Drive unit for a hand-held power tool, and hand-held power tool

Abstract

The invention relates to a drive unit for a hand-held power tool. The drive unit has: a voltage source for providing an output-side DC voltage; an electric motor which can be operated using the output-side DC voltage; and a switching device which is connected between the voltage source and the electric motor and by means of which the output-side DC voltage can be switched in order to control the electric motor. The switching device has at least a first switch and a second switch which is connected in parallel with the first switch, the first switch having a first semiconductor material and the second switch having a second semiconductor material which differs from the first semiconductor material.

Description

[0001] 2024ID00016

[0002] Hilti Aktiengesellschaft in Schaan

[0003] Principality of Liechtenstein

[0004] Drive unit for a hand-held power tool and hand-held power tool

[0005] AREA OF INVENTION

[0006] The present invention relates to a drive unit for a hand-held power tool and a hand-held power tool with such a drive unit.

[0007] A switching device for operating an electric motor in a hand-held power tool is supplied with a direct current voltage, often provided by a battery or rectifier.

[0008] Widebandgap semiconductors, such as gallium nitride (GaN) high electron mobility transistors (HEMTs), have gained increasing popularity in recent years. A key reason for this rising demand is their ability to switch on and off at higher frequencies without incurring significant losses. Every switching operation, whether switching voltage or current on or off, causes losses. The faster the switching frequency, the greater these losses.

[0009] When a transistor is activated, it begins to conduct, causing the voltage across the semiconductor to approach zero while the current begins to flow and increases. These switching operations do not occur instantaneously but take a certain amount of time. For silicon-based metal-oxide-semiconductor field-effect transistors (MOSFETs) or gate-insulated bipolar transistors (IGBTs), these switching times are typically in the range of 150 to 1500 nanoseconds. In contrast, high-electron-mobility transistors (HEMTs) can switch on or off in less than 20 nanoseconds.

[0010] The power loss during the switching process is calculated from the product of current and voltage: P swi t C h = U * I.

[0011] Besides the advantage of faster switching speeds, gallium-based transistors also have characteristics that complicate their use in electronic products, especially those manufactured in large quantities. On the one hand, such transistors are still very expensive. On the other hand, these transistors exhibit conduction losses, particularly when they are switched on or conducting current.

[0012] Therefore, there is still development potential, particularly for switching devices used to control an electric motor in a hand-held power tool, in order to further minimize switching losses.

[0013] Against this background, the object of the present invention is to create an improved drive unit for a hand-held power tool and / or an improved hand-held power tool.

[0014] REVELATION OF THE INVENTION

[0015] According to a first aspect, a drive unit for a hand-held power tool is proposed. The drive unit comprises a voltage source (also called the main power supply of the drive unit) for providing an output DC voltage, an electric motor that can be operated by the output DC voltage, and a switching device. The switching device is connected between the voltage source and the electric motor. The switching device is further configured to switch the output DC voltage to control the electric motor. The switching device has at least a first switch and a second switch connected in parallel to the first switch. The first switch has a first semiconductor material. The second switch has a second semiconductor material. The first semiconductor material differs from the second semiconductor material.

[0016] The present switching device is cost-effective and therefore mass-producible due to the use of at least two switches that differ in their semiconductor material. For example, at least one switch can be used that has a semiconductor material, in particular a widebandgap semiconductor material, which enables particularly fast or high-frequency switching. Conversely, at least one other switch can be used that has a semiconductor material with lower conduction losses compared to the fast-switching switch and is generally only suitable for lower switching frequencies. In this way, the advantages of the high-frequency switch (low switching losses) can be combined with the advantages of the parallel switch (low conduction losses), resulting in a cost-effective and efficient solution.low-loss switching device results in an overall high - 3 - 2024ID00016, particularly due to the parallel connection of at least two switches.

[0017] Switching frequency and efficiency are enabled. Furthermore, the use of the low-frequency switch allows for optimized conductance for the switching device.

