Abstract:
The present invention relates to a backup module for a standard memory chip, more especially a standard memory chip (for example, DIP, QFJ and PLCC packages) having high-density pins for the backup of a personal computer. If the standard memory chip is out of order, the backup module according to the present invention can take the place of the standard memory chip. By switching between two or more chips, the capacity of the memory can be effectively increased as a whole and the content (program or data) of the memory can be easily optimized.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a backup module for a standard memory chip, more especially a standard memory chip (for example, DIP, QFJ and PLCC packages) having high-density pins for the backup of a personal computer. If the standard memory chip is out of order, the backup module according to the present invention can take the place of the standard memory chip. By switching between two or more chips, the capacity of the memory can be effectively increased as a whole and the content (program or data) of the memory can be easily optimized. 
     2. Description of the Related Art 
     A general high-density-pin type of memory chip (for example, DIP, QFJ and PLCC packages) is mounted on a base board in plane. For achieving the purpose of backup or increasing the capacity, the mounting of an additional chip would result in the increase of area occupied by the chip so that the whole area of a base board layout is increased and the manufacture cost is increased accordingly. On the other hand, there is a solution by a cubic arrangement. However, a conventional cubic arrangement is designed for special purpose and can not be used widely. Also, the manufacture for cubic arrangement is very complex and the manufacture cost can not be lowered. 
     In prior art, there is used a memory chip of small sized package for decreasing the area occupied by the chip so that the capacity can be increased. However, the backup chip is not a standard package chip, and the maintain cost would be increased. Since the backup chip is not a standard package chip, the manufacture cost is increased and the usage thereof can not be freely changed. For the user who does not need the backup function, the cost is increased unnecessarily. 
     There is a conventional system in which the data in memory can be changed. However, when the writing of data is defective, the system has a problem that it can not be started up. Under the circumstance, it is necessary for the maintainer to pull out the chip by detaching the whole system and to rewrite the data in memory by an expensive special memory writer. In addition to the expensive cost, the user needs to spend a lot of time. 
     For system software engineers who develop BIOS (basic input/output system), it is necessary to prepare a computer system for developing BIOS, a developed computer system for using BIOS and an apparatus for rewriting the content of memory chip. Therefore, the cost is very expensive. 
     If the source memory chip is arranged at the upper part for discriminating signals from a base board, the base board needs to be designed as having two layers of circuits, In this case, the total height of the base board would be increased excessively and a problem is occurred that an interference between each component is produced. 
     Up to now, there are two types of standard memories, one type is of rectangular shape (DIP package) and the other type is of square shape (QFJ and PLCC packages). With respect to a rectangular memory, please refer to FIG. 1A showing a situation where a source memory  109  is mounted on a memory socket  111  provided on a base board  110  before a memory module having backup function is used, FIG. 18 shows a prior art memory module having backup function which can be inserted in a memory socket  111  provided on a base board  110 , wherein the memory module comprises a first conductor part  101  which can be inserted in the memory socket  111 , a first base board  102 , a second conductor part  103  which can be connected to a second base board  106 , a backup memory  104 , a chip (not shown), a third conductor part  105  which can be connected to the first base board  102 , a second base board  106  and a memory socket  107 . In the case shown in FIG. 18, it is necessary to use two base boards. Therefore, the total height of a memory module having backup function will be increased significantly. Also, the manufacture cost Thereof is very expensive. If the prior art memory module having backup function is designed as having only one single base board as shown in FIG. 1C, the memory module will occupy an area larger than the source memory does. Under the circumstance, the mounting operation of the memory module will be interfered with some other components, and it is necessary to redesign the mother board (printed circuit board). 
     As to a square memory, please refer to FIG. 2A showing a situation where a source memory  209  is mounted on a memory socket  211  provided on a base board  210  before a memory module having backup function is used. FIG. 2B shows a prior art memory module having backup function which can be inserted in a memory socket  211  provided on a base board  210 , wherein the memory module corprises a support part  202 , a first conductor part  201 , a first base board  203 , a chip  204 , a backup memory  205 , a second conductor part  206 , a second base board  207  and a memory socket  208  in which a source memory  209  can be inserted, In the prior art memory module having backup function shown in FIG. 2B, since the chip  204  is mounted beside the backup memory  205 , the memory module will occupy an area larger than the source memory does. Therefore, the mounting operation of the memory module will be interfered with some other components, and it is necessary to redesign the mother board (printed circuit board). The detailed structure of the first conductor part  201  and the support part  202  is shown in FIG. 20 The total height of the first conductor part  201  and the support part  202  would be height h 1  plus height h 2 . Accordingly, the total height of the memory module will be increased unnecessarily. Also, the strength of the first conductor part  201  is very week. This would induce a phenomenon that the first conductor part  201  will be bent over after a long-period use. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a memory module having backup function, comprising: a memory connector having a plurality of pins, adapted to be connected to a memory socket; a backup memory having capacity equivalent to that of a source memory, connected to a main system through a plurality of pins of the memory connector; a switching means for selecting a backup memory or a source memory; and a memory socket for inserting a source memory. 
