Abstract:
The circuit has a power stage (LE) with heat generating components mounted around at least one component that generates less heat mounted in an inner region. The heat generating components are connected to at least one conducting metal body (K 1 ) that is mounted on a cooling body (KK) in electrically insulated manner to cool the components. The cooling body encloses the inner region.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application is a continuation of copending International Application No. PCT/DE02/00601 filed Feb. 20, 2002 and claiming a priority date of Feb. 27, 2001, which designates the United States. 
     
    
     
       TECHNICAL FIELD OF THE INVENTION  
         [0002]    The invention relates to a circuit arrangement, i.e. an arrangement comprising interconnected components. In more specific terms, the invention relates to a circuit arrangement having a power section. The circuit arrangement should therefore be suitable for high currents.  
         BACKGROUND OF THE INVENTION  
         [0003]    The fabrication of circuit arrangements in hybrid technology is known. To this end, chips having semiconductor devices without chip packaging are mounted on a ceramic carrier, in which conducting paths are arranged. The chips are mounted in such a way that a direct electrical contact is formed between the conducting paths and chips. Further electrical conductors for the chips are created via wire bonds.  
           [0004]    Such a circuit arrangement is advantageous in that it has low space requirements as the chips are bare. However, such a circuit arrangement is disadvantageous in that it is not suitable as a power module for very high currents, such as 300 amperes continuous current, as conducting paths arranged in a ceramic carrier cannot generally conduct such high currents.  
           [0005]    A further disadvantage exists in that heat from a circuit arrangement having a ceramic carrier cannot be effectively dissipated. Effective heat dissipation, however, is required for high current applications, as in this case the components usually generate considerable heat losses, which could cause damage to the components.  
         SUMMARY OF THE INVENTION  
         [0006]    The object of the invention is to specify a circuit arrangement, which has low space requirements and at the same time is suitable for high currents.  
           [0007]    The object can be achieved by means of a circuit arrangement having the following features: the circuit arrangement has a power section, comprising heat-generating components and at least one component producing less heat. The component producing less heat is arranged in an internal region of the circuit arrangement. The heat-generating components are arranged around the internal region and are mounted on at least one metallic body acting as an electrical conductor, to which said components are electrically connected. In order to cool the heat-generating components, the body is arranged on a heat sink in an electrically insulating manner, at least in the region of the heat-generating components. The heat sink is embodied running around the internal region.  
           [0008]    The heat-generating components are directly mounted on the body, which at the same time acts as a carrier of the heat-generating components and as an electrical conductor. No further conductors and wires are required between the heat-generating components and the body, which would increase the electrical resistance. The electrical resistance of the body is very low in comparison to conductor paths arranged in an insulating carrier. The circuit arrangement is therefore suitable for high currents.  
           [0009]    Furthermore, it is possible for heat produced in the heat-generating components to be dissipated very quickly, as essentially only the metallic body is arranged between the heat-generating components and the heat sink, and this metallic body is a better thermal conductor than a carrier made of ceramic.  
           [0010]    The circuit arrangement takes up very little space, as the heat sink is only arranged under the components which generate high heat losses.  
           [0011]    This also makes the circuit arrangement very compact, as the heat-generating components are arranged around the component producing less heat, so that it is possible for connections between the components to be very short.  
           [0012]    The dimensioning of the body depends on the amperage and thermal conductivity to be achieved. The body is preferably between approx. 2 mm and 4 mm thick and is essentially made of copper. However, other materials are also suitable for the body, such as aluminum.  
           [0013]    The heat-generating components may be chips, containing for example (power) transistors, diodes or IGBTs. The component producing less heat may for example be a capacitor.  
           [0014]    To reduce the space requirements of the circuit arrangement and to improve the heat dissipation, it is advantageous for the chips to have no packaging.  
           [0015]    The circuit arrangement also preferably has a logic section in addition to the power section, via which the power section can be controlled.  
           [0016]    To reduce the space requirements of the circuit arrangement, it is advantageous for the logic section to be arranged above the internal region. This is advantageous in that electrical connections between the logic section and power section can be very short. The connections can for example be wire bonds. Additional connecting lines and high-cost plug connections susceptible to interference are not necessary.  
           [0017]    The circuit arrangement can have a board which covers the internal region and is arranged above the component producing less heat. The board has at least one opening above the internal region. The component producing less heat is electrically connected to the board by means of a first wired bond, which is led through the opening.  
           [0018]    On account of the first wired bond, the board has areas of non-flatness. To ensure that the logic section can be added to a flat surface, it is advantageous to provide a carrier, which is arranged above the internal region and above the board. The carrier can be electrically insulated from the board by means of an insulating layer. The surface of the carrier facing the board has an indentation in the region of the first wired bond, in order to accommodate the first wired bond. The surface of the carrier facing away from the board, however, is flat. The logic section is electrically insulated on the surface of the carrier facing away from the board. The carrier acts as the mechanical adapter between the board and the logic section.  
           [0019]    If the logic section proves to be faulty, it can easily be removed from the carrier and repaired and/or replaced independently from the power section.  
           [0020]    More than one component producing less heat may be provided, arranged in the internal region of the circuit arrangement and electrically connected to the board by means of the first wired bonds. The carrier accordingly has more than one indentation.  
           [0021]    The carrier is preferably made of a material essentially having high thermal conductivity, so that heat generated in the logic section can be dissipated to the heat sink via the carrier and board. For example the carrier is essentially made of aluminum and is between 1 and 10 mm thick.  
           [0022]    The circuit arrangement is particularly suitable for the parallel connection of half bridges. To this end, the heat-generating components are embodied as bare first chips and second chips, which each contain a transistor, with the first chips being mounted on at least one first metallic body and the second chips being mounted on a second metallic body. The first body is embodied as a bar, which runs along the outer edge of the heat sink. The second body is embodied in the form of a board and covers the internal region and inner edge of the heat sink. The board is arranged on the second body in an electrically insulating manner. The second body has a first opening above the internal region, which is arranged under the opening of the board and through which the first wired bond is led. The second body has at least one second opening above the internal region. The component producing less heat is embodied as a capacitor and is electrically connected to the second body by means of a second wired bond, which is led through the second opening. The first wired bond and the second wired bond are in this case capacitor terminals. The first chips are electrically connected to the board via wire bonds. The second chips are electrically connected to the first body via wire bonds.  
           [0023]    The second body and the board form two metal boards which are electrically insulated from each other and which carry different potentials. The capacitor is placed between the different potentials.  
           [0024]    The first chips are connected in parallel between the first body and the board. The second chips are connected in parallel between the first body and the second body. Each first chip and second chip form a half bridge. The half bridges are connected in parallel between the board and the second body.  
           [0025]    Thanks to the surrounding arrangement of the heat sink, it is possible to ensure a particularly compact arrangement of numerous half bridges. In this way, the second chips are interconnected by means of the second body in the form of a board.  
           [0026]    More than one first bar may be provided, each running along an edge of the cooling body for example. The first bodies are preferably not electrically connected to each other, so that they can conduct different phases.  
           [0027]    The first body, second body and board are made of copper for example. However, other materials are also suitable, for instance aluminum.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    An embodiment of the invention is described in more detail below using the figures.  
         [0029]    [0029]FIG. 1 shows a section of a circuit diagram of a circuit arrangement having first chips, second chips, capacitors, an output terminal, ground terminal and voltage terminal.  
         [0030]    [0030]FIG. 2 shows a three-dimensional view of the circuit arrangement, in which the first chips, second chips, a first body, second body, board, carrier, logic section, heat sink and bonding connections can be seen.  
         [0031]    [0031]FIG. 3 shows a cross-section through an internal region of the circuit arrangement, in which capacitors, first wired bonds, second wired bonds, openings, first openings, second openings, insulating layers, the second body, board, carrier and logic section can be seen. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]    A circuit arrangement is provided in the embodiment, which has a power section LE and a logic section LO.  
