Abstract:
A socket attaches to a first component and includes a receptive area to couple a second component to the first component. A low profile voltage regulator is integrated into the socket and proximately disposed adjacent to the receptive area. The low profile voltage regulator converts a first power signal from the first component to a second power signal for the second component. A chassis encloses the socket and the low profile voltage regulator and serves as a base for a heat sink to be attached to the second component.

Description:
FIELD OF THE INVENTION 
     The present invention pertains to the field of integrated circuits. More particularly, the present invention relates to regulating power supplied to an integrated circuit inserted in a socket. 
     BACKGROUND INFORMATION 
     Advances in integrated circuit technology continue to provide faster, more robust, and more densely packed integrated circuits. With each technological advance, power delivery, input/output, and thermal solutions become more problematic. FIG. 1 illustrates part of a computer system having power delivery, input/output, and thermal solutions common in the prior art. 
     In FIG. 1, system board  110  is a printed circuit board to which various other components are attached. Transformer  123  and capacitors  127  of voltage regulator  120  are soldered to system board  110 . Central processing unit (CPU)  130  is coupled to system board  110  through socket  140 . Heat sink  150  is thermally coupled to CPU  130 . 
     Socket  140  provides the input/output solution for CPU  130 . A number of leads  145  connect the various input/output ports (not shown) on CPU  130  to various buses, control lines, and power lines (not shown) on system board  110 . Each lead  145  has associated with it a certain amount of inductance. Inductance is related to the length of the leads and must be below a certain critical inductance level in order for input and output operations to work properly. The critical inductance decreases as the operating frequency of CPU  130  increases. In which case, the maximum allowable length of leads  145  tends to decrease as operating frequency increases. 
     Voltage regulator  120  provides the power delivery solution for CPU  130 . CPUs usually operate at different voltage levels and tolerance levels than are typically provided by most power supplies used in computer systems. For instance, a CPU may operate at 1.2 volts DC with a tolerance of plus or minus 0.01 volts. A power supply may provide 5 volts DC with a tolerance of plus or minus 0.25 volts. Another type of power supply may provide a high frequency AC voltage. In either case, in FIG. 1, voltage regulator  120  receives power from the power supply (not shown), and converts the power to a voltage level and tolerance level required by CPU  130 . 
     CPUs also commonly consume power at a higher rate than most power supplies provide. The amount of power that a CPU consumes depends on clock speed (operating frequency) and transistor density. For each clock period, hundreds of thousand, if not millions, of transistors draw current simultaneously. The current is drawn in bursts corresponding to the clock periods. The change in current with respect to time (i.e. the slew rate) for each clock period is likely to be faster than a typical power supply can handle. In which case, in FIG. 1, voltage regulator  120  not only converts power to appropriate voltage and tolerance levels, but also supplies power at the required slew rate. Capacitors  127  store power from the power supply so that it can be provided at the faster slew rate. The amount of capacitance needed to sustain the slew rate for CPU  130  increases as the slew rate increases and increases as the distance between capacitors  127  and CPU  130  increases. Larger capacitance generally means larger and/or more capacitors are needed. 
     Heat sink  150  provides the thermal solution for CPU  130 . Heat sink  150  is situated in close proximity to CPU  130  so that the heat sink can absorb and dissipate the heat generated by the CPU. If the operating speed and/or transistor density of CPU  130  is increased, CPU  130  will generate more heat. The more heat that CPU  130  generates, the more surface area heat sink  150  needs to dissipate heat (assuming all other factors are equal). 
     Putting the input/output, power, and thermal solutions together causes a variety of design conflicts. Voltage regulator  120  needs to be as close as possible to CPU  130  to provide power at the required slew rate in an efficient manner. Heat sink  150  must also be close to CPU  150  and also requires a certain surface area to absorb and dissipate the CPU&#39;s heat. As shown in the illustrated embodiment, the size of heat sink  150  limits how close voltage regulator  120  can be to the CPU. If socket  140  were taller, voltage regulator  120  could fit under the heat sink and get closer to CPU  130 . But, the height of socket  140  is limited by the critical inductance of leads  145  and the need for heat sink  150  to be in contact with CPU  130 . 
