DE102012018422A1 - Circuit device for controlling oscillating circuit for e.g. radio frequency-antenna in close system for motor car, has oscillating circuit attached at connection between semiconductors, and controller for directly actuating semiconductors - Google Patents

Abstract

The device has a controller (32') and two power semiconductors (28 ', 28'') i.e. MOSFET, where the power semiconductors are switched in series. An oscillating circuit (29) is electrically attached at a connection (31) between the power semiconductors. The controller directly actuates the power semiconductors. The power semiconductors are arranged in a half bridge (28) such that the controller directly actuates the half bridge. The controller controls a pulse width modulation by an electromotor.

Description

The invention relates to a circuit arrangement for controlling a resonant circuit according to the preamble of patent claim 1.

Such drive circuits are used in particular for inductive antennas in a locking system for a motor vehicle.

Such a circuit arrangement for driving a resonant circuit having a capacitor and a coil operates with a controller. The controller drives two power semiconductors, with the two power semiconductors connected in series. The resonant circuit is in turn electrically connected to the connection between the two power semiconductors. In the known circuit arrangement, there are timing elements between the controller and the power semiconductors for generating the dead times for the control of the power semiconductors. These timers consist of a large number of logic gates, resistors and capacitors, ie of hardware, and are therefore correspondingly expensive. In addition, the variety of components brings a large tolerance for the dead time generation with it.

The invention has for its object to simplify the circuit arrangement for driving the resonant circuit. In particular, the control of a half-bridge comprising two power semiconductors should be carried out by a microcomputer (μC) with as little hardware as possible. In particular, the circuit for the drive should be reset-fixed and suitable for a real-time operating system, i. H. There should be no jitter, exposure or overlapping due to increased interrupt loads of the μC.

This object is achieved in a generic circuit arrangement by the characterizing features of claim 1.

In the circuit arrangement according to the invention, the controller directly controls the two power semiconductors. This eliminates hardware timers, but rather the dead time control of the power semiconductors is done directly by the controller. Further embodiments of the invention are the subject of the dependent claims.

Conveniently, the two power semiconductors are arranged in a half-bridge. In a simple manner, the controller can then drive the half-bridge directly, so that the previously required additional hardware is eliminated.

In a further embodiment of the circuit arrangement according to the invention, a controller suitable for controlling an electric motor by means of pulse width modulation (PWM) is used as the controller. This is a commercially available and therefore cost-effective controller that directly generates dead times.

In a simply constructed circuit arrangement, the controller has a first output for the supply voltage, in particular for switching the high-side FET, and a second output for a dead time in the manner of a time delay, in particular for switching the low-side FET on. In this case, the one power semiconductor, in particular the half-bridge, is then driven by the first output and the other power semiconductor, in particular the half-bridge, by the second output of the controller. In a cost-effective manner, the power semiconductor, in particular for the half-bridge, is a MOSFET.

In a preferred application, the circuit arrangement is part of a locking system, in particular for the access and / or driving authorization in the manner of a KeylessEntry / Go functionality in a motor vehicle. Such a locking system comprises at least two conditions possessing, designed as a control device first means, such as a control device for unlocking and / or locking the car doors, the ignition, the steering wheel lock, to enable and / or blocking the immobilizer, the engine control unit o. The like. , and an associated, in the manner of an electronic key, an ID transmitter, a smart card o. The like. Formed second device. The two devices have for their intended operation transmitter and / or receiver for particular electromagnetic signals. In particular, at least one of the signals transmitted between the second device and the first device is a coded operating signal for authentication of the second device, so that after a positive evaluation of the transmitted operating signal with an authorized second device, a change in the state of the first device can be effected.

In a development, the first device transmits a first electromagnetic signal for the associated second device as a wake-up signal. As a result, the second device is converted from an idle state with a reduced energy requirement into an activated state for the intended operation. After the first electromagnetic signal has been transmitted, the first device can transmit a range delimiter signal as a third electromagnetic signal, with the aid of which the associated second device can determine its location with respect to the first device on and / or in the motor vehicle. The location of the second Device with respect to the first device on and / or in the motor vehicle is then sent with a fourth signal as a response signal from the second to the first device. If these signals are transmitted successfully, the authentication of the second device is finally carried out by means of a further fifth signal as a coded operating signal. Thus, if the preconditions necessary for waking up as well as for area delineation are not met, then the intrinsically complex authentication is not carried out at all, which enables a more efficient mode of operation for the locking system. The fifth electromagnetic signal serving for authentication can finally be transmitted in a theft-proof bidirectional communication consisting of a plurality of sub-signals between the first and the second device.

