The present invention relates to the field of integrated circuit, and more particularly to configurable gate array.
A configurable gate array is a semi-custom integrated circuit designed to be configured by a customer after manufacturing. U.S. Pat. No. 4,870,302 issued to Freeman on Sep. 26, 1989 (hereinafter referred to as Freeman) discloses a configurable gate array. It contains an array of configurable logic elements (also known as configurable logic blocks) and a hierarchy of configurable interconnects (also known as programmable interconnects) that allow the configurable logic elements to be wired together. Each configurable logic element in the array is in itself capable of realizing any one of a plurality of logic functions (e.g. shift, logic NOT, logic AND, logic OR, logic NOR, logic NAND, logic XOR, arithmetic addition “+”, arithmetic subtraction “−”, etc.) depending upon a first configuration signal. Each configurable interconnect can selectively couple or de-couple interconnect lines depending upon a second configuration signal.
Strictly speaking, besides logic functions, each configurable logic element is capable of realizing elementary arithmetic operations (elementary arithmetic operations consist of addition and subtraction). However, the configurable logic elements are incapable of realizing any non-arithmetic functions, i.e. math functions whose operations involve more than elementary arithmetic operations. Exemplary non-arithmetic functions include transcendental functions and special functions. Throughout this specification, the phrase “math functions” refers to only non-arithmetic functions, i.e. math functions whose operations involve more than addition and subtraction.
Complex math functions are widely used in various applications. A complex math function has multiple independent variables (independent variable is also known as input variable or argument). It can be expressed as a combination of basic math functions. A basic math function has a single independent variable. Exemplary basic math functions include transcendental functions, such as exponential function (exp), logarithmic function (log), trigonometric functions (sin, cos, tan, atan) and others. To meet the speed requirements, many high-performance applications require that these complex math functions be implemented in hardware. In conventional configurable gate arrays, complex math functions and/or basic math functions are implemented in fixed computing elements, which are portions of hard blocks and not configurable, i.e. the circuits implementing the complex math functions and/or basic math functions are fixedly connected and are not subject to change by programming. Apparently, fixed computing elements would limit further applications of the configurable gate array. To overcome this difficulty, the present invention expands the original concept of the configurable gate array by making the fixed computing elements configurable. In other words, besides arrays of configurable logic elements, the configurable gate array comprises arrays of configurable computing elements, which can realize any one of a plurality of basic math functions.
Objects and Advantages
It is a principle object of the present invention to extend the applications of a configurable gate array to the field of complex math computation.
It is a further object of the present invention to provide a configurable computing array to realize different complex math functions.
It is a further object of the present invention to provide a configurable computing array with a small physical size and a fast computational speed.
It is a further object of the present invention to provide a configurable computing array with a short time-to-market and good manufacturability.
In accordance with these and other objects of the present invention, the present invention discloses a configurable computing-array package.
The present invention discloses a configurable computing-array package. It comprises a configurable computing die comprising an array of configurable computing elements and a configurable logic die comprising an array of configurable logic elements. The configurable computing-array package further comprises a plurality of configurable interconnects, which are located on the configurable computing die and/or the configurable logic die. Each configurable computing element comprises at least a writable-memory array, which is electrically programmable and can be loaded with a look-up table (LUT) for a math function. Being electrically programmable, the math functions that can be realized by a writable-memory array are essentially boundless.
The usage cycle of the configurable computing element comprises two stages: a configuration stage and a computation stage. In the configuration stage, the LUT for a desired math function is loaded into the writable-memory array. In the computation stage, a selected portion of the LUT for the desired math function is read out from the writable-memory array. For a rewritable-memory array, a configurable computing element can be re-configured to realize different math functions at different time.
Besides configurable computing elements, the preferred configurable computing-array package further comprises configurable logic elements and configurable interconnects. During operation, a complex math function is first decomposed into a combination of basic math functions. Each basic math function is realized by programming the associated configurable computing element. The complex math function is then realized by programming the appropriate configurable logic elements and configurable interconnects.
By using arrays of configurable computing elements, configurable logic elements and configurable interconnects, the present invention realizes configurable hardware computing of complex math functions. Compared with conventional software computing, configurable hardware computing is much faster and more efficient; and, compared with fixed hardware computing, configurable hardware computing offers configurability and generality.
Accordingly, the present invention discloses a configurable computing-array package, comprising: a configurable logic die comprising at least an array of configurable logic elements including a configurable logic element, wherein said configurable logic element selectively realizes a logic function from a logic library; a configurable computing die comprising at least an array of configurable computing elements including first and second configurable computing elements, wherein said first configurable computing element comprises at least a first memory for storing a first look-up table (LUT) for a first non-arithmetic function; and, said second configurable computing element comprises at least a second memory for storing a second LUT for a second non-arithmetic function; a plurality of inter-die connections for communicatively coupling said configurable logic die and said configurable computing die; whereby said configurable computing-array package realizes a third non-arithmetic function by programming said configurable logic elements and said configurable computing elements, wherein said third non-arithmetic function is a combination of at least said first and second non-arithmetic functions.