[0018] The present switching device thus minimizes both conduction and switching losses. This is achieved by combining at least two switches with different semiconductor types and therefore different semiconductor properties in a hybrid circuit and connecting them in parallel. The proposed hybrid circuit thus combines the advantages of two different semiconductor-based switch types. In contrast to a purely high-frequency switching circuit, which, for example, only uses widebandgap semiconductor-based switches such as gallium nitride (GaN)-based transistors, the number of parallel switches, especially transistors, can be reduced and / or more cost-effective switch types can be used.

[0019] The switching device in question can, for example, form part of the power electronics of the drive unit. The switching device can be at least part of a motor inverter and / or a motor control unit and / or a DC / DC converter and / or an AC / DC converter.

[0020] According to a second aspect, a hand-held power tool with such a drive unit is proposed.

[0021] The hand-held power tool is preferably designed as a drill, impact drill, rotary hammer, circular saw, jigsaw, reciprocating saw, angle grinder, mixer, or the like. Preferably, the hand-held power tool or power tool can be battery-operated and have one or more batteries, particularly interchangeable ones, for example, a lithium-ion battery.

[0022] The specifications for the drive unit apply accordingly to the hand-held power tool and vice versa.

[0023] In one embodiment, it is proposed that the first switch comprises a gate-terminal transistor, in particular a metal-oxide-semiconductor field-effect transistor, and / or wherein the second switch comprises a 3-terminal transistor, in particular a high-electron mobility transistor, and / or wherein the first semiconductor material is silicon-based, and / or wherein the second semiconductor material is gallium-based. - 4 - 2024ID00016

[0024] In principle, other semiconductor-based transistor types, such as gate-insulated bipolar transistors (IGBTs), can also be used.

[0025] A three-terminal transistor is preferably an electronic component that has three terminals and is used to control electrical currents. The three terminals comprise a gate (G), which forms the control terminal through which the conductivity of the transistor is controlled; a source (S), which forms the terminal through which the current enters the transistor; and a drain (D), which forms the terminal through which the current leaves the transistor. These three terminals allow the current flow between the source and drain to be controlled by a voltage or current applied to the gate. The specific operating principle depends on the type of transistor. In a metal-oxide-semiconductor field-effect transistor (MOSFET), the voltage at the gate controls the conductivity between the source and drain. In a high-electron-mobility transistor (HEMT), semiconductor materials with high electron mobility (e.g., gallium nitride) are used.The 3-terminal configuration allows the transistor to be used as a switch.

[0026] The ability of gallium-based switches to switch quickly (i.e., at or below 20 nanoseconds) while generating lower switching losses makes them particularly attractive for applications where high switching efficiency and performance are crucial, such as the drive unit in question. Compared to silicon-based switches, gallium-based switches enable significantly faster switching with lower switching losses. Therefore, there are virtually no limitations on implementing high switching frequencies.

[0027] While a gallium-based switch exhibits higher conduction losses (in the closed state), this disadvantage is compensated for in this case by the use of a silicon-based switch connected in parallel to the gallium-based switch. Although these silicon-based switches only allow for slower switching, for example in the range of 150 to 1500 nanoseconds, they exhibit high conductivity, which minimizes the conduction losses of the switching device. The comparatively slow switching of the silicon-based switch therefore has no adverse effect on the performance of the switching device, as this factor can be compensated for by the fast switching capability of the gallium-based switch, particularly through appropriate selection of the switching frequency or switching points of the respective switches. - 5 - 2024ID00016

[0028] In one embodiment, it is proposed that the first switch and the second switch of the switching device are comprised in at least one half-bridge circuit or a low-side circuit or a high-side circuit.