Between the wake-up and the area delineation signal from the first device, a second electromagnetic signal can be sent as a selection signal, which contains in particular information on the identity of the motor vehicle. With the help of the selection signal, the dialogue with the second device can already be prematurely terminated if the second device is associated with another motor vehicle, which may however be of the same type of motor vehicle. Thus, only the same type of motor vehicle associated second devices are activated and / or remain in the activated state and in the activated state, not associated second devices are returned to the idle state. As a result, a further increase in the efficiency of the operation of the locking system is possible in each case.

It is particularly preferred to use an inductive signal for the wake-up and / or the range delineation signal in that the carrier wave for the first signal and / or the third signal has a frequency lying in the inductive, low-frequency (NF) range. Due to the limited range of an inductive signal can thus set the effective range for the locking system in a simple manner. At the same time, this increases the security against manipulation of the locking system by unauthorized users. For example, the frequency for the LF carrier wave may be about 20 kHz, 120 kHz, 125 kHz, or the like. Furthermore, it is preferable to use a radio signal for the selection signal and / or the response signal and / or the coded operating signal, in that the carrier wave for the second signal and / or the fourth and / or the fifth signal has a higher-frequency (RF) range Frequency has. As a result, for reasons of comfort for the user an increased effective range is given. For example, the frequency for the RF carrier wave may be about 315 MHz, 433 MHz, 868 MHz, or the like. Of course, if an increased effective range is not desired, the other signals in the LF range can be transmitted. The low-frequency (NF) carrier wave using first signal for waking and / or the third signal for the area delineation for location determination are transmitted by means of the driven by the cost-effective, inventive circuit arrangement inductive antenna.

For a particularly preferred embodiment of the invention is to be determined below.

It is used for controlling a motor or electric motor PWM unit of the μC for controlling the resonant circuit. This eliminates all hardware timers. Tolerances of the components involved in the timers omitted as well. The motor PWM unit runs completely self-sufficient after initialization. The reset resistance is achieved by a simple pull-up, or current optimized by a small transistor circuit in front of the level converter. Created is thus the excitation of resonant circuits by means of motor PWM controlled half bridges.

The advantages achieved by the invention are in particular that previously required expensive components omitted. In particular, when using the resonant circuit as a low frequency (LF) antenna in a motor vehicle locking system four antennas are present, and in particular each one antenna in the left and right car door, in the front and rear. Then, one logic gate as well as two capacitors and two resistors including the placement costs are saved per LF antenna. Furthermore, a reduced space requirement on the PCB (PCB) and tolerance-free control times are achieved. It is thus an optimization of the existing LF circuit in terms of cost and tolerances by taking advantage of the available features of the controller, which may be, for example, a type V850 achieved.

An embodiment of the invention with various developments and refinements is shown in the drawings and will be described in more detail below. Show it

1 a motor vehicle equipped with a locking system,

2 a schematic block diagram of the locking system with a diagram for transmitting the signals,

3 a circuit arrangement for controlling a resonant circuit according to the prior art and

4 a circuit arrangement according to the invention for controlling a resonant circuit.

In 1 is a motor vehicle 1 with the authorized user 2 to see. The car 1 is for access authorization with a locking system 3 as a door closing system provided with a first device configured as a control device 4 and an associated second device 5 includes. The second device 5 is in the form of an electronic key, an identification (ID) dealer, a smart card, a smart card o. The like. Formed. The second device 5 is owned by the authorized user 2 , with which this within an effective range 8th Access to the motor vehicle 1 has.

