Abstract:
A disclosed circuit module includes: a substrate; a protection circuit mounted on the substrate for protecting a battery; and a charging circuit disposed on the substrate for controlling charging and discharging of the battery.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention generally relates to a circuit module and particularly to a circuit module in which a protection circuit for protecting a battery is mounted on a substrate 
         [0003]    2. Description of the Related Art 
         [0004]    In general, battery packs are used as a driving power supply for driving mobile devices such as mobile telephones. In the battery pack, usually, a lithium ion battery and a protection circuit are built in a single casing. The protection circuit detects an overcharge state, overdischarge state, and overcurrent state by detecting voltage and current of the lithium ion battery. When such states are detected, the protection circuit protects the lithium ion battery from falling into the overcharge state, overdischarge state, and overcurrent state by disconnecting between the lithium ion battery and an output terminal. 
         [0005]    In this case, the protection circuit built in the battery pack is provided as a circuit module having a COB (chip on board) structure. 
         [0006]    On the other hand, in mobile devices, the battery pack is desired to be used in common with other mobile devices. 
         [0007]    In the following, a system of a mobile device driven using a conventional battery pack is described. 
         [0008]      FIG. 1  is a diagram showing a system configuration of the mobile device driven using the battery pack. 
         [0009]    A mobile device  10  includes a device body  11  and a battery pack  12 . The battery pack  12  includes a battery  21  and a circuit module  22  stored in a case  23 . A protection circuit  31  is mounted on the circuit module  22  (refer to Patent Document 1, for example). 
         [0010]    The protection circuit  31  detects voltage, charging and discharging current, and ambient temperature of the battery  21  so as to detect a status immediately before abnormality such as the overcharge state, overdischarge state, overcurrent state, and overheat state. When such a status immediately before abnormality is detected, the protection circuit  31  protects the battery  21  from falling into the overcharge state, overdischarge state, overcurrent state, and overheat state by turning off a switching element connected between the battery  21  and a load in series. The protection circuit  31  is intended only to have a function of protecting the battery  21  from falling into the overcharge state, overdischarge state, overcurrent state, and overheat state, so that the protection circuit  31  is not provided with a function of controlling charging and discharging of the battery  21 . 
         [0011]    Conventionally, charging and discharging control of the battery  21  is performed by a charging and discharging control circuit  41  built in the device body  11 . The charging and discharging control circuit  41  is connected between the battery pack  12  and a device circuit  42  built in the device body  11 . The charging and discharging control circuit  41  controls voltage and current supplied from the battery  21  built in the battery pack  12  to the device circuit  42  and also controls a charging voltage applied from an AC adapter  13  to the battery  21  of the battery pack  12  and a charging current supplied from the AC adapter  13  to the battery  21  of the battery pack  12 . 
         [0012]    In this case, in the AC adapter  13 , a rated current, rated voltage, and the like are set in accordance with functions and specification of the charging and discharging control circuit  41 . Further, in the charging and discharging control circuit  41 , the functions and specification are set in accordance with charging and discharging characteristics of the battery pack  12 . Thus, the device body  11 , battery pack  12 , and AC adapter  13  are required to be used in a set. This hinders the battery pack from being used in common with other mobile devices. 
         [0013]    There has been suggested a battery pack for common use in which a protection function and a charging function are built (refer to Patent Document 2, for example) 
         [0014]    Patent Document 1: Japanese Laid-Open Patent Application No. 2004-6524 
         [0015]    Patent Document 2: Japanese Laid-Open Patent Application No. 2004-296165 
         [0016]    However, battery packs have been made thin and downsized, so that it is difficult to build the protection circuit and a charging circuit in the battery pack. Further, the charging circuit have large heat generation, so that when the protection circuit and the charging circuit are disposed closely to each other, the protection circuit detects the overheat state of the battery due to heat from the charging circuit. Then, the battery is disconnected by the protection circuit and charging is disabled. Thus, there have been demands for a structure in which the protection circuit and the charging circuit are mounted with a reduced influence of heat and a small mounting space. 
       SUMMARY OF THE INVENTION 
       [0017]    It is a general object of the present invention to provide an improved and useful circuit module in which the above-mentioned problems are eliminated. 
         [0018]    A more specific object of the present invention is to provide a circuit module that can modularize the protection circuit and the charging circuit with a small mounting space. 
         [0019]    According to one aspect of the present invention, there is provided a circuit module comprising: a substrate; a protection circuit mounted on the substrate for protecting a battery; and a charging circuit disposed on the substrate for controlling charging and discharging of the battery. Further, the protection circuit and the charging circuit may be sealed with resin. An electronic component constituting the protection circuit and an electronic component constituting the charging circuit may be mounted on a surface of one side of the substrate. 
         [0020]    According to another aspect of the present invention, there is provided a circuit module comprising: a first circuit substrate constituting a first circuit; and a second circuit substrate constituting a second circuit, wherein the first circuit substrate and the second circuit substrate are laminated and connected using a conductive member. 
         [0021]    According to another aspect of the present invention, in the circuit module, an electronic component constituting the first circuit may be mounted on a surface of one side of the first circuit substrate, an electronic component constituting the second circuit may be mounted on a surface of one side of the second circuit substrate, and the first circuit substrate and the second circuit substrate may be laminated so as to dispose a surface of the other side of the first circuit substrate and the surface of one side of the second circuit substrate in an opposing manner and may be connected using the conductive member. Further, the first circuit substrate and the second circuit substrate may be laminated via a radiator plate and connected using the conductive member. 
         [0022]    According to another aspect of the present invention, in the circuit module, an electronic component constituting the first circuit may be mounted on a surface of one side of the first circuit substrate, an electronic component constituting the second circuit may be mounted on a surface of one side of the second circuit substrate, and the first circuit substrate and the second circuit substrate may be laminated so as to dispose the surface of one side of the first circuit substrate and the surface of one side of the second circuit substrate in an opposing manner and may be connected using the conductive member. 
         [0023]    According to another aspect of the present invention, in the circuit module, a clearance between the first circuit substrate and the second circuit substrate may be sealed with resin. 
         [0024]    According to another aspect of the present invention, in the circuit module, an electronic component constituting the first circuit may be mounted on a surface of one side of the first circuit substrate, an electronic component constituting the second circuit may be mounted on a surface of one side of the second circuit substrate, and the first circuit substrate and the second circuit substrate may be laminated so as to dispose a surface of the other side of the first circuit substrate and a surface of the other side of the second circuit substrate in an opposing manner and may be connected using the conductive member. 
         [0025]    According to another aspect of the present invention, in the circuit module, the first circuit may function as a protection circuit for protecting a battery, the second circuit may function as a charging circuit for controlling charging of the battery, and the conductive member may include a first conductive member connected to a power supply terminal and a second conductive member connected to a ground terminal. 
         [0026]    According to the present invention, the charging circuit for controlling charging and discharging of the battery is further disposed on the substrate where the protection circuit for protecting the battery is mounted. Thus, it is possible to mount the protection circuit and the charging circuit on a single substrate and this enables charging with only a battery pack. Moreover, the protection circuit and the charging circuit are mounted on a single substrate, so that it is possible to downsize the circuit module. 
         [0027]    According to the present invention, the first circuit substrate constituting the first circuit and the second circuit substrate constituting the second circuit are laminated and connected using the conductive material. Accordingly, it is possible to reduce transfer of heat between the first circuit and the second circuit. Thus, it is possible to mount the first circuit and the second circuit closely to each other, so that it is possible to construct the first circuit and the second circuit using a small-sized circuit module. 
         [0028]    Other objects, features and advantage of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a diagram showing a configuration of a conventional system as an example; 
           [0030]      FIG. 2A  is a top view showing a configuration according to a first embodiment of the present invention; 
           [0031]      FIG. 2B  is a side elevational view showing a configuration according to a first embodiment of the present invention; 
           [0032]      FIG. 2C  is a bottom view showing a configuration according to a first embodiment of the present invention; 
           [0033]      FIG. 3  is a diagram showing a block configuration according to a first embodiment of the present invention; 
           [0034]      FIG. 4A  is a top view showing a configuration according to a second embodiment of the present invention; 
           [0035]      FIG. 4B  is a side elevational view showing a configuration according to a second embodiment of the present invention; 
           [0036]      FIG. 4C  is a bottom view showing a configuration according to a second embodiment of the present invention; 
           [0037]      FIG. 5  is a diagram showing a block configuration according to a second embodiment of the present invention; 
           [0038]      FIG. 6A  is a top view showing a configuration of a protection circuit substrate; 
           [0039]      FIG. 6B  is a side elevational view showing a configuration of a protection circuit substrate; 
           [0040]      FIG. 6C  is a bottom view showing a configuration of a protection circuit substrate; 
           [0041]      FIG. 7A  is a top view showing a configuration of a charging circuit substrate; 
           [0042]      FIG. 7B  is a side elevational view showing a configuration of a charging circuit substrate; 
           [0043]      FIG. 7C  is a bottom view showing a configuration of a charging circuit substrate; 
           [0044]      FIG. 8A  is a top view showing a configuration of a radiator plate; 
           [0045]      FIG. 8B  is a side elevational view showing a configuration of a radiator plate; 
           [0046]      FIG. 8C  is a bottom view showing a configuration of a radiator plate; 
           [0047]      FIG. 9  is a diagram illustrating a method for assembling a circuit unit according to a second embodiment of the present invention; 
           [0048]      FIG. 10A  is a top view showing a configuration according to a third embodiment of the present invention; 
           [0049]      FIG. 10B  is a side elevational view showing a configuration according to a third embodiment of the present invention; 
           [0050]      FIG. 10C  is a bottom view showing a configuration according to a third embodiment of the present invention; 
           [0051]      FIG. 11A  is a bottom view showing a configuration of another protection circuit substrate; 
           [0052]      FIG. 11B  is a side elevational view showing a configuration of another protection circuit substrate; 
           [0053]      FIG. 11C  is a top view showing a configuration of another protection circuit substrate; 
           [0054]      FIG. 12  is a diagram illustrating a method for assembling a circuit unit according to a third embodiment of the present invention; 
           [0055]      FIG. 13A  is a top view showing a configuration according to a fourth embodiment of the present invention; 
           [0056]      FIG. 13B  is a side elevational view showing a configuration according to a fourth embodiment of the present invention; 
           [0057]      FIG. 13C  is a bottom view showing a configuration according to a fourth embodiment of the present invention; 
           [0058]      FIG. 14A  is a top view showing a configuration of another protection circuit substrate; 
           [0059]      FIG. 14B  is a side elevational view showing a configuration of another protection circuit substrate; 
           [0060]      FIG. 14C  is a bottom view showing a configuration of another protection circuit substrate; 
           [0061]      FIG. 15A  is a bottom view showing a configuration of another charging circuit substrate; 
           [0062]      FIG. 15B  is a side elevational view showing a configuration of another charging circuit substrate; 
           [0063]      FIG. 15C  is a top view showing a configuration of another charging circuit substrate; 
           [0064]      FIG. 16  is a diagram illustrating a method for assembling a circuit unit according to a fourth embodiment of the present invention; and 
           [0065]      FIG. 17  is a cross-sectional view showing an example to which the present invention is applied. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
       [0066]      FIG. 2A  is a top view showing a configuration according to a first embodiment of the present invention.  FIG. 2B  is a side elevational view showing the configuration according to the first embodiment of the present invention.  FIG. 2C  is a bottom view showing the configuration according to the first embodiment of the present invention. 
         [0067]      FIG. 3  is a diagram showing a block configuration according to the first embodiment of the present invention. 
         [0068]    A circuit module  100  in the present embodiment includes a protection circuit unit  112 , a charging circuit unit  113 , and nickel blocks B+ and B− mounted on a single multilayer printed wiring board  111 . 
         [0069]    The multilayer printed wiring board  111  has a substantially rectangular shape. The nickel block B+ is soldered at an end in an arrow X 1  direction on one surface, namely, on a surface in an arrow Z 1  direction. The nickel block B− is soldered at an end in an arrow X 2  direction. The nickel block B+ is connected via a terminal board to an anode of a battery built in a battery pack. The nickel block B− is connected via a terminal board to a cathode of the battery built in the battery pack. 
         [0070]    Further, on the multilayer printed wiring board  111 , connection patterns P+ and P− are exposed in the arrow X 1  direction on the other surface, namely, on a surface in an arrow Z 2  direction. 
         [0071]    The protection circuit unit  112  has so called a COB (chop on board) structure in which electronic components  120  such as a protection IC  121 , a MOSFET  122 , resistances  123  and  124 , a capacitor  125 , and the like are mounted on a surface of a conductive pattern on the multilayer printed wiring board  111 . In this case, the protection IC  121  is constituted using a bare chip, for example. The protection circuit unit  112  is constituted by mounting the electronic components  120  on a surface of an area in the arrow X 1  direction between the nickel block B+ and the nickel block B− on the multilayer printed wiring board  111 . 
         [0072]    The electronic components  120  are sealed with resin  126 . The terminal board having one end connected to the anode of the battery is welded to the nickel block B+ via the other end and the terminal board having one end connected to the cathode of the battery is welded to the nickel block B− via the other end. 