[0029] The switching device can also comprise multiple half-bridge circuits, multiple low-side circuits, or multiple high-side circuits. Such a half-bridge circuit preferably has at least two first switches and at least two second switches. In other words, the half-bridge circuit preferably has at least two switches based on the first semiconductor material and at least two switches based on the second semiconductor material. The half-bridge circuit is a configuration in which at least two first switches are connected in series and two second switches are also connected in series and parallel to the two first switches. Furthermore, there is at least one common connection point that serves as an output, in particular to a load, for example, an electric motor. This configuration is preferably used in inverters and power converters.The low-side connection is a configuration where the second switch is connected between the load and ground. This arrangement connects the load to ground. The high-side connection is a configuration where the second switch is connected between the voltage source and the load. This arrangement connects the load to the voltage source and is preferred when the load needs to be connected to a higher potential.

[0030] In one embodiment, it is proposed that the drive unit further comprises a switch control device which is configured to individually control a switching pulse for switching the first switch and a switching pulse for switching the second switch.

[0031] By using different control timings or switching frequencies, the fast-switching and low-loss second switch can preferably handle the switching operations of the switching device, thus minimizing switching losses. Conversely, the low-loss first switch, which is preferably switched on after the second switch to provide power, can be used for energy or current flow, thereby also minimizing the conduction losses of the switching device. To implement the different control timings or to switch the switches on and off individually, a switch control unit is preferably used. The switch control unit can, for example, be a PC controller that drives the - 6 - 2024ID00016

[0032] The switch control device can be designed to operate independently. The switch control device can also be designed by at least one hardware delay block.

[0033] In one embodiment, it is proposed that the switch control device is configured to control the switching cycle of the second switch in time before the switching cycle of the first switch, and / or to control the switching cycle of the first switch in time before the switching cycle of the second switch.

[0034] To supply energy to the electric motor or to switch it on, the second switch can preferably be activated before the first switch at a switching time determined by the switching frequency of the second switch. This way, the switching losses are absorbed by the second switch. The first switch is preferably only activated when the second switch is conducting the full current and the voltage across both the second and first switches is close to zero. This allows the first switch to be switched without losses (so-called zero-voltage switching).

[0035] To switch off, the second switch can preferably be switched off at a time determined by the switching frequency of the second switch after the first switch. This way, the switching losses are absorbed by the second switch. The first switch is already switched off while the second switch is still on, i.e., still conducting and carrying current. The voltage across the second and first switches is therefore close to zero. Thus, the first switch can be switched off without any loss.

[0036] The overall losses of the switching device are thus effectively minimized.

[0037] In one embodiment, it is proposed that the first semiconductor material has a band gap of less than 2.0 electron volts (eV), and that the second semiconductor material has a band gap of greater than or equal to 2.0 electron volts (eV).

[0038] The band gap (also called bandgap) is preferably the energy required to promote an electron from the valence band to the conduction band of a semiconductor material. Examples of semiconductor materials used include beta-gallium oxide (β-Ga₂O₃), gallium nitride (GaN), and silicon carbide (SiC). Beta-gallium oxide (β-Ga₂O₃) has a band gap of approximately 4.8 to 4.9 eV. Beta-gallium oxide is an ultra-wideband semiconductor used in high-voltage and high-power electronics. Gallium nitride (GaN) has a band gap of approximately 3.4 eV. Gallium nitride is a semiconductor used in high-frequency and high-power electronics. Silicon carbide (SiC) has a band gap of approximately 2.3 to 3.3 eV, depending on the polytype structure (e.g., 4H-SiC, 6H-SiC). Silicon carbide is known for its excellent thermal and electrical performance and is widely used in switching devices and high-temperature applications.These materials offer high efficiency and stability under extreme conditions.

[0039] In one embodiment, it is proposed that the voltage source is provided by at least two contacts that can be connected to at least one battery unit.

[0040] The voltage source is preferably designed to supply a direct current (DC) voltage. The voltage source preferably forms an integral part of the drive unit and is used to supply power to the electric motor. The voltage source preferably has at least two or more contacts or contact points. These contacts are preferably connection points through which electrical energy is transferred from the battery unit to the drive unit. The contacts of the voltage source are preferably designed so that they can be connected to at least one battery unit. The battery unit is preferably a rechargeable energy storage device that can store electrical energy and release it as needed. The arrangement or design ensures that the voltage source, through the aforementioned contacts and their connection options with the battery unit, functions reliably and efficiently.

[0041] In one embodiment, it is proposed that the voltage source has a terminal that includes an AC / DC converter configured to convert a mains AC voltage into a DC voltage.

[0042] Preferably, the claimed switching device can also be at least part of such an AC / DC converter. The connection terminal is preferably a connection or terminal point on the voltage source, via which the voltage source can be connected to other components or an external power source. The AC / DC converter is an electrical component or circuit configured to convert an alternating voltage (AC) into a direct voltage (DC). The converter is preferably integrated into or connected to the connection terminal. A mains-side AC voltage is preferably an AC voltage supplied by an external power grid, typically with standardized voltage and frequency values ​​(e.g., 230V, 50Hz in Europe). - 8 - 2024ID00016

[0043] BRIEF DESCRIPTION OF THE FIGURES

[0044] The following description explains the invention with reference to exemplary embodiments and figures. The figures show:

[0045] Fig. 1 shows a schematic view of a battery-powered hand tool;

[0046] Fig. 2 shows a schematic view of a mains-powered hand-held power tool;

[0047] Fig. 3 shows a schematic view of a switching device;

[0048] Fig. 4 shows a schematic view of a switching device;

[0049] Fig. 5 shows a schematic view of a switching device;

[0050] Fig. 6 shows a schematic voltage-time diagram for switching on a

[0051] Switching device; and

[0052] Fig. 7 shows a schematic voltage-time diagram for switching off a

[0053] Switching device.

[0054] Identical or functionally equivalent elements are indicated by the same reference symbols in the figures, unless otherwise specified.

[0055] - 9 - 2024ID00016

[0056] FORMS OF EXECUTION OF THE INVENTION

[0057] Fig. 1 shows a schematic view of a battery-powered hand tool 1, which here is configured as an impact drill. The hand tool 1 has a mounting bay 4, which in this example has two contacts K1 and K4. The mounting bay 4 is designed to receive a battery unit 30. In each case, the two contacts K1 and K4 of the mounting bay 4 are brought into contact with two corresponding contacts KT and K4' of the battery unit 30.

[0058] A consumer of the hand-held power tool 1, in particular an electric motor (without reference numerals in Fig. 1), is connected between contacts K1 and K4 of the receiving bay 4. In the illustrated example, contacts K1 and K4 are connected to a switching device 2, which switches the drive current for the electric motor. The switching device 2 and the electric motor form part of an electric drive unit 100, which is shown in more detail in Figs. 3 to 5 according to various embodiments.

[0059] The dashed box in Fig. 1 is purely an example of a system 1000 comprising a battery-powered hand tool 1 and a battery unit 30 with several cell arrangements 31 , 32.

[0060] Fig. 2 shows a schematic view of another example of an electric hand-held power tool 1, which is designed as a drilling machine. The hand-held power tool 1 has a tool holder 6 in which a drill bit is inserted as a drilling tool 7. The power tool 1 is driven by an electric motor 8. An operator can guide the hand-held power tool 1 by means of a handle 11 and start it up by means of a push button 12. During operation, the hand-held power tool 1 rotates the drilling tool 7, in particular continuously, about a working axis 13 and can thereby drill the drilling tool 7 into a substrate along the working axis 13.

[0061] The hand-held power tool 1 shows an embodiment of the electric drive unit 100 in Fig. 2. The electric drive unit 100 (see embodiments in Figs. 3 to 5) comprises the electric motor 8 and the switching device 2 for controlling the electric motor 8. The electric drive unit 100 is, by way of example, coupled to a connection terminal 15 via an electrical cable arrangement 14, which can be connected to a power supply (not shown) by means of a plug 16. Alternatively, the hand-held power tool 1 can also be powered by a battery (as shown in Fig. 1). A drive train of the hand-held power tool 1 also includes, for example, a drive shaft and a gearbox between the electric motor 8 and the drive shaft (not shown). The gearbox (not shown) can, for example, adjust the speed of the electric motor 8 to a desired speed of the drill bit 7.