The first device 4 has at least two states, wherein in the first state, a lock and in the second state, an unlocking of the car doors 6 is present. The two facilities 4 . 5 have for their intended operation means for transmitting and / or receiving signals 7 by means of an electromagnetic carrier wave. At least one of these between the second device 5 and the first device 4 transmitted signals 7 it is a coded, electromagnetic operating signal 15 (please refer 2 ). The coded operating signal 15 serves to authenticate the second device 5 , which means authorized second device 5 after a positive evaluation of the transmitted operating signal 15 a change of the state of the first device 4 is feasible. The transmission of the coded operating signal 15 occurs when the authorized user 2 the door handle 16 at the car door 6 pressed or the door handle 16 approaches. This will unlock the car doors 6 triggered according to the KeylessEntry functionality. Just as well, the transmission of the coded operating signal 15 also automatically without the involvement of the user 2 take place as soon as this the effective range 8th which is not considered in the following. Does the user close the car doors 6 from the outside, so there is an automatic locking the car doors 6 , Likewise, the automatic locking of the car doors 6 done after the user reaches the effective range 8th has left.

The locking system 3 continues to provide driving authorization for the motor vehicle 1 firmly. For this purpose, the first device designed as a control device effects 4 also according to the two states, the unlocking and / or locking the ignition 9 (electronic ignition lock EZS) and / or the steering wheel lock 10 (electric steering wheel lock ELV), which in 1 are indicated only schematically. Just as well, another functionally relevant component of the motor vehicle 1 through the first device 4 be controlled accordingly. For example, this can be done by a release and / or blocking an immobilizer, the engine control unit o. The transmission of the coded operating signal 15 for authentication of the second device 5 occurs when the authorized user 2 in the vehicle 1 located and a start / stop switch 11 actuated. As a result, the starting process o. The like. Of the motor vehicle 1 triggered according to the KeylessGo functionality.

The transmission of the signals 7 for the KeylessEntry / Go functionality is by user pressing a switch and / or a sensor 2 triggered. The access authorization may be, for example, the manual operation of the door handle 16 , the rear handle o. The like. Act. This is in the door handle 16 , Rear handle o. The like. Of the motor vehicle 1 a switch, proximity sensor o. The like. Arranged. For driving authorization is the user 2 manually operated start / stop switch 11 in the motor vehicle 1 , Conveniently, the start / stop switch 11 on the gear selector lever, on the ignition lock 9 , in the dashboard, in the center console o. The like. In the vehicle 1 arranged.

The operation of the locking system according to the invention 3 should now be based on the 2 be explained in more detail. First, the first device sends 4 by means of a transmitter / receiver 24 as a means for transmitting and / or receiving signals, a first electromagnetic signal called a wake-up signal 12 for the associated second device 5 , The first device 4 is at least one antenna 29 . 30 for transmitting the signals 7 assigned. By the wake-up signal 12 becomes the second institution 5 converted from a rest state with reduced energy consumption in an activated state for normal operation. After that, the first device sends 4 at least one more, third electromagnetic signal 13 , which is also referred to below as a range delineation signal. This allows the associated second device 5 their location relative to the first facility 4 determine. In particular, it is possible to determine whether the second device 5 outside the vehicle 1 and optionally at which point of the outdoor space 23 and / or in the interior 22 of the motor vehicle 1 is located (see also 1 ). Subsequently, the second device sends 5 by means of a transmitter / receiver 17 a fourth signal including information about the detected location 14 to the first device 4 , which is also referred to below as a response signal. Finally, as already described, the fifth electromagnetic signal then becomes a coded electromagnetic operating signal 15 to Authentication by means of the transmitter / receiver 24 . 17 between the first and the second device 4 . 5 transfer. The signal 15 may in particular consist of several sub-signals and in a bidirectional communication between the two devices 4 . 5 be transmitted. With regard to further details of the bidirectional communication itself is also on the DE 43 40 260 A1 directed.

The second device 5 , which is a schematic block diagram in 2 shown points the transmitter / receiver 17 as a means for transmitting and / or receiving signals and a for example consisting of a microcomputer logic circuit 18 on. Next is in the second facility 5 a means 19 for measuring the field strength of at least one of the first device 4 transmitted signal arranged. The middle 19 For measuring the field strength measures the field strength or the intensity of one of the transmitted signals, namely the area delineation signal 13 , Conveniently, the means 19 designed to measure the field strength as an integrated module, which is also referred to below as RSS (Radio Signal Strength) -Chip. The RSS chip 19 has an entrance 20 that with the transmitter / receiver 17 and an RSSI (Radio Signal Strength Indicator) output 21 that in turn with the logic circuit 18 connected is. The RSS chip 19 gets over the entrance 20 that from the sender / receiver 17 each received signal 13 and generates at its RSSI output 21 in functional dependence on the field strength of the signal 13 standing RSSI signal. For example, the RSSI signal may be proportional or logarithmic to the field strength of the signal 13 be dependent. By appropriate evaluation of the RSSI signal can then be the location determination in the logic circuit 18 make.

