Technical Field
The present invention relates to electronic circuit systems. More particularly, the present invention relates to electronic circuit systems used within electronic warfare (EW) condition. Specifically, the present invention relates to a mezzanine circuit card system that allows new chips to be quickly reconfigured and redesigned and used with existing baseboards.
Background Information
An integrated circuit uses a network of metal interconnects between the individual semiconductor components, which are patterned with standard photolithographic processes during wafer fabrication. Multiple levels of metallized patterns may be used to increase the flexibility of the interconnects.
It has long been recognized that a user-programmable interconnect technique or manufacturer programmability just prior to shipment would allow lower tooling costs and faster delivery time. To such an end, gate array circuits were developed.
A gate array circuit is an array of uncommitted gates with uncommitted wiring channels. To implement a particular circuit function, the circuit is mapped into the array and the wiring channels and appropriate connections are programmed to implement the necessary wiring connections that form the circuit function. The gate array is programmed by developing digital computing tasks in software and compiling the tasks down to a configuration file or bitstream that contains information on how the components should be wired together.
A gate array circuit can be programmed to implement virtually any set of functions. Further, gate arrays can be programmed to implement custom hardware functionality without ever having to pick up a breadboard or soldering iron. Input signals are processed by a programmed circuit to produce the desired set of outputs. Such inputs flow from the user's system, through input buffers, then through the circuit, and finally back out to the user's system via output buffers. Such buffers provide any or all of the following input/output (I/O) functions: voltage gain, current gain, level translation, delay, signal isolation, or hysteresis.
If the wiring channels and appropriate connections are programmed by the manufacturer according to the construction masks, then the gate array circuit is described as a mask-programmable gate array.
If the wiring channels and appropriate connections are programmed by the user according to programmable circuit elements, then the gate array circuit is described as a Field Programmable Gate Array (FPGA).
Gate arrays are ordinarily affixed to a baseboard or motherboard. The baseboard is a static printed circuit board and main contain discrete components or sub-systems such as a processor. The purpose of the baseboard is to hold the crucial electrical components of the system and provide connections between the discrete components, like a connection from a gate array to a processor.
As advantageous as gate arrays have been herein above described, a problem continues to exist with their rapid improvement. Gate arrays continue to be permanently affixed to a hardwired baseboard. When an improved gate array is released by a manufacture, a baseboard must be reconfigured to accept the improved gate array. The baseboard reconfiguration process can take upwards of 15 months.
Others have attempted connecting circuits to mezzanine cards. A mezzanine card or daughterboard is a circuit board meant to be an extension or “daughter” of the baseboard or motherboard. In particular, mezzanine cards often have plugs, sockets, pins, connectors, or other attachments for other boards.
Commercial mezzanine cards, known in the prior art, are designed, in general, to be convection cooled by air. This way of cooling the mezzanine cards allows much better thermal cooling via heat transfer because all of the hot components are faced towards a cooling plate. The cooling plate is the cover of the module. This configuration allows each individual key discrete component (i.e., circuit, transistor, resistor, or the like) in a design to be attached to a mezzanine card so that if component fails, one may remove the mezzanine cards housing the failed component and attach another mezzanine card with having a new component. In general, these prior art mezzanine cards, e.g. FMC, XMC, PMC types, are commercial mezzanine card types that are designed to be air cooled. They can be adapted to be conduction cooled, but those conduction cooled boards are about 50% as dense as may be required for Electronic Warfare (EW) applications so that there may be less ability to input data to those cards and they tend to be much bigger physically.
Previously known and prior designs of durable pressure contact pads of a printed wired circuit on a motherboard or baseboard have been limited to a planar single side of the baseboard. This is because the pressure contact pads, which conduct the electrical signals, are normally electroplated. Often times, the pressure contact pads are electroplated with gold because of gold's excellent conductive and non-corrosive properties. Electroplating pressure contact pads with gold on both planar sides of the baseboard is not practical for most printed wiring board designs because of its increased production and manufacturing costs.
What is needed is a better way of using new integrated circuit chips such as FPGAs, transmitter chips, and receiver chips with existing baseboards.