[0062] Figures 3 to 5 each show a detailed embodiment of the drive unit 100 of the hand-held power tool 1. The drive unit 100 comprises a voltage source 300. As shown in Figures 1 and 5, the voltage source 300 can be a DC voltage U applied between contacts K1 and K4. Alternatively, as shown in Figures 2, 3, and 4, the voltage source 300 can be a connection terminal 15, in which case the connection terminal 15 preferably includes an AC / DC converter (not shown) to convert an AC voltage supplied via the plug 16 into the DC voltage U.

[0063] One switching device 2 is connected between the voltage source 300 and the electric motor 8. The output DC voltage U for controlling the electric motor 8 can be switched via the switching device 2.

[0064] The switching device 2 comprises at least a first switch 302 and a second switch 304 connected in parallel to the first switch 302. The first switch 302 has a first semiconductor material, in the example shown in Figs. 3-5, a silicon-based semiconductor material. The first semiconductor material preferably has a band gap of less than 2.0 electron volts. The first switch 302 can, for example, be configured as a gate-terminal transistor, in particular a metal-oxide-semiconductor field-effect transistor.

[0065] The second switch 304 comprises a second semiconductor material, in the example shown in Fig. 3-5, a gallium-based semiconductor material. The second semiconductor material preferably has a band gap of 2.0 electron volts or greater. The second switch 304 can, for example, be configured as a 3-terminal transistor, in particular a high-electron-mobility transistor. The first semiconductor material thus differs from the second semiconductor material, so that the first switch 302 and the second switch 304 exhibit different properties due to their semiconductor material characteristics.

[0066] The first switch 302 switches more slowly than the second switch 304; that is, its switching time is longer. For example, the switching time of the first switch 302 is 120-150 nanoseconds, whereas the switching time of the second switch can be 20 nanoseconds. The first switch 302 has a higher conductivity for current flow compared to the second switch 304, resulting in lower conduction losses, since:

[0067] P conduction loss — Switch I switch ~ 0 W

[0068] In contrast to the first switch 302, the second switch 304 exhibits lower switching losses due to its fast-switching properties, since:

[0069] Switching loss — Uschalter2 Ischalter2 ~ 0 W

[0070] The first switch 302 preferably comprises at least one gate terminal G. The second switch 304 preferably comprises three terminals, namely a gate terminal G, a source terminal S and a drain terminal D.

[0071] As shown in Fig. 3, the switching device 2 is configured as a low-side circuit. This describes a configuration in which the second switch 304 is connected between the load and ground. The drain terminal D is thus connected to the electric motor 8 (the load). The voltage source 300, on the other hand, is connected to the source terminal S. This arrangement thus connects the load to ground.

[0072] As shown in Fig. 4, the switching device 2 is configured as a high-side circuit. This describes a configuration in which the second switch 304 is connected between the voltage source 300 and the electric motor 8. This arrangement connects the load to the voltage source 300 and is preferred when the load needs to be switched to a higher potential. The source terminal S is thus connected to the electric motor 8 (the load). The voltage source 300, on the other hand, is connected to the drain terminal D.

[0073] Fig. 5 shows the switching device 2 as a half-bridge circuit. The half-bridge circuit comprises two first switches 500, 502 and two second switches 504, 506. The two first switches 500, 502 are connected in series, with a center tap 510 between them leading to the electric motor 8. The two second switches 504, 506 are also connected in series, with a center tap 508 between them leading to the electric motor 8. The two first switches 500, 502 are connected in parallel with the two second switches 504, 506.