The alarm signal 12 may, for example, contain an identifier for the motor vehicle type. After receiving the wake-up signal 12 are all initially in the effective range 8th located second facilities 5 that belong to the same type of motor vehicle activated. In a further embodiment of the locking system 3 sends the first device 4 between the first signal 12 and the third signal 13 a second electromagnetic signal 27 to the second device 5 as a selection signal, as more fully understood by 2 can be seen. The second signal 27 contains information about the closer identity of the motor vehicle 1 , This causes only the actual to the first device 4 associated second facilities 5 remain in the activated state. In the activated state, not to the motor vehicle 1 but associated second devices are returned to the idle state.

It is particularly preferred that the carrier wave for the first signal 12 as a wake-up signal and / or the third signal 13 has a frequency lying in the inductive, low-frequency (LF or LF) range as an area delineation signal. For example, this frequency may be approximately 20 kHz, 120 kHz, 125 kHz or the like. Advantageously, such an inductive signal to the immediate vicinity of the motor vehicle 1 limited range. This will ensure that the second device 5 only activated when in the interior 22 of the motor vehicle 1 or in one of the effective ranges 8th in the outdoor area 23 on the motor vehicle 1 is located, which disturbances and / or security gaps are avoided by overreaching. If desired, the second signal can also be used 27 , as in 2 is shown to have a frequency lying in the low frequency (NF) range. However, it is particularly preferred that the carrier wave for the second signal 27 as a selection signal and / or the fourth signal 14 as a response signal and / or the fifth signal 15 as the operating signal has a higher frequency (RF) range lying frequency. For example, this frequency may be about 315 MHz, 433 MHz, 868 MHz or the like. The antenna 29 is therefore as an inductive LF antenna and the antenna 30 formed as an RF antenna.

The detailed design of the inductive LF antenna 29 for the locking system 3 of the motor vehicle 1 is in 3 or 4 to see. The inductive LF antenna 29 consists of a resonant circuit, which is a capacitor 25 and a coil 26 having. The resonant circuit 29 is powered by a two power semiconductors 28 ' . 28 '' comprehensive half-bridge 28 energized, the two power semiconductors 28 ' . 28 '' are connected in series. The resonant circuit 29 is in turn at the connection 31 between the two power semiconductors 28 ' . 28 '' the half bridge 28 electrically connected.

• – Toleranzbehaftete Totzeitgenerierung.
• – Toleranzabhängig von einer Vielzahl von Bauteilen.
• – Totzeit größer gleich 2 μs ist für einen sicheren Betrieb nötig.
• – Großer Bauteilaufwand.
• – Hohe Bestückkosten.
• – Hohe Kosten für Kondensatorprüfung.
• – Defekt eines Bauteils kann zum Treiberbrand führen.
• – Es ist eine Vielzahl von Bauteilen für den LF-Treiber im Steuergerät (SG) KeylessGo (KG) notwendig.
• – Teure Logik-Gatter kommen zum Einsatz.

The previous, the prior art corresponding circuit arrangement for controlling the resonant circuit 29 is in 3 shown in more detail. The circuit arrangement comprises a controller 32 ' whose output (FREQ 5 V) 33 ' via a dead time generation circuit 35 to the half bridge 28 connected. The dead time generation circuit 35 Complexity consists of a large number of electronic components and has the following properties:

• - Tolerant dead time generation.
• - Tolerance dependent on a variety of components.
• - Dead time greater than or equal to 2 μs is required for safe operation.
• - Large component costs.
• - High placement costs.
• - High cost of capacitor testing.
• - Defective component can lead to driver fire.
• - A large number of components are required for the LF driver in the control unit (SG) KeylessGo (KG).
• - Expensive logic gates are used.

• – Quasi toleranzfreie Totzeitgenerierung.
• – Lediglich Toleranzabhängig von wenigen Bauteilen.
• – Totzeiten sind beliebig einstellbar. Insbesondere sind Totzeiten kleiner 2 μs möglich.
• – Geringer Bauteilaufwand.
• – Geringe Bestückkosten.
• – Keine Kapazitäten, Widerstände o. dgl. sind zu prüfen.
• – Weniger Bauteile mit möglichen Defekten.
• – Lediglich wenige Bauteile für den LF-Treiber im SG KG werden benötigt.
• – Es sind keine Logik-Gatter nötig.

In contrast, the circuit arrangement according to the invention dispenses with the activation of the resonant circuit 29 , in the 4 is shown in detail on a dead time generation circuit. Rather, the controller controls 32 the half bridge 28 directly on, whereby the following properties are achieved:

• - Quasi tolerance-free dead time generation.
• - Only tolerance dependent on a few components.
• - Dead times can be set as desired. In particular, dead times of less than 2 μs are possible.
• - Low component costs.
• - Low placement costs.
• - No capacity, resistors o. The like. Are to be checked.
• - fewer components with possible defects.
• - Only a few components for the LF driver in SG KG are needed.
• - There are no logic gates needed.

In a further embodiment according to 4 this is the controller 32 to a suitable for the control of an electric motor by means of pulse width modulation (PWM) controller. The controller 32 has a first exit 33 for the supply voltage (FREQ 5 V) and a second output 34 for the dead times in the manner of a time delay (FREQ LF DELAY). The one power semiconductor 28 ' the half bridge 28 , the highside FET, is from the first exit 33 as well as the other power semiconductor 28 '' the half bridge 28 , and the lowside FET, is from the second output 34 of the controller 32 driven. In the power semiconductor 28 ' . 28 '' the half bridge 28 it is a transistor, in the present case a MOSFET.

The invention is not limited to the described and illustrated embodiment. Furthermore, the invention also encompasses all expert developments within the scope of the protective rights claims. Thus, the circuit arrangement according to the invention can not only be used in closing systems of motor vehicles but also in other applications in which a resonant circuit is to be controlled, are used.

LIST OF REFERENCE NUMBERS

1

Automobile / vehicle

2

(authorized) user

3

locking system

4

first device

5

second device

6

car door

7

signal

8th

effective range

9

Ignition lock

10

steering wheel lock

11

Start / stop switch / switching element

12

(first) signal / wake-up signal

13

(third) signal / range delineation signal

14

(fourth) signal / response signal

15

(fifth) signal / (coded) operating signal

16

door handle

17

Transmitter / receiver (in the second device)

18

Logic circuitry / microprocessor

19

Means for measuring field strength / RSS chip

20

Input (from RSS-Chip)

21

RSSI output (to RSS chip)

22

Interior (from motor vehicle)

23

Outdoor space (from motor vehicle)

24

Transmitter / receiver (in the first device)

25

capacitor

26

Kitchen sink

27

(second) signal / selection signal

28

half bridge

28 ', 28' '

Power semiconductor

29

Antenna / LF antenna / tank circuit

30

Antenna / RF antenna

31

Connection (between power semiconductors)

32

Controller (new circuit)

32 '

Controller (circuit according to the prior art)

33

(first) output (from controller)

33 '

Output (from controller to prior art)

34

(second) output (from controller)

35

Totzeitgenerierungsschaltung

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

• DE 4340260 A1 [0026]

Claims (8)