         [0073]    The protection IC  121  detects a status immediately before the overcharge, overdischarge, and overcurrent of the battery in accordance with voltage generated in the resistances  123  and  124 , for example, and also detects the overheat state using an internal circuit. The protection IC  121  turns off the MOSFET  122  upon detecting a status immediately before the overcharge, overdischarge, overcurrent, and overheat of the battery. In accordance with this, the protection IC  121  protects the battery from falling into the overcharge state, overdischarge state, overcurrent state, and overheat state by disconnecting the cathode of the battery from the connection pattern P−, the cathode of the battery being connected via the terminal board to the nickel block B−, so as to separate the battery from load. 
         [0074]    The charging circuit unit  113  is constituted by mounting electronic components  130  on a surface of an area in the arrow X 2  direction between the nickel block B+ and the nickel block B− on the multilayer printed wiring board  111 . The charging circuit unit  113  is constituted using a circuit block different from that of the protection circuit unit  112 . 
         [0075]    The charging circuit unit  113  has so called a COB structure in which the electronic components  130  such as a charging IC  131 , a resistance  132 , capacitors  133  and  134 , and the like are mounted on a surface of the conductive pattern on the multilayer printed wiring board  111 . In this case, the charging IC  131  is constituted using a bare chip, for example. 
         [0076]    The charging IC  131  detects voltage between the nickel block B+ and the nickel block B− and also detects current flown to the battery in accordance with voltage applied to the resistance  132 . The charging IC  131  controls a built-in MOSFET and performs charging control of the battery in accordance with the detected voltage and current. 
         [0077]    Moreover, the electronic components  130  are sealed with resin  135 . The resin  135  is separated from the resin  126  for sealing the electronic components  120  of the protection circuit unit  112  on the multilayer printed wiring board  111 . 
         [0078]    Heat generation of the charging circuit unit  113  is larger than that of the protection circuit unit  112 . In this case, by forming different circuit blocks as the charging circuit unit  113  and the protection circuit unit  112 , it is possible to reduce transfer of heat generated in the charging circuit unit  113  to the protection circuit unit  112 . Further, by separating the resin  126  sealing the protection circuit unit  112  from the resin  135  sealing the charging circuit unit  113  on the multilayer printed wiring board  111 , it is possible to further reduce the transfer of heat generated in the charging circuit unit  113  to the protection circuit unit  112 . 
         [0079]    In the present embodiment, the charging control of the charging IC  131  is described. However, a function may be set so as to detect the voltage between the nickel block B+ and the nickel block B− and also detect the current flown from the battery in accordance with the voltage applied to the resistance  132 , so that the built-in MOSFET is controlled and the charging control of the battery is performed in accordance with the detected voltage and current. 
         [0080]    According to the present embodiment, it is possible to reduce an influence of the heat generated in the charging circuit unit  113  on the protection circuit unit  112 , so that it is possible to mount the protection circuit unit  112  and the charging circuit unit  113  on the single multilayer printed wiring board  111 . Moreover, by mounting the protection circuit unit  112  and the charging circuit unit  113  on the single multilayer printed wiring board  111 , it is possible to make the circuit module  100  thin. 
       Second Embodiment 
       [0081]      FIG. 4A  is a top view showing a configuration according to a second embodiment of the present invention.  FIG. 4B  is a side elevational view showing the configuration according to the second embodiment of the present invention.  FIG. 4C  is a bottom view showing the configuration according to the second embodiment of the present invention.  FIG. 5  is a diagram showing a block configuration according to the second embodiment of the present invention. In the drawings, the same reference numerals are assigned to the same constituent elements as in  FIGS. 2A ,  2 B,  2 C, and  3  and description thereof is omitted. 
         [0082]    In a circuit module  200  according to the present embodiment, a protection circuit substrate  211 , a charging circuit substrate  212 , and a radiator plate  213  are laminated, connecting pins  214  and  215  penetrate therethrough and are soldered at the protection circuit substrate  211  and the charging circuit substrate  212 , so that the protection circuit substrate  211 , charging circuit substrate  212 , and radiator plate  213  are formed in an integrated manner. 
         [0083]    First, a configuration of the protection circuit substrate  211  is described. 
         [0084]      FIG. 6A  is a top view showing the configuration of the protection circuit substrate  211 .  FIG. 6B  is a side elevational view showing the configuration of the protection circuit substrate  211 .  FIG. 6C  is a bottom view showing the configuration of the protection circuit substrate  211 . 
         [0085]    In the protection circuit substrate  211 , the electronic components  120 , nickel block B+, and nickel block B− are mounted on top surface of a multilayer printed wiring board  221  in the arrow Z 1  direction. The electronic components  120  are sealed with resin  222 . In the protection circuit substrate  211 , through holes  223  and  224  are formed thereon. 
         [0086]    On a peripheral portion of the through hole  223  on a surface of the multilayer printed wiring board  221  in the arrow Z 1  direction, a connection pattern  225  is formed. The connection pattern  225  is connected to the nickel block B+. The connecting pin  214  is inserted into the through hole  223 . The connecting pin  214  is soldered at the connection pattern  225  formed on the peripheral portion of the through hole  223  and is fixed on the protection circuit substrate  211 . 
         [0087]    On a peripheral portion of the through hole  224  on the surface of the multilayer printed wiring board  221  in the arrow Z 1  direction, a connection pattern  226  is formed. The connection pattern  226  is connected to the nickel block B−. The connecting pin  215  is inserted into the through hole  224 . The connecting pin  215  is soldered at the connection pattern  226  formed on the peripheral portion of the through hole  224  and is fixed on the protection circuit substrate  211 . 
         [0088]    Next, a configuration of the charging circuit substrate  212  is described. 
         [0089]      FIG. 7A  is a top view showing the configuration of the charging circuit substrate  212 .  FIG. 7B  is a side elevational view showing the configuration of the charging circuit substrate  212 .  FIG. 7C  is a bottom view showing the configuration of the charging circuit substrate  212 . 
         [0090]    The charging circuit substrate  212  is constituted by mounting the electronic components  130  on a top surface of a multilayer printed wiring board  231  in the arrow Z 1  direction. The electronic components  130  are sealed with resin  232 . In the charging circuit substrate  212 , through holes  233  and  234  are formed thereon. 
         [0091]    On a peripheral portion of the through hole  233  on a surface of the multilayer printed wiring board  231  in the arrow Z 1  direction, a connection pattern  235  connected to the connection pattern P+ is formed. The connecting pin  214  is inserted into the through hole  233 . The connecting pin  214  is soldered at the connection pattern  235  and is fixed on the charging circuit substrate  212 . 
         [0092]    On a peripheral portion of the through hole  233  on a surface of the multilayer printed wiring board  231  in the arrow Z 2  direction, a connection pattern  237  connected to the connection pattern P+ is formed. The connection pattern  237  connects the through hole  233  to the connection pattern P+. 
         [0093]    On a peripheral portion of the through hole  234  on the surface of the multilayer printed wiring board  231  in the arrow Z 1  direction, a connection pattern  236  connected to the connection pattern P− is formed. The connecting pin  215  is inserted into the through hole  234 . The connecting pin  215  is soldered at the connection pattern  236  and is fixed on the charging circuit substrate  212 . 
         [0094]    On a peripheral portion of the through hole  234  on the surface of the multilayer printed wiring board  231  in the arrow Z 2  direction, a connection pattern  238  connected to the connection pattern P− is formed. The connection pattern  238  connects the through hole  234  to the connection pattern P−. 
         [0095]    Next, a configuration of the radiator plate  213  is described. 
         [0096]      FIG. 8A  is a top view showing the configuration of the radiator plate  213 .  FIG. 8B  is a side elevational view showing the configuration of the radiator plate  213 .  FIG. 8C  is a bottom view showing the configuration of the radiator plate  213 . 
         [0097]    The radiator plate  213  is prepared by forming a material superior in thermal conductively such as aluminum, copper, or the like into a plate-like shape. The shape is determined so as to cover the electronic components  130  constituting the charging circuit of the charging circuit substrate  212  and above the charging circuit substrate  212  in the arrow Z 2  direction. Penetration holes  241  are formed at positions corresponding to the through holes  224  of the protection circuit substrate  211  and the through holes  234  of the charging circuit substrate  212 . The connecting pin  215  is inserted into the penetration hole  241 . The radiator plate  213  is in contact with a top surface of the resin  232  in the arrow Z 1  direction and has a function of radiating heat generated in the electronic components  130 . 
         [0098]    Next, a method for assembling the circuit module  200  is described. 
         [0099]      FIG. 9  is a diagram illustrating the method for assembling the circuit unit  200  according to the second embodiment of the present invention. 
         [0100]    First, the connecting pin  214  is inserted into the through hole  233  and the connecting pin  215  is inserted into the through hole  234  in the charging circuit substrate  212 . In this case, the connecting pins  214  and  215  are positioned such that end faces thereof in the arrow Z 2  direction correspond to the surface of the charging circuit substrate  212  in the arrow Z 2  direction. The connecting pin  214  is soldered at the connection pattern  235  formed on the peripheral portion of the through hole  233  and the connecting pin  215  is soldered at the connection pattern  236  formed on the peripheral portion of the through hole  234 . 