         [0033]    The power section LE comprises a parallel connection of half bridges as well as capacitors K connected in parallel. The capacitors K form components of the circuit arrangement producing less heat.  
         [0034]    The power section LE comprises first chips C 1  as heat-generating components, with said chips being mounted without packaging directly on several first metallic bodies K 1 , which are embodied as bars and are essentially made of copper (see FIG. 2). The first bodies K 1  are arranged along outer edges of a heat sink KK running around an internal region IB of the circuit arrangement. The first chips C 1  each have a transistor. The first chips C 1  are arranged on the first bodies K 1  in such a way that first source/drain areas of the first chips C 1  are electrically connected to the first bodies K 1 .  
         [0035]    The first bodies K 1  are approx. 4 mm thick, approx. 10 mm wide and approx. 12 cm and/or 18 cm long. The first bodies K 1  are electrically separated from each other and conduct different phases.  
         [0036]    The power section LE has second chips C 2  as heat-generating components, said chips being embodied as the first chips C 1  and being mounted without packaging directly on a second metallic body K 2  in such a way that first source/drain areas of the transistors of the second chips C 2  are electrically connected to the second body K 2 . The second body K 2  is embodied in the form of a board, is essentially made of copper and covers the internal region and inner edges of the heat sink KK (see FIG. 2). The capacitors K are arranged under the second body K 2  in the internal region IB (see FIG. 3).  
         [0037]    Second source/drain areas of the second chips C 2  are connected to the first bodies K 1  via bonding connections B.  
         [0038]    A metallic board P, which is essentially made of copper, is arranged on the second body K 2  in an electrically insulating manner by means of a first insulating layer I 1  (see FIGS. 2 and 3). The board P has notch-like projections V, which are arranged between adjacent second chips C 2 . Second source/drain areas of the transistors of the first chips C 1  are connected to the projections V of board P via bonding connections B.  
         [0039]    The second body K 2  has first openings O 1  and second openings O 2  above the internal region. Board P has openings  0  above the first openings O 1  and second openings  02  of the second body K 2 . The capacitors K are electrically connected to board P via first wired bonds B 1 , which are led through the first openings O 1  of the second body K 2  and through the openings O of board P arranged thereabove. The capacitors K are electrically connected to the second body K 2  via second wired bonds B 2 , which are led through the second openings O 2 . The openings O of board P, which are arranged above the second openings of the second body K 2 , accommodate the second wired bonds B 2 . The first wired bonds B 1  and the second wired bonds B 2  form capacitor terminals of capacitors K.  
         [0040]    To avoid shortcircuiting between the first wired bonds B 1  and the second body K 2  and/or between the second wired bonds B 2  and board P, second insulating layers I 2  are applied to the surfaces of openings O, first openings O 1  and second openings O 2 .  
         [0041]    A carrier T made of aluminum is arranged above board P (see FIG. 2). The carrier T is approx. 5 mm thick. The surface of carrier T facing board P has indentations E in the region of the first wired bonds B 1 , to accommodate the first wired bonds B 1 . The surface of carrier T facing away from board P is flat.  
         [0042]    The logic section LO is arranged in an electrically insulating manner on the surface of carrier T facing away from board P and is connected to the power section LE via bonding connections B.  
         [0043]    The first bodies K 1  are connected to output terminals AA (see FIG. 1). The second body K 2  is connected to a voltage terminal SP, which is loaded with approx. 36 volts. The board P is connected to a ground terminal GA, which is loaded with zero volts.  
         [0044]    The capacitors K are connected in parallel between the ground terminal GA and voltage terminal SP.  
         [0045]    The first chips C 1  are connected in parallel between the output terminal AA and ground terminal GA. The second chips C 2  are connected in parallel between the output terminal AA and the voltage terminal SP. The first chips C 1  form a lowside drive. The second chips C 2  form a highside drive. Each first chip C 1  and second chip C 2  form a half bridge. The half bridges are connected in parallel between the ground terminal GA and the voltage terminal SP.