     In the memory module having backup function according to Embodiment 1 of the present invention, the control pins of the memory connector are lead out from a portion near the control pins of the source memory and are not contacted with the control pins of the source memory. 
     In the memory module having backup function according to Embodiment 1 of She present invention, the through hole for the control pin of the memory connector and the through hole for the control pin of the source memory are as near as possible. 
     In the memory module having backup function according to Embodiment 1 of the present invention, an insulator is provided between the control pin of the memory connector and the control pin of the source memory. 
     Another object of the present invention is to provide a memory module having backup function, characterized by comprising: a memory connector consisting of an inner support part and a lead part, the inner support part having a configuration substantially equivalent to that of a source memory, a hollow chip mounting part being provided in the inner support part for mounting a specific chip, the lead part being adapted to be connected to an original memory socket for connecting with the base board of a backup system; a switching means, for selecting a backup memory or a source memory; a backup memory having capacity equivalent to that of the source memory, connected between the switching means and the main system through the pins of the memory connector; a memory socket for inserting a source memory, connected to the main system through the switching means; and a base board on which a specific chip is mounted, having two or more layers of circuits, one layer of circuit being connected to the memory connector, and the other layer of circuit being connected to the backup memory and the memory socket. 
     In the memory module having backup function according to Embodiment 2 of the present invention, the inner support part of the memory connector is made of an insulator having on outer configuration similar to the inner configuration of the original memory socket; a plurality of grooves are provided at the periphery of the inner support part; the conductor part is made of a plurality of conductor posts which are adapted to be inserted into the grooves; and the width and height of the conductor posts are slightly more than those of the inner support part. 
     In the memory module having backup function according to Embodiment 2 of the present invention, the cross section of the grooves provided at the periphery of the inner support part is flask-shaped; the shape of the conductor posts corresponds to that of the grooves; and both ends of the conductor posts are wider than the middle of the conductor posts. 
     In the memory module having backup function according to Embodiment 2 of the present invention, the specific chip is consisted of a plurality of chips. 
     In the memory module having backup function according to the present invention, the backup memory can be used to expand memory capacity. 
     In the memory module having backup function according to the present invention, the backup memory is a DRAM. 
     In the memory module having backup function according to the present invention, the backup memory is a SRAM. 
     In the memory module having backup function according to the present invention, the backup memory is a flash ROM. 
     In the memory module having backup function according to the present invention, the backup memory is a programable semiconductor chip. 
     In the memory module having backup function according to the present invention, the switching means is manual. 
     In the memory module having backup function according to the present invention, the switching means is automatically turned on and off based on the determination of an electrical signal. 
     With the above structure, an optimistic conductivity can be obtained and the manufacture cost of a memory connector can be reduced. In the memory module having backup function according to the present invention, the signal connection through the memory connector is reliable and stabile. 
     With the above structure, the connection between the insulator and the conductor is tight Therefore, the conductor will not be moved due to an external force or heat, and the signal transmission in the memory module having backup function according to the present invention is stabile. 
     When a DRAM is used as a backup memory, BIOS can be easily reset and the manufacture cost can be reduced. When a SRAM is used as a backup memory, BIOS can be fast and easily reset. When a flash ROM is used as a backup memory, user needs not to worry a suddenly shutdown of power. When a programmable semiconductor chip is used as a backup memory, a PAL programmable chip can be replaced and tested for developing a system. 
     When the switching means is manual, a switch can be provided externally for switching the backup memory and source memory at low cost When the switching means is designed as an automatic switch, the switching between the backup memory and source memory can be achieved based on the determination of an electrical signal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A shows a situation where a rectangular source memory is mounted on a memory socket provided on a base board before a memory module having backup function is used; FIG. 1B shows a prior art memory module having backup function, wherein the memory module comprises a first conductor, a first base board, a second conductor part, a backup memory, a chip, a third conductor part, a second base board and a memory socket; and FIG. 1C shows the prior art memory module shown in FIG. 1B when it is redesigned as having only one single base board. 
     FIG. 2A shows a situation where a square source memory is mounted on a memory socket provided on a base board before a memory module having backup function is used; FIG. 2B shows a prior art memory module having backup function, wherein the memory module comprises a support part, a first conductor part, a first base board, a chip, a backup memory, a second conductor part, a second base board and a memory socket in which a source memory can be inserted; and FIG. 2C shows the detailed structure of the first conductor part and the support part. 
     FIG. 3A shows a situation where a rectangular source memory is mounted on a memory socket before a memory module having backup function according to Embodiment 1 of the present invention is used; FIG. 3B shows a memory module having backup function according to Embodiment 1 of the present invention, which comprises a memory connector, a backup memory, a switching means and a memory socket; and FIG. 3C shows a situation where a rectangular source memory is mounted on a memory module having backup function according to Embodiment 1 of the present invention. 
     FIG. 4A shows a situation where a square source memory is mounted on a memory socket before a memory module having backup function according to Embodiment 2 of the present invention is used; FIG. 4B shows a memory module having backup function according to Embodiment 2 of the present invention, which comprises a memory connector, a switching means, a backup memory, a memory socket and a base board; FIG. 4C shows a situation where a square source memory is mounted on a memory module having backup function according to Embodiment 2 of the present invention; and FIG. 4D is a bottom view of the memory module having backup function according to Embodiment 2 of the present invention. 
     FIG. 5A is a sectional view of the regular pin of the memory connector according to Embodiment 1 of the present invention, and FIG. 5B is a sectional view of the control pin of the memory connector according to Embodiment I of the present invention. 
     FIG. 6 is an exploded view of FIG.  4 C. 
     FIG. 7A is a top view of the memory connector according to Embodiment 2 of the present invention, and FIG. 7B is a side view of the memory connector according to Embodiment 2 of the present invention. 
     FIG. 8 is a block diagram showing a computer system in which the memory module having backup function according to the present invention is used. 
     FIG. 9 is a drawing showing that a computer system using the memory module having backup function according to the present invention can be used to replace with a developing computer system, a developed computer system and a writing device for rewriting the content of a memory chip. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 3A shows a situation where a rectangular source memory  1105  is mounted on an original memory socket  1106  of a printed circuit board  1107  before a memory module having backup function according to Embodiment 1 of the present invention is used. As shown in FIG. 3B, a memory module having backup function according to Embodiment 1 of the present invention comprises a memory connector  1101 , a backup memory  1102 , a switching means (not shown) and a memory socket  1104 . The memory connector  1101  has a plurality of pins, adapted to be connected to the original memory socket  1106  of a printed circuit board. The backup memory  1102  has capacity equivalent to that of the source memory  1105  and can be connected to a main system through a plurality of pins of the memory connector  1101 . The switching means is used for selecting a backup memory  1102  or a source memory  1105 . The memory socket  1104  is used for inserting a source memory  1105 . 
     FIG. 4A shows a situation where a square source memory  1207  is mounted on an original memory socket  1208  of a printed circuit board  1209  before a memory module having backup function according to Embodiment 2 of the present invention is used. As shown in FIG. 4B, a memory module having backup function according to Embodiment 2 of the present invention comprises a memory connector  1201 , a switching means (not shown), a backup memory  1202 , a memory socket  1204  and a base board  1205 . The memory connector  1201  is consisted of an inner support part and a lead part. The inner support has a configuration substantially equivalent to that of a source memory. A hollow chip mounting part is provided in the inner support part for mounting a specific chip  1206 . The lead part is connected to the socket of a source memory one hand, and is connected to the base board  1205  of a backup system on the other hand. The switching means is used for selecting a backup memory  1202  or a source memory  1207 . The backup memory  1202  has capacity equivalent to that of the source memory  1207 . The backup memory  1202  can be connected between the switching means and the main system through the pins of the memory connector  1201 . The memory socket  1204  is used for inserting a source memory  1207 , and is connected to the main system through the switching means. The base board  1205  on which a specific chip  1206  is mounted has two or more layers of circuits, one layer of circuit is connected to the memory connector  1201 , and the other layers of circuits are connected to the backup memory  1202  and the memory socket  1204 . 
     FIG. 4C shows a situation where a square source memory is mounted on the memory module having backup function according to Embodiment 2 of the present invention. Due to the design of the hollow chip mounting part of the inner support part, the specific chip  1206  can be mounted on the back side of the base board  1205  without occupying additional height. FIG. 4D is a bottom view of the memory module having backup function according to Embodiment 2 of the present invention, wherein a X-shaped reinforced part is provided inside the inner support part. The X-shaped reinforced part is used to prevent from the deformation of the inner support part after a long-period use. In addition, the X-shaped reinforced part is good for easily manufacturing as well as assembling. 
     In the memory connector  1101 , one type of pins are used as control pins of the memory connector and the other type of pins are regular pins of the memory connector. The sectional view of a regular pin of the memory connector is shown in FIG. 5A, and the sectional view of a control pin of the memory connector is shown in FIG.  513 . As shown in FIG. 5B, the control pin of the memory connector is slightly bent from point A so that the control pin of the memory connector is substantial parallel to the memory socket. When the source memory is mounted on the memory socket  1104 , the control pin of the source memory is connected to point B in FIG.  513 . The distance between point A and point B is designed as short as possible so that the switching between point A and point B can be easily performed and the manufacture cost would be reduced significantly. By switching between point A and point B, the selection of a backup memory or a source memory is performed. The switching between point A and point B can be performed manually by a switching means. Alternatively, the switching between point A and point B can be performed automatically based on the determination of an electrical signal by a specific chip. For avoiding the short circuit between point A and point B, on insulator  1110  is provided at the outside of point B. 
     FIG. 6 is an exploded view of FIG.  4 C. In the memory module having backup function according to Embodiment 2 of the present invention, the backup memory  1202  is mounted on the front side of the base board  1205  and the memory connector  1201  having the inner support part and the lead part is weld on the back side of the base board  1205 . On the other hand, the memory socket  1204  is also weld on the front side of the base board  1205 . The specific chip  1206  can be mounted inside the inner support part on the back side of the base board  1205 . The specific chip  1206  is used for performing the selecting between the source memory  1207  and the backup memory  1202 . The specific chip  1206  can be designed with a switching means for performing the selecting between the source memory  1207  and the backup memory  1202  manually by an external switch. Alternatively, the specific chip  1206  can be designed in a way to be consisted of a plurality of chips so that one of the plurality of chips can perform the selecting between the source memory  1207  and the backup memory  1202  automatically based on the determination of an electrical signal. 
     As shown in FIG. 6, the memory connector  1201  can be mounted on the original memory socket  1208  of the printed circuit board  1209 , and then the source memory  1207  can be mounted on the memory socket  1204 . Since the memory module according to Embodiment 1 or Embodiment 2 of the present invention occupies an area equal to (not larger than) that the source memory does, the mounting operation of the memory module will not be interfered with some other components on the printed circuit board, and thus it is not necessary to redesign the printed circuit board. 
     FIG. 7A is a top view of the memory connector according to Embodiment 2 of the present invention, and FIG. 7B is a side view of the memory connector according to Embodiment 2 of the present invention. The memory connector according to Embodiment 2 of the present invention is consisted of an inner support part and a lead part. The inner support part is made of an insulator  1212  having an outer configuration similar to the inner configuration of the original memory socket  1208 . The lead part is consisted of a plurality of conductor posts  1211 . In the present invention, the conductor post  1211  is flask-shaped. There are provided a plurality of grooves at the periphery of the insulator  1212  for inserting a plurality of conductor posts  1211 . The shape of the conductor post corresponds to that of the groove. With this design, the conductor post will not be easily escaped from the insulator. 
     FIG. 8 shows a block diagram of a computer system in which the memory module having backup function according to the present invention is used. The source memory and the backup memory can be selected by the switching means. Though there is described only one backup memory through the specification, an extra backup memory shown in the dash line part of FIG. 8 can be provided depends on needs. The switching means can be provided in the specific chip. Alternatively, an external manual switch shown in the dash line part of FIG. 8 can be used to replace with the switching means. The external manual switch can be connected to the base board through interface terminals. 
     As shown in FIG. 9, with the memory module having backup Unction according to the present invention, a system software engineer, who develops BIOS (basic input/output system), can use only one single computer system to replace a developing computer system, a developed computer system and a writing device for rewriting the content of a memory chip. 
     Please be noted that the specific chip  1206  can be designed to be consisted of a plurality of chips depends on needs. As a backup memory in the present invention, a DRAM, SRAM, flash ROM or programmable semiconductor chip can be used depending on needs. Also, the backup memory can be used to expand memory capacity. 
     The memory module having backup function according to the present invention has the following advantages: the memory module can be easily mounted on the printed circuit board of a computer system without occupying more area than the source memory does; it is not necessary to redesign a printed circuit board for mounting the memory module; the total height and manufacture cost of the memory module can be significantly reduced since only one base board is used in the memory module; the selecting between a source memory and a backup memory can be performed automatically or manually; a backup memory and an extra backup memory can be used simultaneously depending on needs; and BIOS can be developed or rewritten easily by only one single computer system. 
     While embodiments of the present invention have been described using specific terms, such description is for illustrative purposes only, and it should be understood that changes and variations may be made without departing from the spirit of scope of the following claims: