Abstract:
A system including a printed circuit board having a plurality of vias, a first integrated circuit mounted on a first surface of the printed circuit board, and a casing mounted on a second surface of the printed circuit board. The first surface of the printed circuit board is opposite to the second surface of the printed circuit board. Each of the plurality of vias has (i) a first end extending to the first surface of the printed circuit board and (ii) a second end extending to the second surface of the printed circuit board. The first integrated circuit is in thermal contact with the first ends of the plurality of vias. The casing is in thermal contact with the second ends of the plurality of vias.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present disclosure is a continuation of U.S. patent application Ser. No. 13/540,171 (now U.S. Pat. No. 8,355,221), filed on Jul. 2, 2012, which is a continuation of U.S. patent application Ser. No. 13/154,339 (now U.S. Pat. No. 8,218,261), filed on Jun. 6, 2011, which is a continuation of U.S. patent application Ser. No. 12/842,452 (now U.S. Pat. No. 7,957,094), filed on Jul. 23, 2010, which is a divisional of U.S. patent application Ser. No. 11/495,295 (now U.S. Pat. No. 7,764,462), filed on Jul. 28, 2006, which claims the benefit of U.S. Provisional Application No. 60/759,164, filed on Jan. 13, 2006. The entire disclosures of the above referenced applications are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to hard disk drives (HDD). 
     BACKGROUND 
     Electronic devices such as computers, laptops, personal video recorders (PVRs), MP3 players, game consoles, set-first boxes, digital cameras, and other electronic devices often need to store a large amount of data. Storage devices such as hard disk drives (HDDs) and digital versatile discs (DVDs) may be used to meet these storage requirements. As the size of these devices decreases, heat dissipation has become more problematic. 
     Referring now to  FIG. 1A , hard disk drive (HDD)  10  includes a hard drive assembly (HDA) printed circuit board assembly (PCBA)  14 . A buffer module  18  stores data that is associated with control of the HDD  10 . The buffer module  18  may employ SDRAM or other types of low latency memory. A processor  22  that is arranged on the HDA PCBA  14  performs processing that is related to the operation of the HDD  10 . A hard disk control module (HDC)  26  communicates with an input/output interface  24  and with a spindle/voice coil motor (VCM) driver module  30  and/or a read/write channel module  34 . 
     During write operation, read/write channel module  34  encodes the data to be written via a read/write device  59 , as described in detail hereinbelow. The read/write channel module  34  processes the signal for reliability and may include, for example, error correction coding (ECC), run length limited coding (RLL), and the like. During read operation, the read/write channel module  34  converts an analog output of the read/write device  59  to a digital signal. The converted signal is then detected and decoded by known techniques to recover the data written on the HDD. 
     As can be appreciated, one or more of the functional blocks of the HDA PCBA  14  may be implemented by a single integrated circuit (IC) or chip. For example, a first integrated circuit  1 C- 1  may include the buffer module  18  and the processor  22 . A second integrated circuit  1 C- 2  may implement the HDC module  26 , the spindle VCM module  30 , the read write channel module  34  and/or the I/O interface  24 . Still other component combinations may be implemented as integrated circuit(s). For example, the processor  22  and the HDC module  26  may be implemented by a single integrated circuit. The spindle/VCM driver module  30  and/or the read/write channel module  34  may also be implemented by the same integrated circuit as the processor  22  and/or the HDC module  26 . 
     A hard drive assembly (HDA) case  50  provides a housing for one or more hard drive platters  52 , which include a magnetic coating that stores magnetic fields. The platters  52  are rotated by a spindle motor  54 . Generally the spindle motor  54  rotates the hard drive platter  52  at a fixed speed during the read/write operations. One or more read/write arms  58  move relative to the platters  52  to read and/or write data to/from the hard drive platters  52 . The spindle/VCM driver module  30  controls the spindle motor  54 , which rotates the platter  52 . The spindle/VCM driver module  30  also generates control signals that position the read/write arm  58 , for example using a voice coil actuator, a stepper motor or any other suitable actuator. 
     The read/write device  59  is located near a distal end of the read/write arm  58 . The read/write device  59  includes a write element such as an inductor that generates a magnetic field. The read/write device  59  also includes a read element (such as a magneto-resistive (MR) element) that senses the magnetic field on the platter  52 . A preamp module  60  amplifies analog read/write signals. When reading data, the preamp module  60  amplifies low level signals from the read element and outputs the amplified signal to the read/write channel device. While writing data, a write current is generated which flows through the write element of the read/write device  59  is switched to produce a magnetic field having a positive or negative polarity. The positive or negative polarity is stored by the hard drive platter  52  and is used to represent data. 
