Half-bridge module and switching power supply circuit

Abstract

The invention discloses a half-bridge module and a switching power supply circuit. The half-bridge module comprises an enhancement mode device serving as an upper tube and a depletion mode device serving as a lower tube; the source electrode of the enhancement mode device and the drain electrode of the depletion mode device are electrically connected and form a common node, and the node is used for inputting or outputting power; the drain electrode of the enhanced device is used as the high-voltage end of the half-bridge module, and the source electrode of the depletion device is used as the low-voltage end of the half-bridge module; the grid electrode of the enhancement type device is used for accessing an upper tube driving signal, the grid electrode of the depletion type device is used for accessing a lower tube driving signal, and the enhancement type device and the depletion type device are configured to be in complementary conduction. According to the half-bridge module provided by the invention, the enhanced device is naturally closed when no control signal exists, and a built-in safety characteristic is provided. The depletion type device reduces conduction loss and switching loss and improves overall efficiency due to low conduction resistance and stray capacitance of the depletion type device.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to a half-bridge module and a switching power supply circuit. Background Technology

[0002] Half-bridge modules have a wide range of applications. For example, in switching power supplies, half-bridge circuits are commonly found in Buck, Boost, FPC, LLC, and DAB circuits. With the rise of artificial intelligence, high-efficiency step-down circuits play a crucial role in server power supplies. From a circuit safety perspective, traditional half-bridge modules, such as... Figure 1 As shown in (a), it is typically composed of two normally off (enhancement-mode / E-mode) devices cascaded together, or as... Figure 1 (b) It integrates or packages the driver, or integrates the logic chip, or such as Figure 1 (c) shows two cascaded Cascode structures. The aforementioned half-bridge module suffers from high switching and conduction losses due to the parasitic capacitance and on-resistance of the switching devices, making it difficult to improve overall efficiency. In applications with high switching frequencies and large currents, such as server power supplies, efficiency drops significantly.

[0003] Therefore, there is an urgent need for a half-bridge module and switching power supply circuit to solve the above-mentioned technical problems. Summary of the Invention

[0004] This invention provides a half-bridge module and a switching power supply circuit to solve the problem that the high switching loss and conduction loss of the half-bridge module in the related technology make it difficult to improve the overall efficiency.

[0005] To achieve the above objectives, this application employs the following technical solution:

[0006] This application provides a half-bridge module, which includes an enhancement-mode device as the upper transistor and a depletion-mode device as the lower transistor;

[0007] The source of the enhancement-mode device and the drain of the depletion-mode device are electrically connected to form a common node, which is used to receive or output power.

[0008] The drain of the enhancement-mode device serves as the high-voltage terminal of the half-bridge module, and the source of the depletion-mode device serves as the low-voltage terminal of the half-bridge module.

[0009] The gate of the enhancement-mode device is used to receive the upper-side drive signal, and the gate of the depletion-mode device is used to receive the lower-side drive signal. The enhancement-mode device and the depletion-mode device are configured to be complementaryly turned on according to the upper-side drive signal and the lower-side drive signal.

[0010] In one embodiment, the half-bridge module further includes functional devices, which include driving devices and / or logic devices;

[0011] The output terminal of the functional device is electrically connected to the gate of the enhancement-mode device and the gate of the depletion-mode device, respectively, so that the gate of the enhancement-mode device is connected to the upper-side drive signal through the functional device, and the gate of the depletion-mode device is connected to the lower-side drive signal through the functional device.

[0012] In one embodiment, the enhancement-mode device includes any normally-off device selected from silicon MOSFET, SiC MOSFET, pGaN Gate HEMT, and GaN trench gate MIS-HEMT;

[0013] The depletion-type device includes any one of the normally-on devices of SiC JFET, GaN JFET, GaN MIS-HEMT, and Ga2O3 MOSFET.

[0014] In one embodiment, the enhancement-mode device and the depletion-mode device are packaged together or integrated on the same substrate.

[0015] In one embodiment, the depletion-type device is a MIS-HEMT, and the enhancement-type device is a pGaN GateHEMT, which achieves a positive threshold by depleting a two-dimensional electron gas through pGaN islands.

[0016] In one embodiment, the enhancement-mode device is a trench-gate enhancement-mode high electron mobility transistor, and the depletion-mode device is a metal-insulator-semiconductor depletion-mode high electron mobility transistor.

[0017] This application also provides a switching power supply circuit, wherein the switching power supply circuit is a half-bridge module as described in any of the above claims.

[0018] In one embodiment, the switching power supply circuit is a buck circuit, and the buck circuit further includes a low-voltage side load and a drive module;

[0019] The driving module is used to generate upper-side drive signals and lower-side drive signals and enable the upper-side and lower-side transistors of the half-bridge module to conduct complementaryly, respectively; one end of the low-voltage side load is connected to the node of the half-bridge module, and the other end of the low-voltage side load is connected to the source of the depletion-type device of the half-bridge module.

[0020] In one embodiment, the depletion-mode device of the half-bridge module includes a GaN D-Mode MIS-HEMT device.

[0021] In one embodiment, the switching power supply circuit further includes a first capacitor and a first inductor, one end of the low-voltage side load is connected to a node of the half-bridge module through the first inductor, and the first capacitor and the load resistor are connected in parallel.

[0022] Compared with the prior art, the half-bridge module and switching power supply circuit provided by the present invention have the following technical advantages:

[0023] The source of the enhancement-mode device and the drain of the depletion-mode device are connected to form a common node, which is then connected to a switching signal. The gate of the enhancement-mode device is connected to the upper drive signal, and the gate of the depletion-mode device is connected to the lower drive signal. The enhancement-mode and depletion-mode devices are configured to conduct complementaryly; that is, when one device is on, the other is off, and vice versa. Because the upper device is an enhancement-mode device, the circuit remains in a safe state even when high voltage is applied, as it is not conducting. Moreover, because the lower device is a depletion-mode device, optimal device performance can be achieved, reducing losses and improving the efficiency of the entire half-bridge module. When the half-bridge module is used in a buck circuit, the duty cycle of the lower device is usually higher, and a portion of the losses in the buck circuit mainly come from the conduction and switching losses of the devices. Therefore, when the half-bridge module provided in this embodiment is used in a buck circuit, the lower device can provide lower conduction losses, resulting in a more significant performance improvement for the half-bridge module. Thus, the half-bridge module provided in this application does not suffer from the performance limitations encountered in low-voltage applications where sufficient voltage is required to maintain the conduction of the depletion-mode device. Enhanced-mode devices shut down naturally when there is no control signal, providing a built-in safety feature. Depletion-mode devices, due to their small parasitic capacitance, can respond quickly to control signals, reducing switching losses. At the same time, their low resistance reduces conduction losses and improves overall efficiency. Attached Figure Description

[0024] Figure 1 The diagram shows the structural schematics of three types of half-bridge modules provided by related technologies.

[0025] Figure 2 The diagram shows the structural schematics of three half-bridge modules provided in the embodiments of this application.

[0026] Figure 3 A schematic diagram of an implementation method of a half-bridge module provided in an embodiment of this application is shown.

[0027] Figure 4 A schematic diagram of another implementation method of the half-bridge module provided in this application embodiment is shown.

[0028] Figure 5 A schematic diagram of a switching power supply circuit provided in an embodiment of this application is shown. Detailed Implementation

[0029] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many other different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] The following is a brief description of the relevant technologies and terms used in the embodiments of this application.

[0032] In related technologies, wide-bandgap semiconductors, including GaN, AlN, SiC, and gallium oxide, offer superior material properties compared to silicon (e.g., Baliga has high performance indicators), leading to significant advancements in the power supply field. However, some challenges remain in fully leveraging the advantages of these materials in half-bridge modules. For example, manufacturing E-mode devices is difficult, and the performance of E-mode devices is inferior to that of D-mode devices.

[0033] Taking GaN as an example, there are currently two types of devices: D-mode MIS-HEMT and E-mode pGaN GateHEMT, both of which have been applied to a certain extent in the consumer electronics field. MIS-HEMT devices are manufactured in a process compatible with CMOS, the barrier layer is not dry-etched, and the channel resistance is low, theoretically resulting in lower resistance per unit area. Compared to pGaN GateHEMT, MIS-HEMT has better gate reliability, higher saturation current density, and is less affected by temperature. Related technologies can be applied to server power supplies using half-bridge low-voltage modules based on pGaN Gate HEMT. Although D-mode GaN MIS-HEMT devices have better performance, they cannot be directly used in half-bridge modules for safety reasons. Using them after passing through a cascade gate will reduce performance, and cascade itself does not offer performance advantages in the low-voltage domain. The cascade structure represents a common-source, common-gate structure.

[0034] MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) refers to a metal-oxide-semiconductor field-effect transistor. JFET refers to a junction field-effect transistor. HEMT refers to a high-electron-mobility transistor. MIS refers to a metal-insulator-semiconductor structure. D-mode refers to a depletion-mode device, and E-mode refers to an enhancement-mode device.

