Abstract:
A small portable power supply is connected to a circuit board comprising a volatile memory unit. The main circuit board power supply is then disconnected from the circuit board, and the board may now be physically moved to another location without the loss of the data contained within the volatile memory. At the new location, another main circuit board power supply may be connected to the circuit board, and the small portable power supply may be disconnected, completing the transfer of the circuit board without any loss of data.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to the field of electronic circuits, and more particularly to the field of retaining programming in volatile memory elements of an electronic circuit during transportation.  
         BACKGROUND OF THE INVENTION  
         [0002]    Volatile memory units such as random access memories (RAMs) and field programmable gate arrays (FPGAs) have long been used in the design of electronic devices. They allow the designer to locally store data and instructions, and to quickly and easily change the custom programming of a gate array device. Often a designer will program the FPGA or load the RAM on a design station and later will need to take the circuit board including the FPGA and/or RAM to an emulator station where the full circuit will undergo testing. It may even sometimes be necessary to ship the circuit board to a remote site for diagnosis or evaluation. Normally this involves disconnecting the circuit board from a power supply and physically moving the board to the emulator station. Once the power supply is disconnected, the FPGA and RAM lose their programming and the designer must reprogram the FPGA and re-load the RAM data on the emulator station. This requires the designer to transport the FPGA programming data and memory data from the design station to the emulator station either through removable storage media or across a network connection. This process of transporting this data is open to several possibilities for errors or difficulties to enter the process. For example, the designer may accidentally copy the wrong version of the data to the removable storage media, then spend a great amount of time finding this problem once the incorrect data is used to program the FPGA or load the memory unit on the emulator station. Also, transfer of the data either through the network or removable storage media increases the possibility of incomplete transfers or other errors. These errors also may take a great amount of time to discover on the emulator station. Thus, there is a need in the art for an apparatus and method for transporting volatile memory units while retaining their contents.  
         SUMMARY OF THE INVENTION  
         [0003]    A small portable power supply is connected to a circuit board comprising a volatile memory unit. The main circuit board power supply is then disconnected from the circuit board, and the board may now be physically moved to another location without the loss of the data contained within the volatile memory. At the new location, another main circuit board power supply may be connected to the circuit board, and the small portable power supply may be disconnected, completing the transfer of the circuit board without any loss of data.  
           [0004]    Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 is a schematic diagram of a device for use in transporting circuit boards without losing the programming data of any attached volatile memory units.  
         [0006]    [0006]FIG. 2 is a flowchart of a method for transporting circuit boards without losing the programming data of any attached volatile memory units.  
     
    
     DETAILED DESCRIPTION  
       [0007]    [0007]FIG. 1 is a schematic diagram of a device for use in transporting circuit boards without losing the programming data of any attached volatile memory units. One or more volatile memory unit  100  is included within the circuitry on a circuit board  102 . A positive power supply connection node  104  and a negative power supply connection node  106  are included on the circuit board. During normal operation the circuit board  102  is powered by a circuit board power supply  108 . This circuit board power supply  108  has at least two outputs, a positive power supply output  120 , and a negative power supply output  122 . The positive power supply output  120  is normally connected to the positive power supply connection node  104  and the negative power supply output  122  is normally connected to the negative power supply connection node  106 . The positive power supply connection node  104  and the negative power supply connection node  106  in an example embodiment of the present invention are non-permanent connections such that the circuit board power supply  108  may be easily connected and disconnected. In other embodiments of the present invention the positive power supply connection node  104  and the negative power supply connection node  106  may be physically coupled in a single connector that includes both positive and negative connection nodes. A portable power supply  110  may be connected in parallel with the circuit board power supply  108 . In an example embodiment of the present invention, the portable power supply  110  comprises a battery  112  and a diode  114  connected in series. The diode  114  protects the battery  112  from a reverse voltage created when the circuit board power supply  108  is connected at the same time as the portable power supply  110 . This diode  114  is optional in some embodiments of the present invention. The negative node of the battery  112  is electrically connected to the negative output  118  of the portable power supply  110  and the positive node of the battery  112  is connected to the anode of the diode  114 . The cathode of the diode  114  is connected to the positive output  116  of the portable power supply  110 . The negative output  118  of the portable power supply  110  is configured to allow connection to the negative power supply connection node  106  and the positive output  116  of the portable power supply  110  is configured to allow connection to the positive power supply connection node  104 .  
         [0008]    In an example embodiment of the present invention the battery  112  is a  9 -volt battery. In this embodiment, the circuit board may include a voltage converter capable of stepping down the output of the 9-volt battery to a level usable by the electronic devices such as 5 volts or 3.3 volts. Many such converters are capable of receiving a wide range of input voltages. This allows the use of different voltages in the circuit board power supply  108  and the portable power supply  110 . Note that if different voltages are used, input protection must be present to avoid damage to the supplies. In another embodiment of the present invention, the battery  112  is a rechargeable battery that is configured such that it automatically recharges when the portable power supply  110  is connected in parallel with the circuit board power supply  108 .  
         [0009]    Note that if the volatile memory unit comprises dynamic RAM (DRAM), in addition to providing power to the DRAM, the portable power supply must also supply power to the peripheral circuitry required by the DRAM to refresh its array, or the contents of the DRAM will be lost.  
         [0010]    [0010]FIG. 2 is a flowchart of a method for transporting circuit boards without losing the programming data of any attached volatile memory units. In a step  200 , a circuit board power supply  108  is electrically connected to a circuit board  102  containing at least one volatile memory unit  100 . In a step  202 , this one or more volatile memory unit  100  is programmed by the user. This volatile memory unit may be a FPGA, static RAM (SRAM), dynamic RAM (DRAM), or any other volatile memory in any combination. In a step  204 , a portable power supply  110  is connected to the circuit board  102  in parallel with the circuit board power supply  108 . In a step  206 , the circuit board power supply  110  is disconnected, leaving the portable power supply  110  powering the circuit board  102 . In a step  208 , the circuit board  102  and portable power supply  110  are transported to a different location. Note that this different location is not limited in scope to a building, city, state or country. The different location may be anywhere reachable within the time available given the amount of charge in the battery. In a step  210 , a circuit board power supply  110  at the new location is connected to the circuit board  102  in parallel with the portable power supply  110 . Note that this circuit board power supply  110  is likely to be an equivalent but different supply than that used to power the circuit board  102  during programming. In a step  212 , the portable power supply  110  is disconnected from the circuit board  102 , leaving it powered by the circuit board power supply  108 . Alternately, in an example embodiment of the present invention, the portable power supply  110  may remain connected in parallel with the circuit board power supply  108  for recharging of the battery  112  within the portable power supply  110 . Alternately, in another example embodiment of the present invention, there may be no need to connect the circuit board power supply  108  at all at the new location. For example, if the board is being moved for a short period of time for testing, it may be possible to leave the board powered by the portable power supply  110  during testing. After testing, the board can be moved back to the original location and reattached to the original circuit board power supply  108 . Note that in some implementations of the present invention, the portable power supply  110  may be incorporated into the circuit board  102  such that it is an integral part of the circuit board  102 . This would allow a manufacturer to ship a complex electronic product, such as a computer server, to a customer including a board with a portable power supply  110  incorporated into the board  102 . Then, if fatal errors were encountered in the field, the manufacturer could have the customer, or their service technicians, swap boards and ship the error prone board back to the manufacturer for failure analysis. The circuit board  102  incorporating the portable power supply  110  would retain all of the information in the volatile memory devices included on the circuit board  102 . In another example embodiment of the present invention similar to the previous example, a manufacturer would ship a portable power supply  110  to a customer with instructions on connecting the portable power supply  110  to a problematic circuit board before powering down the equipment. The customer could then mail the circuit board and supply to the manufacturer for failure analysis facilitated by the information present in the volatile memory units.  
         [0011]    The foregoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.