DE102010046427A1 - Power transmission device for use in driver circuit of transistor circuit for controlling e.g. synchronous machine in electric vehicle, has common secondary coil assigned to driver circuits of low side transistors - Google Patents

Abstract

The device has two half-bridges (2, 3), where one of the half-bridges comprises a high side transistor (4) and a low side transistor (5), where control inputs of the transistors are connected with driver circuits (9, 10). Electrical power is transferred from a primary side to a secondary side for a power supply of the driver circuits. Other half-bridge comprises a high side transistor (6) and a low side transistor (7). A secondary coil is assigned to each driver circuit of the high side transistors. A common secondary coil is assigned to the driver circuits of the low side transistors. An independent claim is also included for a method for power transmission in driver circuits of a transistor circuit.

Description

The invention relates to a method and a device for power transmission in driver circuits of a transistor circuit.

Transistor circuits, in particular bridge circuits, u. a. used to control electrical machines. In the automotive sector, such transistor circuits can be used for example for controlling synchronous or asynchronous machines, which serve to generate mechanical drive energy, in particular in so-called electric or hybrid vehicles.

In such transistor circuits power transistors are used, for example, so-called IGBT or MOSFET. A dynamic behavior of the transistors is in this case controlled via a control input of the transistors, which can also be referred to as a gate terminal. The generation of a control signal takes place here by means of so-called driver circuits. These driver circuits generate depending on a, z. B. generated by a microcontroller input signal, a control signal for the transistor. To generate the control signal in this case a power transmission in the driver circuit is necessary, in particular for generating a supply voltage of the driver circuit, in response to this supply voltage and the input signal of the driver circuit then the control signal for the transistor is generated.

To prevent damage to electrical components, two types of potential separation can be made for such driver circuits. On the one hand a potential separation in the power transmission is necessary, on the other hand, a potential separation may also be required or desired in the transmission of the input signal of the driver circuit. For this purpose, in the case of power transmission potential-separating converter, in particular transformers used. In the case of transmission of the input signal of the driver circuit also converters, in particular also transformers or optocouplers, are used. Thus, the driver circuit is on the one hand electrically isolated from the electrical system, which provides the power for generating the control signal of the transistors available. Furthermore, the driver circuit is galvanically separated from a circuit for generating the input signal, for example a microcontroller. This leads to greater circuit safety.

It is known that each driver circuit of each transistor is associated with an individual converter for power transmission, in particular an individual transformer. In the case of a so-called H-bridge thus four transformers for the power transmission in the driver circuits of the four transistors are needed.

The US 5,596,466 discloses a power module. The power module includes at least one power transistor connected to an output of the power module, each transistor having a gate control terminal. Furthermore, the power module comprises at least one isolation transformer with a primary winding and at least one secondary winding. An isolated driver communication interface is connected to the primary winding of each isolation transformer, the isolated driver communication interface serving to convert logic signals to primary primary drive signals. Furthermore, the power module comprises at least one insulated gate driver, which is connected to at least one secondary winding of an isolation transformer and to the control terminal of each power transistor.

The technical problem arises of providing a method and a device for power transmission in driver circuits of a transistor circuit, in particular of bridge circuits, which requires fewer switching elements and thus less installation space and manufacturing costs.

The solution of the technical problem results from the objects having the features of claims 1 and 7. Further advantageous embodiments of the invention will become apparent from the dependent claims.

A device for power transmission is proposed in driver circuits of a transistor circuit. The transistor circuit may in this case be a bridge circuit, in particular a so-called H-bridge or B6-bridge. The driver circuits serve to generate a control signal for a control terminal of the transistor. The transistors may be, for example, IGBT or MOSFET transistors. Here, the so-called gate or the gate terminal is the control terminal. Depending on a control signal, in particular a control voltage (gate voltage), the transistor is turned on or off. The control voltage is in this case based on a reference potential of the transistor, in particular a potential of a source terminal of a MOSFET transistor or an emitter terminal of an IGBT transistor.