     Referring now to  FIG. 1B , an exemplary DVD system  61 . A DVD PCBA  62  includes a buffer  64  that stores read data, write data and/or volatile control code that is associated the control of the DVD system  61 . The buffer  64  may employ volatile memory such as SDRAM or other types of low latency memory. Nonvolatile memory  66  such as flash memory can also be used for critical data such as data relating to DVD write formats and/or other nonvolatile control code. A processor  68  arranged on the DVD PCBA  62  performs data and/or control processing that is related to the operation of the DVD system  61 . The processor  68  also performs decoding of copy protection and/or compression/decompression as needed. A DVD control module  70  communicates with an input/output interface  72  and with a spindle/feed motor (FM) driver  74  and/or a read/write channel module  76 . The DVD control module  70  coordinates control of the spindle/FM driver  74 , the read/write channel module  76  and the processor  68  and data input/output via the interface  72 . 
     During write operations, the read/write channel module  76  encodes the data to be written by an optical read/write (ORW) or optical read only (OR) device  78  to the DVD platter. The read/write channel module  76  processes the signals for reliability and may apply, for example, ECC, RLL, and the like. During read operations, the read/write channel module  76  converts an analog output of the ORW or OR device  78  to a digital signal. The converted signal is then detected and decoded by known techniques to recover the data that was written on the DVD. 
     A DVD assembly (DVDA)  82  includes a DVD medium  84  that stores data optically. The medium  84  is rotated by a spindle motor that is schematically shown at  86 . The spindle motor  86  rotates the DVD medium  84  at a controlled and/or variable speed during the read/write operations. The ORW or OR device  78  moves relative to the DVD medium  84  to read and/or write data to/from the DVD medium  84 . The ORW or OR device  78  typically includes a laser and an optical sensor. 
     For DVD read/write and DVD read only systems, the laser is directed at tracks on the DVD that contain lands and pits during read operations. The optical sensor senses reflections caused by the lands/pits. In some DVD read/write (RW) applications, a laser may also be used to heat a die layer on the DVD platter during write operations. If the die is heated to one temperature, the die is transparent and represents one binary digital value. If the die is heated to another temperature, the die is opaque and represents the other binary digital value. Other techniques for writing DVDs may be employed. 
     The spindle/FM driver  74  controls the spindle motor  80 , which controllably rotates the DVD medium  84 . The spindle/FM driver  74  also generates control signals that position the feed motor  90 , for example using a voice coil actuator, a stepper motor or any other suitable actuator. The feed motor  90  typically moves the ORW or OR device  78  radially relative to the DVD medium  84 . A laser driver  92  generates a laser drive signal based on an output of the read/write channel module  76 . The DVDA  82  includes a preamp circuit  93  that amplifies analog read signals. When reading data, the preamp circuit  93  amplifies low level signals from the ORW or OR device and outputs the amplified signal to the read/write channel module device  76 . 
     The DVD system  61  may further include a codec module  94  that encodes and/or decodes video such as any of the MPEG formats. A scrambler  97  may be used to perform data scrambling. Audio and/or video digital signal processors and/or modules  96  and  95 , respectively, perform audio and/or video signal processing, respectively. 
     SUMMARY 
     A drive system including: a printed circuit board; a first integrated circuit mounted onto the printed circuit board; a drive assembly case that is connected to the printed circuit board; and a first thermal interface material thermally coupled between i) the printed circuit board and ii) the drive assembly case. Thermal energy generated by the first integrated circuit is dissipatable by the drive assembly case through the first interface material. 
     Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the disclosure, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1A  is a functional block diagram of an exemplary hard disk drive according to the prior art; 
         FIG. 1B  is a functional block diagram of an exemplary digital versatile disc (DVD) according to the prior art; 
         FIG. 2A  illustrates a first drive system that is thermally coupled to a drive assembly case according to the present disclosure; 
         FIG. 2B  illustrates the first drive system with an integrated circuit in direct physical contact with the drive assembly case; 
         FIG. 3  illustrates a second drive system that is thermally coupled to a drive assembly case according to the present disclosure; 
         FIG. 4  illustrates a third drive system that is thermally coupled to a drive assembly case according to the present disclosure; 
         FIG. 5  illustrates a fourth drive system that is thermally coupled to a drive assembly case according to the present disclosure; 
         FIG. 6A  is a functional block diagram of a high definition television; 
         FIG. 6B  is a functional block diagram of a vehicle control system; 
         FIG. 6C  is a functional block diagram of a cellular phone; 
         FIG. 6D  is a functional block diagram of a set top box; and 
         FIG. 6E  is a functional block diagram of a media player. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the term module, circuit and/or device refers to an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical or. It should be understood that steps within a method may be executed in different order without altering the principles of the present disclosure. 
     The present disclosure relates to a low cost thermal solution for dissipating heat when high power integrated circuits (ICs) are used in drive systems. For example, the present invention may be used in hard disk drive (HDD) and digital versatile disc (DVD) systems. The HDD includes a hard disk assembly (HDA) and a HDD printed circuit board assembly (HDD PCBA) with one or more Integrated Circuits (ICs) and/or other electronics components mounted thereon. Some types of HDDs include an external case that is connected to the HDD PCB. While the certain portions of the present disclosure relate to HDD systems, the present disclosure can also be used to dissipate heat within DVD systems. 
     The ICs tend to generate a lot of heat due to high data flow speeds of the HDD or DVD and integration of more functions and features. As the form factor of the HDD or DVD becomes smaller, the PCB also becomes smaller. Dissipating heat generated by the IC or ICs of the PCB becomes more challenging. According to the present disclosure, the drive assembly case can be used as a thermal heatsink by making the surface of one or more ICs directly contact the drive assembly case and/or using a thermal interface material to allow the thermal contact between the IC or ICs and the drive assembly case. 
     Referring now to  FIGS. 2A and 2B , the drive assembly case can be used as a thermal heatsink by making the printed circuit board (PCB) contact the drive assembly case through a thermal interface material. More particularly, in  FIG. 2A  a PCB  100  includes an outer side  101  and an inner side  102 . First and second integrated circuits (ICs)  104  and  108  and/or other components  112  are mounted on the outer and/or inner sides  101  and  102  of the PCB  100 . 
     A drive assembly case  118  is connected to the inner side  102  of the PCB  100 . A second side of the IC  108  includes a thermal interface material  120  that is located between the IC  108  and the drive assembly case  118 . The terminal interface material  120  thermally couples the second side of the IC  108  to the drive assembly case  118 . As a result, heat generated by the IC  108  is dissipated by the relatively large surface area of the drive assembly case  118 . In  FIG. 2B , the IC  108  directly contacts the drive assembly case  118 . 
     Referring now to  FIG. 3 , additional thermal vias can be added at the contact area of PCB to further improve thermal performance. One side  149  of a PCB  150  includes first and second ICs  154  and  158  and/or other components  155 . The PCB  150  includes vias  160  that extend from the one side  149  of the PCB  150  to another side  151  thereof. A thermal interface material  164  thermally couples opposite ends of the vias  160  of the PCB  150  to a drive assembly case  166 . Other components of the HDD or DVD may be connected to either side of the PCB  150  as shown. Direct contact between the vias and the drive assembly case can also be used. 
     Referring now to  FIG. 4 , for HDDs or DVDs with the external cases over the PCB, the external case can be used as a thermal heatsink by making the surface of one or more ICs directly contact the external case and/or through a thermal interface material. A PCB  200  includes first and second ICs  202  and  204  and/or other components  206  mounted thereon. The PCB  200  is mounted to the drive assembly case  210  and covered by an external cover  212 . The IC  204  includes an outer surface  219  that contacts a thermal interface material  220 . The thermal interface material  220 , in turn, contacts the external cover  212 . 
     Referring now to  FIG. 5 , more thermal vias can be added at the contact area of PCB to further improve the thermal performance. The PCB  200  includes vias  230  that extend through and/or provide a thermal path through the PCB  200 . A thermal interface material  240  provides a thermal path between the vias and the drive assembly case  210 . 
     As can be appreciated, while only one IC is shown in contact with the drive assembly case in  FIGS. 2-5 , the solution can be applied to two or more ICs on the PCB. Furthermore, while  FIG. 2B  shows direct physical contact between the drive assembly case and the IC,  FIGS. 3-5  may also be arranged in direct physical contact as well. Furthermore, embodiments may include ICs in direct and/or indirect contact via the thermal interface material. 
     Suitable examples of thermal interface materials include thermal conductive adhesive tape, thermal conductive elastomer, thermal conductive compound and thermal grease although other thermal interface materials can be used. 
     Referring now to  FIG. 6A , the present invention can be implemented in mass data storage and/or a DVD of a high definition television (HDTV)  420 . The HDTV  420  receives HDTV input signals in either a wired or wireless format and generates HDTV output signals for a display  426 . In some implementations, signal processing circuit and/or control circuit  422  and/or other circuits (not shown) of the HDTV  420  may process data, perform coding and/or encryption, perform calculations, format data and/or perform any other type of HDTV processing that may be required. 
     The HDTV  420  may communicate with mass data storage  427  that stores data in a nonvolatile manner such as optical and/or magnetic storage devices. The HDD may be a mini HDD that includes one or more platters having a diameter that is smaller than approximately 1.8″. The HDTV  420  may be connected to memory  428  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. The HDTV  420  also may support connections with a WLAN via a WLAN network interface  429 . 