[0035] This application proposes a half-bridge module and a switching power supply circuit, focusing on its application in the field of power electronics. By configuring enhancement-mode and depletion-mode devices, which are used as the upper and lower transistors respectively, in a complementary conduction mode, it solves the problem of high switching and conduction losses in related half-bridge modules. The half-bridge module will be described first, followed by a description of the switching power supply circuit.

[0036] Half-bridge module implementation example.

[0037] This embodiment provides a half-bridge module, which includes an enhancement-mode device as the upper transistor and a depletion-mode device as the lower transistor;

[0038] The source of the enhancement-mode device and the drain of the depletion-mode device are electrically connected to form a common node, which is used for power input or output.

[0039] The drain of the enhancement-mode device serves as the high-voltage terminal of the half-bridge module, and the source of the depletion-mode device serves as the low-voltage terminal of the half-bridge module.

[0040] The gate of the enhancement-mode device is used to receive the upper-side drive signal, and the gate of the depletion-mode device is used to receive the lower-side drive signal. The enhancement-mode device and the depletion-mode device are configured to be complementaryly turned on according to the upper-side drive signal and the lower-side drive signal.

[0041] See Figure 2 (a) The half-bridge module consists of two complementary power switching devices. The drain of the enhancement-mode device serves as the high-voltage terminal of the half-bridge module and is connected to the power supply VDC on the high-voltage side. The source of the depletion-mode device serves as the low-voltage terminal of the half-bridge module. The low-voltage terminal can be the ground terminal GND.

[0042] The source of the enhancement-mode device and the drain of the depletion-mode device are connected to form a common node, which is connected to a switching signal SW (e.g., load or power supply). The gate GH of the enhancement-mode device is connected to the upper-side drive signal, and the gate GL of the depletion-mode device is connected to the lower-side drive signal. The control signal can be generated by the PWM controller of the switching power supply to precisely control the switching time and sequence of the devices. The enhancement-mode and depletion-mode devices are configured to conduct complementaryly, that is, when one device is on, the other is off, and vice versa. In practical applications, to avoid a short circuit caused by both devices conducting simultaneously, the switching actions of the upper and lower MOSFETs are driven by the upper-side drive signal and the lower-side drive signal, respectively. A certain dead time can be set, during which both devices remain off.

[0043] Because the upper MOSFET is an enhancement-mode (E-Mode) device, the circuit remains in a safe state even when high voltage is applied, as it is not conducting. Furthermore, because the lower MOSFET is a depletion-mode (D-Mode) device, optimal device performance is achieved, reducing losses and improving the overall efficiency of the half-bridge module. In the following text, "upper MOSFET" refers to an enhancement-mode device, and "lower MOSFET" refers to a depletion-mode device.

[0044] When a half-bridge module is used in a buck circuit, the duty cycle of the lower transistor is usually relatively high. Since a significant portion of the losses in a buck circuit comes from the conduction and switching losses of the components, using the half-bridge module provided in this embodiment in a buck circuit allows the lower transistor to provide lower conduction losses. In this case, the performance improvement of the half-bridge module will be more significant.

[0045] Therefore, this embodiment provides a half-bridge module that, compared to related technologies, avoids the performance limitations encountered in low-voltage applications where sufficient voltage is required to maintain the conduction of depletion-type devices. The enhancement-type devices naturally turn off in the absence of a control signal, providing a built-in safety feature. Due to their small parasitic capacitance, depletion-type devices can respond quickly to control signals, reducing switching losses; simultaneously, their low resistance reduces conduction losses and improves overall efficiency.

[0046] In one embodiment, the enhancement-mode device includes any normally-off device selected from silicon MOSFET, SiC MOSFET, pGaN Gate HEMT, and GaN trench gate MIS-HEMT;

[0047] The depletion-type device includes any one of the normally-on devices of SiC JFET, GaN JFET, GaN MIS-HEMT, and Ga2O3 MOSFET.

[0048] In one embodiment, the enhancement-mode device and the depletion-mode device are packaged together or integrated on the same substrate.

[0049] In one embodiment, the half-bridge module further includes functional devices, which include driving devices and / or logic devices;

[0050] The output terminal of the functional device is electrically connected to the gate of the enhancement-mode device and the gate of the depletion-mode device, respectively, so that the gate of the enhancement-mode device is connected to the upper-side drive signal through the functional device, and the gate of the depletion-mode device is connected to the lower-side drive signal through the functional device.

[0051] See Figure 2 (b) illustrates a half-bridge module with driver D as the functional device. The input of the driver is connected to a positive power supply voltage VCC, a high-side input signal HIN, a low-side input signal LIN, and a negative power supply voltage VSS.

[0052] The function of the driver (D) is to provide the appropriate voltage and current to the gate of the switching device (enhancement-mode and depletion-mode devices) to ensure that the switching device can switch quickly and accurately. The driver (D) can be a gate driver, a microcontroller (MCU), or a driver IC (integrated circuit).

[0053] See Figure 2 (c) illustrates a half-bridge module with a driver device D and a logic device L as functional devices, wherein the driver device D is disposed between the gates of the logic device L and the switching device. The input terminals of the logic device L are connected to logic pins (p1, p2, p2...pn) for receiving logic signals.

[0054] A logic device L refers to a logic circuit used to control the gate signal of a switching device. When the logic device L is positioned between the driver device D and the gate of the switching device, it processes signals from the control terminal of the driver device and generates appropriate gate drive signals to be sent to the gate of the switching device. Examples include voltage converters.

[0055] In specific applications, functional devices may also include other devices or chips, and this application does not restrict their selection.

[0056] In a specific application, see Figure 3 The enhancement-mode device is a pGaN gate HEMT, and the depletion-mode device is a MIS-HEMT. The half-bridge module is packaged from both a pGaN gate HEMT and a MIS-HEMT. Because the depletion-mode device does not have a pGaN island, it is easier to achieve a smaller gate length, and the resistance per unit area can be made smaller.

[0057] Figure 3The disclosed half-bridge module has a D-Mode HEMT on the left (lower transistor) and an E-Mode HEMT on the right (upper transistor). This half-bridge module can achieve a positive threshold for the E-Mode HEMT by depleting the lower 2DEG (two-dimensional electron gas) using pGaN. The upper and lower transistors can be packaged together to achieve integration of the half-bridge module.

[0058] The lower transistor comprises, from top to bottom, a dielectric layer, an aluminum gallium nitride (AlGaN) layer, a gallium nitride channel layer, a gallium nitride buffer layer, and a substrate.

[0059] The dielectric layer serves as the gate insulating layer. The AlGaN layer is a semiconductor material, an alloy of aluminum and gallium nitrides. In HEMT structures, the AlGaN layer can act as a barrier layer, facilitating the formation of a two-dimensional electron gas (2DEG). These structural layers are stacked in a specific order to achieve specific electronic properties and performance.

[0060] The source (SL) of the lower transistor is connected to ground (GND), the gate (GL) is led out from the package structure, and the drain (DL) is connected to the source (SH) of the upper transistor. The gate (GH) of the upper transistor is led out from the package structure, and the drain (DH) is connected to the high-voltage side power supply (VDC).

[0061] Therefore, in the design of the upper and lower transistors of the half-bridge module, the upper transistor uses a pGaN gate HEMT, which can achieve a positive threshold voltage through the above mechanism, while the lower transistor uses a MIS-HEMT, which conducts naturally when there is no gate voltage. This design combines the advantages of both devices, improving the overall performance and safety of the module.

[0062] In one embodiment, the enhancement-mode device is a trench-gate enhancement-mode high electron mobility transistor, and the depletion-mode device is a metal-insulator-semiconductor depletion-mode high electron mobility transistor.

[0063] In another specific application, see Figure 4 (a) The depletion-mode device (lower transistor) is a D-ModeMIS-HEMT. A positive threshold can be achieved by thinning the AlGaN layer to reduce the 2DEG below the gate G.

[0064] See Figure 4 (b) The enhancement-mode device (upper transistor) is a slot-gate E-mode HEMT. See also Figure 4 (c) By placing the upper and lower transistors on the same substrate, the above-mentioned half-bridge module can be integrated on a single chip.

[0065] Example of a switching power supply circuit.

[0066] This embodiment provides a switching power supply circuit, which includes the half-bridge module described in any of the above embodiments. Specific embodiments can be found in the above half-bridge module embodiments, and will not be repeated in this embodiment.

[0067] See Figure 5 In one embodiment, the switching power supply circuit is a step-down circuit, which includes a half-bridge module, a low-voltage side load R1, and a drive module. The drive module is used to generate an upper MOSFET drive signal and a lower MOSFET drive signal and respectively enable the upper MOSFET and the lower MOSFET of the half-bridge module to conduct complementaryly.

[0068] One end of the low-voltage side load R1 is connected to a node of the half-bridge module, and the other end of the low-voltage side load R1 is connected to the source of the depletion-type device of the half-bridge module.

[0069] Before the drive circuit is powered on, if voltage is applied to the high-voltage terminal, the circuit safety can be ensured because the upper transistor is in the off state. The drive signal is as follows: Figure 5 As shown, the narrow platform corresponds to the upper transistor being on and the lower transistor being off. The upper transistor's drive pulse PWMH is similar to that in a normal half-bridge, while the lower transistor's drive pulse PWML is inverted and scaled towards the negative voltage direction. Its minimum voltage should be lower than the lower transistor's threshold to ensure that the lower transistor is effectively turned off. Since the upper transistor is a normally off device, the low-voltage side is in a safe state at the instant the high-voltage side VDC is applied.

[0070] In one embodiment, the lower transistor is a GaN D-Mode MIS-HEMT device. Since the lower transistor has a long on-time in a single switching cycle, using a GaN D-Mode MIS-HEMT device can reduce conduction and switching losses and improve energy conversion efficiency compared to an E-Mode pGaN GateHEMT.

[0071] In one embodiment, a first capacitor C1 and a first inductor L1 are also included. One end of the low-voltage side load R1 is connected to a node of the half-bridge module through the first inductor L1. The first capacitor C1 and the load resistor R1 are connected in parallel.

[0072] The first inductor L1 serves to store energy and smooth current in the switching power supply circuit. Meanwhile, the first capacitor C1 is connected in parallel with the load resistor R1. When the first inductor L1 releases energy, the first capacitor C1 absorbs some of the energy and stabilizes the output voltage.

[0073] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A half-bridge module, characterized in that, The half-bridge module includes an enhancement-mode device as the upper transistor and a depletion-mode device as the lower transistor. The source of the enhancement-mode device and the drain of the depletion-mode device are electrically connected to form a common node, which is used for input or output power. The drain of the enhancement-mode device serves as the high-voltage terminal of the half-bridge module, and the source of the depletion-mode device serves as the low-voltage terminal of the half-bridge module. The gate of the enhancement-mode device is used to receive the upper-side drive signal, and the gate of the depletion-mode device is used to receive the lower-side drive signal. The enhancement-mode device and the depletion-mode device are configured to be complementaryly turned on according to the upper-side drive signal and the lower-side drive signal.

2. The half-bridge module according to claim 1, characterized in that, The half-bridge module also includes functional devices, which include driving devices and / or logic devices; The output terminal of the functional device is electrically connected to the gate of the enhancement-mode device and the gate of the depletion-mode device, respectively, so that the gate of the enhancement-mode device is connected to the upper-side drive signal through the functional device, and the gate of the depletion-mode device is connected to the lower-side drive signal through the functional device.

3. The half-bridge module according to claim 1, characterized in that, The enhancement-type device includes any normally off device among silicon MOSFET, SiC MOSFET, pGaN Gate HEMT, and GaN trench gate MIS-HEMT. The depletion-type device includes any normally-on device among SiC JFET, GaN JFET, MIS-HEMT, and Ga2O3 MOSFET.

4. The half-bridge module according to claim 3, characterized in that, The enhancement-mode device is a pGaN Gate HEMT, and the depletion-mode device is a MIS-HEMT; the enhancement-mode device achieves a positive threshold by depleting a two-dimensional electron gas through pGaN islands.

5. The half-bridge module according to claim 1, characterized in that, The enhancement-mode device is an enhancement-mode high electron mobility transistor with a trench gate structure, and the depletion-mode device is a depletion-mode high electron mobility transistor with a metal-insulator-semiconductor structure.

6. The half-bridge module according to claim 1, characterized in that, Enhancement-mode and depletion-mode devices are packaged together or integrated on the same substrate.

7. A switching power supply circuit, characterized in that, The switching power supply circuit includes the half-bridge module as described in any one of claims 1-6.

8. The switching power supply circuit according to claim 7, characterized in that, The switching power supply circuit is a step-down circuit, and the step-down circuit also includes a low-voltage side load and a drive module. The driving module is used to generate upper-side drive signals and lower-side drive signals and enable the upper-side and lower-side transistors of the half-bridge module to conduct complementaryly, respectively; one end of the low-voltage side load is connected to the node of the half-bridge module, and the other end of the low-voltage side load is connected to the source of the depletion-type device of the half-bridge module.

9. The switching power supply circuit according to claim 8, characterized in that, The depletion-mode devices in the half-bridge module include GaN D-Mode MIS-HEMT devices.

10. The switching power supply circuit according to claim 8, characterized in that, The switching power supply circuit further includes a first capacitor and a first inductor. One end of the low-voltage side load is connected to the node of the half-bridge module through the first inductor. The first capacitor and the load resistor are connected in parallel.

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