By a suitable control of transistors of a bridge circuit can thus advantageously temporal courses of one or more phase voltages of an electrical machine are generated, wherein the strands are arranged between the individual half-bridges of the bridge circuit.

The transistor circuit comprises at least a first half-bridge. The first half-bridge comprises a so-called high-side transistor and a so-called low-side transistor. Between the high-side transistor and the low-side transistor in this case a center of the half-bridge is arranged. At this midpoint z. B. a strand of an electrical machine can be connected. In this case, the high-side transistor is arranged between a supply potential (the bridge circuit of, for example, a battery output voltage of a traction battery and the center point.) The low-side transistor is in this case between the center point and a ground potential, which corresponds, for example, to zero volt battery voltage. arranged.

Control inputs, in particular gate terminals, of the transistors are each connected to a driver circuit. Control signals for the individual transistors can be generated by means of the driver circuits. In particular, in the case of a MOSFET, a so-called gate-source voltage can be adjusted by means of the control signal. Depending on the gate-source voltage, the MOSFET conducts or blocks. Similarly, by means of the control signal, a gate-emitter voltage can also be set, wherein an IGBT blocks or conducts as a function of the gate-emitter voltage.

By means of at least one transformer, electrical power for powering the driver circuits from a primary side to a secondary side is transferable. The transformer is in this case an element for galvanic isolation, ie for the potential separation of the primary and secondary side, is. If the primary side of the transformer z. B. connected to an electrical system of a motor vehicle, the driver circuit is electrically isolated from the electrical system, if the driver circuit is arranged on the secondary side. By means of the transformer can thus be transmitted inductively power from the primary side to the secondary side. In particular, an alternating voltage having a predetermined frequency and a predetermined amplitude can be transmitted. In this case, a supply voltage of the driver circuit with a predetermined voltage level, for example +/- 15 V, can be generated on the secondary side from the transmitting AC voltage. The driver circuit can then generate the control signal as a function of an input signal of the driver circuit and as a function of the supply voltage.

According to the invention, the transistor circuit comprises at least one further half-bridge, wherein the at least one further half-bridge comprises a high-side transistor and a low-side transistor of the further half-bridge.

Each driver circuit of the high-side transistors is associated with an individual secondary coil of a transformer. Each driver circuit of the high-side transistors may each be associated with a transformer, wherein each driver circuit is then associated with the secondary coil of one of these transformers. Also, all driver circuits of the high-side transistors may be associated with a common transformer having a plurality of secondary coils, wherein each driver circuit is then associated with one of these secondary coils. Furthermore, all drive circuits of the low-side transistors are assigned a common secondary coil of the common transformer or of a further transformer. All drive circuits of all low-side transistors are thus assigned a common secondary coil, which is assigned to the common transformer (all driver circuits of the high-side transistors) or to a further, exclusively all drive circuits of all low-side transistors associated transformer.

In the transistor circuit, all low-side transistors are connected on the ground side. If the low-side transistors are designed as MOSFETs, all the source terminals of the transistors have the same potential. If the low-side transistors are designed as IGBTs, all emitter connections have the same potential. In this case, use is made of the fact that a control signal of the high-side transistors (gate-source voltage, gate-emitter voltage) relates to different reference potentials, in particular to different source potentials or emitter potentials. Since all source terminals or emitter terminals of the low-side transistors are electrically conductively connected or have the same potential, control voltages (gate-source voltages, gate-emitter voltages) of the low-side transistors also relate to the same reference potential, in particular the uniform potential of the source and emitter terminals.

Since the control signals (control voltages) of the transistors each relate to a reference potential of the transistors (potential of the source or emitter terminal), the supply voltage of the driver circuits must also refer to these reference voltages. In particular, the supply voltage must have a predetermined voltage difference, for example ± 15 V, with respect to the reference voltage so that the driver circuit can set a control signal, which likewise relates to the reference voltage, such that the respective transistor conducts ( Control voltage z. +15 V) or blocks (control voltage eg -15 V).

Since all low-side transistors have the same reference potential, relative to this reference potential supply voltage can be generated by means of a common secondary coil for all low-side transistors. Thus, each driver circuit of the low-side transistors is supplied by means of a common secondary coil with a supply voltage of a predetermined height.

This results in an advantageous manner that at least one transformer core and a primary winding of a low-side transistor can be saved, with less switching or components are necessary for power transmission in driver circuits of a transistor circuit. The power transmission can thus be realized space-saving and less expensive.

In a further embodiment, the device has a plurality of transformers. Each driver circuit of the high-side transistors is assigned a respective transformer. Each transformer has a primary winding, a transformer core and a secondary winding. Furthermore, all driver circuits of the low-side transistors are assigned a common transformer. Here, the common transformer on a primary winding, a transformer core and the common secondary coil. Overall, therefore, therefore, a transformer for a driver circuit of a low-side transistor can be saved. As stated above results in an advantageous manner, a space and cost reduction.

In an alternative embodiment, the device comprises only a single transformer. In this case, the transformer has a primary winding on the primary side. Next, the transformer on the secondary side a plurality of secondary windings. The transformer also has a single transformer core. On the secondary side, the transformer has one secondary coil per high-side transistor. Furthermore, the transformer on the secondary side for all, low-side transistors on a common secondary coil. As a result, all driver circuits can be supplied with energy or power by means of a single transformer. This results in an advantageous manner, a further space and cost reduction.

In a further embodiment, the transistor circuit comprises two half-bridges (H-bridge). Here, the driver circuit of the high-side transistor of the first half-bridge is associated with a first secondary coil. Further, the driver circuit of the high-side transistor of the second half-bridge is associated with a second secondary coil. Next, the driver circuit of the low-side transistor of the first half-bridge and the driver circuit of the low-side transistor of the second half-bridge is associated with a third secondary coil. In this case, therefore, a power transmission for all driver circuits of the transistor circuit can be ensured by means of a transformer having a plurality of secondary windings.

It should be noted that a transformer core in this case must not be dimensioned larger than a transformer core of a transformer, which is used for power transmission in a single driver circuit of a transistor. Because under normal operating conditions of the transistor circuit, in particular if the transistor circuit of. Actuation of an electrical machine is used, a power transmission takes place in only one driver circuit. To z. B. to apply a arranged between the centers of the two half-bridges of the H-bridge strand of an electric machine with a desired strand voltage or a temporal strand voltage curve, in this case diagonally opposite transistors of the H-bridge are turned on in an initial phase, while the remaining, also diagonally opposite transistors remain blocked. In this, usually short time, initial phase in this case a power transmission in the driver circuits of the transistors to be turned on is required. In the following operation on the initial phase, ie under the previously mentioned operating conditions, for example in a pulse width modulation, then only one of the diagonally opposite, in the initial phase turned on, transistors are operated clocked, d. H. alternately switched to conducting or blocking. In this mode, therefore, a power transmission only in the driver circuit of the clocked transistor operated, ie a single, is necessary.

In a further embodiment, the transistor circuit comprises three half-bridges. Here, the driver circuit of the high-side transistor of the first half-bridge is associated with a first secondary coil. Further, the driver circuit of the high-side transistor of the second half-bridge is associated with a second secondary coil. Furthermore, the driver circuit of the high-side transistor of the third half-bridge is assigned a third secondary coil. Further, the driver circuit of the low-side transistor of the first half-bridge and the driver circuit of the low-side transistor of the second half-bridge and the driver circuit of the low-side transistor of the third half-bridge is assigned a common fourth secondary coil. The Transistor circuit may in this case form a so-called B6 bridge circuit. Compared to a conventional power supply of each driver circuit with an individual transformer, five primary windings, five transformer cores and two secondary coils are advantageously saved in this case. As explained above, this results in an advantageous manner, a space and cost reduction.

In a further embodiment, the device comprises an element for galvanic isolation, wherein an input signal of a driver circuit can be transmitted to the driver circuit by means of the element for electrical isolation. In this case, the input signal can be generated, for example, by means of a control unit, for example a microcontroller. The element for galvanic isolation may be an optocoupler. Also, the element for electrical isolation can be an element for inductive separation (for example, a transformer) or for capacitive separation. As a result, a potential separation between a unit for generating the input signal of the driver circuit and the driver circuit itself is ensured in an advantageous manner.

In a further embodiment, a first terminal of a secondary coil, which is assigned to a driver circuit of a transistor, has a reference potential for the control input of the transistor. A second terminal of the secondary coil is connected to a rectifier circuit, wherein by means of the rectifier circuit, a supply voltage of a predetermined height for the driver circuit can be generated. The rectifier circuit may in this case preferably be a so-called half-bridge rectifier. As a result, a supply voltage of the driver circuit can be generated in an advantageous manner, which is relative to the reference potential of the transistor, in particular relative to the potential of a source terminal (MOSFET) or an emitter terminal (IGBT). It should be noted that the reference potentials of the individual transistors may be sliding potentials. In particular, the reference potentials of the high-side transistors in this case can vary between a voltage near a supply voltage of the transistor circuit and a potential near a ground potential of the transistor circuit. In an H-bridge, for example, the reference potential of the high-side transistor, that is, the potential of the source or emitter terminal, between one to a drain-source voltage and collector-emitter voltage of the high-side transistor reduced supply voltage of the transistor circuit, for example, the output voltage of a traction battery, and fluctuate to a drain-source voltage or collector-emitter voltage of the low-side transistor of the first half-bridge ground potential fluctuate. As a result of the interconnection of the secondary winding according to the invention, a supply voltage can thus always be generated relative to the sliding reference potential of the respective transistor.

Further proposed is a method for power transmission in driver circuits of a transistor circuit. Here, the transistor circuit is one of the foregoing. disclosed embodiments formed. According to the invention, power is transmitted into the driver circuits of the transistors by means of the at least one transformer, in particular to ensure a supply voltage relative to a reference potential of the individual transistors.

The invention will be explained in more detail with reference to two embodiments. The figures show:

1 a schematic block diagram of an H-bridge,

2 a schematic block diagram of a device for power transmission in driver circuits of in 1 represented H-bridge and

3 a schematic block diagram of another device for power transmission in driver circuits of in 1 illustrated H-bridge.

Hereinafter, like reference numerals designate elements having the same or similar technical characteristics.

In 1 is a schematic block diagram of an H-bridge 1 shown. The H bridge 1 includes a first half bridge 2 and a second half bridge 3 , The first half bridge 2 includes a high-side transistor 4 the first half bridge 2 and a low-side transistor 5 the first half bridge 2 , Analogously, the second half-bridge comprises 3 a high-side transistor 6 and a low-side transistor 7 the second half bridge 3 , The high-side transistor 4 the first half bridge 2 has a gate terminal G _T1 (control terminal) and an emitter terminal labeled E _T1 . Analog have the other transistors 5 . 6 . 7 Gate terminals G _T2 , G _T3 , G _T4 and emitter terminals E _T2 , E _T3 , E _T4 on. The first half bridge 2 also has a center M1 of the first half bridge 2 and the second half bridge 3 a midpoint M2 of the second half-bridge 3 on. Between the centers M1, M2 is a strand 8th connected an electric machine, not shown. The gate terminals G _T1 , G _T2 , G _T3 , G _T4 are here with driver circuits 9 . 10 . 11 . 12 connected. Here, the gate terminal G _{T1 of} the high-side transistor 4 the first half bridge 2 with a driver circuit 9 connected. Analogously, the other gate terminals G _T2 , G _T3 , G _T4 with driver circuits 10 . 11 . 12 connected. By means of the driver circuits 9 . 10 . 11 . 12 are here gate-emitter voltages of the transistors 4 . 5 . 6 . 7 adjustable. For example, by means of the driver circuit 9 of the high-side transistor 4 the first half bridge 2 a gate-emitter voltage (G _T1 -E _T2 ) between the gate terminal G _T1 and the emitter terminal E _T1 adjustable. For this purpose, the driver circuit 9 Connections for a supply voltage V _{D1 of} the driver circuit 9 on. The supply voltage V _{D1 in} this case has a predetermined level, for example 15 V on. Thus, the driver circuit 9 the gate-emitter voltage of the high-side transistor 4 the first half bridge 2 between +15 V and -15 V, with the high-side transistor 4 conducts if the gate-emitter voltage is +15 V and the high-side transistor 4 the first half bridge 2 locks if the gate-emitter voltage is -15V. The supply voltage V _D1 is in this case by means of a device 14 . 14a provided for power transmission, which in 2 and 3 is explained in more detail. Next are all driver circuits 9 . 10 . 11 . 12 by means of a control unit 13 controllable. Here, the control unit 13 for example, be a microcontroller. Preferably, the microcontroller 13 galvanically from the driver circuits 9 . 10 . 11 . 12 , preferably by means of an optocoupler, separated. It should be noted that in 1 the emitter terminals E _T2 , E _{T4 of} the low-side transistors 5 . 7 the first and second half bridge 2 . 3 have the same potential, ie z. B. are electrically connected. At the non-designated collector terminals of the high-side transistors 4 . 6 the first and second half bridge 2 . 3 in this case is a supply voltage V _T , for example, an output voltage of a traction battery to.