The present invention further discloses another configurable computing-array package, comprising: a configurable logic die comprising at least an array of configurable logic elements including a configurable logic element, wherein said configurable logic element selectively realizes a logic function from a logic library; a configurable computing die comprising at least an array of configurable computing elements including first and second configurable computing elements, wherein said first configurable computing element comprises at least a first memory for storing a first look-up table (LUT) for a first non-arithmetic function; and, said second configurable computing element comprises at least a second memory for storing a second LUT for a second non-arithmetic function; a plurality of configurable interconnects including a configurable interconnect, wherein said configurable interconnect selectively realizes an interconnect from an interconnect library; a plurality of inter-die connections for communicatively coupling said configurable logic die and said configurable computing die; whereby said configurable computing-array package realizes a third non-arithmetic function by programming said configurable logic elements, said configurable computing elements and said configurable interconnects, wherein said third non-arithmetic function is a combination of at least said first and second non-arithmetic functions.
It should be noted that all the drawings are schematic and not drawn to scale. Relative dimensions and proportions of parts of the device structures in the figures have been shown exaggerated or reduced in size for the sake of clarity and convenience in the drawings. The same reference symbols are generally used to refer to corresponding or similar features in the different embodiments. As used herein, the phrases “write”, “program” and “configure” are used interchangeably; the symbol “/” means a relationship of “and” or “or”; the phrase “communicatively coupled” is used in its broadest sense to mean any coupling whereby information may be passed from one element to another element.
Those of ordinary skills in the art will realize that the following description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons from an examination of the within disclosure.
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The implementation of math functions is much more complicated than the implementation of logic functions. The LUT stored in the configurable computing element 100 includes numerical values related to a math function, whereas the LUT stored in a configurable logic element of the conventional configurable gate array includes only logic values of a logic function. Numerical values are denoted by a large number of bits. For example, a half-precision floating-point number comprises 16 bits; a single-precision floating-point number comprises 32 bits; a double-precision floating-point number comprises 64 bits. In comparison, the logic values can be denoted by a single bit and have only two values, i.e. “true” and “false”. Accordingly, the LUT size in the configurable computing element 100 is substantially larger than that in the configurable logic element.
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The configurable computing-array package 400 in
The configurable computing-array package 400 in
Because the configurable computing die 100W and the configurable logic die 200W are located in a same package, this type of integration is referred to as 2.5-D integration. The 2.5-D integration excels the conventional 2-D integration in many aspects. Firstly of all, the footprint of a conventional 2D-integrated configurable computing array is roughly equal to the sum of those of the configurable computing elements, the configurable logic elements and the configurable interconnects. On the other hand, because the 2.5-D integration moves the configurable computing elements from aside to above, the configurable computing-array package 400 becomes smaller and computationally more powerful. Secondly, because they are physically close and coupled by a large number of inter-die connections 160, the configurable computing die 100W and the configurable logic die 200W have a larger communication bandwidth than the conventional 2D-integrated configurable computing array. Thirdly, the 2.5-D integration benefits manufacturing process. Because the configurable computing die 100W and the configurable logic die 200W are separate dice, the memory transistors in the configurable computing die 100W and the logic transistors in the configurable logic die 200W are formed on separate semiconductor substrates. Consequently, their manufacturing processes can be individually optimized.
The preferred embodiments of the present invention are field-programmable computing-array (FPCA) package. For an FPCA package, all manufacturing processes of the configurable computing die and the configurable logic die are finished in factory. The function of the FPCA package can be electrically defined in the field of use. The concept of FPCA package can be extended to mask-programmed computing-array (MPCA) package. For a MPCA package, the wafers containing the configurable computing elements and/or the wafer containing the configurable logic elements are prefabricated and stockpiled. However, certain interconnects on these wafers are not fabricated until the function of the MPCA package is finally defined.
While illustrative embodiments have been shown and described, it would be apparent to those skilled in the art that many more modifications than that have been mentioned above are possible without departing from the inventive concepts set forth therein. The invention, therefore, is not to be limited except in the spirit of the appended claims.
Number | Date | Country | Kind |
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201610125227.8 | Mar 2016 | CN | national |
201610307102.7 | May 2016 | CN | national |
201710996864.7 | Oct 2017 | CN | national |
201710980817.3 | Oct 2017 | CN | national |
201710998652.2 | Oct 2017 | CN | national |
This application is a continuation-in-part of U.S. patent application Ser. No. 15/793,968, filed Oct. 25, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 15/450,049, filed Mar. 6, 2017, now U.S. Pat. No. 9,838,021, issued Dec. 5, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 15/450,017, filed Mar. 5, 2017, now U.S. Pat. No. 9,948,306, issued Apr. 17, 2018. This application claims priorities from Chinese Patent Application No. 201610125227.8, filed Mar. 5, 2016; Chinese Patent Application No. 201610307102.7, filed May 10, 2016; Chinese Patent Application No. 201710996864.7, filed Oct. 19, 2017; Chinese Patent Application No. 201710998652.2, filed Oct. 20, 2017; Chinese Patent Application No. 201710980817.3, filed Oct. 20, 2017, in the State Intellectual Property Office of the People's Republic of China (CN), the disclosure of which are incorporated herein by reference in their entireties.
Number | Date | Country | |
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Parent | 15793968 | Oct 2017 | US |
Child | 16199178 | US | |
Parent | 15450049 | Mar 2017 | US |
Child | 15793968 | US | |
Parent | 15450017 | Mar 2017 | US |
Child | 15450049 | US |