[0074] The drive unit 100, as shown in Fig. 5, includes, by way of example, a switch control unit 512, which is configured to individually control a switching cycle for switching the first switches 500, 502 and a switching cycle for switching the second switches 504, 506. The switching devices 2, as shown in Figs. 3 and 4, can of course also have a corresponding switch control unit. In this case, the switch control unit 512 is connected to the gate terminal G of the respective switch 500, 502, 504, 506 for control signal transmission.

[0075] The switch control device 512 is configured to individually control the switching cycle of the second switches 504, 506 during the switch-on process, prior to the switching cycle of the parallel first switches 500, 502. Alternatively or additionally, the switch control device 512 is configured to individually control the switching cycle of the first switches 500, 502 during the switch-off process, prior to the switching cycle of the second switches 504, 506.

[0076] The switching sequence of a switch-on and a switch-off process of the switching device 2 is shown in Fig. 6. In Fig. 6, a switch-on edge is shown first, followed by a switch-off edge. In Fig. 7, a switch-off edge is shown first, followed by a switch-on edge.

[0077] The voltage U of the gate control signals of the various switches (on the respective abscissa) is plotted against time t (on the respective ordinate). The time-shifted switching of the first switch 500 and the second switch 504 (see Fig. 5) on the high side of the half-bridge is shown as an example. The explanations apply analogously to the parallel-connected switches 302 and 304, as shown in Fig. 4 (high-side circuit).

[0078] To switch on, at switching time ti,so4, switch 504 is closed or switched on, thus allowing current to flow through switch 504 via the center tap 508, at least temporarily. At a switching time t2,soo, which occurs after switching time ti,so4, the first switch 500 is then closed or switched on. Since the first switch 500 has a lower conductance than the second switch 504, the current flows through switch 500 via the center tap 508 with minimal loss for the remaining duration of a switch-on interval E. Overall, this minimizes both switching and conduction losses.

[0079] To switch off, switch 500 is opened at switching time L.soo, so that a current flow via the center tap 508 through switch 504 is at least temporarily possible. At a switching time t4,504, which is after switching time t 3iIf the position is such that the second switch 504 is opened, then the second switch 504 (-13-2024ID00016) is opened. Since the first switch 500 has higher switching losses than the second switch 504, the first switch 500 is switched off beforehand in order to minimize the switching losses.

[0080] The switching timing of a turn-on and a turn-off process of the switching device 2 is further shown in Fig. 7. The voltage U of the gate control signals of the various switches (on the respective abscissa) is plotted against time t (on the respective ordinate). The time-shifted switching of the first switch 502 and the second switch 506 (see Fig. 5) on the low side of the half-bridge is shown as an example. The explanations apply analogously to the parallel-connected switches 302 and 304, as shown in Fig. 3 (low-side circuit).

[0081] Initially, voltage is applied to both gate control signals. To switch off, switch 502 is opened at switching time t-1,502, thus allowing current flow via the center tap 508 through the second switch 506, at least temporarily. At switching time t2,506, which is after switching time t-1,502, the second switch 506 is then opened. Since the first switch 502 has higher switching losses than the second switch 506, the first switch 502 is opened beforehand to minimize these losses.

[0082] To switch on, the second switch 506 is closed or switched on at a switching time ta.soe, so that a current flow through the second switch 506 via the center tap 508 is at least temporarily possible. At a switching time 1,502, which is after the switching time ta, 506, the first switch 502 is then closed or switched on. Since the first switch 502 has a lower conduction resistance than the second switch 506, the current flows through the first switch 502 via the center tap 510 with minimal loss for the remaining period of a switch-on interval E. Overall, this minimizes both switching losses and conduction losses.