In 2 is a first embodiment of a device 14 for power transmission in the in 1 illustrated driver circuits 9 . 10 . 11 . 12 shown. The device 14 in this case comprises a first transformer 15 , a second transformer 16 and a third transformer 17 , The first transformer 15 has a primary winding 18 and a secondary winding 19 and a transformer core 20 of the first transformer 15 on. One connection of the secondary winding 19 is conducting with the in 1 illustrated emitter terminal E _{T1 of} the high-side transistor 4 the first half bridge 2 connected. A second connection of the secondary winding 19 is here with a rectifier 21 connected, by means of the rectifier 21 the supply voltage V _{D1 of} the driver circuit 9 of the high-side transistor 4 the first half bridge 2 provided. This z. B. an alternating voltage to the primary winding 18 applied, with an inductive power transfer takes place and correspondingly an AC voltage in the secondary winding 19 is induced. The operation of the second and the third transformer 16 . 17 is the same as the operation of the first transformer 15 , Here, the second transformer is used 16 the provision of the supply voltage V _{D3 of} the high-side transformer 6 the second half bridge 3 , For this purpose, the secondary winding with a connection to a corresponding rectifier 21 connected and with a second terminal to the emitter terminal E _{T3 of} the high-side transistor 6 the second half bridge 3 , The driver circuits 10 . 12 the low-side transistors 5 . 7 the first and second half bridge 2 . 3 in this case by means of a single transformer, namely the third transformer 17 supplied with a supply voltage. This exploits that the emitter terminals E _T2 , E _{T4 of} the low-side transistors 5 . 7 the first and second half bridge 2 . 3 have the same potential and thus the supply voltages V _D2 , V _{D4 of} the driver circuits 10 . 12 relative to the same reference potential, namely the potential of the emitter terminals E _T2 , E _T4 , are.

In 3 is another embodiment of a device 14a for power transmission in driver circuits 9 . 10 . 11 . 12 the in 1 illustrated H-bridge 1 shown. The other device 14a includes a single transformer 22 , where the transformer 22 a primary winding 23 , a transformer core 24 , a first secondary winding 25 , a second secondary winding 26 and a third secondary winding 27 having. Here, the first secondary winding is used 25 the generation of a supply voltage V _{D1 of} the driver circuit 9 of the high-side transistor 4 the first half bridge 2 , For this purpose, a connection of the first secondary winding 25 with the emitter terminal E _{T1 of} the high-side transistor 4 the first half bridge 2 conductively connected. Further generates one with the second terminal of the first secondary winding 25 connected rectifier 21 the supply voltage V _{D1 of} the driver circuit 9 of the high-side transistor 4 the first half bridge 2 , Analog generates the second secondary winding 26 by means of a rectifier 21 a supply voltage V _{D3 of} the high-side transistor 6 the second half bridge 3 , The third secondary winding 27 generates supply voltages V _D2 , V _{D4 of} the low-side transistors 5 . 7 the first and second half bridge 2 . 3 , In this case, it is advantageously used that the emitter terminals E _T2 , E _{T4 of} the low-side transistors 5 . 7 the first and second half bridge 2 . 3 have the same potential, whereby a single secondary winding, namely the third secondary winding 27 , Is sufficient to produce relative to this reference potential supply voltages V _D2 , V _D4 .

LIST OF REFERENCE NUMBERS

1

H-bridge

2

first half bridge

3

second half bridge

4

High-side transistor

5

Low-side transistor

6

High-side transistor

7

Low-side transistor

8th

strand

9

driver circuit

10

driver circuit

11

driver circuit

12

driver circuit

13

control unit

14, 14a

Device for power transmission

15

first transformer

16

second transformer

17

third transformer

18

primary

19

secondary winding

20

transformer core

21

rectifier

22

transformer

23

primary

24

transformer core

25

first secondary winding

26

second secondary winding

27

third secondary winding

V _T

Supply voltage of the H-bridge

V _D1

Supply voltage of a driver circuit

V _D2

Supply voltage of a driver circuit

V _D3

Supply voltage of a driver circuit

V _D4

Supply voltage of a driver circuit

G _T1

Gate terminal of the high-side transistor 4

G _T2

Gate terminal of the low-side transistor 5

G _T3

Gate terminal of the high-side transistor 6

G _T4

Gate terminal of the low-side transistor 7

E _T1

Emitter terminal of the high-side transistor 4

E _T2

Emitter terminal of the low-side transistor 5

e _T3

Emitter terminal of the high-side transistor 6

E _T4

Emitter terminal of the low-side transistor 7

M1

Center of the first half bridge

M2

Center of the second half bridge

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5596466 [0006]

Claims (10)

Device for power transmission in driver circuits ( 9 . 10 . 11 . 12 ) of a transistor circuit, wherein the transistor circuit has a first half-bridge ( 2 ), wherein the first half-bridge ( 2 ) a high-side transistor ( 4 ) and a low-side transistor ( 5 ) of the first half-bridge ( 2 ), wherein control inputs of the transistors ( 4 . 5 ) each with a driver circuit ( 9 . 10 ), wherein by means of at least one transformer ( 15 . 17 . 22 ) electrical power for powering the driver circuits ( 9 . 10 ) is transferable from a primary side to a secondary side, characterized in that the transistor circuit has at least one further half-bridge ( 3 ), wherein the at least one further half-bridge ( 3 ) a high-side transistor ( 6 ) and a low-side transistor ( 7 ) of the further half-bridge ( 3 ), each driver circuit ( 9 . 11 ) of the high-side transistors ( 4 . 6 ) each have a secondary coil ( 19 . 25 . 26 ) and all driver circuits ( 10 . 12 ) of the low-side transistors ( 5 . 7 ) a common secondary coil ( 17 . 27 ) assigned. Device according to claim 1, characterized in that the device ( 14 ) a plurality of transformers ( 15 . 16 . 17 ), each driver circuit ( 9 . 11 ) of the high-side transistors ( 4 . 6 ) one transformer each ( 15 . 16 ) and all driver circuits ( 10 . 12 ) of the low-side transistors ( 5 . 7 ) a common transformer ( 17 ) assigned. Device according to claim 1, characterized in that the device ( 14a ) only one transformer ( 22 ), wherein the transformer ( 22 ) a primary winding on the primary side ( 23 ), wherein the transformer ( 22 ) on the secondary side a plurality of secondary windings ( 25 . 26 . 27 ) having. Device according to Claim 3, characterized in that the transistor circuit has two half-bridges ( 2 . 3 ), wherein the driver circuit ( 9 ) of the high-side transistor ( 4 ) of the first half-bridge ( 2 ) a first secondary coil ( 25 ), wherein the driver circuit ( 11 ) of the high-side transistor ( 6 ) of the second half-bridge ( 3 ) a second secondary coil ( 26 ), wherein the driver circuit ( 10 ) of the low-side transistor ( 5 ) of the first half-bridge ( 2 ) as well as the driver circuit ( 12 ) of the low-side transistor ( 7 ) of the second half-bridge ( 3 ) a third secondary coil ( 27 ) assigned. Apparatus according to claim 3, characterized in that the transistor circuit comprises three half-bridges, wherein the driver circuit of the high-side transistor of the first half-bridge is associated with a first secondary coil, wherein the driver circuit of the high-side transistor of the second half-bridge is associated with a second secondary coil wherein the driver circuit of the high-side transistor of the third half-bridge is associated with a third secondary coil, wherein the driver circuit of the low-side transistor of the first half-bridge and the driver circuit of the low-side transistor of the second half-bridge and the driver circuit of the low-side Transistor of the third half-bridge is associated with a fourth secondary coil. Device according to one of the preceding claims, characterized in that the device ( 14 . 14a ) comprises an element for galvanic isolation, wherein by means of the element for galvanic isolation an input signal of a driver circuit ( 9 . 10 . 11 . 12 ) to the driver circuit ( 9 . 10 . 11 . 12 ) is transferable. Device according to one of the preceding claims, characterized in that a first terminal of a secondary coil ( 19 . 25 . 26 . 27 ), which is a driver circuit ( 9 . 10 . 11 . 12 ) of a transistor ( 4 . 5 . 6 . 7 ), a reference potential for the control input of the transistor ( 4 . 5 . 6 . 7 ), wherein a second terminal of the secondary coil ( 19 . 25 . 26 . 27 ) to a rectifier circuit ( 21 ) is connected, wherein by means of the rectifier circuit ( 21 ) a supply voltage (V _D1 , V _D2 , V _D3 , V _D4 ) with a predetermined height for the driver circuit ( 9 . 10 . 11 . 12 ) is producible. Method for power transmission in driver circuits ( 9 . 10 . 11 . 12 ) of a transistor circuit, wherein the transistor circuit has at least one first half-bridge ( 2 ), wherein the first half-bridge ( 2 ) a high-side transistor ( 4 ) and a low-side transistor ( 5 ) of the first half-bridge ( 2 ), wherein control inputs of the transistors ( 4 . 5 ) each with a driver circuit ( 9 . 10 ), at least one transformer ( 15 . 17 . 22 ) electrical power for powering the driver circuits ( 9 . 10 ) transmits from a primary side to a secondary side, characterized in that the transistor circuit has at least one further half-bridge ( 3 ), wherein the at least one further half-bridge ( 3 ) a high-side transistor ( 6 ) and a low-side transistor ( 7 ) of the further half-bridge ( 3 ), each driver circuit ( 9 . 11 ) of the high-side transistors ( 4 . 6 ) each have a secondary coil ( 19 . 25 . 26 ) and all driver circuits ( 10 . 12 ) of the low-side transistors ( 5 . 7 ) a common secondary coil ( 17 . 27 ) assigned. Method according to claim 8, characterized in that each driver circuit ( 9 . 11 ) of the high-side transistors ( 4 . 6 ) one transformer each ( 15 . 16 ) and all driver circuits ( 10 . 12 ) of the low-side transistors ( 5 . 7 ) a common Transformer ( 17 ), wherein electrical energy for supplying the driver circuits ( 9 . 10 . 11 . 12 ) via the respective transformers ( 15 . 16 . 17 ) or electrical energy for supplying all driver circuits ( 9 . 10 . 11 . 12 ) via a transformer ( 22 ), the transformer ( 22 ) a primary winding on the primary side ( 23 ), wherein the transformer ( 22 ) on the secondary side a plurality of secondary windings ( 25 . 26 . 27 ) having. Method according to claim 8 or 9, characterized in that an input signal of a driver circuit ( 9 . 10 . 11 . 12 ) via an element for galvanic isolation to the driver circuit ( 9 . 10 . 11 . 12 ) is transmitted.

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