Short-circuit protection device of GaN power switch device

Abstract

The invention discloses a short-circuit protection device of a GaN power switch device. The short-circuit protection device comprises a GaN power switch; the current detection resistor is connected between the source electrode of the GaN power switch and the ground and is used for detecting the current in the circuit; the input end of the comparator receives the amplified current signal and the voltage signal subjected to voltage division processing respectively, and the comparator is used for comparing the two signals and outputting a comparison result; the driving circuit is used for receiving a control signal from the microcontroller so as to control the grid voltage of the GaN power switch; the microcontroller is used for monitoring the output of the comparator and controlling the driving circuit according to a monitoring result, so that the GaN power switch is controlled; the microcontroller further reads the output of the comparator through the ADC so as to monitor the current and voltage states of the circuit in real time, and corresponding protection measures are taken when abnormity is detected. According to the invention, effective management and protection of the GaN power switch are realized, and powerful support is provided for safe operation of a power electronic system.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a short-circuit protection device for a GaN power switch device. Background Art

[0002] In the field of power electronics, as the demand for power conversion efficiency and power density continues to increase, GaN (gallium nitride) power switches are widely used in various high-performance power conversion systems due to their high-speed switching performance and low-loss characteristics. However, GaN power switches may encounter extreme conditions such as overload and short circuit during operation, which can cause device damage or even failure of the entire system. Therefore, it is crucial to develop a circuit system that can effectively monitor and protect GaN power switches.

[0003] Existing protection schemes usually rely on complex hardware circuits and software algorithms, which not only increase the cost and complexity of the system, but also may cause response time delays in some cases, affecting the protection effect. For example, traditional protection circuits often use discrete components, such as thermistors and temperature sensors, to achieve over-temperature protection; or use external current detection resistors and analog comparators to detect over-current conditions. Although these methods can achieve protection functions to a certain extent, they still need to be improved in terms of accuracy, response speed and integration.

[0004] In addition, microcontrollers used in modern power electronic systems usually have rich interface resources, such as ADC (analog-to-digital converter), GPIO (general purpose input and output), etc., which makes it possible to implement higher-level protection strategies. However, how to effectively utilize these resources and combine them with the protection circuit of GaN power switches remains a challenge. Summary of the invention

[0005] The purpose of the present invention is to provide a short-circuit protection device for a GaN power switch device, which realizes effective management and protection of the GaN power switch by combining advanced microcontroller technology and a dedicated drive circuit, and provides strong support for the safe operation of the power electronic system.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A short-circuit protection device for a GaN power switch device, comprising:

[0008] GaN power switches, used to control the on and off of circuits;

[0009] A current detection resistor connected between the source of the GaN power switch and ground to detect the current in the circuit;

[0010] A comparator, whose input terminals receive the amplified current signal and the voltage signal processed by voltage division, respectively, and is used to compare the two signals and output the comparison result;

[0011] A driving circuit receives a control signal from a microcontroller to control a gate voltage of the GaN power switch;

[0012] A microcontroller, used to monitor the output of the comparator and control the driving circuit according to the monitoring result, thereby realizing the control of the GaN power switch;

[0013] The microcontroller also reads the output of the comparator through the ADC to monitor the current and voltage status of the circuit in real time and take corresponding protection measures when an abnormality is detected.

[0014] Further preferably, it also includes: a differential amplifier, which is used to amplify the voltage signal across the current detection resistor and input the amplified signal to an input terminal of the comparator.

[0015] Further preferably, it also includes: a voltage detection circuit, including two voltage-dividing resistors connected in series between the output voltage and ground, for dividing the output voltage into a range that the comparator can handle, and inputting the divided voltage signal to another input terminal of the comparator.

[0016] Further preferably, when the microcontroller detects that the current or voltage exceeds a preset threshold, the microcontroller controls the driving circuit to turn off the GaN power switch to protect the circuit from overcurrent or overvoltage damage.

[0017] Further preferably, it also includes: an isolated power supply for providing independent power supply for the driving circuit and the differential amplifier to improve the electromagnetic compatibility and safety of the system.

[0018] Further preferably, it also includes: a thermal management device for monitoring the temperature of the GaN power switch, and taking heat dissipation measures or shutting down the GaN power switch when the temperature exceeds a preset threshold to prevent overheating damage.

[0019] Further preferably, the microcontroller also has a fault recovery function, and after detecting that the circuit has returned to normal, the drive circuit is re-enabled after a preset delay time to restore the normal operation of the GaN power switch.

[0020] In summary, the present invention has the following beneficial effects:

[0021] First, it improves the protection response speed: through integrated circuit design and optimized control algorithms, it can quickly detect overcurrent, overvoltage or overtemperature and take corresponding protection measures immediately, thereby significantly shortening the protection response time and reducing the potential risks caused by delays.