         [0101]    In accordance with this, the connecting pins  214  and  215  are implanted in the charging circuit substrate  212  as shown in FIG.  9 -( a ). 
         [0102]    Next, as shown in FIG.  9 -( b ), the connecting pin  215  is allowed to penetrate through the penetration hole  241  of the radiator plate  213 , so that the radiator plate  213  is disposed on the resin  232 . In this case, the radiator plate  213  may be bonded to the resin  232  or to the protection circuit substrate  211  using adhesive, for example. In the present embodiment, the radiator plate  213  is extended in the arrow X 2  direction. However, by further extending the radiator plate  213  in the arrow X 1  direction so as to increase an area thereof, efficiency of heat radiation is improved. 
         [0103]    Next, the protection circuit substrate  211  is laminated on the charging circuit substrate  212  and the radiator plate  213  such that the connecting pin  214  penetrates through the through hole  223  and the connecting pin  215  penetrates through the through hole  224 . The connecting pins are soldered at the connection pattern  225  formed on the peripheral portion of the through hole  223  and the connection pattern  226  formed on the peripheral portion of the through hole  224 . 
         [0104]    In accordance with this, as shown in  FIGS. 4A ,  4 B,  4 C, and FIG.  9 -( c ), the protection circuit substrate  211 , charging circuit substrate  212 , and radiator plate  213  are formed in an integrated manner. 
         [0105]    By laminating the protection circuit substrate  211  and the charging circuit substrate  212  in an integrated manner, it is possible to form a circuit module having a protection function and a charging function with the same projected area as in a conventional circuit module having only a protection function. In accordance with this, it is possible to construct a battery pack with the same cross-sectional area as in a conventional battery pack on which a circuit module having only a protection circuit is mounted. 
         [0106]    Further, in the present embodiment, by disposing the radiator plate  213 , it is possible to efficiently radiate heat generated in the electronic components  120  constituting the charging circuit. 
       Third Embodiment 
       [0107]      FIG. 10A  is a top view showing a configuration according to a third embodiment of the present invention.  FIG. 10B  is a side elevational view showing the configuration according to the third embodiment of the present invention.  FIG. 10C  is a bottom view showing the configuration according to the third embodiment of the present invention. In the drawings, the same reference numerals are assigned to the same constituent elements as in  FIGS. 4A ,  4 B, and  4 C and description thereof is omitted. 
         [0108]    A circuit module  300  according to the present embodiment has a configuration in which the electronic components  120  constituting the protection circuit of a protection circuit substrate  311  and the electronic components  130  constituting the charging circuit of the charging circuit substrate  212  are disposed in an opposing manner. A configuration of the protection circuit substrate  311  is different from the case of the second embodiment. 
         [0109]    In the following, the protection circuit substrate  311  according to the present embodiment is described. 
         [0110]      FIG. 11A  is a bottom view showing a configuration of the protection circuit substrate  311 .  FIG. 11B  is a side elevational view showing the configuration of the protection circuit substrate  311 .  FIG. 11C  is a top view showing the configuration of the protection circuit substrate  311 . 
         [0111]    The protection circuit substrate  311  according to the present embodiment has a configuration in which the electronic components  120  constituting the protection circuit are mounted on a surface of a multilayer printed wiring board  321  in the arrow Z 2  direction and battery connection patterns Pb+ and Pb− are formed on a surface of the multilayer printed wiring board  321  in the arrow Z 1  direction. The multilayer printed wiring board  321  has the through holes  223  and  224  and connection patterns  331  and  332  are formed on a peripheral portion of the through holes  223  and  224  on the surface in the arrow Z 2  direction. The connecting pins  214  and  215  are soldered at the connection patterns  331  and  332 . 
         [0112]    In addition, the charging circuit substrate  212  has the same configuration as in the charging circuit substrate  212  shown in  FIGS. 7A ,  7 B, and  7 C. 
         [0113]      FIG. 12  is a diagram illustrating a method for assembling the circuit module  300  according to the third embodiment of the present invention. 
         [0114]    First, the connecting pin  214  is inserted into the through hole  233  and the connecting pin  215  is inserted into the through hole  234  in the charging circuit substrate  212 . In this case, the connecting pins  214  and  215  are positioned such that end faces thereof in the arrow Z 2  direction correspond to the surface of the charging circuit substrate  212  in the arrow Z 2  direction. The connecting pin  214  is soldered at the connection pattern  235  formed on the peripheral portion of the through hole  233  and the connecting pin  215  is soldered at the connection pattern  236  formed on the peripheral portion of the through hole  234 . It is possible to perform soldering between the connecting pins  214  and  215  and the connection patterns  235 ,  236 ,  331 , and  332  via flow soldering, reflow soldering, or the like. 
         [0115]    Next, as shown in FIG.  12 -( b ), the protection circuit substrate  311  is laminated on the charging circuit substrate  212  such that the connecting pin  214  is inserted into the through hole  223  and the connecting pin  215  is inserted into the through hole  224 . The connecting pins  214  and  215  are soldered at the connection pattern  331  formed at the peripheral portion of the through hole  223  and the connection pattern  332  formed at the peripheral portion of the through hole  224 . 
         [0116]    In accordance with this, the protection circuit substrate  311  and charging circuit substrate  212  are laminated and formed in an integrated manner. 
         [0117]    Next, as shown in FIG.  12 -( c ), resin  341  is filled between the protection circuit substrate  311  and the charging circuit substrate  212  so as to dispose and seal the electronic components  120  constituting the protection circuit and the electronic components  130  constituting the charging circuit between the protection circuit substrate  311  and the charging circuit substrate  212 . 
         [0118]    By laminating the protection circuit substrate  311  and the charging circuit substrate  212  in an integrated manner, it is possible to form a circuit module having a protection function and a charging function with the same projected area as in a conventional circuit module having only a protection function. In accordance with this, it is possible to construct a battery pack with the same cross-sectional area as in a conventional battery pack. 
         [0119]    Further, according to the present embodiment, the protection circuit substrate  311  and the charging circuit substrate  212  are laminated in an integrated manner via the resin  341 , so that it is possible to substantially improve mechanical strength of the circuit module  300 . 
         [0120]    Moreover, the electronic components  120  constituting the protection circuit and the electronic components  130  constituting the charging circuit are disposed between the protection circuit substrate  311  and the charging circuit substrate  212 . Thus, it is possible to completely seal the electronic components  120  constituting the protection circuit of the protection circuit substrate  311  and the electronic components  130  constituting the charging circuit of the charging circuit substrate  212  with the resin  341  and to improve reliability of the circuit module  300 . 
         [0121]    In the present embodiment, the electronic components  120  mounted on the protection circuit substrate  311  and the electronic components  130  mounted on the charging circuit substrate  212  are sealed with the resin  222  and  232 , then the protection circuit substrate  311  and the charging circuit substrate  212  are laminated in an integrated manner such that the electronic components  120  and the electronic components  130  are disposed in an opposing manner, and the electronic components  120  and the electronic components  130  are further sealed with the resin  341 . However, before the sealing with the resin  222  and resin  232 , namely, while the bare chip is exposed, the protection circuit substrate  311  and the charging circuit substrate  212  may be laminated in an integrated manner such that the electronic components  120  and the electronic components  130  are disposed in an opposing manner and the electronic components  120  and the electronic components  130  may be sealed by filling the resin  341  between the protection circuit substrate  311  and the charging circuit substrate  212 . 
         [0122]    In accordance with this, it is possible to eliminate the step of sealing the electronic components  120  and  130  with the resin  222  and  232 . 
       Fourth Embodiment 
       [0123]      FIG. 13A  is a top view showing a configuration according to a fourth embodiment of the present invention.  FIG. 13B  is a side elevational view showing the configuration according to the fourth embodiment of the present invention.  FIG. 13C  is a bottom view showing the configuration according to the fourth embodiment of the present invention. In the drawings, the same reference numerals are assigned to the same constituent elements as in  FIGS. 4A ,  4 B, and  4 C and description thereof is omitted. 
         [0124]    A circuit module  400  according to the present embodiment has a configuration in which a protection circuit substrate  411  and a charging circuit substrate  412  are laminated via connecting pins  413  and  414 . 
         [0125]    In the following, the protection circuit substrate  411  according to the present embodiment is described. 
         [0126]      FIG. 14A  is a top view showing a configuration of the protection circuit substrate  411 .  FIG. 14B  is a side elevational view showing the configuration of the protection circuit substrate  411 .  FIG. 14C  is a bottom view showing the configuration of the protection circuit substrate  411 . 
         [0127]    The protection circuit substrate  411  according to the present embodiment has a configuration in which the electronic components  120  constituting the protection circuit are mounted on a surface of a multilayer printed wiring board  421  in the arrow Z 1  direction and are sealed with resin  422 . Further, the battery connection patterns Pb+ and Pb− are formed on the surface of the multilayer printed wiring board  421  in the arrow Z 1  direction. A battery is connected to the battery connection patterns Pb+ and Pb−. 
