Removable Memory Devices

Abstract

To realize a removable memory device capable of facilitating design of a host-side power supply configuration.SOLUTION: If a consumption current class supported by a removable memory device is another consumption current class that differs from a first consumption current class for which a consumption current value is largest among a plurality of varieties of consumption current classes, a first consumption current value that the removable memory device consumes from a first power source is equal to or lower than a third allowable current value related to the first power source defined by the other consumption current class, and a second consumption current value that the removable memory device consumes from a second power source is equal to or lower than a fourth allowable current value related to the second power source defined by the other consumption current class.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] An embodiment of the present invention relates to a removable memory device that operates with multiple types of power sources supplied from a host. [Background technology]

[0002] In recent years, small, high-speed, and large-capacity removable memory devices have been developed.

[0003] As such removable memory devices, there are known removable memory devices that operate on a plurality of types of power supplies having different voltages.

[0004] When standardizing such removable memory devices with multiple power supplies, it is necessary to realize a new technology that can facilitate the design of the host-side power supply configuration required to operate the removable memory device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-173765 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a removable memory device that can facilitate the design of the power supply configuration on the host side. [Means for solving the problem]

[0007] According to an embodiment, a removable memory device is insertable into and removable from a socket in a host, and operates with first and second power supplies supplied from the host. The voltages of the first and second power supplies are different from each other. The removable memory device is configured to support one of a plurality of current consumption classes that define a plurality of current consumptions different from each other. In each of the plurality of current consumption classes, both a current consumption related to the first power supply and a current consumption related to the second power supply are defined. When the one current consumption class supported by the removable memory device is a first current consumption class having the largest current consumption value among the multiple types of current consumption classes, a first current consumption value consumed by the removable memory device from the first power source is less than or equal to a first allowable current value which is the maximum current value allowable to be supplied from the host to the one or more first power source terminals of the removable memory device via the contact resistance value between the terminals of the socket and the terminals of the removable memory device, and a second current consumption value consumed by the removable memory device from the second power source is less than or equal to a second allowable current value which is the maximum current value allowable to be supplied from the host to the one or more second power source terminals of the removable memory device via the contact resistance value. When the one current consumption class supported by the removable memory device is another current consumption class different from the first current consumption class, the first current consumption value is less than or equal to a third allowable current value for the first power supply defined in the other current consumption class, and the second current consumption value is less than or equal to a fourth allowable current value for the second power supply defined in the other current consumption class. The first allowable current value is determined based on the nominal voltage value of the first power supply, a power supply fluctuation rate of the first power supply, the contact resistance value, and a lower limit voltage value of the first power supply required for operation of the removable memory device, and the second allowable current value is determined based on the nominal voltage value of the second power supply, a power supply fluctuation rate of the second power supply, the contact resistance value, and a lower limit voltage value of the second power supply required for operation of the removable memory device. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 2 is a plan view of a first surface side of the removable memory device according to the embodiment. [Figure 1B] FIG. 2 is a side view of a removable memory device according to an embodiment. [Figure 1C] FIG. 2 is a plan view of a second surface side of the removable memory device according to the embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the arrangement of a removable memory device according to the embodiment. [Diagram 3] 1 is a plan view showing an example of the outer shape of a removable memory device according to an embodiment and an arrangement of a plurality of terminals. [Figure 4] 1 is a plan view showing an example of the outer shape of a socket into which a removable memory device according to an embodiment is inserted and an arrangement of a plurality of lead terminals; [Diagram 5] 1 is a side view showing a state in which a removable memory device according to an embodiment is inserted into a socket. [Figure 6] 1 is a diagram showing an example of the arrangement of a plurality of power supply terminals of a removable memory device according to an embodiment that operates with two power supplies; [Figure 7] FIG. 2 is a block diagram showing an example of the power supply configuration of a removable memory device according to an embodiment that operates with two power supplies. [Figure 8] FIG. 13 is a block diagram showing another example of the power supply configuration of a removable memory device according to an embodiment that operates with two power supplies. [Figure 9] 1A and 1B are diagrams showing examples of the arrangement of a plurality of power supply terminals of a removable memory device according to an embodiment that operates with three power supplies. [Figure 10] FIG. 2 is a block diagram showing an example of the power supply configuration of a removable memory device according to an embodiment that operates with three power supplies. [Figure 11] FIG. 13 is a block diagram showing another example of the power supply configuration of a removable memory device according to an embodiment that operates with three power supplies. [Figure 12] 3A to 3C are diagrams showing examples of four types of power supply configurations applicable to the removable memory device according to the embodiment. [Figure 13] FIG. 1 is a diagram showing a plurality of types of current consumption classes. [Figure 14] FIG. 13 is a diagram showing a current consumption calculation formula and an allowable current reduction rate, which are defined for each power supply in each current consumption class. [Figure 15] 5A and 5B are diagrams showing examples of current consumption calculation formulas and allowable current reduction rates, which are defined for each power supply in each current consumption class; [Figure 16] 6 is a diagram showing an allowable current value of a first power supply calculated based on a contact resistance value, a power supply fluctuation rate of the first power supply, and a lower limit voltage of the first power supply. [Figure 17] 13 is a diagram showing an allowable current value of a second power supply calculated based on a contact resistance value, a power supply fluctuation rate of the second power supply, and a lower limit voltage of the second power supply. [Figure 18] 13 is a diagram showing the allowable current ratio to CC1max and the allowable current of each power source for each of four current classes CC1 to CC4. [Figure 19A] FIG. 2 is a diagram showing a current consumption class guide indicating the allowable current value and device performance of each power supply for each category of a plurality of types of current consumption class guides. [Figure 19B] A diagram showing the current class and current class guide (1) for the case of IP1=IP2 and -1% variation. [Figure 19C] A diagram showing the current class and current class guide (2) for the case of IP1=IP2 and -2% fluctuation. [Figure 19D] A diagram showing the current class and current class guide (1') when IP1 ≠ IP2 and -1% fluctuation. [Figure 19E] A diagram showing the current class and current class guide (2') when IP1 ≠ IP2 and -2% fluctuation. [Figure 20] 1A and 1B are diagrams showing a logo and a two-dimensional barcode marked on one surface of a package of a removable memory device according to an embodiment, and a logo and a two-dimensional barcode marked on a housing of a host. [Figure 21] 11 is a flowchart showing the procedure of device initialization processing executed in the host. [Figure 22] 1A and 1B are diagrams illustrating cutouts formed in the package of a removable memory device according to an embodiment for identifying a current consumption class supported by the removable memory device. [Diagram 23] FIG. 1 shows examples of host-side power supply configurations corresponding to four different current consumption classes. [Figure 24] FIG. 1 is a diagram showing the heat dissipation paths of a device. [Diagram 25] FIG. 13 is a diagram showing an example of the configuration of a heat dissipation mechanism on the host side corresponding to a power supply configuration of a large current consumption class; [Figure 26] FIG. 13 is a diagram showing an example of the configuration of a heat dissipation mechanism on the host side corresponding to a power supply configuration of a small current consumption class; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. First, the external shape of a removable memory device 10 according to an embodiment will be described with reference to Figures 1A, 1B, and 1C. Figure 1A is a plan view showing one surface of the removable memory device 10. Figure 1B is a side view showing a side surface of the removable memory device 10. Figure 1C is a plan view showing another surface of the removable memory device 10.

[0010] In this specification, an X-axis, a Y-axis, and a Z-axis are defined. The X-axis, the Y-axis, and the Z-axis are mutually perpendicular. The X-axis is along the width of the removable memory device 10. The Y-axis is along the length (height) of the removable memory device 10. The Z-axis is along the thickness of the removable memory device 10.

[0011] The removable memory device 10 is a memory device that can be inserted into and removed from a socket in a host (host equipment). The removable memory device 10 is configured to operate with multiple types of power supplies supplied from the host. The multiple types of power supplies have different voltages. Each of the multiple types of power supplies supplied from the host to the removable memory device 10, or the power supply wiring for supplying each of the multiple types of power supplies from the host to the removable memory device 10, is called a power rail.

[0012] For example, when the removable memory device 10 is realized as a memory device having a power supply configuration that operates with two types of power supplies supplied from the host, a first power supply having a first voltage is supplied from a first power management IC in the host to the removable memory device 10 via a first power rail, and a second power supply having a second voltage is supplied from a second power management IC in the host to the removable memory device 10 via a second power rail.

[0013] 1A, the removable memory device 10 includes a thin, plate-like package (main body) 11. The main body 11 of the removable memory device 10 is formed, for example, in a substantially rectangular plate shape extending in the Y-axis direction. The Y-axis direction is the longitudinal direction of the main body 11 of the removable memory device 10.

[0014] The main body 11 is plate-shaped and has a first surface 21, a second surface 22, and an outer edge 23. The first surface 21 and the second surface 22 are formed in a substantially quadrangular (rectangular) shape extending in the Y-axis direction. That is, the Y-axis direction is also the longitudinal direction of the first surface 21 and the second surface 22.

[0015] The first surface 21 is a substantially flat surface facing in the positive direction of the Z axis. The second surface 22 is located on the opposite side of the first surface 21, and is a substantially flat surface facing in the negative direction of the Z axis.

[0016] The outer edge 23 is provided between the first surface 21 and the second surface 22, and is connected to an edge of the first surface 21 and an edge of the second surface 22. The outer edge 23 has a first edge 31, a second edge 32, a third edge 33, a fourth edge 34, a first corner 35, a second corner 36, a third corner 37, and a fourth corner 38.

[0017] The first edge 31 extends in the X-axis direction and faces the positive direction of the Y-axis. The X-axis direction is the short-side direction of the main body 11, the first surface 21, and the second surface 22, and includes the positive direction of the X-axis and the negative direction of the X-axis.

[0018] The second edge 32 extends in the Y-axis direction and faces the negative direction of the X-axis. The third edge 33 is located opposite the second edge 32, extends in the Y-axis direction and faces the positive direction of the X-axis. The fourth edge 34 is located opposite the first edge 31, extends in the X-axis direction and faces the negative direction of the Y-axis.

[0019] The second edge 32 and the third edge 33 each have a length greater than the first edge 31 and the fourth edge 34. The first edge 31 and the fourth edge 34 form the short sides of the generally rectangular memory device 10, and the second edge 32 and the third edge 33 form the long sides (sides) of the generally rectangular removable memory device 10.

[0020] The first corner 35 is a corner portion between the first edge 31 and the second edge 32, and connects the end of the first edge 31 in the negative direction of the X-axis and the end of the second edge 32 in the positive direction of the Y-axis.

[0021] The first corner portion 35 extends linearly between an end of the first edge 31 in the negative direction of the X-axis and an end of the second edge 32 in the positive direction of the Y-axis. The corner between the first edge 31 and the second edge 32 is set to a so-called C1.1 corner chamfer (also called C chamfer), thereby providing the first corner portion 35. In other words, the first corner portion 35 is a corner chamfer portion C formed between the first edge 31 and the second edge 32.

[0022] The second corner 36 is a corner portion between the first edge 31 and the third edge 33, and connects the end of the first edge 31 in the positive direction of the X-axis with the end of the third edge 33 in the positive direction of the Y-axis. The second corner 36 extends in an arc shape between the end of the first edge 31 in the positive direction of the X-axis and the end of the third edge 33 in the positive direction of the Y-axis. The second corner 36 is provided by setting the corner between the first edge 31 and the third edge 33 to a so-called round chamfer of R0.2 (also called R chamfer). In this way, the shape of the first corner 35 and the shape of the second corner 36 are different from each other.

[0023] The third corner 37 connects the end of the second edge 32 in the negative direction of the Y axis to the end of the fourth edge 34 in the negative direction of the X axis. The fourth corner 38 connects the end of the third edge 33 in the negative direction of the Y axis to the end of the fourth edge 34 in the positive direction of the X axis. The third corner 37 and the fourth corner 38 each extend in an arc shape, similar to the second corner 36.

[0024] The length of the main body 11, the first surface 21, and the second surface 22 in the Y-axis direction is set to about 18±0.10 mm, and the length in the X-axis direction is set to about 14±0.10 mm. That is, the distance between the first edge 31 and the fourth edge 34 in the Y-axis direction is set to about 18±0.1 mm, and the distance between the second edge 32 and the third edge 33 in the X-axis direction is set to about 14±0.10 mm. Note that the lengths of the main body 11, the first surface 21, and the second surface 22 in the X-axis direction and the Y-axis direction are not limited to this example.

[0025] The thickness of the main body 11 and the outer edge 23 in the Z-axis direction is set to about 1.4 mm ± 0.10 mm. That is, the distance between the first surface 21 and the second surface 22 in the Z-axis direction is set to about 1.4 mm ± 0.10 mm. Note that the length of the outer edge 23 in the Z-axis direction is not limited to this example.