[0022] Second, the accuracy and reliability of protection are enhanced: the use of high-precision sensors and advanced signal processing technology enables the system to more accurately monitor the working status of GaN power switches. This helps reduce false alarms and missed alarms, and improves the overall reliability and accuracy of the protection mechanism.

[0023] Third, it reduces system cost and complexity: By streamlining the hardware configuration and making full use of the internal resources of the microcontroller (such as ADC, GPIO, etc.), the external circuit design is simplified and the number of required discrete components is reduced, thereby reducing costs and improving the overall integration of the system.

[0024] Fourth, it improves the maintainability and scalability of the system: the modular design concept is adopted to facilitate later maintenance and upgrades. In addition, with the powerful computing power and rich interface resources of the microcontroller, the protection strategy can be flexibly adjusted according to different application scenarios, which enhances the adaptability and flexibility of the system.

[0025] Fifth, the robustness of the system is enhanced: Through enhanced over-current, over-voltage and over-temperature protection mechanisms, as well as intelligent fault diagnosis functions, the system can maintain stable operation in more severe working environments, improving the robustness of the entire power electronics system.

[0026] Sixth, improved energy efficiency: Through efficient management of GaN power switches, unnecessary energy loss is reduced, the overall energy efficiency ratio of the system is improved, which helps save energy and reduce emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the overall circuit diagram of the present invention;

[0028] Figure 2 is a circuit diagram of a voltage detection circuit. DETAILED DESCRIPTION

[0029] The following is a further detailed description of a short-circuit protection device for a GaN power switch device proposed by the present invention in combination with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will become clearer. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. The same or similar reference numerals in the accompanying drawings represent the same or similar components.

[0030] Example, see Figure 1-2 A short-circuit protection device for a GaN power switch device is disclosed. The operating voltage of the circuit designed here is 48V. The GaN power switch adopts EPC2018 (rated voltage 60V, maximum current 15A) and is controlled by a microcontroller STM32F030.

[0031] Components List

[0032] 1.GaN power switch (MOSFET): EPC2018

[0033] 2. Current detection resistor: Rshunt (10mΩ, 2W)

[0034] 3. Comparator: LM393

[0035] 4. Driving circuit: EPC9117

[0036] 5. Microcontroller: STM32F030

[0037] 6.Isolated power supply: to power the drive circuit

[0038] 7.Resistors: R1, R2, R3, R4 (10kΩ), R5 (1kΩ)

[0039] 8. Capacitor: C1, C2 (10nF)

[0040] Circuit Connection

[0041] 1. Current detection circuit

[0042] ●Component: Rshunt (10mΩ, 2W)

[0043] ●Connection: One end of Rshunt is connected to the source (S) of the GaN switch, and the other end is grounded (GND). ·Function:

[0044] Used to sense the current flowing through the GaN switch.

[0045] The current is measured indirectly by measuring the voltage across Rshunt.

[0046] 2. Voltage detection circuit

[0047] Components: R1 (10kΩ), R2 (10kΩ)

[0048] ●Connection:

[0049] One end of R1 is connected to the output voltage (assumed to be 48V), and the other end is connected to R2 and one input of the comparator.

[0050] The other end of R2 is grounded.

[0051] ·effect:

[0052] Voltage division is used to reduce the output voltage to a level that the comparator can handle.

[0053] When the output voltage is lower than a certain threshold, the protection action is triggered.

[0054] 3. Current Sense Amplifier

[0055] ●Component: OPA2333 (differential amplifier)

[0056] ·connect:

[0057] The non-inverting input of OPA2333 is connected to one end of Rshunt (not the ground end).

[0058] The inverting input of OPA2333 is grounded through R3 (10kΩ).

[0059] The output of the OPA2333 is connected to one input of the comparator.

[0060] The power supply of the OPA2333 is connected to the isolated power supply.

[0061] ·effect:

[0062] Amplify the voltage across Rshunt.

[0063] Provides a high enough signal for the comparator to detect.

[0064] 4. Comparator circuit

[0065] ●Component:LM393

[0066] ●Connection:

[0067] One input of the LM393 is connected to the output of the OPA2333.

[0068] The other input of the LM393 is connected to the node divided by R1 and R2.

[0069] The output of LM393 is connected to the ADC pin of the microcontroller.

[0070] The power supply of LM393 is connected to the isolated power supply.

[0071] ●Function:

[0072] Compare the amplified current signal and the divided voltage signal.

[0073] When the current or voltage exceeds the threshold, the output signal changes.

[0074] 5. Driving circuit

[0075] ●Component:EPC9117

[0076] ●Connection:

[0077] The control input (CTRL) of the EPC9117 is connected to a GPIO pin of the microcontroller.