         [0128]    Moreover, through holes  431  and  432  penetrating trough the multilayer printed wiring board  421  in the arrows Z 1  and Z 2  directions are formed between the resin  422  and the battery connection patterns Pb+ and Pb− on the multilayer printed wiring board  421 . Connection patterns  441  and  442  are formed on peripheral portions of the through holes  431  and  432  on the surface of the multilayer printed wiring board  421  in the arrow Z 1  direction. The connecting pins  413  and  414  are soldered at the connection patterns  441  and  442 . 
         [0129]    In the following, the charging circuit substrate  412  according to the present embodiment is described. 
         [0130]      FIG. 15A  is a bottom view showing a configuration of the charging circuit substrate  412 .  FIG. 15B  is a side elevational view showing the configuration of the charging circuit substrate  412 .  FIG. 15C  is a top view showing the configuration of the charging circuit substrate  412 . 
         [0131]    The charging circuit substrate  412  according to the present embodiment has a configuration in which the electronic components  130  constituting the charging circuit are mounted on a surface of a multilayer printed wiring board  451  in the arrow Z 2  direction and are sealed with resin  452 . On the surface of the multilayer printed wiring board  451  in the arrow Z 2  direction, the connection patterns P+ and P− are formed. The connection patterns P+ and P− are used as charging and discharging terminals of a battery pack. 
         [0132]    Moreover, in the multilayer printed wiring board  451 , through holes  461  and  462  penetrating trough the multilayer printed wiring board  451  in the arrows Z 1  and Z 2  directions are formed between the resin  452  and the connection patterns P+ and P−. On peripheral portions of the through holes  461  and  462  on the surface of the multilayer printed wiring board  451  in the arrow Z 2  direction, connection patterns  471  and  472  are formed. The connecting pins  413  and  414  are soldered at the connection patterns  471  and  472 . 
         [0133]      FIG. 16  is a diagram illustrating a method for assembling the circuit module  400  according to the fourth embodiment of the present invention. 
         [0134]    First, as shown in FIG.  16 -( a ), the connecting pin  413  is inserted into the through hole  461  and the connecting pin  414  is inserted into the through hole  462  in the charging circuit substrate  412 . The connecting pin  413  is soldered at the connection pattern  471  formed on the peripheral portion of the through hole  461  and the connecting pin  414  is soldered at the connection pattern  472  formed on the peripheral portion of the through hole  462 . 
         [0135]    Next, as shown in FIG.  16 -( b ), the protection circuit substrate  411  is laminated on the charging circuit substrate  412  such that the connecting pin  413  is inserted into the through hole  431  and the connecting pin  414  is inserted into the through hole  432 . The connecting pin  413  is soldered at the connection pattern  441  formed on the peripheral portion of the through hole  431  and the connecting pin  414  is soldered at the connection pattern  442  formed on the peripheral portion of the through hole  432 . 
         [0136]    In accordance with this, it is possible to form the protection circuit substrate  411  and the charging circuit substrate  412  in an integrated manner. In the above-mentioned second to fourth embodiments, by connecting a power supply to the ground using the connecting pins  214  and  413  connected to a power supply terminal and the connecting pins  215  and  414  connected to a ground terminal, it is possible to reduce resistance resulting from the pattern wiring. 
       APPLICATION EXAMPLE 
       [0137]      FIG. 17  is a cross-sectional view showing an example to which the present invention is applied. 
         [0138]    In the present application example, a battery pack  500  including the circuit modules  100 ,  200 ,  300 , and  400  built therein is described. 
         [0139]    The battery pack  500  has a configuration in which a battery  511 , the circuit modules  100 ,  200 ,  300 , and  400  are stored in a case  512 . In the circuit modules  100 ,  200 ,  300 , and  400 , one end of a connection member  521  is welded to the nickel block B+ or the battery connection pattern Pb+ and one end of a connection member  522  is welded to the nickel block B− or the battery connection pattern Pb−. The other end of the connection member  521  is connected to an anode of the battery  511  and the other end of the connection member  522  is connected to a cathode of the battery  511 . 
         [0140]    In addition, the circuit modules  100 ,  200 ,  300 , and  400  are stored in the case  512  such that the connection pattern P+ and P− are exposed on an end surface of the case  512  in the arrow Z 1  direction. 
         [0141]    The present invention is not limited to the specifically disclosed embodiment, and variations and modifications may be made without departing from the scope of the present invention. 
         [0142]    The present application is based on Japanese priority application No. 2006-285241 filed Oct. 19, 2006, the entire contents of which are hereby incorporated herein by reference.