[0026] 1B, the main body 11 further has an inclined portion 39. The inclined portion 39 is an angle portion between the first surface 21 and the first edge 31, and extends linearly between the end of the first surface 21 in the positive direction of the Y axis and the end of the first edge 31 in the positive direction of the Z axis.

[0027] As shown in Fig. 1A, a plurality of terminals are disposed on a first surface 21 of the removable memory device 10. Each of the plurality of terminals is also referred to as an external connection terminal. In Fig. 1A, the plurality of terminals are represented by small rectangles.

[0028] The terminals are arranged in three rows, for example, a first row R1, a second row R2, and a third row R3. The terminal group arranged in the first row R1 is called a first row terminal group. The first row terminal group includes, for example, a plurality of signal terminals for transmitting and receiving differential signals for two lanes defined by the PCI Express (registered trademark) (PCIe) standard. The signal terminals corresponding to one lane include two terminals assigned with a receiving differential signal pair and two terminals assigned with a transmitting differential signal pair. The two terminals assigned with the receiving differential signal pair and the two terminals assigned with the transmitting differential signal pair are adjacent to each other with a ground terminal interposed between them. In other words, any two terminals assigned with a differential signal pair are surrounded by two ground terminals located on both sides of the two terminals.

[0029] The terminal group of the second row R2 is referred to as the second row terminal group. The second row terminal group may include, for example, some signal terminals for option signals, and may also include an additional power terminal to support a three-power supply configuration.

[0030] The terminal group in the third row R3 is referred to as a third row terminal group. The third row terminal group includes several signal terminals to which sideband signals (e.g., a reset signal PERST#, a clock request signal CLKREQ#, and a reference clock pair CLKREF) defined in the PCIe standard are assigned, one or more first power supply terminals to which a first power supply having a first voltage is supplied, one or more second power supply terminals to which a second power supply having a second voltage different from the first voltage is supplied, and several ground terminals.

[0031] FIG. 2 shows an example of the configuration of the removable memory device 10. 2, a body 11 of the removable memory device 10 includes a substrate 12, a NAND flash memory 13, and a controller 14 that controls the NAND flash memory 13. The NAND flash memory 13 and the controller 14 are mounted on the surface of the substrate 12. The NAND flash memory 13 includes a plurality of NAND flash memory dies stacked on the surface of the substrate 12.

[0032] The back surface of substrate 12, which is the opposite side to the front surface of substrate 12, is exposed and functions as first surface 21. On the back surface of substrate 12, a plurality of terminals described with reference to Fig. 1A are arranged.

[0033] The NAND flash memory 13 and the controller 14 are covered and sealed by a molding resin 40 that is molded to form the body (main body 11) of the removable memory device 10.

[0034] FIG. 3 is a plan view showing an example of the outer shape of the removable memory device 10 and an arrangement of a number of terminals. As shown in FIG. 3, the removable memory device 10 has a plurality of terminals P. The terminals P may also be referred to as pads. FIG. 3 illustrates an example in which the removable memory device 10 has 32 terminals P, but the number of terminals P is merely an example and is not limited to this example. That is, the number of terminals P may be less than 32 or more than 32. The plurality of terminals P are disposed on the rear surface of the substrate 12 and exposed on the first surface 21. No terminals P are provided on the second surface 22. The second surface 22 may be used, for example, as a marking area.

[0035] 3, the first row terminal group arranged in the first row R1 includes thirteen terminals P101 to P113 arranged at intervals in the X-axis direction at a position closer to the first edge 31 than the fourth edge 34. The terminals P101 to P113 are arranged in the X-axis direction near the first edge 31 and along the first edge 31.

[0036] The second row terminal group arranged in the second row R2 includes six terminals P114 to P119 arranged at intervals in the X-axis direction at positions closer to the fourth edge 34 than the first edge 31. The terminals P114 to P116 are arranged in the X-axis direction along the fourth edge 34 at positions closer to the second edge 32 than the third edge 33. The terminals P117 to P119 are arranged in the X-axis direction along the fourth edge 34 at positions closer to the third edge 33 than the second edge 32. In other words, the terminals P114 to P116 are arranged between the center line (indicated by a dashed line) of the removable memory device 10 and the main body 11 in the X-axis direction and the second edge 32, and the terminals P117 to P119 are arranged between the center line of the removable memory device 10 and the main body 11 in the X-axis direction and the third edge 33. The distance between terminals P116 and P117 belonging to the second row terminal group is wider than the distance between other terminals belonging to the second row terminal group and adjacent to each other in the X-axis direction (specifically, the distance between terminals P114 and P115, the distance between terminals P115 and P116, the distance between terminals P117 and P118, and the distance between terminals P118 and P119).

[0037] The third row terminal group arranged in the third row R3 includes 13 terminals P120 to P132 arranged at intervals in the X-axis direction at a position closer to the fourth edge 34 than the first edge 31. The terminals P120 to P132 belonging to row R3 are arranged at a position closer to the fourth edge 34 than the terminals P114 to P119 belonging to row R2.

[0038] FIG. 4 is a plan view showing an example of the outer shape of the socket 100 into which the removable memory device 10 is inserted and an arrangement of a number of lead terminals.

[0039] In the socket 100, a plurality of lead terminals 104 are arranged in three rows, rows r1, r2, and r3, so as to correspond to the first row group of terminals, the second row group of terminals, and the third row group of terminals, respectively, of the removable memory device 10. The lead terminals are sometimes called spring leads. The removable memory device 10 is placed on the socket 100 of FIG. 4 with the first surface 21 facing the plurality of lead terminals 104 of the socket 100.

[0040] In the first row r1, 13 lead terminals 104 are arranged. Similarly, in the second row r2, 6 lead terminals 104 are arranged, and in the third row r3, 13 lead terminals 104 are arranged.

[0041] Each lead terminal 104 includes a contact portion 105 that contacts a corresponding terminal of the removable memory device 10. Each lead terminal 104 is bonded to a frame 106 of the socket 100.

[0042] Frame 106 of socket 100 has a first edge 111, a second edge 112, a third edge 113, a fourth edge 114, and a connection portion 115. First edge 111, second edge 112, third edge 113, and fourth edge 114 correspond to the four sides, top, bottom, left and right, of rectangular frame 106. Connection portion 115 connects between the middle portion of second edge 112 and the middle portion of third edge 113.

[0043] The thirteen lead terminals 104 in the first row r1 are bonded to a first edge 111 of the frame 106. The six lead terminals 104 in the second row r2 are bonded to a connection portion 115 of the frame 106. The thirteen lead terminals 104 in the third row r3 are bonded to a fourth edge 114 of the frame 106.

[0044] FIG. 5 is a side view showing the removable memory device 10 inserted into the socket 100. As shown in FIG.

[0045] Although various types of sockets 100 can be used, such as a push-push type, a push-pull type, and a hinge type, a hinge type socket 100 will be described here as an example.

[0046] The cover 120 is attached to the frame 106 so as to rotate about a shaft 121 that functions as a hinge portion. With the cover 120 raised to the open position, the removable storage device 10 is inserted into the cover 120. When the cover 120 is closed, each terminal P arranged on the first surface 21 of the removable storage device 10 comes into contact with a contact portion 105 of a corresponding lead terminal 104 in the socket 100, as shown in Fig. 5. As a result, each terminal P arranged on the first surface 21 of the removable storage device 10 is electrically connected to a wiring on a printed circuit board in the host.

[0047] In this way, the removable storage device 10 is electrically connected to the printed circuit board in the host through the socket 100. Therefore, compared to an embedded type memory device in which each terminal is directly soldered to a printed circuit board in the host, such as a ball grid array (BGA) type memory device, the number of terminals that can be arranged in the removable storage device 10 is smaller. Due to this restriction on the number of terminals, the number of power supply terminals per power supply is also limited. Therefore, in the removable storage device 10, the current value supplied to one power supply terminal tends to be relatively large.

[0048] Furthermore, there is a contact resistance between each terminal P of the removable storage device 10 and each lead terminal 104 (contact portion 105) of the socket 100. Since the terminal P and the lead terminal 104 are not attached by soldering, the contact resistance between the terminal P and the lead terminal 104 is relatively large. The voltage value of the power supplied from the host to each power terminal of the removable storage device 10 is reduced by the amount of the voltage drop caused by this contact resistance. The contact resistance value between the terminal P and the lead terminal 104 is also referred to as the contact resistance value of the device socket.

[0049] In this way, the voltage value supplied to each power supply terminal of the removable storage device 10 is reduced due to the voltage drop caused by the contact resistance, so the margin between the voltage value supplied to each power supply terminal and the lower limit voltage value of each power supply required for operation of the removable storage device 10 tends to be relatively small.

[0050] Next, an example of the power supply configuration of the removable storage device 10 will be described.

[0051] First, a removable memory device 10 having a dual power supply configuration, that is, a removable memory device 10 that operates with two power supplies, will be described.

[0052] Fig. 6 is a diagram showing an example of the arrangement of a plurality of power supply terminals of a removable memory device 10 that operates with two power supplies. Fig. 6 illustrates an example in which the number of power supply terminals to which the first power supply is supplied is three, and the number of power supply terminals to which the second power supply is supplied is three. However, the number of power supply terminals to which the first power supply is supplied and the number of power supply terminals to which the second power supply is supplied are not limited to this example, and the number of power supply terminals to which the first power supply is supplied may be one or more, and the number of power supply terminals to which the second power supply is supplied may also be one or more.

[0053] The first power supply (i.e., power rail PWR_1) has a voltage of, for example, 3.3 V or 2.5 V. In the following, a case where the first power supply (PWR_1) has 2.5 V will be mainly described. 2.5 V is a nominal value of the voltage of the first power supply (PWR_1), and in reality, the first power supply (PWR_1) has a voltage range corresponding to a certain power supply regulation rate.

[0054] The first power supply (PWR_1) is supplied to, for example, three terminals included in the third row terminal group, that is, terminal P128, terminal P130, and terminal P131. The terminals P128, terminal P130, and terminal P131 function as power supply terminals for the first power supply (PWR_1).

[0055] The second power supply (i.e., power rail PWR_2) has, for example, a voltage of 1.2 V. 1.2 V is the nominal value of the voltage of the second power supply (PWR_2), and in reality, the second power supply (PWR_2) has a voltage range that corresponds to a certain power supply regulation rate.

[0056] The second power supply (PWR_2) is supplied to, for example, three terminals included in the third row terminal group, that is, terminals P124, P125, and P127. The terminals P124, P125, and P127 function as power supply terminals for the second power supply (PWR_2).

[0057] FIG. 7 is a block diagram showing an example of the power supply configuration of the removable memory device 10 that operates on two power supplies.

[0058] The NAND type flash memory 13 included in the removable memory device 10 includes a NAND interface circuit 131 and a memory cell array 132 called a NAND cell array.

[0059] The NAND interface circuit 131 performs the following operations: receiving command sequences (read command sequence, write command sequence, erase command sequence, etc.) and data from the controller 14; writing data to the NAND cell array based on the received write command sequence; reading data from the NAND cell array based on the received read command sequence; erasing data in block units based on the received erase command sequence; and transmitting status and read data to the controller 14.

[0060] The memory cell array 132 includes a plurality of blocks. Each of the plurality of blocks includes a plurality of pages. Each of the plurality of blocks is a unit of a data erase operation. Each of the plurality of pages is a unit of a data write operation and a data read operation.

[0061] The first power supply (PWR_1) having 2.5 V is mainly used as a power supply for operating the memory cell array 132. The second power supply (PWR_2) having 1.2 V is mainly used as a power supply for operating the NAND interface circuit 131.

[0062] The controller 14 includes a physical layer (PHY-A) 141 including an analog circuit, a core logic 142, and a NAND interface circuit 143.

[0063] The physical layer (PHY-A) 141 communicates with the host via a PCIe serial bus. More specifically, the physical layer (PHY-A) 141 communicates with the host using multiple lanes (e.g., two lanes) of PCIe signals (two pairs of differential signals per lane), and also transmits and receives some PCIe sideband signals to and from the host.

[0064] The core logic 142 includes various logics for executing the internal operations of the controller 14. The core logic 142 performs, for example, processing for interpreting and executing commands from the host, ECC (Error Correcting Code) encoding / decoding processing, and the like.

[0065] The NAND interface circuit 143 is an interface circuit that executes communication with the NAND flash memory 13. The NAND interface circuit 143 executes an operation of transmitting command sequences (read command sequence, write command sequence, erase command sequence, etc.) and data to the NAND flash memory 13, and an operation of receiving status and read data from the NAND flash memory 13.

[0066] In the power supply configuration (Case-1) of Figure 7, a first power supply (PWR_1) having 2.5 V is further used to generate an internal power supply for operating the physical layer (PHY-A) 141 and an internal power supply for operating the core logic 142.

[0067] Here, a DC / DC converter or a step-down converter such as an LDO (Low drop output) regulator is used. In the following explanation, the term DC / DC converter is used as a general term.

[0068] More specifically, a first power supply (PWR_1) of 2.5V is supplied to both the DC / DC converter 151 and the DC / DC converter 152. The DC / DC converter 151 converts the first power supply (PWR_1) of 2.5V to a predetermined voltage (e.g., 1.8V) lower than 2.5V, and supplies the converted predetermined voltage to the physical layer (PHY-A) 141 as an internal power supply for operating the physical layer (PHY-A) 141. The DC / DC converter 152 converts the first power supply (PWR_1) of 2.5V to another predetermined voltage (e.g., 0.8V) lower than 2.5V, and supplies the converted other predetermined voltage to the core logic 142 as an internal power supply for operating the core logic 142.

[0069] The current consumption value consumed by the first power supply (PWR_1) in the removable memory device 10 is the sum of the current consumption value of the memory cell array 132, the current consumption value of the core logic 142, and the current consumption value of the physical layer (PHY-A) 141. Therefore, the current consumption value consumed by the first power supply (PWR_1) in the removable memory device 10 depends on the configurations of the memory cell array 132, the core logic 142, and the physical layer (PHY-A) 141, and the performance of the removable memory device 10.

[0070] The current consumption value consumed by the second power supply (PWR_2) in the removable memory device 10 is the sum of the current consumption value of the NAND interface circuit 131 in the NAND flash memory 13 and the current consumption value of the NAND interface circuit 143 in the controller 14. Therefore, the current consumption value consumed by the second power supply (PWR_2) in the removable memory device 10 depends on the configuration of each of these NAND interface circuits 131, 143 and the performance of the removable memory device 10.

[0071] FIG. 8 is a block diagram showing another example of the power supply configuration of the removable memory device 10 that operates with two power supplies.

[0072] In the power supply configuration (Case-2) of Fig. 8, the internal power supply for operating the core logic 142 is generated from a second power supply (PWR_2) having 1.2 V, instead of a first power supply (PWR_1) of 2.5 V. Other points are similar to the power supply configuration (Case-1) of Fig. 7.

[0073] A second power supply (PWR_2) having 1.2V is supplied to a DC / DC converter 201. The DC / DC converter 201 converts the second power supply (PWR_2) of 1.2V to a predetermined voltage (e.g., 0.8V) lower than 1.2V, and supplies the converted predetermined voltage to the core logic 142 as an internal power supply for operating the core logic 142.

[0074] The current consumption value consumed by the first power supply (PWR_1) in the removable memory device 10 is the sum of the current consumption value of the memory cell array 132 and the current consumption value of the physical layer (PHY-A) 141. Therefore, the current consumption value consumed by the first power supply (PWR_1) in the removable memory device 10 depends on the configurations of the memory cell array 132 and the physical layer (PHY-A) 141, and the performance of the removable memory device 10.

[0075] The current consumption value consumed by the second power supply (PWR_2) in the removable memory device 10 is the sum of the current consumption value of the NAND interface circuit 131 in the NAND flash memory 13, the current consumption value of the NAND interface circuit 143 in the controller 14, and the current consumption value of the core logic 142. Therefore, the current consumption value consumed by the second power supply (PWR_2) in the removable memory device 10 depends on the configurations of the NAND interface circuits 131, 143, and the core logic 142, and the performance of the removable memory device 10.

[0076] Next, a removable memory device 10 having a triple power supply configuration, that is, a removable memory device 10 that operates with three power supplies, will be described.

[0077] 9 is a diagram showing an example of the arrangement of a plurality of power supply terminals of a removable memory device 10 that operates with three power supplies. In FIG. 9, a case is illustrated in which the number of power supply terminals to which the first power supply is supplied is three, the number of power supply terminals to which the second power supply is supplied is three, and the number of power supply terminals to which the third power supply is supplied is one. However, the number of power supply terminals to which the first power supply is supplied, the number of power supply terminals to which the second power supply is supplied, and the number of power supply terminals to which the third power supply is supplied are not limited to this example, and the number of power supply terminals to which the first power supply is supplied may be one or more, the number of power supply terminals to which the second power supply is supplied may be one or more, and the number of power supply terminals to which the third power supply is supplied may be one or more.

[0078] A first power supply (PWR_1) having 2.5V is supplied to three terminals included in the third row terminal group, namely, terminal P128, terminal P130, and terminal P131, as in the two power supply configuration. A second power supply (i.e., power rail PWR_2) having 1.2V is also supplied to three terminals included in the third row terminal group, namely, terminal P124, terminal P125, and terminal P127, as in the two power supply configuration.

[0079] The third power supply (i.e., power rail PWR_3) has a voltage of, for example, 1.8 V. 1.8 V is the nominal value of the voltage of the third power supply (PWR_3), and in practice, the third power supply (PWR_3) has a voltage range that corresponds to a certain power supply regulation rate.

[0080] A third power supply (PWR_3) having 1.8V is supplied to, for example, one terminal included in the second row terminal group, that is, terminal P117.

[0081] FIG. 10 is a block diagram showing an example of the power supply configuration of the removable memory device 10 that operates on three power supplies.

[0082] The power supply configuration (Case-3) of Figure 10 differs from the power supply configuration (Case-1) of Figure 7 only in that a third power supply (PWR_3) of 1.8 V is used as an internal power supply for operating the physical layer (PHY-A) 141.

[0083] The current consumption value consumed by the first power supply (PWR_1) in the removable memory device 10 is the sum of the current consumption value of the memory cell array 132 and the current consumption value of the core logic 142. Therefore, the current consumption value consumed by the first power supply (PWR_1) in the removable memory device 10 depends on the configurations of the memory cell array 132 and the physical layer (PHY-A) 141, and the performance of the removable memory device 10.

[0084] The current consumption value consumed by the second power supply (PWR_2) in the removable memory device 10 is the sum of the current consumption value of the NAND interface circuit 131 in the NAND flash memory 13 and the current consumption value of the NAND interface circuit 143 in the controller 14. Therefore, the current consumption value consumed by the second power supply (PWR_2) in the removable memory device 10 depends on the configuration of each of these NAND interface circuits 131, 143 and the performance of the removable memory device 10.

[0085] The current consumption value consumed by the third power supply (PWR_3) in the removable memory device 10 is the current consumption value of the physical layer (PHY-A) 141. The current consumption value consumed by the third power supply (PWR_3) in the removable memory device 10 depends on the configuration of the physical layer (PHY-A) 141 and the performance of the removable memory device 10.

[0086] FIG. 11 is a block diagram showing another example of the power supply configuration of the removable memory device 10 that operates on three power supplies.

[0087] The power supply configuration (Case-4) of Figure 11 differs from the power supply configuration (Case-2) of Figure 8 only in that a third power supply (PWR_3) of 1.8 V is used as an internal power supply for operating the physical layer (PHY-A) 141.

[0088] The current consumption value consumed by the first power supply (PWR_1) in the removable memory device 10 is the current consumption value of the memory cell array 132. Therefore, the current consumption value consumed by the first power supply (PWR_1) in the removable memory device 10 depends on the configuration of the memory cell array 132 and the performance of the removable memory device 10.

[0089] The current consumption value consumed by the second power supply (PWR_2) in the removable memory device 10 is the sum of the current consumption value of the NAND interface circuit 131 in the NAND flash memory 13, the current consumption value of the NAND interface circuit 143 in the controller 14, and the current consumption value of the core logic 142. Therefore, the current consumption value consumed by the second power supply (PWR_2) in the removable memory device 10 depends on the configurations of the NAND interface circuits 131, 143, and the core logic 142, and the performance of the removable memory device 10.

[0090] The current consumption value consumed by the third power supply (PWR_3) in the removable memory device 10 is the current consumption value of the physical layer (PHY-A) 141. The current consumption value consumed by the third power supply (PWR_3) in the removable memory device 10 depends on the configuration of the physical layer (PHY-A) 141 and the performance of the removable memory device 10.

[0091] FIG. 12 is a diagram showing four types of power supply configuration examples applicable to the removable memory device 10. In FIG.

[0092] In Case 1, a first power supply (PWR_1) having 3.3 V or 2.5 V is used as a power supply for operating the memory cell array (NAND Cell) 132, the physical layer (PHY-A) 141, and the core logic 142. A second power supply (PWR_2) having 1.2 V is used as a power supply for operating the NAND interface circuits 131 and 143.

[0093] In Case 2, a first power supply (PWR_1) having 3.3 V or 2.5 V is used as a power supply for operating the memory cell array (NAND Cell) 132 and the physical layer (PHY-A) 141. A second power supply (PWR_2) having 1.2 V is used as a power supply for operating the core logic 142 and the NAND interface circuits 131 and 143.

[0094] In Case 3, a first power supply (PWR_1) having 3.3V or 2.5V is used as a power supply for operating the memory cell array (NAND Cell) 132 and the core logic 142. A second power supply (PWR_2) having 1.2V is used as a power supply for operating the NAND interface circuits 131 and 143. A third power supply (PWR_3) having 1.8V is used as a power supply for operating the physical layer (PHY-A) 141.

[0095] In Case 4, a first power supply (PWR_1) having 3.3V or 2.5V is used as a power supply for operating the memory cell array (NAND Cell) 132. A second power supply (PWR_2) having 1.2V is used as a power supply for operating the core logic 142 and the NAND interface circuits 131 and 143. A third power supply (PWR_3) having 1.8V is used as a power supply for operating the physical layer (PHY-A) 141.

[0096] Next, a description will be given of the current consumption class applied to the removable memory device 10 having a multiple power supply configuration according to this embodiment.

[0097] If the mechanical and electrical specifications of the removable memory device 10 with multiple power sources are standardized, multiple vendors (multiple device manufacturers) will manufacture multiple types of device products that meet the same mechanical and electrical specifications as the removable memory device 10 with multiple power sources. For this reason, a current consumption regulation is required to ensure the interconnectivity and interchangeability between these multiple types of device products and the host.

[0098] In this case, the current consumption of each power supply may differ depending on the implementation of the device product. Therefore, if only one current consumption regulation is defined, only the maximum current consumption of each power supply is regulated, which is not an optimal guideline for the development, design, and manufacture of the device product and the host. In addition, even if only the total power consumption of the device product is regulated, the current consumption of the device product from each power supply is unknown, so it is necessary to provide a power supply circuit with excessive capacity on the host side, which causes unnecessary cost increase.

[0099] Therefore, in this embodiment, a plurality of types of current consumption classes having different current consumption values ​​are defined, and each of the plurality of current consumption classes specifies the current consumption for each power supply.

[0100] For example, for a removable memory device 10 that operates with dual power supplies, each of the multiple types of current consumption classes defines both the current consumption related to the first power supply (PWR_1) and the current consumption related to the second power supply (PWR_2). The removable memory device 10 that operates with dual power supplies is configured to support one of the multiple types of current consumption classes.

[0101] For example, it is assumed that one current consumption class supported by the removable memory device 10 is a first current consumption class that has the largest current consumption value among a plurality of types of current consumption classes.

[0102] In this case, the first consumption current value consumed by the removable memory device 10 from the first power supply (PWR_1) is equal to or less than a first allowable current value, which is the maximum current value allowed to be supplied from the host to the first power supply terminals (P128, P130, P131) of the removable memory device 10 through the contact resistance between the terminals of the socket 100 and the terminals of the removable memory device 10. In other words, the first allowable current value is the maximum current specified so that the voltage value of each first power supply terminal does not fall below the lower limit voltage value of the first power supply (PWR_1) required for the operation of the removable memory device 10 due to a voltage drop caused by the contact resistance value. Moreover, the second consumption current value consumed by the removable memory device 10 from the second power supply (PWR_2) is equal to or less than a second allowable current value, which is the maximum current value allowed to be supplied from the host to the second power supply terminals (P124, P125, P127) of the removable memory device 10 via the contact resistance between the terminals of the socket 100 and the terminals of the removable memory device 10. In other words, the second allowable current value is the maximum current specified so that the voltage value of each second power supply terminal does not fall below the lower limit voltage value of the second power supply (PWR_2) required for the operation of the removable memory device 10 due to a voltage drop caused by the contact resistance value.

[0103] Assume that one current consumption class supported by the removable memory device 10 is another current consumption class that consumes less current than the first current consumption class.

[0104] In this case, the first current consumption value consumed by the removable memory device 10 from the first power source (PWR_1) is less than or equal to the third allowable current value for the first power source (PWR_1) defined in this other current consumption class, and the second current consumption value consumed by the removable memory device 10 from the second power source (PWR_2) is less than or equal to the fourth allowable current value for the second power source (PWR_2) defined in this other current consumption class.

[0105] This makes it possible to determine the current consumption value (maximum current consumption value) required for the operation of the removable memory device 10 for each power source depending on which of the multiple current consumption classes the removable memory device 10 supports.

[0106] Therefore, when the current consumption class of the removable memory device 10 to be used in the host is the first current consumption class, the host manufacturer can adopt a power supply configuration in which a power supply circuit capable of supplying the first and second allowable current consumption values ​​corresponding to the first current consumption class is installed in the host. This allows any device product that supports the first current consumption class to be used normally in a host that supports the first current consumption class.

[0107] Furthermore, if the current consumption class of the removable memory device 10 to be used in the host is another current consumption class that consumes less current than the first current consumption class, the host manufacturer can optimize the capacity of the host-side power supply circuit for each power supply based on the allowable current consumption value corresponding to this other current consumption class, thereby reducing the cost of the host-side power supply circuit.

[0108] FIG. 13 is a diagram showing a plurality of types of current consumption classes.

[0109] In this embodiment, three or four types of current consumption classes are defined. The current consumption classes are also referred to as "current classes."

[0110] In the removable memory device 10 with a dual power supply configuration, a maximum current consumption value for the first power supply (PWR_1) and a maximum current consumption value for the second power supply (PWR_2) are specified for each current class. The maximum current consumption value is specified using an allowable current value, which is the maximum current permitted to be supplied from the host to the removable memory device 10 via a contact resistance value. In other words, an allowable current value is specified for each power supply in each current class.

[0111] In a removable memory device 10 having a three-power supply configuration, an allowable current value for the first power supply (PWR_1), an allowable current value for the second power supply (PWR_2), and an allowable current value for the third power supply (PWR_3) are specified for each current class.

[0112] For the first current class CC1, the allowable current value for the first power source (PWR_1) is represented as IP1C1, the allowable current value for the second power source (PWR_2) is represented as IP2C1, and the allowable current value for the third power source (PWR_3) is represented as IP3C1.

[0113] For the second current class CC2, the allowable current value for the first power source (PWR_1) is expressed as IP1C2, the allowable current value for the second power source (PWR_2) is expressed as IP2C2, and the allowable current value for the third power source (PWR_3) is expressed as IP3C2.

[0114] For the third current class CC3, the allowable current value for the first power source (PWR_1) is represented as IP1C3, the allowable current value for the second power source (PWR_2) is represented as IP2C3, and the allowable current value for the third power source (PWR_3) is represented as IP3C3.

[0115] For the fourth current class CC4, the allowable current value for the first power supply (PWR_1) is expressed as IP1C4, the allowable current value for the second power supply (PWR_2) is expressed as IP2C4, and the allowable current value for the third power supply (PWR_3) is expressed as IP3C4.

[0116] Among the current classes CC1 to CC4, the current class with the largest current consumption value (allowable current value) is the first current class CC1. The current class with the second largest current consumption value (allowable current value) is the second current class CC2. The current class with the third largest current consumption value (allowable current value) is the third current class CC3. The current class with the smallest current consumption value (allowable current value) is the fourth current class CC4.

[0117] The allowable current value of each power supply (PWR allowable current value) is calculated taking into consideration the power supply fluctuation rate (lower limit fluctuation rate) of each power supply and the contact resistance value between the terminal of the removable memory device 10 and the lead terminal of the socket 100. Therefore, the current class can be expressed by the following current class symbols that include not only classes (1 to 4) but also parameters indicating the power supply fluctuation rate of the power supplies and parameters indicating the contact resistance values.

[0118] Current class symbol: CC#$% Here, # indicates the class. # indicates any one of 1 to 4. $ indicates the contact resistance value. The contact resistance value is generally specified for each socket product.

[0119] For example, $ indicates one of 3 (=30mΩ), 4 (=40mΩ), 5 (=50mΩ), 6 (=60mΩ), 7 (=70mΩ), or 8 (=80mΩ).

[0120] The percentage indicates the power supply fluctuation rate (lower limit fluctuation rate) of the power supply. The power supply fluctuation rate (lower limit fluctuation rate) is determined by the performance of the power supply circuit (power management IC: PMIC) installed in the host. For example, the percentage indicates one of 1 (-1% fluctuation) or 2 (-2% fluctuation).

[0121] For the first current class CC1, the allowable current value IP1C1 for the first power supply (PWR_1) is expressed by the following formula. IP1C1 = PWR_1 allowable current value × N The PWR_1 allowable current value indicates the allowable current value of the first power supply (PWR_1) per terminal. The PWR_1 allowable current value is the maximum current specified so that the voltage value of the first power supply terminal does not fall below the lower limit voltage value of the first power supply (PWR_1) required for the operation of the removable memory device 10 due to a voltage drop caused by the contact resistance value of the device socket. N indicates the number of first power supply terminals to which the first power supply (PWR_1) is supplied. Six PWR_1 allowable current values ​​corresponding to six types of contact resistance values ​​are obtained for each of the cases of -1% fluctuation and -2% fluctuation.

[0122] For the first current class CC1, the allowable current value IP2C1 for the second power supply (PWR_2) is expressed by the following formula. IP2C1 = PWR_2 allowable current value × M The PWR_2 allowable current value indicates the allowable current value of the second power supply (PWR_2) per terminal. The PWR_2 allowable current value is the maximum current specified so that the voltage value of the second power supply terminal does not fall below the lower limit voltage value of the second power supply (PWR_2) required for the operation of the removable memory device 10 due to a voltage drop caused by the contact resistance value of the device socket. M indicates the number of second power supply terminals to which the second power supply (PWR_2) is supplied. Six PWR_2 allowable current values ​​corresponding to six types of contact resistance values ​​are obtained for each of the cases of -1% fluctuation and -2% fluctuation.

[0123] For the first current class CC1, the allowable current value IP3C1 for the third power supply (PWR_3) is expressed by the following formula. IP3C1 = PWR_3 allowable current value × L The PWR_3 allowable current value indicates the allowable current value of the third power supply (PWR_3) per terminal. The PWR_3 allowable current value is the maximum current specified so that the voltage value of the third power supply terminal does not fall below the lower limit voltage value of the third power supply (PWR_3) required for the operation of the removable memory device 10 due to a voltage drop caused by the contact resistance value of the device socket. L indicates the number of third power supply terminals to which the third power supply (PWR_3) is supplied. Six PWR_3 allowable current values ​​corresponding to six types of contact resistance values ​​are obtained for each of the cases of -1% fluctuation and -2% fluctuation.

[0124] In this embodiment, six allowable current values ​​IP1 (six IP1C1) corresponding to six contact resistance values ​​and six allowable current values ​​IP2 (six IP2C1) corresponding to six contact resistance values ​​are defined for each of the cases of -1% and -2% fluctuation for current class CC1. Similarly, six allowable current values ​​IP1 corresponding to six contact resistance values ​​and six allowable current values ​​IP2 corresponding to six contact resistance values ​​are defined for each of the cases of -1% and -2% fluctuation for current class CC2 to CC4.

[0125] For the current class CC1, six types of allowable current values ​​IP1 corresponding to six types of contact resistance values ​​are calculated based on the nominal voltage value (2.5V) of the first power supply (PWR_1), the power supply fluctuation rate of the first power supply (PWR_1), the lower limit voltage value (e.g., 2.4V) of the first power supply (PWR_1) required for the operation of the removable memory device 10, and six types of contact resistance values. The six types of allowable current values ​​IP1 are calculated for each of the cases of -1% fluctuation and -2% fluctuation. Details of calculation examples of the six types of allowable current values ​​IP1 for each of the cases of -1% fluctuation and -2% fluctuation will be described later with reference to FIG. 16.

[0126] Similarly, for the current class CC1, six types of allowable current values ​​IP2 corresponding to six types of contact resistance values ​​are calculated based on the nominal voltage value (1.2 V) of the second power supply (PWR_2), the power supply fluctuation rate of the second power supply (PWR_2), the lower limit voltage value (e.g., 1.14 V) of the second power supply (PWR_2) required for the operation of the removable memory device 10, and six types of contact resistance values. The six types of allowable current values ​​IP2 are calculated for each of the cases of -1% fluctuation and -2% fluctuation.

[0127] For current class CC2, the allowable current value IP1 corresponding to any one of the six types of contact resistance values ​​is defined as the minimum value of the following (1) and (2). (1) IP1 corresponding to the contact resistance value specified in CC1 (2) The maximum IP1 among the six IP1 types specified in CC1 multiplied by the ratio (%) assigned to CC2 Here, IP1 corresponding to the contact resistance value specified by CC1 is a value obtained by multiplying the PWR_1 allowable current value corresponding to the contact resistance value by the number (N) of the first power terminals. Also, maximum IP1 is a value obtained by multiplying the maximum value (IP1C1max) of the six types of PWR_1 allowable current values ​​specified by CC1 by the number (N) of the first power terminals.

[0128] This ratio is also referred to as the allowable current consumption reduction rate or CC current ratio.

[0129] For current class CC2, the allowable current value IP2 corresponding to any one of the six types of contact resistance values ​​is specified as the minimum value of the following (3) and (4). (3) IP1 corresponding to the contact resistance value specified in CC1 (4) The maximum IP2 among the six types of IP2 specified in CC1 multiplied by the above-mentioned percentage assigned to CC2. For current class CC3, the allowable current value IP1 corresponding to any one of the six types of contact resistance values ​​is defined as the minimum value of the following (1) and (2). (1) IP1 corresponding to the contact resistance value specified in CC1 (2) The maximum IP1 among the six IP1 types specified in CC1 multiplied by the ratio (%) assigned to CC3 The percentage assigned to CC3 is set to a smaller value than the percentage assigned to CC2.

[0130] For current class CC3, the permissible current value IP2 corresponding to any one of the six types of contact resistance values ​​is specified as the minimum value of the following (3) and (4). (3) IP2 corresponding to the contact resistance value specified in CC1 (4) The maximum IP2 among the six IP2s specified in CC1 multiplied by the above-mentioned percentage assigned to CC3. For current class CC4, the allowable current value IP1 corresponding to any one of the six types of contact resistance values ​​is defined as the minimum value of the following (1) and (2). (1) IP1 corresponding to the contact resistance value specified in CC1 (2) The maximum IP1 among the six IP1 types specified in CC1 multiplied by the ratio (%) assigned to CC4 The percentage assigned to CC4 is set to a smaller value than the percentage assigned to CC3.

[0131] For current class CC4, the allowable current value IP2 corresponding to any one of the six types of contact resistance values ​​is specified as the minimum value of the following (3) and (4). (3) IP2 corresponding to the contact resistance value specified in CC1 (4) The maximum IP2 among the six IP2s specified in CC1 multiplied by the above-mentioned percentage assigned to CC4. FIG. 14 is a diagram showing current consumption (allowable current) calculation formulas and allowable current reduction rates corresponding to current classes CC2 to CC4.

[0132] The allowable current value IP1 of the first power supply (PWR_1) is calculated by the following formula. IP1=MIN[IP1C1,IP1C1max×N×ratio] In other words, when IP1C1 is equal to or smaller than IP1C1max×N×ratio, IP1=IP1C1, and when IP1C1 is greater than IP1C1max×N×ratio, IP1=IP1C1max×N×ratio.

[0133] Here, IP1C1max indicates the maximum value among the six types of PWR_1 allowable current values ​​defined in CC1. The PWR_1 allowable current value when the contact resistance value is 30 mΩ is used as IP1C1max. N indicates the number of first power terminals. Therefore, IP1C1max × N indicates the maximum IP1 among the six types of IP1 (IP1C1) defined in CC1.

[0134] The allowable current value IP2 of the second power supply (PWR_2) is calculated using the following formula. IP2=MIN[IP2C1,IP2C1max×M×ratio] Here, IP2C1max indicates the maximum value among the six types of PWR_2 allowable current values ​​specified in CC1. The PWR_2 allowable current value when the contact resistance value is 30mΩ is used as IP2C1max. M indicates the number of second power terminals. Therefore, IP2C1max × M indicates the maximum IP2 among the six types of IP2 (IP2C1) specified in CC1.

[0135] The allowable current value IP3 of the third power supply (PWR_3) is calculated using the following formula. IP3=MIN[IP3C1,IP3C1max×L×ratio] Here, IP3C1max indicates the maximum value among the six types of PWR_3 allowable current values ​​specified in CC1. The PWR_3 allowable current value when the contact resistance value is 30mΩ is used as IP3C1max. L indicates the number of third power terminals. Therefore, IP3C1max × L indicates the maximum IP3 among the six types of IP3 (IP3C1) specified in CC1.

[0136] 14 indicates a predetermined ratio (allowable current reduction rate). In this embodiment, the "ratio" allocated to CC2 is, for example, 72%. The "ratio" allocated to CC3 is, for example, 56%. The "ratio" allocated to CC4 is, for example, 47%.

[0137] In each of the current classes CC2 to CC4, it is possible to use case 1 where IP1=IP2 and case 2 where IP1≠IP2.

[0138] In Case 1, six types of IP1 corresponding to six types of contact resistance values ​​are substituted with six types of IP2 corresponding to six types of contact resistance values. Therefore, if the IP2 corresponding to a certain contact resistance value is smaller than the IP1 corresponding to this contact resistance value, the IP2 value corresponding to this contact resistance value is used as the IP1 value corresponding to this contact resistance value.

[0139] In Case 2, six types of IP1 corresponding to six types of contact resistance values ​​and six types of IP2 corresponding to six types of contact resistance values ​​are calculated individually, and no process is performed to assign IP2 corresponding to the corresponding contact resistance value to IP1 corresponding to each contact resistance value.

[0140] Next, a calculation example of the PWR allowable current value will be described. Fig. 15 is a diagram showing an example of a calculation formula for current consumption and an example of an allowable current reduction rate, which are defined for each power source in each current class.

[0141] Here, it is assumed that the maximum PWR current value per terminal is 1.2 A. The maximum PWR current value per terminal indicates the maximum current value that can be supplied to one power terminal of the removable memory device 10 without considering the contact resistance value and the power supply fluctuation rate of each power supply. In other words, the maximum PWR current value per terminal is the maximum current value that can be flowed from the host to one lead terminal of the socket 100.

[0142] Also, here, it is assumed that the number of first power supply terminals supplied with the first power supply (PWR_1) is three, the number of second power supply terminals supplied with the second power supply (PWR_2) is three, and the number of third power supply terminals supplied with the third power supply (PWR_3) is one.

[0143] The allowable current value IP1C1 of the first power supply (PWR_1) of current class CC1 is: IP1C1 = PWR_1 allowable current value x 3 It can be calculated as follows.

[0144] As described above, the PWR_1 allowable current value is the maximum current defined so that the voltage value of the first power supply terminal does not fall below the lower limit voltage value of the first power supply (PWR_1) required for operation of the removable memory device 10 due to voltage drop caused by contact resistance.

[0145] The allowable current value IP2C1 of the second power supply (PWR_2) of current class CC1 is: IP2C1 = PWR_2 allowable current value x 3 It can be calculated as follows.

[0146] As described above, the PWR_2 allowable current value is the maximum current defined so that the voltage value of the second power supply terminal does not fall below the lower limit voltage value of the second power supply (PWR_1) required for operation of the removable memory device 10 due to voltage drop caused by contact resistance.

[0147] The allowable current IP3C1 of the third power supply (PWR_3) of current class CC1 is: IP3C1 = PWR_3 allowable current value x 3 It can be calculated as follows.

[0148] As described above, the PWR_3 allowable current value is the maximum current defined so that the voltage value of the third power supply terminal does not fall below the lower limit voltage value of the third power supply (PWR_3) required for operation of the removable memory device 10 due to voltage drop caused by contact resistance.

[0149] In addition, the allowable current value of PWR_1, the allowable current value of PWR_2, and the allowable current value of PWR_3 are as follows: PWR allowable current value ≦ PWR maximum current value (e.g. 1.2A) There is a constraint. In other words, when the contact resistance is small, the voltage drop due to the contact resistance is small, so the PWR allowable current value that can guarantee that the voltage value of the power terminal does not fall below the lower limit voltage value increases. However, the maximum value of this PWR allowable current value is limited to the maximum PWR current value (e.g. 1.2A). The maximum value of the six types of PWR_1 allowable current values ​​corresponding to the six types of contact resistance values ​​specified in CC1 corresponds to the PWR_1 allowable current value when the contact resistance value is 30mΩ. This maximum value of the six types of PWR_1 allowable current values ​​corresponding to the six types of contact resistance values ​​specified in CC1 is limited to 1.2A. In other words, the maximum IP1 of the six types of IP1 corresponding to the six types of contact resistance values ​​specified in CC1 is limited to 3.6A (=3 x 1.2A). Similarly, the maximum value of the six types of PWR_2 allowable current values ​​corresponding to the six types of contact resistance values ​​specified in CC1 corresponds to the PWR_2 allowable current value when the contact resistance value is 30mΩ. The maximum value of the six types of PWR_2 allowable current values ​​corresponding to the six types of contact resistance values ​​specified by CC1 is limited to 1.2 A. In other words, the maximum IP2 of the six types of IP2 specified by CC1 is limited to 3.6 A (= 3 x 1.2 A).

[0150] Next, the allowable current value of each power supply in current class CC2 will be described. In current class CC2, for example, 72% is used as the allowable current reduction rate.

[0151] The allowable current value IP1C2 of the first power supply (PWR_1) of current class CC2 is: IP1C2=MIN[IP1C1,IP1C1max×3×72%] It can be calculated as follows.

[0152] IP1C1max is the maximum value of the six PWR_1 allowable current values ​​corresponding to the six contact resistance values ​​specified by CC1. IP1C1max indicates the PWR_1 allowable current value when the contact resistance value is 30mΩ, that is, the PWR_1 allowable current value when "CC13%".

[0153] The allowable current value IP2C2 of the second power supply (PWR_2) of current class CC2 is: IP2C2=MIN[IP2C1,IP2C1max×3×72%] It can be calculated as follows.

[0154] IP2C1max is the maximum value of the six PWR_2 allowable current values ​​corresponding to the six contact resistance values ​​specified by CC1. IP2C1max corresponds to the PWR_2 allowable current value when the contact resistance value is 30mΩ. In the case where the PWR_1 allowable current value when the contact resistance value is 30mΩ is 1.2A and the PWR_2 allowable current value when the contact resistance value is 30mΩ is 1.2A, IP2C1max is equal to the PWR_1 allowable current value when "CC13%".

[0155] The allowable current IP3C2 of the third power supply (PWR_3) of current class CC2 is: IP3C2=MIN[IP3C1,IP3C1max×1×72%] It can be calculated as follows.

[0156] IP3C1max is the maximum value of the six PWR_3 allowable current values ​​corresponding to the six contact resistance values ​​specified by CC1. IP3C1max corresponds to the PWR_3 allowable current value when the contact resistance value is 30mΩ. In the case where the PWR_1 allowable current value when the contact resistance value is 30mΩ is 1.2A and the PWR_3 allowable current value when the contact resistance value is 30mΩ is 1.2A, IP3C1max is equal to the PWR_1 allowable current value when "CC13%".

[0157] In the same manner as for current class CC2, IP1C3, IP2C3, and IP3C3 for current class CC3 and IP1C4, IP2C4, and IP3C4 for current class CC4 are calculated. In calculating the allowable current value of each power supply for current class CC3, for example, 56% is used as the allowable current reduction rate. In calculating the allowable current value of each power supply for current class CC4, for example, 47% is used as the allowable current reduction rate.

[0158] FIG. 16 is a diagram showing an example of the PWR_1 allowable current value of the current class CC1.

[0159] 16, it is assumed that Vps=2.50 V and Vd_min=2.40 V. Vps is the nominal voltage value (nominal) of the first power supply (PWR_1). Vd_min indicates the lower limit voltage value of the first power supply (PWR_1) required for the operation of the removable memory device 10.

[0160] For example, in the case where the contact resistance value is 60 mΩ and the fluctuation rate of the first power supply (PWR_1) is −2%, the PWR_1 allowable current value is calculated by the following formula. PWR_1 allowable current=(2.5V-0.05V(2%drop)-2.4V(Vd_min)) / 60mΩ=0.83A The allowable current value IP1C1 for the first power supply (PWR_1) is calculated by the following formula. IP1C1=0.83×3=2.5A Similarly, in the case where the contact resistance value is 60 mΩ and the fluctuation rate of the first power supply (PWR_1) is −1%, the PWR_1 allowable current value is calculated by the following formula. PWR_1 allowable current=(2.5V-0.025V(1%drop)-2.4V(Vd_min)) / 60mΩ=1.25A In this case, due to the constraint that the PWR_1 allowable current is a maximum of 1.20 A, the PWR_1 allowable current is specified as 1.20 A. Therefore, the allowable current value IP1C1 for the first power supply (PWR_1) is 3.6 A.

[0161] FIG. 17 is a diagram showing an example of the PWR_2 allowable current value of the current class CC1.

[0162] 17, it is assumed that Vps=1.20 V and Vd_min=1.14 V. Vps is the nominal voltage value (nominal) of the second power supply (PWR_2). Vd_min indicates the lower limit voltage value of the second power supply (PWR_2) required for the operation of the removable memory device 10.

[0163] For example, in the case where the contact resistance value is 60 mΩ and the fluctuation rate of the first power supply (PWR_2) is −2%, the PWR_2 allowable current value is calculated by the following formula. PWR_2(allowable current)=(1.20V-0.024V(2%drop)-1.14V(Vd_min)) / 60mΩ=0.60A The allowable current value IP2C1 for the second power supply (PWR_2) is calculated by the following formula. IP2C1=0.60×3=1.80A FIG. 18 is a diagram showing the allowable current ratio to CC1max and the allowable current of each power source for each of the four types of current classes CC1 to CC4.

[0164] CC1max is the maximum allowable current value of each power supply in current class CC1. The allowable current ratio of current class CC1 is 100%, the allowable current ratio of current class CC2 is 72%, the allowable current ratio of current class CC3 is 56%, and the allowable current ratio of current class CC4 is 47%.

[0165] When the allowable current value IP1 of the first power supply (PWR_1) in the current class CC1 is 3.6 A, the allowable current value IP1 of the current class CC2 is 2.6 A, the allowable current value IP1 of the current class CC3 is 2.0 A, and the allowable current value IP1 of the current class CC4 is 1.7 A. When the allowable current value IP2 of the second power supply (PWR_1) in the current class CC1 is 3.6 A, the allowable current value IP2 of the current class CC2 is 2.6 A, the allowable current value IP2 of the current class CC3 is 2.0 A, and the allowable current value IP2 of the current class CC4 is 1.7 A.

[0166] In this way, in each of the multiple classes, multiple types of allowable current values ​​corresponding to multiple types of contact resistance values ​​are defined as the current consumption for the first power source (PWR_1), and multiple types of allowable current values ​​corresponding to multiple types of contact resistance values ​​are defined as the current consumption for the second power source (PWR_2).

[0167] Assume that one of the current classes supported by the removable memory device 10 is CC1, and the contact resistance value between the terminal of the socket 100 and the terminal of the removable memory device 10 is a specific contact resistance value among multiple types of contact resistance values.

[0168] In this case, the first current consumption value consumed by the removable memory device 10 from the first power supply (PWR_1) is less than or equal to IP1 corresponding to this specific contact resistance value specified in CC1, that is, less than or equal to the first allowable current value determined based on the nominal voltage value (2.5 V) of the first power supply (PWR_1), the power supply regulation rate of the first power supply (PWR_1), this specific contact resistance value, and the lower limit voltage value (e.g., 2.4 V) of the first power supply (PWR_1) required for operation of the removable memory device 10. In addition, the second consumption current value consumed by the removable memory device from the second power supply (PWR_2) is less than or equal to IP2 corresponding to this specific contact resistance value specified in CC1, that is, less than or equal to a second allowable current value determined based on the nominal voltage value (1.2V) of the second power supply (PWR_2), the power supply fluctuation rate of the second power supply (PWR_2), this specific contact resistance value, and the lower limit voltage value of the second power supply (PWR_2) required for operation of the removable memory device 10.

[0169] Assume that the current class supported by the removable memory device 10 is one of the current classes CC2 to CC4, and the contact resistance value between the terminal of the socket 100 and the terminal of the removable memory device 10 is this specific contact resistance value.

[0170] In this case, the first current consumption value consumed by the removable memory device 10 from the first power source (PWR_1) is equal to or less than the minimum of (1) IP1 (i.e., the first allowable current value described above) corresponding to this specific contact resistance value defined in CC1, and (2) the maximum allowable current value (IP1C1max) of the multiple allowable current values ​​for the first power source (PWR_1) defined in CC1 multiplied by the ratio assigned to this one current class. Also, the second current consumption value consumed by the removable memory device 10 from the second power source (PWR_1) is equal to or less than the minimum of (3) IP2 (i.e., the second allowable current value described above) corresponding to this specific contact resistance value defined in CC1, and (4) the maximum allowable current value (IP2C1max) of the multiple allowable current values ​​for the second power source (PWR_2) defined in CC1 multiplied by the ratio assigned to this one current class.

[0171] Next, the current consumption class guide used in this embodiment will be described.

[0172] When six types of contact resistance (30mΩ, 40mΩ, 50mΩ, 60mΩ, 70mΩ, 80mΩ) and two types of power supply fluctuation (-1% fluctuation, -2% fluctuation) are combined with four types of current classes CC1 to CC4, there are 12 classifications per current class. Therefore, the total number of categories that can be classified by CCG#$% (#:1-4, $:3-8, %:1-2) is 48.

[0173] Although the CCG#$% is useful as information for identifying the removable memory device 10, the current consumption class guide can be used to make the removable memory device 10 easier to identify.

[0174] The current consumption class guide is also referred to as the current class guide CCG. The current class guide CCG defines a plurality of categories (CCG categories) having different combinations of current consumption value and performance. For example, a data transfer rate can be used as an index indicating the performance.

[0175] FIG. 19A is a diagram showing a current consumption class guide list indicating the allowable current value and device performance of each power supply for each category of the current class guide.

[0176] 19A illustrates a case where, for example, four categories, namely, CCG-A, CCG-B, CCG-C, and CCG-D, are defined in the current class guide CCG. For each of CCG-A of CCG-A, CCG-B, CCG-C, and CCG-D, a current range corresponding to IP1, a current range corresponding to IP2, and performance are specified.

[0177] In CCG-A, the current range corresponding to IP1 is 2.6A<current range≦3.6A. The current range corresponding to IP2 is also 2.6A<current range≦3.6A. The performance is 4~8GB / s.

[0178] In CCG-B, the current range corresponding to IP1 is 2.0A<current range≦2.6A. The current range corresponding to IP2 is also 2.0A<current range≦2.6A. The performance is 2~5GB / s.

[0179] In CCG-C, the current range corresponding to IP1 is 1.7A<current range≦2.0A. The current range corresponding to IP2 is also 1.7A<current range≦2.0A. The performance is 1~3GB / s.

[0180] For CCG-D, the current range corresponding to IP1 is less than 1.7 A. The current range corresponding to IP2 is also less than 1.7 A. The performance is less than 23 GB / s.

[0181] The 48 types of current class classifications represented by CCG#$%(#: 1~4, $: 3~8, %: 1~2) are classified into several categories using the Current Class Guide CCG. For example, the 48 types of current class classifications are classified into 8 categories: CCG-A(1), CCG-A(2), CCG-B(1), CCG-B(2), CCG-C(1), CCG-C(2), CCG-D(1), and CCG-D(2).

[0182] The classification conditions are to satisfy the following (1) or (2). (1) Both IP1 and IP2 are within the current range of Figure 19A. (2) Either IP1 or IP2 is within the current range of Figure 19A, and the other is a current value below the current range.

[0183] For example, when both IP1 and IP2 of a certain current class classification are within the current range corresponding to CCG-A, the category of this current class classification is CCG-A(1). Also, when either IP1 or IP2 of a certain current class classification is within the current range corresponding to CCG-A, and the other is a current value below the current range corresponding to CCG-A, the category of this current class classification is CCG-A(2).

[0184] In addition, when the condition (CCG<IP) that the minimum value (=MIN[IP1, IP2]) of IP1 and IP2 of a certain current class classification exceeds the upper limit current value of a certain current range is satisfied, the category corresponding to this current range may be determined as the category of this current class classification. For example, when the minimum value (=MIN[IP1, IP2]) of IP1 and IP2 of a certain current class classification exceeds the upper limit current value of the current range corresponding to CCG-B, the category of this current class classification is CCG-B.

[0185] Next, the current classes and current class guides (1) for the case of IP1 = IP2 and a -1% variation, the current classes and current class guides (2) for the case of IP1 = IP2 and a -2% variation, the current classes and current class guides (1’) for the case of IP1 ≠ IP2 and a -1% variation, and the current classes and current class guides (2’) for the case of IP1 ≠ IP2 and a -2% variation will be described.

[0186] Figure 19B is a diagram showing the current class and current class guide (1). Figure 19C is a diagram showing the current class and current class guide (2). Figure 19C is a diagram showing the current class and current class guide (1’). Figure 19D is a diagram showing the current class and current class guide (2’).

[0187] In the current class and current class guide (1), the table of CC1 is divided into CC0 (maximum allowable current table) and CC1 (1%) (a table showing the current value rounded to one decimal place and CCG). In the table of CC1 (1%), for each of the six types of contact resistance values, a column “IP1” indicating IP1, a column “IP2” indicating IP2, a column “TTL” indicating the sum of these IP1 and IP2, a column “CCG” indicating the CCG category, and a column “CCG<IP” indicating the CCG category based on another classification method are defined. In each of the tables of CC2 (1%) to CC4 (1%), for each of the six types of contact resistance values, a column “IP1” indicating IP1, a column “IP2” indicating IP2, a column “TTL” indicating the sum of these IP1 and IP2, a column “CCG” indicating the CCG category, and a column “CCG<IP” indicating the CCG category based on another classification method are defined.

[0188] The six types of IP1 in the CC1 (1%) table are calculated based on the nominal voltage value (2.5V) of the first power supply (PWR_1), the power supply variation rate (-1%) of the first power supply (PWR_1), the lower limit voltage value (e.g., 2.4V) of the first power supply (PWR_1) required for the operation of the removable memory device 10, and six types of contact resistance values. The six types of IP2 in the CC1 (1%) table are calculated based on the nominal voltage value (1.2V) of the second power supply (PWR_2), the power supply variation rate (-1%) of the second power supply (PWR_2), the lower limit voltage value (e.g., 1.14V) of the second power supply (PWR_2) required for the operation of the removable memory device 10, and six types of contact resistance values.

[0189] In each of the CC2 (1%) table to the CC4 (1%) table, the six types of IP2 are calculated based on the formula IP2 = MIN[IP2C1, IP2C1max × M × ratio] explained in FIG. 15. The six types of IP1 are calculated such that IP1 = IP2.

[0190] In the current class and current class guide (2) of FIG. 19C, the CC1 table is also divided into a CC0 (maximum allowable current table) and a CC1 (2%) (a table showing the current values rounded to one decimal place and CCG). In the CC1 (2%) table, for each of the six types of contact resistance values, a column "IP1" indicating IP1, a column "IP2" indicating IP2, a column "TTL" indicating the sum of these IP1 and IP2, a column "CCG" indicating the CCG category, and a column "CCG<IP" indicating the CCG category based on another classification method are defined. In each of the CC2 (2%) table to the CC4 (2%) table, for each of the six types of contact resistance values, a column "IP1" indicating IP1, a column "IP2" indicating IP2, a column "TTL" indicating the sum of these IP1 and IP2, a column "CCG" indicating the CCG category, and a column "CCG<IP" indicating the CCG category based on another classification method are defined.

[0191] The six types of IP1 in the CC1 (2%) table are calculated based on the nominal voltage value (2.5V) of the first power supply (PWR_1), the power supply fluctuation rate (-2%) of the first power supply (PWR_1), the lower limit voltage value (e.g., 2.4V) of the first power supply (PWR_1) required for the operation of the removable memory device 10, and six types of contact resistance values. The six types of IP2 in the CC1 (2%) table are calculated based on the nominal voltage value (1.2V) of the second power supply (PWR_2), the power supply fluctuation rate (-2%) of the second power supply (PWR_2), the lower limit voltage value (e.g., 1.14V) of the second power supply (PWR_2) required for the operation of the removable memory device 10, and six types of contact resistance values.

[0192] In each of the CC2 (2%) table to the CC4 (2%) table, the six types of IP2 are calculated based on the formula IP2 = MIN[IP2C1, IP2C1max × M × ratio]. The six types of IP1 are calculated such that IP1 = IP2.

[0193] In the current class and current class guide (1’) of FIG. 19D, the CC1 table is also divided into a CC0 (maximum allowable current table) and a CC1 (1%) (a table showing the current value rounded to one decimal place and CCG). In the CC1 (1%) table, for each of the six types of contact resistance values, there are defined a column “IP1” indicating IP1, a column “IP2” indicating IP2, a column “TTL” indicating the sum of these IP1 and IP2, a column “CCG” indicating the CCG category, and a column “CCG<IP” indicating the CCG category based on another classification method. In each of the CC2 (1%) table to the CC4 (1%) table, for each of the six types of contact resistance values, there are defined a column “IP1” indicating IP1, a column “IP2” indicating IP2, a column “TTL” indicating the sum of these IP1 and IP2, a column “CCG” indicating the CCG category, and a column “CCG<IP” indicating the CCG category based on another classification method.

[0194] The six types of IP1 in the CC1 (1%) table are calculated based on the nominal voltage value (2.5 V) of the first power supply (PWR_1), the power supply fluctuation rate (-1%) of the first power supply (PWR_1), the lower limit voltage value (e.g., 2.4 V) of the first power supply (PWR_1) required for the operation of the removable memory device 10, and six types of contact resistance values. The six types of IP2 in the CC1 (1%) table are calculated based on the nominal voltage value (1.2 V) of the second power supply (PWR_2), the power supply fluctuation rate (-1%) of the second power supply (PWR_2), the lower limit voltage value (e.g., 1.14 V) of the second power supply (PWR_2) required for the operation of the removable memory device 10, and six types of contact resistance values.

[0195] In each of the CC2 (1%) table to the CC4 (1%) table, the six types of IP1 are calculated based on the formula IP1 = MIN[IP1C1, IP1C1max × M × ratio] described in FIG. 15. The six types of IP2 are calculated based on the formula IP2 = MIN[IP2C1, IP2C1max × M × ratio].

[0196] Also in the current class and current class guide (2’) of FIG. 19E, the CC1 table is divided into a CC0 (maximum allowable current table) and a CC1 (2%) (a table showing the current values rounded to one decimal place and CCG). In the CC1 (2%) table, for each of the six types of contact resistance values, a column "IP1" indicating IP1, a column "IP2" indicating IP2, a column "TTL" indicating the sum of these IP1 and IP2, a column "CCG" indicating the CCG category, and a column "CCG<IP" indicating the CCG category based on another classification method are defined. In each of the CC2 (2%) table to the CC4 (2%) table, for each of the six types of contact resistance values, a column "IP1" indicating IP1, a column "IP2" indicating IP2, a column "TTL" indicating the sum of these IP1 and IP2, a column "CCG" indicating the CCG category, and a column "CCG<IP" indicating the CCG category based on another classification method are defined.

[0197] The six types of IP1 in the table of CC1(2%) are calculated based on the nominal voltage value (2.5V) of the first power supply (PWR_1), the power supply fluctuation rate (-2%) of the first power supply (PWR_1), the lower limit voltage value (e.g., 2.4V) of the first power supply (PWR_1) required for the operation of the removable memory device 10, and six types of contact resistance values. The six types of IP2 in the table of CC1(2%) are calculated based on the nominal voltage value (1.2V) of the second power supply (PWR_2), the power supply fluctuation rate (-2%) of the second power supply (PWR_2), the lower limit voltage value (e.g., 1.14V) of the second power supply (PWR_2) required for the operation of the removable memory device 10, and six types of contact resistance values.

[0198] In each of the tables CC2(2%) to CC4(2%), the six types of IP1 are calculated based on the formula IP1=MIN[IP1C1,IP1C1max×M×ratio]. The six types of IP2 are calculated based on the formula IP2=MIN[IP2C1,IP2C1max×M×ratio].

[0199] In each of the current class and current class guide (1), the current class and current class guide (2), the current class and current class guide (1'), and the current class and current class guide (2'), the 24 types of current class classifications are assigned current class guide categories based on the current class guide list in Figure 19A.

[0200] For example, focus on current class CC1 with a power supply fluctuation of -2% and a contact resistance value of 60 mΩ (CC162 in FIG. 19C). CC162[IP1,IP2] is [≦2.5A,≦1.8A]. IP1=2.5A is within the current range of CCG-B (2.0 to 2.6), and IP2=1.8A is a current value below the current range of CCG-B (2.0 to 2.6). Therefore, CCG-B(2) is assigned to CC162. A device with CC162[IP1,IP2]=[≦2.5A,≦1.8A] is determined to be a device compatible with CCG-B(2).

[0201] Also, for example, focus on current class CC4 where the power supply fluctuation is -1% and the contact resistance value is 50 mΩ (CC451 in Fig. 19B). CC451[IP1, IP2] is [≤1.7A, ≤1.7A]. Since 1.7A is included in the current range of CCG-D (<1.7), CCG-D(1) is assigned to CC451. A device with CC451[IP1, IP2] = [≤1.7A, ≤1.7A] is determined as a device corresponding to CCG-D(1).

[0202] Note that, as described above, the category of the current class guide can also be determined using the condition (CCG<IP) that MIN[IP1, IP2]) exceeds the upper limit current value. For example, focusing on CC151 in Fig. 19B, the minimum value of 3.6A and 2.8A, which is 2.8A, exceeds the upper limit current value of 2.6A for CCG-B. Therefore, CCG-B is assigned to the "CCG<IP" column of CC151. In this case, a device with CC151[IP1, IP2] = [≤3.6A, ≤2.8A] is determined as a device corresponding to CCG-B.

[0203] The current class and current class guide (1), the current class and current class guide (2), the current class and current class guide (1'), and the current class and current class guide (2') can be used as follows in a B2B (Business to Business) environment.

[0204] The host manufacturer determines the CC (Current Class) from the power supply fluctuation rate (1% or 2%) of the power supply circuit for the device, the contact resistance value of the device socket, and the maximum current that can be distributed to the device. Next, the host manufacturer determines the CCG in consideration of the required performance for the removable memory device. Then, the host manufacturer uses the RFI (Request For Information) to request the device manufacturer for a device that meets the required performance and CC. A device that meets the CC is a device that meets CCG-A to CCG-D in the "CCG" column or the "CCG<IP" column.

[0205] (Example 1) When the power supply fluctuation rate of the power supply circuit for the device = 1%, the contact resistance value of the device socket = 60 mΩ, the device distribution current consumption [IP1, IP2] = [2.4 A, 2.0 A], and the required performance = 3 GB / s, the host manufacturer selects CC261 and requests a device with CCG-B or less in the RFI to the device manufacturer.

[0206] (Example 2) When the power supply fluctuation rate of the power supply circuit for the device = 2%, the contact resistance value of the device socket = 60 mΩ, the device distribution current consumption [IP1, IP2] = [1.7 A, 1.7 A], and the required performance = 2 GB / s, the host manufacturer selects CC462 and requests a device with CCG-D or less in the RFI to the device manufacturer.

[0207] The device manufacturer determines the device product specifications such that the current consumption is below the current of any of CCG-A to D in the current class guide list of FIG. 19A and the required performance is satisfied.

[0208] (Example 1) For a device product with a performance of 2.5 GB / s and a current consumption of IP1 = 2.4 A, IP2 <= 2.0 A, the device manufacturer declares CCG-B and guarantees to operate within the current consumption corresponding to CCG-B. As a method of declaring CCG-B, a method of describing CCG-B in the data sheet or a method of marking a logo indicating CCG-B on the device product can be used.

[0209] (Example 2) For a device product with a performance of 2.0 GB / s and current consumption IP1 = 1.9 A and IP2 = 1.7 A, the device manufacturer declares CCG-C.

[0210] Instead of the logo indicating the category of the current class guide, a logo indicating the current class (all or part of CC#$%) may be used. Also, information indicating the category of the current class guide or information indicating the current class may be stored in a register in the controller 14 that can be read from the host.

[0211] FIG. 20 is a diagram showing a logo and a two-dimensional barcode marked on one surface 22 of the package 11 of the removable memory device 10 of the embodiment, and a logo 1003 and a two-dimensional barcode 1004 marked on the host housing 1001.

[0212] In the removable memory device 10, a logo and a two-dimensional barcode are marked on one surface 22 of the package 11 to allow a user to visually identify the current consumption class or current consumption class guide supported by the removable memory device 10.

[0213] If the removable memory device 10 supports CC1, the logo 51 on one surface 22 of the package 11 of the removable memory device 10 indicates that the removable memory device 10 supports CC1. The two-dimensional barcode 61 on one surface 22 of the removable memory device 10 also indicates that the removable memory device 10 supports CC1. The two-dimensional barcode 61 may also include information indicating the current consumption value of each power source of the removable memory device 10.

[0214] Alternatively, if the removable memory device 10 is classified as the current consumption class guide CCG-A, the logo 51 may display CCG-A. Also, the two-dimensional barcode 61 may indicate that the removable memory device 10 is classified as the current consumption class guide CCG-A.

[0215] Similarly, if removable memory device 10 supports CC2, then logo 52 on one surface 22 of packaging 11 of removable memory device 10 indicates that removable memory device 10 supports CC2.

[0216] The two-dimensional barcode 62 on the one surface 22 of the removable memory device 10 also indicates that the removable memory device 10 supports CC2. The two-dimensional barcode 62 may also include information indicating the current consumption value of each power source of the removable memory device 10.

[0217] Alternatively, if the removable memory device 10 is classified as the current consumption class guide CCG-B, the logo 52 may display CCG-B. Also, the two-dimensional barcode 62 may indicate that the removable memory device 10 is classified as the current consumption class guide CCG-B.

[0218] If the removable memory device 10 supports CC3, the logo 53 on one surface 22 of the package 11 of the removable memory device 10 indicates that the removable memory device 10 supports CC3. Also, a two-dimensional barcode 63 on one surface 22 of the removable memory device 10 indicates that the removable memory device 10 supports CC3. Also, the two-dimensional barcode 63 may include information indicating the current consumption value of each power supply of the removable memory device 10.

[0219] Alternatively, if the removable memory device 10 is classified as the current consumption class guide CCG-C, the logo 53 may display CCG-C. Also, the two-dimensional barcode 63 may indicate that the removable memory device 10 is classified as the current consumption class guide CCG-C.

[0220] If the removable memory device 10 supports CC4, the logo 54 on one surface 22 of the package 11 of the removable memory device 10 indicates that the removable memory device 10 supports CC4. Also, a two-dimensional barcode 64 on one surface 22 of the removable memory device 10 indicates that the removable memory device 10 supports CC4. Also, the two-dimensional barcode 64 may include information indicating the current consumption value of each power supply of the removable memory device 10.

[0221] Alternatively, if the removable memory device 10 is classified as the current consumption class guide CCG-D, the logo 54 may display CCG-D. Also, the two-dimensional barcode 64 may indicate that the removable memory device 10 is classified as the current consumption class guide CCG-D.

[0222] In addition, a logo 1003 and a two-dimensional barcode 1004 for indicating the current consumption class supported by the host may be marked on the side of the host housing 1001. The logo 1003 and the two-dimensional barcode 1004 may be marked on the same side where the insertion slot 1002 of the removable memory device 10 is provided.

[0223] The logo 1003 indicates a current consumption class supported by the host. The logo 1003 may also include information such as a contact resistance value, a power supply fluctuation, and a current consumption class guide in the host. The two-dimensional barcode 1004 indicates that the removable memory device 10 supports CC4. The two-dimensional barcode 1004 may also include information such as a contact resistance value, a power supply fluctuation, and a current consumption class guide in the host.

[0224] Alternatively, the logo 1003 may display a current consumption class guide into which the host is classified. Also, the two-dimensional barcode 1003 may indicate a current consumption class guide into which the host is classified.

[0225] A user can identify whether or not the removable memory device 10 and the host are a usable combination by referring to the logo and two-dimensional barcode displayed on the removable memory device 10 and the host, respectively.

[0226] FIG. 21 is a flowchart showing the procedure of device initialization processing executed in the host.

[0227] First, when the removable memory device 10 is inserted into the host's socket 100 while the host is powered on, or when the host is powered on with the removable memory device 10 already inserted into the host's socket 100, the host starts an initialization process (step S101).

[0228] The host reads the CC value in the register of the removable memory device 10 (step S102). The register is provided in the controller 14, and may store information indicating a current consumption class supported by the removable memory device 10, or information indicating a current consumption value related to the first power supply (PWR_1), a current consumption value related to the second power supply (PWR_2), and a current consumption class category into which the removable memory device 10 is classified.

[0229] The host checks whether normal operation is possible (step S103).

[0230] If the number of the current consumption class supported by the host is smaller than the number of the current consumption class supported by the removable memory device 10 (HostCC≦DeviceCC in step S103), the host ends the initialization process (step S104).

[0231] On the other hand, if the number of the current consumption class supported by the host is larger than the number of the current consumption class supported by the removable memory device 10 (HostCC>DeviceCC in step S103), the host shuts down the power supply of the removable memory device 10 (step S105). This is because the current value of each power supply that the host can supply is smaller than the current value of each power supply required by the removable memory device 10.

[0232] Thereafter, when the removable memory device 10 inserted in the host is replaced by the user (step S106), the host starts the initialization process again (step S101).

[0233] FIG. 22 is a diagram showing a notch formed in the package 11 of the removable memory device 10 according to the embodiment for identifying the current consumption class supported by the removable memory device 10. As shown in FIG.

[0234] The removable memory device 10 may have a notch as a mechanism for the host to identify the current consumption class supported by the removable memory device 10 .

[0235] A removable memory device 10 supporting CC1 has a notch 71 on one side 32 of the package 11, a removable memory device 10 supporting CC2 has a notch 72 on one side 32 of the package 11, and a removable memory device 10 supporting CC3 has a notch 73 on one side 32 of the package 11. Each of the notches provided in the package 11 may be provided on any side of the package 11 as long as it does not affect each of the terminals of the removable memory device 10.

[0236] Also, for example, two switches may be provided in the socket 100 to distinguish between the four current consumption classes CC1 to CC4. These switches may detect the notch when the removable memory device 10 is inserted into the socket 100.

[0237] The host identifies the current consumption class of the removable memory device 10 inserted into the socket 100 from the combination of on and off of each of the two switches.

[0238] The information identified by the notch may also be the current consumption class category to which the removable memory device 10 is classified.

[0239] FIG. 23 is a diagram showing an example of the power supply configuration on the host side corresponding to each of the four types of current classes.

[0240] FIG. 23 shows a state in which a removable memory device 10 supporting each current consumption class is inserted into a socket 100 on a printed circuit board of a host.

[0241] The host's printed circuit board is provided with a socket 100, a power supply circuit (Power Management Integrated Circuit, PMIC) 501 for supplying a first power supply (PWR_1) to the removable memory device 10, and a power supply circuit (PMIC) 502 for supplying a second power supply (PWR_2) to the removable memory device 10.

[0242] When the current consumption class supported by the removable memory device 10 and the host is CC1, the allowable current consumption reduction rate in CC1 is 100% for the current consumption value related to the first power supply and 100% for the current consumption value related to the second power supply. The removable memory device 10 and the host are designed taking into consideration the current consumption class supported by each of them. Therefore, the first power supply circuit (PMIC) 501 and the second power supply circuit (PMIC) 502 on the printed circuit board of the host are designed to be able to output a current corresponding to the current consumption defined by CC1.

[0243] Moreover, when the current consumption class supported by the removable memory device 10 and the host is CC2, the allowable current consumption reduction rate is 72%. The removable memory device 10 and the host are designed taking into consideration the current consumption class supported by each of them. Therefore, the first power supply circuit (PMIC) 601 and the second power supply circuit (PMIC) 602 on the printed circuit board of the host are designed to be able to output a current corresponding to the current consumption defined by CC2. In other words, in the design of a host supporting CC2, the output current value of the first power supply circuit (PMIC) 601 is designed in advance to be lower than the output current value of the first power supply circuit (PMIC) 501 in CC1, thereby preventing the first power supply circuit (PMIC) 601 from being over-specified, and reducing costs and optimizing the design.

[0244] Furthermore, the first power supply circuit (PMIC) 601 can be realized with a lower output current value than the first power supply circuit (PMIC) 501, thereby making it possible to reduce the area occupied by the power supply circuit on the host's printed circuit board.

[0245] When the current consumption class supported by the removable memory device 10 and the host is CC3, the allowable current consumption reduction rate is 56%. The removable memory device 10 and the host are designed taking into consideration the current consumption class supported by each of them. Therefore, the first power supply circuit (PMIC) 701 and the second power supply circuit (PMIC) 702 on the printed circuit board of the host are designed to be able to output a current corresponding to the current consumption stipulated by CC3. In other words, in the design of a host supporting CC3, the output current values ​​of the first power supply circuit (PMIC) 701 and the second power supply circuit (PMIC) 702 are designed in advance to be lower than the output current values ​​of the first power supply circuit (PMIC) 501 and the second power supply circuit (PMIC) 502 of CC1, respectively, thereby preventing the first power supply circuit (PMIC) 701 and the second power supply circuit (PMIC) 702 from being over-specified, and reducing costs and optimizing the design.

[0246] Also, the first power supply circuit (PMIC) 701 and the second power supply circuit (PMIC) 702 can be realized with a lower output current value than the first power supply circuit (PMIC) 501 and the second power supply circuit (PMIC) 502, thereby making it possible to reduce the area occupied by the power supply circuit on the host's printed circuit board. Furthermore, the second power supply circuit (PMIC) 702 is expected to be realized smaller than the second power supply circuit (PMIC) 602 in CC2. Therefore, the area occupied by the power supply circuit on the host's printed circuit board supporting CC3 is expected to be smaller than the area occupied by the power supply circuit on the host's printed circuit board supporting CC2.

[0247] Furthermore, when the current consumption class supported by the removable memory device 10 and the host is CC4, the allowable current consumption reduction rate in CC4 is 47%. The removable memory device 10 and the host are designed taking into consideration the current consumption class supported by each of them. Therefore, the first power supply circuit (PMIC) 801 and the second power supply circuit (PMIC) 802 on the printed circuit board of the host are designed to be able to output a current corresponding to the current consumption defined by CC4. That is, in the design of a host supporting CC4, the output current values ​​of the first power supply circuit (PMIC) 801 and the second power supply circuit (PMIC) 802 are designed in advance to be lower than the output current values ​​of the first power supply circuit (PMIC) 501 and the second power supply circuit (PMIC) 502 of CC1, respectively, thereby preventing the first power supply circuit (PMIC) 801 and the second power supply circuit (PMIC) 802 from being over-specified, and reducing costs and optimizing the design.

[0248] Also, the first power supply circuit (PMIC) 801 and the second power supply circuit (PMIC) 802 can be realized with a lower output current value than the first power supply circuit (PMIC) 501 and the second power supply circuit (PMIC) 502, thereby making it possible to reduce the area occupied by the power supply circuit on the host's printed circuit board. Furthermore, the first power supply circuit (PMIC) 801 is expected to be realized smaller than the first power supply circuit (PMIC) 701 in CC3. Therefore, the area occupied by the power supply circuit on the host's printed circuit board supporting CC4 is expected to be smaller than the area occupied by the power supply circuit on the host's printed circuit board supporting CC3.

[0249] In other words, by knowing in advance the expected current consumption class of the host, it is possible to optimize the size of the power supply circuit.

[0250] FIG. 24 is a diagram showing heat dissipation paths of a device.

[0251] In a typical device 200, heat generated by the operation of the device 200 is dissipated mainly along the three heat dissipation paths (1) to (3).

[0252] (1) is a path for heat conduction to the top surface of the package of device 200 and then from the package to the air.

[0253] (2) is a path for heat conduction via the terminals connecting the device 200 and the PCB, and for heat transfer from the PCB to the air.

[0254] (3) is a path through which heat is conducted to the side surface of the package of device 200 and then transferred from the package to the air.

[0255] If a thermally conductive member such as a thermal interface material (TIM) is not attached to the upper surface of the package, (2) becomes the main dissipation path for heat generated in the device 200.

[0256] FIG. 25 is a diagram showing an example of the configuration of a heat dissipation mechanism on the host side corresponding to a power supply configuration of a current consumption class of the maximum current consumption.

[0257] In the power supply configuration of a host that supports current consumption class CC1, the current consumption value is maximum. Therefore, it is expected that the amount of heat generated by the removable memory device 10 will be greater than that of other current consumption classes. Therefore, measures such as attaching a thermal conductive material such as TIM500 can be designed in advance.

[0258] On the other hand, FIG. 26 is a diagram showing an example of the configuration of a heat dissipation mechanism on the host side corresponding to a power supply configuration of a small current consumption class.

[0259] In the power supply configuration of a host supporting current consumption class CC4, the current consumption value is smaller than that of a host supporting CC1. Therefore, the amount of heat generated by the operation of a removable memory device 10 supporting CC4 is smaller than that of a removable memory device 10 supporting CC1. Therefore, there is no need to prepare a thermal conductive member such as TIM500 as shown in FIG. 25.

[0260] In other words, by considering the current consumption class, it is possible to understand the heat dissipation design required for the host printed circuit board, and to avoid the costs associated with taking excessive measures.

[0261] As described above, according to this embodiment, a plurality of current classes having different current consumptions are defined. In each current class, a current consumption (allowable current value) is defined for each power source of the removable memory device 10 having a multiple power source configuration. When the current class supported by the removable memory device 10 is CC1, the first current consumption value consumed by the removable memory device 10 from the first power source (PWR_1) is equal to or less than the first allowable current value, which is the maximum current value allowed to be supplied from the host to the first power source terminals (P128, P130, P131) of the removable memory device 10 via the contact resistance between the terminals of the socket 100 and the terminals of the removable memory device 10. In addition, the second consumption current value consumed by the removable memory device 10 from the second power source (PWR_2) is less than or equal to a second allowable current value, which is the maximum current value allowed to be supplied from the host to the second power terminals (P124, P125, P127) of the removable memory device 10 via the contact resistance value between the terminals of the socket 100 and the terminals of the removable memory device 10.

[0262] When the current consumption class supported by the removable memory device 10 is one of CC2 to CC4, a first current consumption value consumed by the removable memory device 10 from the first power source (PWR_1) is less than or equal to a third allowable current value for the first power source (PWR_1) defined in this CC class, and a second current consumption value consumed by the removable memory device 10 from the second power source (PWR_2) is less than or equal to a fourth allowable current value for the second power source (PWR_2) defined in this other current consumption class.

[0263] Therefore, it is possible to identify the current consumption value (maximum current consumption value) required for the operation of the removable memory device 10 for each power supply depending on which of the multiple current classes the removable memory device 10 supports.

[0264] Therefore, when the current consumption class of the removable memory device 10 to be used in the host is CC1, the host manufacturer can adopt a power supply configuration in which a power supply circuit capable of supplying the first and second allowable current consumption values ​​corresponding to CC1 is installed in the host. This allows any device product that supports CC1 to be used normally in a host that supports CC1.

[0265] Furthermore, if the current class of the removable memory device 10 to be used in the host is any one of CC2 to CC4, which consumes less current than CC1, the host manufacturer can optimize the capacity of the host-side power supply circuit for each power supply based on the allowable current consumption value of each power supply corresponding to this current class, thereby reducing the cost of the host-side power supply circuit.

[0266] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0267] 10... removable memory device, 13... NAND flash memory, 14... controller, 100... socket, first power supply terminal... P128, P130, P131, second power supply terminal... P124, P125, P127.

Claims

1. A removable memory device that is insertable into and removable from a socket in a host and operates on first and second power supplies supplied from the host, the first and second power supplies having different voltages; a plurality of terminals including one or more first power supply terminals to which the first power supply is supplied and one or more second power supply terminals to which the second power supply is supplied; A non-volatile memory; A controller for controlling the non-volatile memory, the removable memory device is configured to support one of a plurality of current consumption classes that define a plurality of current consumptions different from one another, and in each of the plurality of current consumption classes, both a current consumption related to the first power supply and a current consumption related to the second power supply are defined; When the one current consumption class supported by the removable memory device is a first current consumption class having the largest current consumption value among the multiple types of current consumption classes, a first current consumption value consumed by the removable memory device from the first power source is equal to or less than a first allowable current value which is a maximum current value allowed to be supplied from the host to the one or more first power source terminals of the removable memory device via a contact resistance value between a terminal of the socket and a terminal of the removable memory device, and a second current consumption value consumed by the removable memory device from the second power source is equal to or less than a second allowable current value which is a maximum current value allowed to be supplied from the host to the one or more second power source terminals of the removable memory device via the contact resistance value, when the one current consumption class supported by the removable memory device is another current consumption class different from the first current consumption class, the first current consumption value is equal to or less than a third allowable current value for the first power supply defined in the other current consumption class, and the second current consumption value is equal to or less than a fourth allowable current value for the second power supply defined in the other current consumption class; the first allowable current value is determined based on a nominal voltage value of the first power supply, a power supply fluctuation rate of the first power supply, the contact resistance value, and a lower limit voltage value of the first power supply required for operation of the removable memory device; A removable memory device, wherein the second allowable current value is calculated based on a nominal voltage value of the second power supply, a power supply fluctuation rate of the second power supply, the contact resistance value, and a lower limit voltage value of the second power supply required for operation of the removable memory device.

2. A removable memory device that is insertable into and removable from a socket in a host and operates on first and second power supplies supplied from the host, the first and second power supplies having different voltages; a plurality of terminals including one or more first power supply terminals to which the first power supply is supplied and one or more second power supply terminals to which the second power supply is supplied; A non-volatile memory; A controller for controlling the non-volatile memory, the removable memory device is configured to support one of a plurality of current consumption classes that define a plurality of current consumptions different from one another, and in each of the plurality of current consumption classes, both a current consumption related to the first power supply and a current consumption related to the second power supply are defined; When the one current consumption class supported by the removable memory device is a first current consumption class having the largest current consumption value among the multiple types of current consumption classes, a first current consumption value consumed by the removable memory device from the first power source is equal to or less than a first allowable current value which is a maximum current value allowed to be supplied from the host to the one or more first power source terminals of the removable memory device via a contact resistance value between a terminal of the socket and a terminal of the removable memory device, and a second current consumption value consumed by the removable memory device from the second power source is equal to or less than a second allowable current value which is a maximum current value allowed to be supplied from the host to the one or more second power source terminals of the removable memory device via the contact resistance value, when the one current consumption class supported by the removable memory device is another current consumption class different from the first current consumption class, the first current consumption value is equal to or less than a third allowable current value for the first power supply defined in the other current consumption class, and the second current consumption value is equal to or less than a fourth allowable current value for the second power supply defined in the other current consumption class; the first allowable current value is a value obtained by multiplying an allowable current value of the first power supply per one power supply terminal by the number of the first power supply terminals, the allowable current value of the first power supply per one power supply terminal is calculated based on a nominal voltage value of the first power supply, a power supply fluctuation rate of the first power supply, the contact resistance value, and a lower limit voltage value of the first power supply required for operation of the removable memory device; the second allowable current value is a value obtained by multiplying an allowable current value of the second power supply per one power supply terminal by the number of the second power supply terminals, A removable memory device, wherein the allowable current value of the second power supply per one power supply terminal is calculated based on a nominal voltage value of the second power supply, a power supply fluctuation rate of the second power supply, the contact resistance value, and a lower limit voltage value of the second power supply required for operation of the removable memory device.

3. A removable memory device as described in claim 1 or claim 2, wherein information indicating the one current consumption class supported by the removable memory device, or information indicating one of a plurality of categories into which the removable memory device is classified based on the first and second current consumption values ​​of the removable memory device and the performance of the removable memory device, is stored in a register in the controller readable by the host.

4. A removable memory device as described in claim 1 or claim 2, wherein a logo indicating one of the current consumption classes supported by the removable memory device, or a logo indicating one of a plurality of categories into which the removable memory device is classified based on the first and second current consumption values ​​of the removable memory device and the performance of the removable memory device, is marked on one surface of the package of the removable memory device.

5. A removable memory device as described in claim 1 or claim 2, wherein a two-dimensional barcode indicating information regarding the one current consumption class supported by the removable memory device, or a two-dimensional barcode indicating information regarding one of a plurality of categories into which the removable memory device is classified based on the first and second current consumption values ​​of the removable memory device and the performance of the removable memory device, is marked on one surface of the package of the removable memory device.

6. A removable memory device as described in claim 1 or claim 2, wherein a notch is formed in the package of the removable memory device for identifying the one current consumption class supported by the removable memory device, or for identifying one of a plurality of categories into which the removable memory device is classified based on the first and second current consumption values ​​of the removable memory device and the performance of the removable memory device.

7. A removable memory device that is insertable into and removable from a socket in a host and operates on first and second power supplies supplied from the host, the first and second power supplies having different voltages; a plurality of terminals including one or more first power supply terminals to which the first power supply is supplied and one or more second power supply terminals to which the second power supply is supplied; A non-volatile memory; A controller for controlling the non-volatile memory, the removable memory device is configured to support one of a plurality of current consumption classes, and in each of the plurality of current consumption classes, a plurality of allowable current values ​​corresponding to a plurality of contact resistance values ​​are defined as the current consumption related to the first power source, and a plurality of allowable current values ​​corresponding to the plurality of contact resistance values ​​are defined as the current consumption related to the second power source, when the one current consumption class supported by the removable memory device is a first current consumption class having the largest current consumption value among the multiple types of current consumption classes, and a contact resistance value between a terminal of the socket and a terminal of the removable memory device is a first contact resistance value among the multiple types of contact resistance values, a first current consumption value consumed by the removable memory device from the first power supply is equal to or less than a first allowable current value determined based on a nominal voltage value of the first power supply, a power supply fluctuation rate of the first power supply, the first contact resistance value, and a lower limit voltage value of the first power supply required for operation of the removable memory device, and a second current consumption value consumed by the removable memory device from the second power supply is equal to or less than a second allowable current value determined based on a nominal voltage value of the second power supply, a power supply fluctuation rate of the second power supply, the first contact resistance value, and a lower limit voltage value of the second power supply required for operation of the removable memory device, A removable memory device, wherein when the one current consumption class supported by the removable memory device is another current consumption class different from the first current consumption class, and when a contact resistance value between a terminal of the socket and a terminal of the removable memory device is the first contact resistance value, the first current consumption value is equal to or less than the minimum of (1) the first allowable current value and (2) a value obtained by multiplying a maximum allowable current value among the multiple types of allowable current values ​​for the first power source defined in the first current consumption class by a ratio assigned to the other current consumption class, and the second current consumption value is equal to or less than the minimum of (3) the second allowable current value and (4) a value obtained by multiplying a maximum allowable current value among the multiple types of allowable current values ​​for the second power source defined in the first current consumption class by the ratio.

Images