     As technology allows CPU  130  to run faster and include more transistors, the design conflicts among the three solutions get worse. The components of voltage regulator  120  get larger, heat sink  150  gets larger, and socket  140  gets shorter. In fact, as power requirements increase, voltage regulator  120  generates so much heat that it needs its own thermal solution, adding complexity and cost to the design. For instance, a typical thermal solution for voltage regulator  120  may includes an additional fan (not shown) which occupies valuable space on system board  110  and requires additional power. 
     SUMMARY OF THE INVENTION 
     A socket attaches to a first component and includes a receptive area to couple a second component to the first component. A low profile voltage regulator is integrated into the socket and proximately disposed adjacent to the receptive area. The low profile voltage regulator converts a first power signal from the first component to a second power signal for the second component. A chassis encloses the socket and the low profile voltage regulator and serves as a base for a heat sink to be attached to the second component. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Examples of the present invention are illustrated in the accompanying drawings. The accompanying drawings, however, do not limit the scope of the present invention. Like references in the drawings indicate similar elements. 
     FIG. 1 illustrates a prior art socket configuration. 
     FIG. 2 illustrates one embodiment of the present invention. 
     FIG. 3 illustrates another embodiment of the present invention. 
     FIG. 4 illustrates one embodiment of a system in which the present invention can be used. 
     FIG. 5 illustrates another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, those skilled in the art will understand that the present invention may be practiced without these specific details, that the present invention is not limited to the depicted embodiments, and that the present invention may be practiced in a variety of alternate embodiments. In other instances, well known methods, procedures, components, and circuits have not been described in detail. 
     Parts of the description will be presented using terminology commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. Also, parts of the description will be presented in terms of operations performed through the execution of programming instructions. As well understood by those skilled in the art, these operations often take the form of electrical, magnetic, or optical signals capable of being stored, transferred, combined, and otherwise manipulated through, for instance, electrical components. 
     Various operations will be described as multiple discrete steps performed in turn in a manner that is helpful in understanding the present invention. However, the order of description should not be construed as to imply that these operations are necessarily performed in the order they are presented, or even order dependent. Lastly, repeated usage of the phrase “in one embodiment” does not necessarily refer to the same embodiment, although it may. 
     The present invention integrates compact, high power voltage regulator components into the form factor of a socket. Integrating the voltage regulator into a socket allows the regulator to be closer to the target load and more efficiently supply power. In various embodiments, as discussed below, integrating the voltage regulator into the socket also simplifies thermal solutions and input/output solutions. In general, the present invention alters the form factor of prior art sockets, such as socket  140  of FIG.  1 . The form factor retains the requisite low profile to meet the critical inductance requirements for the socketed component (such as CPU  130  of FIG.  1 ), but with additional space to accommodate the voltage regulator and leave room for the thermal solution (such as heat sink  150  of FIG.  1 ). 
     FIG. 2 illustrates one embodiment of the present invention. Central processing unit (CPU)  130  inserts into socket  240  in receptive area  242 . Socket  240  provides the input/output (I/O) solution between CPU  130  and system board  110 . In the illustrated embodiment, socket  240  has a cutaway in its chassis  244  to reveal where voltage regulator  220  is integrated into the socket. Voltage regulator  220  provides the power solution for CPU  130 . Voltage regulator  220  is comprised of compact components that provide power at the relatively large rate required by CPU  130 , and yet the components fit within the limited height of socket  240 . 
     By integrating voltage regulator  220  into socket  240 , voltage regulator  220  can be positioned as close as possible to CPU  130  without actually being integrated into CPU  130 . In comparison to the prior art system of FIG. 1, capacitors  127  are bulk capacitors. The form factor for capacitors  127  are typically on the order of 0.5 inches tall and 0.25 inches in diameter. Socket  140  is typically on the order of 0.2 to 0.25 inches tall. In which case, bulk capacitors  127  cannot get any closer to CPU  130  in FIG. 1 than the perimeter of socket  140  because the capacitors cannot fit within the form factor of the socket. 
     The amount of capacitance needed to power CPU  130  increases the farther away the capacitors are located. In the present invention, as illustrated in FIG. 2, the compact components of regulator  220  can be positioned very close the CPU  130 . In which case, regulator  220  provides power more efficiently and does not need as much capacitance as regulator  120  to provide the same rate of power. Socket  240  also has the same height requirements as socket  140 . In which case, the components of voltage regulator  220  must be able to fit in a form factor having a height on the order of 0.2 to 0.25 inches. 
     FIG. 3 illustrates another embodiment the present invention including a thermal solution and a support structure for the thermal solution. Support plate  360  mounts to the bottom of system board  110  to provide additional structural integrity to support the bulk of heat sink  350  coupled to the top of socket  340 . Chassis  344  of socket  340  serves as a base for heat sink  350 . Heat sink  350 , like heat sink  150  in FIG. 1, makes contact with CPU  130  to absorb and dissipate heat from the CPU. In which case, the height of socket  340  is limited not only by the inductance of leads (not shown) within socket  340 , but also by the requirement that heat sink  350  be close enough to CPU  130  to absorb heat. That is, in the illustrated embodiment, the height of socket  340  is limited by the maximum length of the leads and the height of CPU  130  such that the top of socket  340  is at most flush with the top of CPU  130  to provide heat sink  350  with a direct thermal connection to the CPU. 
     Socket  340  is virtually identical to socket  240  from FIG. 2 with the exception of the cutaway that reveals the integrated voltage regulator. The voltage regulator (not shown) integrated in socket  340  can generate a great deal of heat. As discussed above, prior art voltage regulators often include their own thermal solutions such as an extra fan. In the present invention however, as illustrated in FIG. 3, the voltage regulator fits within socket  340  so it can take advantage of the same thermal solution provided for CPU  130 . That is, heat sink  350  not only absorbs and dissipates heat from CPU  130 , heat sink  350  also absorbs and dissipates heat from the voltage regulator integrated into socket  340 . 
     FIG. 4 illustrates one embodiment of a computer system  400  including a processor package  420  according to the teachings of the present invention. Processor package  420  is similar to the embodiment of the present invention illustrated in FIG. 3, and includes a socket having an integrated voltage regulator, a CPU, and a heat sink (all not shown). Bus  460  couples processor package  420  to chip set  470 , and from there through buses  461 ,  462 , and  463  to memory  410 , I/O ports  430 , and riser cards  450 . 
     Computer system  400  is intended to represent a broad category of electronic devices known in the art, such as personal computers, work stations, set-top boxes, internet appliances, etc. Those skilled in the art will recognize that alternate embodiments may not include all of the illustrated components, may combine one or more of the components, may include additional components known in the art, and may be organized in any number of configurations. 
     Those skilled in the art will also recognize that the present invention is applicable to a wide range of applications and form factors. The present invention could be used for virtually any socketed device that requires high power voltage regulation. For instance, many specialized processors, such as graphics processors, are likely to have similar power and thermal solution requirements that CPUs have. The present invention may also be applicable to sockets for lower power devices, like memory. 
     The sockets in the embodiments of FIGS. 1-3 are land grid array sockets, which use flexible circuit material to make contact between the ports on the CPU and the leads in the socket. Those skilled in the art will recognize that the invention is similarly applicable to other types of sockets, including pin sockets such as those used for edge mounted devices. FIG. 5 illustrates one embodiment of a pin socket  540  to couple CPU  530  to system board  510 . Socket  540  has height limitations much like socket  340  in FIG.  3 . That is, the height of the socket is limited by the inductance of leads (not shown) within the socket, as well as by the size and proximity of heat sinks  550  to CPU  530 . Socket  540  includes an integrated voltage regulator (not shown) like the integrated voltage regulator  220  in FIG.  2 . 
     Any number of approaches can be used to integrate the voltage regulator into the socket. For instance, the compact components can be mounted onto the same sub-straight used to support the socket leads, and the chassis can be an injection mold used to enclose all of the components. 
     Thus, an integrated circuit socket having a built-in voltage regulator is described. Whereas many alterations and modifications of the present invention will be comprehended by a person skilled in the art after having read the foregoing description, it is to be understood that the particular embodiments shown and described by way of illustration are in no way intended to be considered limiting. Therefore, references to details of particular embodiments are not intended to limit the scope of the claims.