Circuit arrangement for controlling a resonant circuit ( 29 ), in particular for an inductive antenna ( 29 ) in a locking system ( 3 ) for a motor vehicle ( 1 ), wherein the resonant circuit ( 29 ) a capacitor ( 25 ) and a coil ( 26 ), with a controller ( 32 ), and with two power semiconductors ( 28 ' . 28 '' ), wherein the two power semiconductors ( 28 ' . 28 '' ) are connected in series, and wherein the resonant circuit ( 29 ) at the connection ( 31 ) between the two power semiconductors ( 28 ' . 28 '' ) is electrically connected, characterized in that the controller ( 32 ) the two power semiconductors ( 28 ' . 28 '' ) directly drives. Circuit arrangement according to Claim 1, characterized in that the two power semiconductors ( 28 ' . 28 '' ) in a half-bridge ( 28 ) are arranged, in particular such that the controller ( 32 ) the half bridge ( 28 ) directly drives. Circuit arrangement according to Claim 1 or 2, characterized in that the controller ( 32 ) is a suitable for the control of an electric motor by means of pulse width modulation (PWM) controller. Circuit arrangement according to Claim 1, 2 or 3, characterized in that the controller ( 32 ) a first output ( 33 ) for the supply voltage (FREQ 5 V) and a second output ( 34 ) for a dead time, in particular in the manner of a time delay (FREQ LF DELAY), and that the one power semiconductor ( 28 ' ), in particular the half-bridge ( 28 ), from the first exit ( 33 ) as well as the other power semiconductor ( 28 '' ), in particular the half-bridge ( 28 ), from the second exit ( 34 ) of the controller ( 32 ) is driven. Circuit arrangement according to one of claims 1 to 4, characterized in that it is in the power semiconductor ( 28 ' . 28 '' ), in particular the half-bridge ( 28 ) is a MOSFET. Circuit arrangement according to one of claims 1 to 5, characterized in that the circuit arrangement is part of a locking system ( 3 ), in particular for the access and / or driving authorization in a motor vehicle ( 1 ) in the manner of a KeylessEntry / Go functionality, wherein the locking system ( 3 ) has at least two states, designed as a control device first means ( 4 ), such as a control device for unlocking and / or locking the car doors ( 6 ), of the ignition lock ( 9 ), the steering wheel lock ( 10 ), for releasing and / or blocking the immobilizer, the engine control unit o. The like., And an associated, designed in the manner of an electronic key, an ID transmitter, a smart card o. The like. Second device ( 5 ), the two institutions ( 4 . 5 ) for their intended operation transmitters and / or receivers ( 24 . 17 ) for in particular electromagnetic signals ( 7 ), and in particular at least one of the between the second device ( 5 ) and the first facility ( 4 ) transmitted signals ( 7 ) is a coded operating signal ( 15 ) for authentication of the second device ( 5 ), so that after a positive evaluation of the transmitted operating signal ( 15 ) in the case of an authorized second device ( 5 ) a change in the state of the first device ( 4 ) is feasible. Circuit arrangement according to one of Claims 1 to 6, characterized in that the first device ( 4 ) a first signal ( 12 ) for the associated second establishment ( 5 ) as a wake-up signal, such that the second device ( 5 ) is converted from an idle state with reduced energy consumption in an activated state for normal operation, preferably that the first device ( 4 ) after transmission of the first signal ( 12 ) at least one further, third signal ( 13 ) as a range delineation signal such that the associated second device ( 5 ) their location in relation to the first facility ( 4 ), in particular on and / or in the motor vehicle ( 1 ), it can further be determined that the second device ( 5 ) a further, fourth signal containing the location ( 14 ) to the first body ( 4 ) sends even more preferably the encoded operating signal ( 15 ) for authentication of the second device ( 5 ) as the fifth signal ( 15 ) between the second device ( 5 ) and the first facility ( 4 ), the authentication signal being the fifth electromagnetic signal ( 15 ) preferably in a bidirectional communication consisting of a plurality of partial signals between the first and the second device ( 4 . 5 ), and even more preferably the first device ( 4 ) between the first and the third signal ( 12 . 13 ) a second signal ( 27 ) to the second body ( 5 ) sends as a selection signal, in particular the second signal ( 27 ) information about the identity of the motor vehicle ( 1 ) so that the first device ( 4 ) associated second facilities ( 5 ) remain in the activated state and located in the activated state, not associated second facilities are returned to the idle state. Circuit arrangement according to one of Claims 1 to 7, characterized in that the carrier wave for the first signal ( 12 ) and / or the third signal ( 13 ) has a frequency lying in the inductive, low-frequency (NF) range, which is for example approximately 20, 120, 125 kHz or the like, that preferably the carrier wave for the second signal ( 27 ) and / or the fourth signal ( 14 ) and/ or the fifth signal ( 15 ) has a frequency lying in the higher frequency (RF) range, which is in particular approximately 315, 433, 868 MHz or the like, and that more preferably the first signal ( 12 ) for the wake-up and / or the third signal ( 13 ) for the area delineation for location determination by means of the inductive antenna ( 29 ) is transmitted.

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