[0083] - 14 - 2024ID00016

[0084] REFERENCE MARK LIST

[0085] 1 hand-held power tool

[0086] 2 Switching device

[0087] 4 Receiving bay

[0088] 5 main switches

[0089] 6 Tool holder

[0090] 7 Drilling tool

[0091] 8 Electric motor

[0092] 9 Stator winding

[0093] 10 Rotor winding

[0094] 11 Handle

[0095] 12 buttons

[0096] 13 working axis

[0097] 14. Line arrangement

[0098] 15 connection terminals

[0099] 16 plugs

[0100] 30 battery units

[0101] 31 cell arrangement

[0102] 32 cell arrangement

[0103] 33 cells

[0104] 100 drive units

[0105] 300 voltage source

[0106] 302 switches

[0107] 304 switches

[0108] 500 switches

[0109] 502 switches

[0110] 504 switches

[0111] 506 switches

[0112] 508 Center tap

[0113] 510 Center tap

[0114] 512 Switch control unit

[0115] D Drain Terminal

[0116] E Switch-on interval

[0117] G Gate Terminal - 15 - 2024ID00016

[0118] K1 Contact

[0119] K1 ' Contact

[0120] K4 Contact

[0121] K4' Contact S Source Terminal

[0122] DC voltage ti,504 Switching time t2,500 Switching time ta.soo Switching time t4,504 Switching time ti,502 Switching time t2,506 Switching time ta.soe Switching time t4,502 Switching time t Time

Claims

- 16 - 2024ID00016 PATENT CLAIMS 1. Drive unit (100) for a hand-held power tool (1), comprising: a voltage source (300) for providing an output DC voltage (II); an electric motor (8) that can be operated by the output DC voltage (II); and a switching device (2) that is connected between the voltage source (300) and the electric motor (8), and by which the output DC voltage (U) can be switched to control the electric motor (8), wherein the switching device (2) has at least a first switch (302, 500, 502) and a second switch (304, 504, 506) that is connected in parallel to the first switch (302, 500, 502), wherein the first switch (302, 500, 502) has a first semiconductor material, wherein the second switch has a second semiconductor material, and wherein the first semiconductor material is different from the second semiconductor material.

2. Drive unit (100) according to claim 1, wherein the first switch (302, 500, 502) comprises a gate-terminal transistor, in particular a metal oxide semiconductor field-effect transistor, wherein the second switch (304, 504, 506) comprises a 3-terminal transistor, in particular a high-electron-mobility transistor, wherein the first semiconductor material is silicon-based, and wherein the second semiconductor material is gallium-based.

3. Drive unit (100) according to claim 1 or 2, wherein the first switch (302, 500, 502) and the second switch (304, 504, 506) of the switching device (2) are comprised in a half-bridge circuit or a low-side circuit or a high-side circuit.

4. Drive unit (100) according to one of claims 1 to 3, wherein the drive unit (100) further comprises a switch control device (512) which is configured to control a switching pulse for switching the first switch (302, 500, 502) and a switching pulse for switching the second switch (304, 504, 506) individually. - 17 - 2024ID00016 5. Drive unit (100) according to claim 4, wherein the switch control device (512) is configured to control the switching cycle of the second switch (304, 504, 506) in time before the switching cycle of the first switch (302, 500, 502), and / or to control the switching cycle of the first switch (302, 500, 502) in time before the switching cycle of the second switch (304, 504, 506).

6. Drive unit (100) according to one of claims 1 to 5, wherein the first semiconductor material has a band gap of less than 2.0 electron volts, and wherein the second semiconductor material has a band gap of greater than or equal to 2.0 electron volts.

7. Drive unit (100) according to one of claims 1 to 6, wherein the voltage source (300) is provided by at least two contacts (K1-K4) which can be connected to at least one battery unit (19, 20, 30).

8. Drive unit (100) according to one of claims 1 to 7, wherein the voltage source (300) has a connection terminal (15) comprising an AC / DC converter configured to convert a mains AC voltage into a DC voltage (II).

9. Hand-held power tool (1) with a drive unit (100) according to one of claims 1 to 8.

10. System (1000) comprising a hand-held power tool (1) according to claim 9, a battery unit (19, 20, 30) and a charging device for charging the battery unit (19, 20, 30).

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