[0078] The output (GATE) of the EPC9117 is connected to the gate (G) of the GaN switch.

[0079] The power supply (VCC) of the EPC9117 is connected to an isolated power supply.

[0080] Connect the ground line (GND) of EPC9117 to the ground line.

[0081] ·effect:

[0082] The gate voltage of the GaN switch is driven according to the instructions of the microcontroller.

[0083] Control the on and off of the GaN switch.

[0084] 6. Microcontroller circuit

[0085] ●Component: STM32F030

[0086] ·connect:

[0087] The GPIO pins of the STM32F030 are connected to the CTRL pin of the EPC9117.

[0088] The ADC pin of STM32F030 is connected to the output of LM393.

[0089] ·effect:

[0090] Monitor the comparator output to determine whether a short circuit or voltage abnormality has occurred.

[0091] Control the on and off of EPC9117, thereby controlling the state of the GaN switch.

[0092] Input and Output Summary

[0093] Input:

[0094] Power input: 48V

[0095] Microcontroller power supply: 3.3V

[0096] Isolated power supply: 5V (to power the drive circuit)

[0097] Output:

[0098] Microcontroller GPIO output: control EPC9117

[0099] LM393 output: informs the microcontroller about short circuit or voltage abnormality

[0100] How it works

[0101] ●Normal operation:

[0102] The microcontroller enables the EPC9117 and the GaN switch turns on.

[0103] The output voltage and current are both within the normal range.

[0104] The microcontroller reads the output of the LM393 through the ADC to monitor the current and voltage status. Short Circuit Detection:

[0105] When a short circuit occurs, the current increases dramatically.

[0106] The voltage Vshunt across Rshunt increases accordingly.

[0107] The OPA2333 amplifies Vshunt.

[0108] When Vshunt exceeds the threshold, LM393 outputs a high level.

[0109] The microcontroller detects the change in the LM393 output and turns off the EPC9117, protecting the GaN switch.

[0110] Fault recovery:

[0111] The microcontroller goes into wait mode and monitors the LM393 output.

[0112] When the LM393 output returns to normal state, the microcontroller re-enables the EPC9117 after a delay.

[0113] Precautions

[0114] ● Protect circuits: Ensure that all circuits have adequate protection measures, such as over-temperature protection. · Electromagnetic compatibility: Use appropriate filtering and shielding techniques to reduce electromagnetic interference.

[0115] ● Thermal management: Provide good heat dissipation conditions for GaN switches.

[0116] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A short-circuit protection device for a GaN power switch device, characterized in that: include: GaN power switches, used to control the on and off of circuits; A current detection resistor connected between the source of the GaN power switch and ground to detect the current in the circuit; A comparator, whose input terminals receive the amplified current signal and the voltage signal processed by voltage division, respectively, and is used to compare the two signals and output the comparison result; A driving circuit receives a control signal from a microcontroller to control a gate voltage of the GaN power switch; A microcontroller, used to monitor the output of the comparator and control the driving circuit according to the monitoring result, thereby realizing the control of the GaN power switch; The microcontroller also reads the output of the comparator through the ADC to monitor the current and voltage status of the circuit in real time and take corresponding protection measures when an abnormality is detected.

2. A short-circuit protection device for a GaN power switch device according to claim 1, characterized in that: Also includes: The differential amplifier is used to amplify the voltage signal across the current detection resistor and input the amplified signal to one input terminal of the comparator.

3. The short-circuit protection device of a GaN power switch device according to claim 1, characterized in that: Also includes: The voltage detection circuit includes two voltage-dividing resistors connected in series between the output voltage and the ground, which are used to divide the output voltage into a range that the comparator can handle, and input the divided voltage signal to the other input terminal of the comparator.

4. The short-circuit protection device of a GaN power switch device according to claim 1, characterized in that: When the microcontroller detects that the current or voltage exceeds the preset threshold, it controls the drive circuit to turn off the GaN power switch to protect the circuit from overcurrent or overvoltage damage.

5. The short-circuit protection device of a GaN power switch device according to claim 4, characterized in that: Also includes: Isolated power supply is used to provide independent power supply for the driving circuit and differential amplifier to improve the electromagnetic compatibility and safety of the system.

6. A short-circuit protection device for a GaN power switch device according to any one of claims 1 to 5, characterized in that: Also includes: A thermal management device is also included to monitor the temperature of the GaN power switch and take heat dissipation measures or shut down the GaN power switch when the temperature exceeds a preset threshold to prevent overheating damage.

7. The short-circuit protection device for a GaN power switch device according to claim 6, characterized in that: The microcontroller also has a fault recovery function. After detecting that the circuit has returned to normal, it re-enables the drive circuit after a preset delay time to restore the normal operation of the GaN power switch.

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