the control signal state immediately when it detects that the exit condition is met, and the GaN power device quickly closes the avalanche channel and returns to the normal off state after receiving the exit signal.

[0091] Figure 3 is a structural schematic diagram of an electronic device according to an example embodiment. As shown in Figure 3 The electronic device 300 provided in this embodiment includes a processor 301 and a memory 302. The memory 302 is used to store computer programs, and the memory can also be a flash memory.

[0092] The processor 301 is used to execute the execution instructions stored in the memory to implement each step in the above method. For details, please refer to the related description in the method embodiment.

[0093] Optionally, the memory 302 can be independent or integrated with the processor 301.

[0094] When the memory 302 is a device independent of the processor 301, the electronic device 300 can further include: A bus 303 is used to connect the memory 302 and the processor 301.

[0095] This embodiment also provides a readable storage medium, and the readable storage medium stores a computer program. When at least one processor of an electronic device executes the computer program, the electronic device executes the method provided in the various embodiments.

[0096] This embodiment also provides a program product, and the program product includes a computer program stored in a readable storage medium. At least one processor of an electronic device can read the computer program from the readable storage medium, and the at least one processor executes the computer program to make the electronic device implement the method provided in the various embodiments.

[0097] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0098] It is to be understood that the application is not limited to the precise construction herein disclosed and shown in the drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the claims that follow.

Claims

1. A control method of a vertical structure GaN power device, characterized by, The application relates to a control method of a vertical-structure GaN power device. When the vertical-structure GaN power device is in a normal-off state, if a drain-source voltage of the GaN power device reaches an avalanche breakdown voltage, the GaN power device is controlled to enter an avalanche mode. In the avalanche mode, the GaN power device clamps the drain-source voltage in a power consumption voltage range corresponding to the avalanche breakdown voltage, so as to perform an external heat dissipation operation through an avalanche current generated by the GaN power device in the power consumption voltage range. After the external heat dissipation operation is completed, the GaN power device is controlled to exit the avalanche mode and enter the normal-off state.

2. The control method of a vertical structure GaN power device according to claim 1, characterized by, The avalanche breakdown voltage is determined based on a preset safe avalanche working area corresponding to the GaN power device.

3. The method of controlling a vertical structure GaN power device according to claim 1, wherein The drain-source voltage of the GaN power device reaching the avalanche breakdown voltage is caused by an overvoltage spike of a device external circuit.

4. The method of claim 1, wherein the method further comprises: When the avalanche current of the GaN power device is reduced to below a preset current safety value, it is determined that the external heat dissipation operation is completed.

5. The method of claim 1, wherein the method further comprises: When a time length during which the avalanche current of the GaN power device is maintained below the preset current safety value exceeds a preset minimum dissipation time length, it is determined that the external heat dissipation operation is completed.

6. The control method of a vertical structure GaN power device according to claim 5, characterized by, The preset minimum dissipation time length is determined according to a load type of a load device in a circuit to which the GaN power device is applied.

7. The control method of the vertical structure GaN power device according to claim 6, characterized by, The load type includes an inductive load and a capacitive load.

8. The method of claim 4-7, wherein the method further comprises: The preset current safety value is determined according to a working current of the load device in the circuit to which the GaN power device is applied and a preset current safety base value.

9. The method of claim 1-7, wherein the method further comprises: The avalanche breakdown voltage is determined according to a preset voltage fluctuation range of the GaN power device in the application circuit and a preset safe avalanche working area.

10. A switching power supply circuit, characterized by comprising: The application relates to a vertical-structure GaN power device. The vertical-structure GaN power device is overvoltage-protected by the control method of the vertical-structure GaN power device in any one of claims 1-8.

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