     Referring now to  FIG. 6B , the present invention may implement and/or be implemented in mass data storage of a vehicle control system and/or a vehicle-based DVD. In some implementations, the present invention implement a powertrain control system  432  that receives inputs from one or more sensors such as temperature sensors, pressure sensors, rotational sensors, airflow sensors and/or any other suitable sensors and/or that generates one or more output control signals such as engine operating parameters, transmission operating parameters, and/or other control signals. 
     The present invention may also be implemented in other control systems  440  of the vehicle  430 . The control system  440  may likewise receive signals from input sensors  442  and/or output control signals to one or more output devices  444 . In some implementations, the control system  440  may be part of an anti-lock braking system (ABS), a navigation system, a telematics system, a vehicle telematics system, a lane departure system, an adaptive cruise control system, a vehicle entertainment system such as a stereo, DVD, compact disc and the like. Still other implementations are contemplated. 
     The powertrain control system  432  may communicate with mass data storage  446  that stores data in a nonvolatile manner. The mass data storage  446  may include optical and/or magnetic storage devices for example hard disk drives HDD and/or DVDs. The HDD may be a mini HDD that includes one or more platters having a diameter that is smaller than approximately 1.8″. The powertrain control system  432  may be connected to memory  447  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. The powertrain control system  432  also may support connections with a WLAN via a WLAN network interface  448 . The control system  440  may also include mass data storage, memory and/or a WLAN interface (all not shown). 
     Referring now to  FIG. 6C , the present invention can be implemented in mass data storage and/or a DVD of a cellular phone  450  that may include a cellular antenna  451 . In some implementations, the cellular phone  450  includes a microphone  456 , an audio output  458  such as a speaker and/or audio output jack, a display  460  and/or an input device  462  such as a keypad, pointing device, voice actuation and/or other input device. The signal processing and/or control circuits  452  and/or other circuits (not shown) in the cellular phone  450  may process data, perform coding and/or encryption, perform calculations, format data and/or perform other cellular phone functions. 
     The cellular phone  450  may communicate with mass data storage  464  that stores data in a nonvolatile manner such as optical and/or magnetic storage devices for example hard disk drives HDD and/or DVDs. The HDD may be a mini HDD that includes one or more platters having a diameter that is smaller than approximately 1.8″. The cellular phone  450  may be connected to memory  466  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. The cellular phone  450  also may support connections with a WLAN via a WLAN network interface  468 . 
     Referring now to  FIG. 6D , the present invention can be implemented in mass data storage and/or a DVD of a set top box  480 . The set top box  480  receives signals from a source such as a broadband source and outputs standard and/or high definition audio/video signals suitable for a display  488  such as a television and/or monitor and/or other video and/or audio output devices. The signal processing and/or control circuits  484  and/or other circuits (not shown) of the set top box  480  may process data, perform coding and/or encryption, perform calculations, format data and/or perform any other set top box function. 
     The set top box  480  may communicate with mass data storage  490  that stores data in a nonvolatile manner. The mass data storage  490  may include optical and/or magnetic storage devices for example hard disk drives HDD and/or DVDs. The HDD may be a mini HDD that includes one or more platters having a diameter that is smaller than approximately 1.8″. The set top box  480  may be connected to memory  494  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. The set top box  480  also may support connections with a WLAN via a WLAN network interface  496 . 
     Referring now to  FIG. 6E , the present invention can be implemented in mass data storage and/or a DVD of a media player  500 . In some implementations, the media player  500  includes a display  507  and/or a user input  508  such as a keypad, touchpad and the like. In some implementations, the media player  500  may employ a graphical user interface (GUI) that typically employs menus, drop down menus, icons and/or a point-and-click interface via the display  507  and/or user input  508 . The media player  500  further includes an audio output  509  such as a speaker and/or audio output jack. The signal processing and/or control circuits  504  and/or other circuits (not shown) of the media player  500  may process data, perform coding and/or encryption, perform calculations, format data and/or perform any other media player function. 
     The media player  500  may communicate with mass data storage  510  that stores data such as compressed audio and/or video content in a nonvolatile manner. In some implementations, the compressed audio files include files that are compliant with MP3 format or other suitable compressed audio and/or video formats. The mass data storage may include optical and/or magnetic storage devices for example hard disk drives HDD and/or DVDs. The HDD may be a mini HDD that includes one or more platters having a diameter that is smaller than approximately 1.8″. The media player  500  may be connected to memory  514  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. The media player  500  also may support connections with a WLAN via a WLAN network interface  516 . Still other implementations in addition to those described above are contemplated. 
     Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims.