US20160077561A1 - Memory system - Google Patents
Memory system Download PDFInfo
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- US20160077561A1 US20160077561A1 US14/632,297 US201514632297A US2016077561A1 US 20160077561 A1 US20160077561 A1 US 20160077561A1 US 201514632297 A US201514632297 A US 201514632297A US 2016077561 A1 US2016077561 A1 US 2016077561A1
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- power supply
- power
- memory system
- volatile memory
- memory
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/26—Power supply means, e.g. regulation thereof
- G06F1/266—Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/26—Power supply means, e.g. regulation thereof
- G06F1/263—Arrangements for using multiple switchable power supplies, e.g. battery and AC
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/26—Power supply means, e.g. regulation thereof
- G06F1/32—Means for saving power
- G06F1/3203—Power management, i.e. event-based initiation of a power-saving mode
- G06F1/3206—Monitoring of events, devices or parameters that trigger a change in power modality
- G06F1/3212—Monitoring battery levels, e.g. power saving mode being initiated when battery voltage goes below a certain level
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/26—Power supply means, e.g. regulation thereof
- G06F1/32—Means for saving power
- G06F1/3203—Power management, i.e. event-based initiation of a power-saving mode
- G06F1/3234—Power saving characterised by the action undertaken
- G06F1/325—Power saving in peripheral device
- G06F1/3275—Power saving in memory, e.g. RAM, cache
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/26—Power supply means, e.g. regulation thereof
- G06F1/32—Means for saving power
- G06F1/3203—Power management, i.e. event-based initiation of a power-saving mode
- G06F1/3234—Power saving characterised by the action undertaken
- G06F1/3287—Power saving characterised by the action undertaken by switching off individual functional units in the computer system
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0602—Interfaces specially adapted for storage systems specifically adapted to achieve a particular effect
- G06F3/0625—Power saving in storage systems
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0628—Interfaces specially adapted for storage systems making use of a particular technique
- G06F3/0629—Configuration or reconfiguration of storage systems
- G06F3/0635—Configuration or reconfiguration of storage systems by changing the path, e.g. traffic rerouting, path reconfiguration
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0628—Interfaces specially adapted for storage systems making use of a particular technique
- G06F3/0655—Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0668—Interfaces specially adapted for storage systems adopting a particular infrastructure
- G06F3/0671—In-line storage system
- G06F3/0683—Plurality of storage devices
- G06F3/0688—Non-volatile semiconductor memory arrays
Definitions
- Embodiments described herein relate generally to memory system.
- a memory system having a volatile memory such as a DRAM built therein maintains data in the volatile memory by supplying power to the volatile memory from an external power supply.
- FIG. 1 is a block diagram that illustrates the configuration of a memory system according to a first embodiment
- FIG. 2 is a diagram that illustrates the configuration of a memory cell array
- FIG. 3 is a flowchart that illustrates switching between a normal mode and a DEVSLP mode of the memory system
- FIG. 4 is a diagram that illustrates power consumption in the normal mode and the DEVSLP mode of the memory system
- FIG. 5 is a block diagram that illustrates the configuration of a memory system according to a second embodiment
- FIG. 6 is a block diagram that illustrates the configuration of a memory system according to a third embodiment
- FIG. 7 is a block diagram that illustrates the configuration of a memory system according to a fourth embodiment.
- FIG. 8 is a block diagram that illustrates the configuration of a memory system according to a fifth embodiment.
- a memory system includes a non-volatile memory, a volatile memory, an internal power supply, a power supply circuit, and a controller.
- the non-volatile memory temporarily stores data to be written into the non-volatile memory or data read from the non-volatile memory.
- the power supply circuit includes a first power supply path in which power supplied from a host device is supplied to the volatile memory, a second power supply path in which the power is supplied from the internal power supply to the volatile memory, and a switching device that switches between the first power supply path and the second power supply path.
- the controller In response to an instruction for a transition to a low power consumption mode received from the host device, the controller outputs, to the switching device, an instruction to switch the power supply circuit from the first power supply path to the second power supply path.
- FIG. 1 is a block diagram that illustrates the configuration of a memory system 1 according to a first embodiment.
- the memory system 1 serves as an external storage device of a host device 2 .
- the memory system 1 includes: a serial ATA (SATA) connector 3 as a host interface; a NAND flash memory (hereinafter, referred to as a “NAND memory”) 4 as a non-volatile memory; a DRAM 5 as a volatile memory; a capacitor 6 as an internal power supply; a controller 7 ; a power supply circuit 8 ; a voltage detector (hereinafter, referred to as a “V.DET”) 9 a; and a fuse 10 .
- SATA serial ATA
- NAND memory NAND flash memory
- the SATA connector 3 is connected to an SATA I/F 70 of the controller 7 , performs a process according to an interface standard for the host device 2 , and outputs a read command, a write command, user data and the like received from the host device 2 to the SATA I/F 70 .
- the SATA connector 3 transmits user data read from the NAND memory 4 , a response from the controller 7 , and the like to the host device 2 .
- the NAND memory 4 is configured by one or more memory chips each having a memory cell array A 1 illustrated in FIG. 2 .
- the memory cell array A 1 is a NAND cell-type memory cell array and is configured to include a plurality of NAND cells in which the plurality of memory cells 41 are arranged in a matrix pattern.
- One NAND cell is configured by a memory string MS that is formed by the memory cells 41 connected in series and selection gates G 1 and G 2 that are connected to both ends thereof.
- the selection gate G 1 is connected to bit lines BL 0 to BL n-1
- the selection gate G 2 is connected to a source line SRC. Control gates of the memory cells 41 arranged in the same row are connected to word lines WL 0 to WL m-1 so as to be common thereto.
- the first selection gate G 1 is commonly connected to a selection line SGD
- the second selection gate G 2 is commonly connected to a selection line SGS.
- the memory cell array A 1 includes one or more planes P 1 .
- Each plane P 1 includes a plurality of blocks 42 .
- Each block 42 is configured by a plurality of NAND cells and is a unit for data deletion.
- a plurality of memory cells 41 connected to one word line configure one physical sector 43 .
- Data is written and read for each physical sector 43 .
- a two bits/cell writing system quad values
- in one physical sector 43 for example, data corresponding to two pages is stored.
- a one bit/cell writing system binary values
- in one physical sector 43 for example, data corresponding to one page is stored.
- one physical sector 43 for example, data corresponding to three pages is stored.
- a read operation, a program verification operation, or a program operation is performed, one word line is selected in accordance with a physical address received from the NAND I/F 74 of the controller 7 , whereby the physical sector 43 is selected.
- the conversion of a page into the physical sector 43 is performed using the physical address.
- the memory system 1 illustrated in FIG. 1 instead of the NAND memory 4 , may include a magnetoresistive random access memory (MRAM) or a resistance random access memory (ReRAM) as the non-volatile memory.
- MRAM magnetoresistive random access memory
- ReRAM resistance random access memory
- the DRAM 5 serves as a transmission buffer for writing data and read data between the host device 2 and the NAND memory 4 and serves as a storage area of various kinds of management table data (hereinafter, referred to as “management data”).
- the management data is used for controlling the transmission of writing data and read data between the host device 2 and the NAND memory 4 .
- the management data for example, includes mapping information that represents relation between a logical address designated by the host device 2 and a storage position (physical address) on the NAND memory 4 .
- the DRAM 5 in order to maintain data, needs a refreshing operation rewriting (charging capacitors configuring the DRAM 5 ) the data on a regular basis.
- the memory system 1 instead of the DRAM 5 , may include a static random access memory (SRAM) as the volatile memory.
- SRAM static random access memory
- the controller 7 controls a write command and a read command transmitted from the host device 2 .
- the controller 7 includes: a SATA interface (hereinafter, referred to as a “SATA I/F”) 70 ; a processor 71 ; a system 72 (logic circuit) and a general purpose input output (GPIO) 73 as interfaces; a NAND interface (hereinafter, referred to as a “NAND I/F”) 74 ; a DRAM interface (hereinafter, referred to as a “DRAM I/F”) 75 ; and an internal bus B 1 .
- the SATA I/F 70 , the processor 71 , the system 72 , the GPIO 73 , the NAND I/F 74 , and the DRAM I/F 75 are interconnected through the internal bus B 1 .
- the SATA I/F 70 is connected to the SATA connector 3 , converts a write command, a read command, or the like, which is transmitted from the host device 2 , received through the SATA connector 3 into an internal signal of the controller 7 , and outputs the internal signal to the internal bus B 1 .
- the SATA I/F 70 converts a command or the like received from the inside of the controller 7 through the internal bus B 1 into an external signal of the controller 7 , and transmits the external signal to the SATA connector 3 .
- the processor 71 uses the DRAM 5 as a buffer for writing data and writes the writing data into the NAND memory 4 based on the write command, management data stored in the DRAM 5 , and the like.
- the processor 71 reads data from the NAND memory 4 based on the read command, the management data stored in the DRAM 5 , and the like and transmits the read data to the host device 2 using the DRAM 5 as a buffer for the read data.
- the system 72 is connected to the SATA connector 3 in addition to the internal bus B 1 and, as will be described later, controls the power supply circuit 8 .
- the GPIO 73 controls the power supply circuit 8 .
- the NAND I/F 74 directly controls writing data into the NAND memory 4 and reading data from the NAND memory 4 based on a command transmitted from the processor 71 .
- the DRAM I/F 75 directly controls wiring data into the DRAM 5 and reading data from the DRAM 5 based on a command transmitted from the processor 71 .
- the capacitor 6 can supply power to the DRAM 5 through the power supply circuit 8 .
- the capacitor 6 is charged by receiving supply of power from any other power supply.
- the static capacitance of the capacitor 6 for example, is about 0.01 to 0.047 (F).
- the power supply circuit 8 is also connected to the NAND memory 4 , the DRAM 5 , the capacitor 6 , and the controller 7 and can supply the power delivered from the host device 2 to the NAND memory 4 , the DRAM 5 , the capacitor 6 , and the controller 7 .
- the host device 2 serves as an external power supply for the memory system 1 .
- the power supply circuit 8 is assumed to be in a state (power supply steady state) in which power is supplied from the host device 2 unless otherwise mentioned.
- the power supply circuit 8 can supply power from the capacitor 6 to the DRAM 5 .
- the power supply circuit 8 includes: switching devices 81 a and 81 b; DC/DC converters 82 a and 82 b; low drop-outs (LDO) 83 a to 83 c; and an input resistor 84 .
- the switching device 81 a is interposed between the capacitor 6 and the SATA connector 3 .
- the switching device 81 a in an On state illustrated in FIG. 1 , connects the capacitor 6 and the SATA connector 3 .
- the switching device 81 a in an Off state, causes the capacitor 6 and the SATA connector 3 not to be connected to each other.
- the switching device 81 b is interposed between the capacitor 6 , the DC/DC converter 82 a, and the LDO 83 a.
- the switching device 81 b in a first switching state illustrated in FIG. 1 , connects the DC/DC converter 82 a and the LDO 83 a and causes the capacitor 6 and the LDO 83 a not to be connected to each other.
- the switching device 81 b in a second switching state not illustrated in FIG. 1 , causes the DC/DC converter 82 a and the LDO 83 a not to be connected to each other and connects the capacitor 6 and the LDO 83 a.
- the DC/DC converter 82 a is connected to the SATA connector 3 through the fuse 10 .
- the DC/DC converter 82 a monitors the level of an enable signal (hereinafter, referred to as an “EN signal”) S 1 to be described later and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S 1 .
- an enable signal hereinafter, referred to as an “EN signal”
- the DC/DC converter 82 a in the conductive state, supplies power delivered from the host device 2 to the NAND I/F 74 , each component (the processor 71 , the DRAM I/F 75 , and the like; here, the system 72 , the GPIO 73 , and the NAND I/F 74 are excluded; hereinafter, referred to as “the other components”) of the controller 7 , and the LDO 83 a.
- This DC/DC converter 82 a converts the output voltage of the host device 2 into a predetermined voltage that is required for the NAND I/F 74 and the other components of the controller 7 and outputs the predetermined voltage.
- the DC/DC converter 82 a in the non-conductive state, cuts off the supply of power delivered from the host device 2 to the NAND I/F 74 , the other components of the controller 7 , and the LDO 83 a.
- the DC/DC converter 82 b is connected to the SATA connector 3 through the fuse 10 .
- the DC/DC converter 82 b monitors the level of an EN signal S 2 to be described later and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S 2 .
- the DC/DC converter 82 b in the conductive state, supplies power delivered from the host device 2 to the NAND memory 4 .
- This DC/DC converter 82 b converts the output voltage of the host device 2 into a predetermined voltage that is required for the NAND memory 4 and outputs the predetermined voltage.
- the DC/DC converter 82 b in the non-conductive state, cuts off the supply of power delivered from the host device 2 to the NAND memory 4 .
- the LDO 83 a is connected to the capacitor 6 and the DC/DC converter 82 a through the switching device 81 b.
- the LDO 83 a monitors the level of an EN signal S 4 to be described later and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S 4 .
- the LDO 83 a in the conductive state, supplies power delivered from the host device 2 or power supplied from the capacitor 6 to the DRAM 5 through the DC/DC converter 82 a in accordance with switching of the switching devices 81 a and 81 b.
- the LDO 83 a converts the output voltage of the DC/DC converter 82 a and the output voltage of the capacitor 6 into a predetermined voltage that is required for the DRAM 5 and outputs the predetermined voltage. In addition, the LDO 83 a, in the non-conductive state, cuts off the supply of power delivered from the host device 2 or the capacitor 6 to the DRAM 5 .
- the LDO 83 b is connected to the SATA connector 3 through the fuse 10 .
- the LDO 83 b monitors the level of an EN signal S 5 to be described later and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S 5 .
- the LDO 83 b in the conductive state, supplies power delivered from the host device 2 to the GPIO 73 and the LDO 83 c.
- the LDO 83 b converts the output voltage of the host device 2 into a predetermined voltage that is required for the GPIO 73 and outputs the predetermined voltage.
- the LDO 83 b in the non-conductive state, cuts off the supply of power delivered from the host device 2 to the GPIO 73 and the LDO 83 c, Furthermore, the DC/DC converters 82 a and 82 b and the LDO 83 b are connected to a branch point BP and are connected to the fuse 10 through the branch point BP.
- the LDO 83 c is connected to the SATA connector 3 through the LDO 83 b and the fuse 10 .
- the LDO 83 c in the conductive state, supplies power delivered from the host device 2 through the LDO 83 b to the system 72 .
- This LDO 83 c converts the output voltage of the LDO 83 b into a predetermined voltage required for the system 72 and outputs the predetermined voltage.
- An input resistor 84 is connected to the capacitor 6 in series and suppresses a current input to the capacitor 6 when the capacitor 6 is charged.
- a V.DET 9 a is connected between the input resistor 84 of the power supply circuit 8 and the capacitor 6 , monitors the output voltage of the capacitor 6 , and outputs a result of the monitoring to the GPIO 73 .
- the fuse 10 is interposed between the SATA connector 3 and the power supply circuit 8 and blows so as to protect the power supply circuit 8 in a case where an excessive current is supplied from the host device 2 .
- the memory system 1 transits to a low power consumption mode (DEVSLP mode) in which the supply of power from the host device 2 for the operation is suppressed, for example to be 5 (mW) or less.
- DEVSLP mode low power consumption mode
- the SATA connector 3 outputs a DEVSLP signal S 0 for switching the memory system 1 between the DEVSLP mode and a normal mode (a state in which the DEVSLP mode is disabled) to the system 72 .
- the SATA connector 3 switches the DEVSLP signal S 0 to a high level.
- the SATA connector 3 switches the DEVSLP signal S 0 to a low level.
- FIG. 3 is a flowchart that illustrates switching between the normal mode and the DEVSLP mode of the memory system 1 .
- the system 72 illustrated in FIG. 1 monitors the DEVSLP signal S 0 transmitted from the SATA connector 3 at a predetermined interval in Step S 1 and determines whether or not the memory system 1 is in the normal mode based on the level of the DEVSLP signal S 0 in Step S 2 . In a case where the DEVSLP signal S 0 is in the low level, the system 72 determines that the memory system 1 is in the normal mode (Yes in Step S 2 ) and monitors whether or not the DEVSLP signal S 0 is switched to the high level in Step S 3 .
- Step S 4 when the DEVSLP signal S 0 is switched to the high level, the system 72 executes a transition from the normal mode to the DEVSLP mode in Step S 4 .
- Step S 3 in a case where the DEVSLP signal S 0 is determined to be in the low level without being switched to the high level (No in Step S 3 ), the system 72 does not execute the transition to the DEVSLP mode.
- Step S 2 in a case where the DEVSLP signal S 0 is in the high level, the system 72 determines the memory system 1 to be not in the normal mode but in the DEVSLP mode (No in Step S 2 ) and monitors whether or not the DEVSLP signal S 0 is switched to the low level in Step S 5 .
- Step S 5 in a case where the DEVSLP signal S 0 is determined to be in the high level without being switched to the low level (No in Step S 5 ), the system 72 does not execute a transition from the DEVSLP mode to the normal mode.
- the system 72 illustrated in FIG. 1 outputs an EN signal S 1 switched between the high level and the low level to the DC/DC converter 82 a and, when the DEVSLP signal S 0 is switched from the low level to the high level (corresponding to Yes in Step S 3 illustrated in FIG. 3 ), the system 72 switches the EN signal S 1 to the low level.
- the DC/DC converter 82 a outputs an EN signal S 2 switched between the high level and the low level to the DC/DC converter 82 b and, when an EN signal S 1 is switched to the low level, switches the EN signal S 2 to the low level and transits to the non-conductive state, thereby cutting out the supply of power from the host device 2 to the NAND I/F 74 and the other components of the controller 7 .
- the DC/DC converter 82 b transits to the non-conductive state, thereby cutting off the supply of power from the host device 2 to the NAND memory 4 .
- the EN signal S 2 may be configured to be directly output from the system 72 to the DC/DC converter 82 b.
- the GPIO 73 outputs control signals S 31 and S 32 switched between the high level and the low level to the switching devices 81 a and 81 b.
- the system 72 switches the control signals S 31 and S 32 from the high level to the low level.
- the switching device 81 a is switched from the On state illustrated in FIG. 1 to the Off state.
- the switching device 81 b is switched from the first switching state illustrated in FIG. 1 to a second switching state.
- the capacitor 6 and the LDO 83 a are connected to each other, and accordingly, the LDO 83 a receives the supply of power from the capacitor 6 .
- the LDO 83 a maintains to be in the conductive state, and accordingly, the DRAM 5 receives supply of power from the capacitor 6 . Accordingly, when the transition to the DEVSLP mode is made, the power supply source of the DRAM 5 is switched from the host device 2 to the capacitor 6 . As long as the supply of power is continued from the capacitor 6 , the DRAM 5 performs a refreshing operation using the power and continues to maintain the management data, whereby loss of the data in the DEVSLP mode can be prevented.
- the LDO's 83 b and 83 c maintain the conductive state. Accordingly, the system 72 and the GPIO 73 receive the supply of power from the host device 2 through the LDO's 83 b and 83 c.
- the system 72 causes the memory system 1 to transit from the DEVSLP mode to the normal mode (corresponding to Step S 6 illustrated in FIG. 3 ).
- the system 72 and the GPIO 73 perform a control process that is reverse to the control process performed in the DEVSLP mode.
- the system 72 switches the EN signal S 1 to the high level.
- the DC/DC converter 82 a transits to the conductive state, supplies power supplied from the host device 2 to the NAND I/F 74 and the other components of the controller 7 , and switches the EN signal S 2 to the high level.
- the DC/DC converter 82 b transits to the conductive state and supplies power supplied from the host device 2 to the NAND memory 4 .
- the system 72 switches the control signals S 31 and S 32 output from the GPIO 73 from the low level to the high level.
- the switching devices 81 a and 81 b are switched from the Off state or the second switching state to the On state illustrated in FIG. 1 or the first switching state.
- these switching devices 81 a and 81 b are switched to the On state illustrated in FIG.
- the capacitor 6 and the LDO 83 a are in the non-conductive state, and the LDO 83 a and the DC/DC converter 82 a are connected to each other, whereby the LDO 83 a receives the supply of power from the host device 2 through the DC/DC converter 82 a.
- the switching device 81 a When the memory system 41 transits to the normal mode, the switching device 81 a is in the On state, and the capacitor 6 and the host device 2 are connected to each other. Accordingly, the capacitor 6 receives the supply of power from the host device 2 and is charged. According to such charging, the capacitor 6 , in the DEVSLP mode, can recover the power that is reduced due to the supply of power to the DRAM 5 .
- the LDO's 83 a to 83 c maintain the conductive state. Accordingly, even when the memory system 1 transits to the normal mode, the DRAM 5 receives the supply of power from the host device 2 through the LDO 83 a. In addition, the system 72 and the GPIO 73 receive the supply of power from the host device 2 through the LDO's 83 b and 83 c.
- the LDO's 83 a and 83 b can be caused to the non-conductive state in accordance with the EN signals S 4 and S 5 .
- the EN signal S 4 is output from the GPIO 73 and is switched between the high level and the low level.
- the LDO 83 a transits to the non-conductive state and cuts off the supply of power to the DRAM 5 .
- the EN signal S 5 is an input voltage of the LDO 83 b and is switched between the high level and the low level in accordance with an input voltage.
- the LDO 83 b transits to the non-conductive state and cuts off the supply of power to the GPIO 73 and the LDO 83 c.
- the EN signals S 4 and S 5 may be switched to the high level.
- FIG. 4 is a diagram that illustrates power consumption in the normal mode and the DEVSLP mode of the memory system 1 .
- the horizontal axis represents the time.
- the vertical axis represents power (power consumption of the memory system 1 ) supplied from the host device 2 to the memory system 1 .
- the memory system 1 In the normal mode, the memory system 1 , as described above, supplies power delivered from the host device 2 to the NAND memory 4 , the DRAM 5 , the capacitor 6 , and the controller 7 . Accordingly, the power consumption of the memory system 1 in the normal mode, for example, is about 50 to 100 (mW).
- the memory system 1 limits the supply of power from the host device 2 to the system 72 and the GPIO 73 . Accordingly, the power consumption of the memory system 1 in the DEVSLP mode is lower than the power consumption of the memory system 1 in the normal mode, for example, to be 5 (mW) or less as represented by a dashed line K 0 in FIG. 4 .
- the GPIO 73 illustrated in FIG. 1 receives a monitoring result of the output voltage of the capacitor 6 from the V.DET 9 a and notifies the system 72 of the monitoring result.
- the system 72 detects such a decrease in the remaining power, outputs a control signal (not illustrated in the figure) of the high level to the switching device 81 a even in the DEVSLP mode, and turns on the switching device 81 a so as to connect the host device 2 and the capacitor 6 , thereby charging the capacitor 6 .
- a control signal not illustrated in the figure
- the power consumption of the memory system 1 temporarily increases as denoted as periods T 1 and T 2 in FIG. 4 .
- the memory system 1 when transiting to the DEVSLP mode, the memory system 1 stops the supply of power from the host device 2 to the DRAM 5 , the NAND memory 4 , the NAND I/F 74 , and the other components of the controller 7 and supplies power from the capacitor 6 to the DRAM 5 . Accordingly, in order to suppress the power consumption of the host device 2 , even when the supply of power from the host device 2 to the DRAM 5 is cut off, the memory system 1 maintains the management data stored in the DRAM 5 continuously in the DRAM 5 , whereby loss of the data can be prevented.
- the memory system 1 even when transiting to the DEVSLP mode, the memory system 1 continuously maintains the management data stored in the DRAM 5 in the DRAM 5 without copying the management data to the NAND memory 4 . Accordingly, differently from the comparative example, the memory system 1 does not consume much power according to the copying process. In addition, according to the memory system 1 , differently from the comparative example, since stress according to the copying process is not applied to the NAND memory 4 , a decrease in the life of the NAND memory 4 can be suppressed.
- FIG. 5 is a block diagram that illustrates the configuration of a memory system 1 according to a second embodiment.
- the memory system 1 not only responds to a DEVSLP mode but appropriately protects data stored in a DRAM 5 even when a transition to a state in which the supply of power from an external power supply (host device 2 ) to a power supply circuit 8 is completely cut off is made.
- host device 2 external power supply
- a power supply circuit 8 power supply circuit 8
- the memory system 1 includes a super capacitor 11 and a V.DET 9 b.
- the super capacitor 11 serves as an internal power supply replacing the capacitor 6 according to the first embodiment.
- the super capacitor 11 for example, has static capacitance of about 1 (F) and has a power supply capability that is superior to the capacitor 6 according to the first embodiment as an internal power supply and has capacitance enabling writing data temporarily stored in the DRAM 5 and management data stored in the DRAM 5 to be copied to a NAND memory 4 .
- the super capacitor 11 is charged by receiving supply of power from another power supply.
- a V.DET 9 b is connected between a fuse 10 and a power supply circuit 8 (between the fuse 10 and a switching device 81 c to be described later), monitors an output voltage of the host device 2 for the power supply circuit 8 , and transmits a monitoring result thereof to a GPIO 73 .
- the V.DET 9 b based on the monitoring result, outputs a control signal S 70 switched between the high level and the low level to switching devices 81 c, 81 e, and 81 f to be described later and outputs an EN signal S 71 switched between the high level and the low level to a converter 86 to be described later.
- the V.DET 9 b controls the switching devices 81 c, 81 e, and 81 f and the converter 86 using the control signal S 70 and the EN signal S 71 .
- the V.DET 9 a is connected between the power supply circuit 8 and the super capacitor 11 , monitors an output voltage of the super capacitor 11 , and outputs a monitoring result thereof to the GPIO 73 .
- the power supply circuit 8 includes: switching devices 81 c to 81 f replacing the switching device 81 a according to the first embodiment; a charger 85 replacing the input resistor 84 ; and newly the converter 86 .
- the switching device 81 c is interposed in a first path.
- This first path is a section from the fuse 10 to a branch point BP.
- the switching device 81 c connects DC/DC converters 82 a and 82 b and an LDO 83 b to a SATA connector 3 through the fuse 10 .
- the switching device 81 c causes the DC/DC converters 82 a and 82 b and the LDO 83 b not to be connected to the SATA connector 3 .
- Switching devices 81 d to 81 f are interposed in a second path.
- This second path is connected to the first path in parallel between the switching device 81 c and the branch point BP.
- the switching devices 81 d to 81 f are in mutually-serial relation in the second path.
- the charger 85 is interposed in the second path.
- the converter 86 is interposed in the second path, between the switching device 81 e and the switching device 81 f.
- a first electrode of the super capacitor 11 is connected.
- the switching device 81 d connects the charger 85 to the first path.
- the switching device 81 d causes the charger 85 not to be connected to the first path.
- the switching device 81 e connects the charger 85 to the super capacitor 11 and the converter 86 .
- the switching device 81 e causes the charger 85 not to be connected to the super capacitor 11 and the charger 85 .
- the switching device 81 f connects the super capacitor 11 to the first path through the converter 86 .
- the switching device 81 f causes the converter 86 and the super capacitor 11 not to be connected to the first path.
- the switching device 81 b connects the DC/DC converter 82 a and the LDO 83 a and causes the super capacitor 11 and the LDO 83 a not to be connected to each other.
- the switching device 81 b causes the DC/DC converter 82 a and the LDO 83 a not to be connected to each other and connects the super capacitor 11 and the LDO 83 a.
- the charger 85 is connected to the super capacitor 11 through the switching device 81 e.
- the charger 85 improves the charging efficiency of the super capacitor 11 by controlling the charging of the super capacitor 11 .
- the converter 86 is connected to the super capacitor 11 and performs control such that the output voltage of the super capacitor 11 is the same as the output voltage of the host device 2 and outputs the output voltage.
- the converter 86 monitors the level of the EN signal S 71 and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S 71 .
- the converter 86 outputs power supplied from the super capacitor 11 to the DC/DC converters 82 a and 82 b and the LDO 83 b.
- the converter 86 cuts off such an output.
- the DC/DC converters 82 a and 82 b transits to the non-conductive state in accordance with EN signals S 1 and S 2 of the low level.
- the GPIO 73 outputs a control signal S 61 that is switched between the high level and the low level to the switching device 81 b.
- the GPIO 73 outputs a control signal S 62 that is switched between the high level and the low level to the switching devices 81 d and 81 e.
- a system 72 switches the switching devices 81 b, 81 d, and 81 e from the On state illustrated in FIG. 5 or the first switching state to the Off state or the second switching state by switching the control signals S 61 and S 62 output from the GPIO 73 to the low level.
- the super capacitor 11 and the LDO 83 a are connected, and the LDO 83 a receives the supply of power from the super capacitor 11 . Accordingly, the power supply source of the DRAM 5 that receives the supply of power through the LDO 83 a is switched from the host device 2 to the super capacitor 11 . As long as the supply of power from the super capacitor 11 is received, the DRAM 5 performs a refreshing operation using the supplied power and continuously maintains management data, thereby preventing loss of the management data in the DEVSLP mode.
- the switching device 81 c is controlled to be in the On state, the system 72 and the GPIO 73 receives supply of power from the host device 2 through the LDO's 83 b and 83 c.
- the switching device 81 f is controlled to be in the Off state illustrated in FIG. 5 .
- the DC/DC converters 82 a and 82 b are in the non-conductive state, and, even when being connected to the host device 2 or the super capacitor 11 , the DC/DC converters 82 a and 82 b cuts off power supplied from the host device 2 and the super capacitor 11 to the NAND memory 4 , the NAND I/F 74 , the LDO 83 a, and the other components of the controller 7 .
- the memory system 1 detects a decrease in the remaining power and, even in the DEVSLP mode, switches the control signal S 62 to the high level and causes the switching devices 81 d and 81 e to be in the On state so as to connect the host device 2 and the super capacitor 11 , thereby charging the super capacitor 11 .
- the memory system 1 in a case where the fuse 10 blows or a power failure occurs, there are cases where the memory system 1 according to the second embodiment transits to a state (power supply cut-off state) in which the supply of power from the host device 2 as an external power supply to the power supply circuit 8 is completely cut off.
- the V.DET 9 b in a case where the output voltage of the host device 2 for the power supply circuit 8 is determined to be a threshold or less, detects such a power supply cut-off state. In such a case, the V.DET 9 b switches the control signal S 70 and the EN signal S 71 to the low level and transmits a result of the detection of the power supply cut-off state to the GPIO 73 .
- the switching devices 81 c and 81 e are switched from the On state illustrated in FIG. 5 to the Off state.
- the switching device 81 f is switched from the Off state illustrated in FIG. 5 to the On state.
- the converter 86 is switched to the conductive state.
- the super capacitor 11 and the LDO 83 b are connected, and the power supply source of the system 72 and the GPIO 73 to which power is supplied through the LDO 83 b is switched from the host device 2 to the super capacitor 11 .
- the system 72 and the GPIO 73 continue to operate, the remaining power of the super capacitor 11 is monitored by the GPIO 73 , and the DC/DC converters 82 a and 82 b can be controlled by the system 72 .
- the memory system 1 In the normal mode, when the power supply cut-off state is detected, the memory system 1 according to the second embodiment operates to copy the management data from the DRAM 5 to the NAND memory 4 . Even when the memory system 1 transits to the power supply cut-off state as above, the system 72 performs control of the DC/DC converters 82 a and 82 b to be in the conductive state. For this reason, even in the power supply cut-off state, the NAND memory 4 , the other components (the processor 71 , the DRAM I/F 75 , and the like) of the controller 7 , the NAND I/F 74 , and the DRAM 5 operate by receiving the supply of power from the super capacitor 11 .
- the GPIO 73 transmits a result of the detection of the power supply cut-off state that is transmitted from the V.DET 9 b to the processor 71 through the internal bus B 1 .
- the processor 71 transmits a data copy command for copying data (the writing data, the management data, and the like) stored in the DRAM 5 to the NAND memory 4 to the NAND I/F 74 and the DRAM I/F 75 .
- the NAND I/F 74 and the DRAM I/F 75 copies the data from the DRAM 5 to the NAND memory 4 in accordance with the command.
- the system 72 stops the supply of power from the super capacitor 11 to the NAND memory 4 , the other components (the processor 71 , the DRAM I/F 75 , and the like) of the controller 7 , the NAND I/F 74 and the DRAM 5 by performing control of the DC/DC converters 82 a and 82 b to be in the non-conductive state.
- the memory system 1 maintains the supply of power from the super capacitor 11 to the DRAM 5 by performing control of the switching device 81 b to be in the second switching state, thereby continuously maintaining the management data in the DRAM 5 using the power supplied from the super capacitor 11 .
- the V.DET 9 b determines that the power supply cut-off state is released and switches the control signal S 70 and the EN signal S 71 to the high level.
- the switching devices 81 c and 81 e are switched from the Off state to the On state illustrated in FIG. 5 .
- the switching device 81 f is switched from the On state to the Off state illustrated in FIG. 5 .
- the converter 86 is switched to the non-conductive state. Accordingly, the power supply source of the system 72 and the GPIO 73 is switched from the super capacitor 11 to the host device 2 .
- the memory system 1 When the power supply cut-off state is detected in the DEVSLP mode, the memory system 1 according to the second embodiment, in order to appropriately protect the management data stored in the DRAM 5 , can operate to copy the management data from the DRAM 5 to the NAND memory 4 by consuming the power of the super capacitor 11 . More specifically, in a case where output voltage information of the super capacitor 11 is received from the V.DET 9 a in the middle of the power supply cut-off state in the DEVSLP mode, the GPIO 73 outputs the voltage information to the system 72 through the internal bus B 1 .
- the system 72 switches the EN signal S 1 to the high level so as to cause the DC/DC converter 82 a to be in the conductive state.
- the DC/DC converter 82 a switches the EN signal S 2 to the high level so as to cause the DC/DC converter 82 b to be in the conductive state.
- the converter 86 is in the conductive state, and the switching device 81 f is in the On state.
- the NAND memory 4 , the other components (the processor 71 , the DRAM I/F 75 , and the like) of the controller 7 , and the NAND I/F 74 are connected to the super capacitor 11 through the DC/DC converters 82 a and 82 b and operate by receiving the supply of power from the super capacitor 11 .
- the processor 71 transmits a data copy command for copying the management data stored in the DRAM 5 to the NAND memory 4 to the NAND I/F 74 and the DRAM I/F 75 .
- the NAND I/F 74 and the DRAM I/F 75 copy the management data from the DRAM 5 to the NAND memory 4 in accordance with the command.
- the threshold of the output voltage of the super capacitor 11 is set to a voltage value for which the management data stored in the DRAM 5 can be copied to the NAND memory 4 using the remaining power of the super capacitor 11 . For this reason, the management data can be appropriately protected before the management data cannot be maintained in the DRAM 5 due to a decrease in the remaining power of the super capacitor 11 as the power supply cut-off state lasts for a long time.
- the DC/DC converters 82 a and 82 b transit to the conductive state based on the EN signals S 1 and S 2 of the high level.
- the system 72 switches the switching devices 81 b, 81 d, and 81 e from the Off state or the second switching state to the On state illustrated in FIG. 5 or the first switching state by switching the control signals S 61 and S 62 output from the GPIO 73 to the high level.
- the LDO 83 a is caused not to be connected to the super capacitor 11 but is connected to the DC/DC converter 82 a, and similar to the first embodiment, receives the supply of power from the host device 2 through the DC/DC converter 82 a.
- the switching device 81 c is controlled to be in the On state and enables the supply of power from the host device 2 to the DC/DC converters 82 a and 82 b and the LDO 83 b.
- the switching device 81 f is controlled to be in the Off state.
- the super capacitor 11 is connected to the host device 2 through the charger 85 and is charged by receiving the supply of power from the host device 2 . Through such a charging process, the super capacitor 11 can recover the remaining power lowered in the DEVSLP mode or the like.
- the memory system 1 when transiting to the DEVSLP mode, the memory system 1 stops the supply of power from the host device 2 to the DRAM 5 , the NAND memory 4 , the NAND I/F 74 , and the other components of the controller 7 and supplies power from the super capacitor 11 to the DRAM 5 . Accordingly, similar to the first embodiment, in order to suppress the power consumption of the host device 2 , even when the supply of power from the host device 2 to the DRAM 5 is cut off, the memory system 1 maintains the management data continuously in the DRAM 5 without copying the management data stored in the DRAM 5 into the NAND memory 4 , whereby loss of the data can be prevented.
- the memory system 1 when the power supply cut-off state is detected in the DEVSLP mode, the memory system 1 supplies power from the super capacitor 11 to the GPIO 73 and the system 72 . Accordingly, even when transiting to the power supply cut-off state, the memory system 1 monitors the remaining power of the super capacitor 11 by operating the system 72 and the GPIO 73 , whereby the DC/DC converters 82 a and 82 b can be controlled.
- the memory system 1 copies the management data stored in the DRAM 5 into the NAND memory 4 by consuming the power of the super capacitor 11 . Accordingly, even in a case where the power supply cut-off state lasts for a long time, the memory system 1 can appropriately protect the management data stored in the DRAM 5 before the remaining power of the super capacitor 11 becomes insufficient.
- FIG. 6 is a block diagram that illustrates the configuration of a memory system 1 according to a third embodiment.
- the memory system 1 does not respond to a DEVSLP mode but protects data stored in a DRAM 5 even when a transition to a state in which the supply of power from an external power supply to a power supply circuit 8 is completely cut off is made.
- the same reference numeral will be assigned to the same configuration as that of the first embodiment, and duplicate description thereof will not be presented.
- the memory system 1 includes: a primary battery 12 as an internal power supply; a V.DET 9 c; and an LED device 13 as an alert display unit.
- the primary battery 12 serves as an internal power supply replacing the capacitor 6 according to the first embodiment.
- the primary battery 12 is a button-type battery.
- the primary battery 12 is not connected to a SATA connector 3 .
- the V.DET 9 c is connected between a fuse 10 and a power supply circuit 8 (a path connecting DC/DC converters 82 a and 82 b and an LDO 83 b to the fuse 10 ), monitors the output voltage of a host device 2 for the power supply circuit 8 , and outputs a monitoring result thereof to the GPIO 73 .
- the LED device 13 has an LED built therein and, when an EN signal S 8 to be described later is switched to the high level, turns on the LED so as to display an alert for promoting the replacement of the primary battery 12 .
- the LED is attached to a position that is viewable from a user, and the LED device 13 turns off the LED when the EN signal S 8 is switched to the low level.
- the power supply circuit 8 includes a switching device 81 g replacing the switching device 81 a according to the first embodiment in addition to a switching device 81 b.
- the switching device 81 g is interposed between a branch point BP and the LDO 83 b and the primary battery 12 .
- the switching device 81 g connects the LDO 83 b and the SATA connector 3 in a first switching state illustrated in FIG. 6 and causes the LDO 83 b and the primary battery 12 not to be connected to each other.
- the switching device 81 g causes the LDO 83 b and the SATA connector 3 not to be connected to each other and connects the LDO 83 b and the primary battery 12 .
- the switching device 81 b In the first switching state illustrated in FIG. 6 , the switching device 81 b according to the third embodiment connects the LDO 83 a and the DC/DC converter 82 a and causes the LDO 83 a and the primary battery 12 not to be connected to each other. To the contrary, in a second switching state not illustrated in FIG. 6 , the switching device 81 b causes the LDO 83 a and the DC/DC converter 82 a not to be connected to each other and connects the LDO 83 a and the primary battery 12 .
- the V.DET 9 a is connected between the power supply circuit 8 and the primary battery 12 , monitors the output voltage of the primary battery 12 , and outputs a monitoring result thereof to the GPIO 73 .
- the memory system 1 transits to a state (power supply cut-off state) in which the supply of power from the host device 2 to the power supply circuit 8 is cut off. In such cases, it is necessary to protect data (writing data, management data, and the like) stored in the DRAM 5 .
- the memory system 1 switches the power supply source of the NAND memory 4 , the DRAM 5 , and the controller 7 from the host device 2 to the primary battery 12 , thereby protecting the data stored in the DRAM 5 .
- the GPIO 73 outputs a control signal S 9 switched between the high level and the low level to the switching devices 81 b and 81 g.
- the GPIO 73 detects the power supply cut-off state and switches the control signal S 9 to the low level.
- the switching devices 81 b and 81 g are switched from the first switching state illustrated in FIG. 6 to the second switching state.
- the switching devices 81 b and 81 g are switched to the second switching state, the LDO's 83 a and 83 b are connected to the primary battery 12 and receive supply of power from the primary battery 12 . Accordingly, when the supply of power is received through the LDO's 83 a and 83 b, the power supply source of the DRAM 5 , the system 72 , and the GPIO 73 is switched to the primary battery 12 .
- the LDO 83 a maintains the conductive state and supplies power delivered from the primary battery 12 to the DRAM 5 .
- the DRAM 5 performs a refreshing operation using the power, the data stored in the DRAM 5 is continuously maintained, whereby loss of the data can be prevented.
- the LDO's 83 b and 83 c maintain the conductive states.
- the system 72 and the GPIO 73 operate by receiving the supply of power from the primary battery 12 .
- the GPIO 73 receives a monitoring result of the output voltage of the primary battery 12 from the V.DET 9 a and determines the output voltage to be a threshold or less, thereby detecting a decrease in the remaining power.
- the GPIO 73 outputs an EN signal S 8 switched between the high level and the low level to the LED device 13 and, in a case where the output voltage of the primary battery 12 is a threshold or less, switches the EN signal S 8 to the high level.
- the LED device 13 When the EN signal S 8 is switched to the high level, the LED device 13 turns on the LED built in the LED device 13 , thereby allowing the user to recognize an alert for promoting the replacement of the primary battery 12 .
- the GPIO 73 switches the EN signal S 8 to the low level, thereby turning off the LED of the LED device 13 .
- the GPIO 73 determines that the power supply cut-off state is released and switches the control signal S 9 to the high level.
- the switching devices 81 b and 81 g are switched from the second switching state to the first switching state illustrated in FIG. 6 .
- the LDO's 83 a and 83 b are caused not to be connected to the primary battery 12 and are connected to the host device 2 through the SATA connector 3 .
- the LDO's 83 a to 83 c and the DC/DC converters 82 a and 82 b are controlled to be in the conductive state. Accordingly, the NAND memory 4 , the DRAM 5 , and the controller 7 receive the supply of power from the host device 2 .
- the memory system 1 when the power supply cut-off state is detected, the memory system 1 supplies power from the primary battery 12 to the DRAM 5 .
- the memory system 1 continuously maintains the data, which is stored in the DRAM 5 , in the DRAM 5 , thereby preventing loss of the data.
- FIG. 7 is a block diagram that illustrates the configuration of a memory system 1 according to a fourth embodiment.
- the memory system 1 according to the fourth embodiment compared to the memory system 1 according to the third embodiment, has a superior power supply capability of the internal power supply.
- the same reference numeral will be assigned to the same configuration as that of the first or third embodiment, and duplicate description thereof will not be presented.
- the memory system 1 according to the fourth embodiment includes: a plurality of primary batteries 12 connected in parallel as internal power supplies; a plurality of diodes 87 ; and a plurality of V.DET's 9 a, which is different from the memory system 1 according to the third embodiment.
- Each diode 87 is connected to a corresponding primary battery 12 in series.
- Each diode 87 serves to enable the supply of power from a primary battery 12 that is connected thereto in series to LDO's 83 a and 83 b and to cut off the supply of power from a primary battery 12 connected thereto in parallel to the primary battery 12 connected thereto in series. Accordingly, even when the output voltages of the primary battery 12 are different from each other, the memory system 1 can appropriately supply power to the LDO's 83 a and 83 b without consuming power of the primary batteries 12 inside the plurality of primary batteries 12 .
- Each V.DET 9 a is connected between the diode 87 and the primary battery 12 that are connected in series, monitors the output voltage of each primary battery 12 , and outputs a monitoring result thereof to the GPIO 73 .
- the GPIO 73 switches the EN signal S 8 to the high level.
- the LED device 13 turns on an LED built in the LED device 13 , thereby allowing the user to recognize an alert for promoting the replacement of the primary battery 12 .
- the GPIO 73 switches the EN signal S 8 to the low level, thereby turning off the LED of the LED device 13 .
- the memory system 1 may be configured to include three or more primary batteries 12 , three or more diodes 87 , and three or more V.DET's 9 a.
- the switching device 81 g connects the LDO 83 b and the SATA connector 3 and causes the LDO 83 b and the plurality of the primary batteries 12 not to be connected to each other.
- the switching device 81 g causes the LDO 83 b and the SATA connector 3 not to be connected to each other and connects the LDO 83 b and the plurality of the primary batteries 12 .
- the switching device 81 b connects the LDO 83 a and the DC/DC converter 82 a and causes the LDO 83 a and the plurality of the primary batteries 12 not to be connected to each other.
- the switching device 81 b causes the LDO 83 a and the DC/DC converter 82 a not to be connected to each other and connects the LDO 83 a and the plurality of the primary batteries 12 .
- the memory system 1 since the memory system 1 includes the plurality of the primary batteries 12 , there are more power supply sources of the DRAM 5 , the system 72 , and the GPIO 73 than those of the memory system 1 according to the third embodiment, and, even in the power supply cut-off state, power can be supplied to the DRAM 5 , the system 72 , and the GPIO 73 for a long time.
- the memory system 1 since the memory system 1 includes the plurality of the primary batteries 12 , the primary batteries 12 are replaced in turns, and accordingly, the power supply cut-off state can be further continued.
- FIG. 8 is a block diagram that illustrates the configuration of a memory system 1 according to a fifth embodiment.
- the memory system 1 according to the fifth embodiment not only responds to a DEVSLP mode but protects data stored in a DRAM 5 even when a transition to a state in which the supply of power from an external power supply (host device 2 ) to a power supply circuit 8 is completely cut off is made.
- host device 2 external power supply
- FIG. 8 is a block diagram that illustrates the configuration of a memory system 1 according to a fifth embodiment.
- the memory system 1 according to the fifth embodiment not only responds to a DEVSLP mode but protects data stored in a DRAM 5 even when a transition to a state in which the supply of power from an external power supply (host device 2 ) to a power supply circuit 8 is completely cut off is made.
- host device 2 external power supply
- the memory system 1 according to the fifth embodiment additionally includes a primary battery 12 , V.DET's 9 c and 9 d, and an LED device 13 as an alert display unit in addition to the memory system 1 according to the first embodiment.
- the primary battery 12 serves as an internal power supply of the memory system 1 and is connected to a capacitor 6 in parallel.
- the primary battery 12 is a button-type battery.
- the output voltage of the primary battery 12 is lower than the output voltage of the capacitor 6 that is sufficiently charged.
- the V.DET 9 c is connected between a fuse 10 and a power supply circuit 8 (a path connecting DC/DC converters 82 a and 82 b and an LDO 83 b to the fuse 10 ), monitors the voltage that is supplied from a host device 2 for the power supply circuit 8 , and outputs a monitoring result thereof to the GPIO 73 .
- the V.DET 9 d is connected between the power supply circuit 8 and the primary battery 12 , monitors the output voltage of the primary battery 12 , and outputs a monitoring result thereof to the GPIO 73 .
- the LED device 13 has an LED built therein and, when an EN signal S 8 to be described later is switched to the high level, turns on the LED so as to display an alert for promoting the replacement of the primary battery 12 .
- the LED is attached to a position that is viewable from a user, and the LED device 13 turns off the LED when the EN signal S 8 is switched to the low level.
- the power supply circuit 8 additionally includes a switching device 81 h and a diode 87 .
- the switching device 81 h is interposed between the LDO 83 b and the capacitor 6 and the primary battery 12 and a branch point BP.
- the switching device 81 h connects the LDO 83 b and the SATA connector 3 and causes the LDO 83 b not to be connected to the capacitor 6 and the primary battery 12 .
- the switching device 81 h causes the LDO 83 b and the SATA connector 3 not to be connected to each other and connects the LDO 83 b to the capacitor 6 and the primary battery 12 .
- the switching device 81 h is switched between the first switching state and the second switching state in accordance with the level of a control signal S 10 that is output from the GPIO 73 .
- the switching device 81 h is in the first switching state illustrated in FIG. 8 in accordance with the control signal S 10 of the high level and is in the second switching state in accordance with the control signal S 10 of the low level. In the DEVSLP mode and the normal mode, the switching device 81 h is in the first switching state in accordance with the control signal S 10 of the high level.
- the switching device 81 a connects the capacitor 6 and the primary battery 12 to the SATA connector 3 .
- the switching device 81 a causes the capacitor 6 and the primary battery 12 not to be connected to the SATA connector 3 .
- the switching device 81 b connects the LDO 83 a and the DC/DC converter 82 a and causes the LDO 83 a not to be connected to the capacitor 6 and the primary battery 12 .
- the switching device 81 b causes the LDO 83 a and the DC/DC converter 82 a not to be connected to each other and connects the LDO 83 a to the capacitor 6 and the primary battery 12 .
- the diode 87 is connected to the primary battery 12 in series.
- the diode 87 serves to enable the supply of power from the primary battery 12 to the LDO's 83 a and 83 b and to cut off the supply of power from the capacitor 6 connected thereto in parallel to the primary battery 12 . Accordingly, even when the output voltage of the capacitor 6 connected in parallel is higher than the output voltage of the primary battery 12 , the power of the capacitor 6 is not consumed by the primary battery 12 but is appropriately supplied to the LDO's 83 a and 83 b.
- the DC/DC converters 82 a and 82 b transit to the non-conductive state in accordance with EN signals S 1 and S 2 of the low level.
- control signals S 31 and S 32 are in the low level and causes the switching devices 81 a and 81 b to be switched to the On state illustrated in FIG. 8 or the first switching state to the Off state or the second switching state.
- the capacitor 6 and the primary battery 12 are connected to the LDO 83 a.
- the output voltage of the primary battery 12 is lower than the output voltage of the capacitor 6 that is sufficiently charged.
- the primary battery 12 does not serve as a power supply source of the LDO 83 a and does not consume power.
- the DRAM 5 receives the supply of power from the capacitor 6 through the LDO 83 a.
- the DRAM 5 in the DEVSLP mode, performs a refreshing operation using the power and continuously maintains the management data without copying the management data to the NAND memory 4 , thereby preventing loss of the data.
- the system 72 In the DEVSLP mode, in a case where the output voltage of the capacitor 6 that is monitored through the V.DET 9 a and the GPIO 73 is determined to be a threshold or less, the system 72 outputs a control signal (not illustrated in the figure) of the high level to the switching device 81 a so as to cause the switching device 81 a to be in the On state and connects the host device 2 and the capacitor 6 , thereby charging the capacitor 6 .
- the memory system 1 can maintain the output voltage of the capacitor 6 to be higher than the output voltage of the primary battery 12 , whereby unnecessary power consumption of the primary battery 12 not corresponding to charging can be prevented.
- the DC/DC converters 82 a and 82 b transit to the conductive state based on the EN signals S 1 and S 2 of the high level.
- the switching devices 81 a and 81 b are switched from the Off state or the second switching state to the On state illustrated in FIG. 8 or the first switching state in accordance with the control signals S 31 and S 32 .
- the LDO 83 a is caused not to be connected to the capacitor 6 and the primary battery 12 and is connected to the DC/DC converter 82 a.
- the DRAM 5 receives the supply of power from the host device 2 through the LDO 83 a and the DC/DC converter 82 a.
- the switching device 81 a By causing the switching device 81 a to be in the On state, the capacitor 6 and the host device 2 are connected to each other, and the capacitor 6 is charged by receiving the supply of power from the host device 2 .
- the memory system 1 transits to a state (power supply cut-off state) in which the supply of power from the host device 2 to the power supply circuit 8 is cut off. In such cases, it is necessary to protect data (writing data, management data, and the like) stored in the DRAM 5 .
- the memory system 1 switches the power supply source of the DRAM 5 , the system 72 , and the GPIO 73 from the host device 2 to the capacitor 6 and the primary battery 12 , thereby protecting the data stored in the DRAM 5 .
- the GPIO 73 detects the power supply cut-off state, switches the control signals S 31 and S 32 to the low level, outputs the control signals S 31 and S 32 to the switching devices 81 a and 81 b, switches the control signal S 10 to the low level, and outputs the control signal S 10 to the switching device 81 h.
- the switching devices 81 a, 81 b and 81 h are switched from the On state illustrated in FIG. 8 or the first switching state to the Off state or the second switching state.
- the switching devices 81 a and 81 b have already been switched to the Off state or the second switching state, and accordingly, even when the control signals S 31 and S 32 are switched to the low level, the switching devices 81 a and 81 b continuously remain to be in the Off state or the second switching state.
- the LDO's 83 a and 83 b are connected to the capacitor 6 and the primary battery 12 .
- the LDO's 83 a and 83 b receive the supply of power from one, of which the output voltage is higher, out of the capacitor 6 and the primary battery 12 . Accordingly, the power supply source of the DRAM 5 , the system 72 , and the GPIO 73 that receive the supply of power through the LDO's 83 a and 83 b is switched to the capacitor 6 or the primary battery 12 .
- the LDO's 83 a and 83 b receive the supply of power from the capacitor 6 .
- the LDO 83 a maintains to be in the conductive state and supplies power supplied from one, of which the output voltage is higher, out of the capacitor 6 and the primary battery 12 to the DRAM 5 .
- the DRAM 5 performs a refreshing operation using the supplied power and continuously maintains data stored in the DRAM 5 , thereby preventing loss of the management data.
- the switching device 81 a since the switching device 81 a is in the Off state, the supply of power from the capacitor 6 or the primary battery 12 to the host device 2 is cut off, and unnecessary power consumption of the capacitor 6 and the primary battery 12 is prevented.
- the GPIO 73 receives a monitoring result of the output voltage of the primary battery 12 from the V.DET 9 d and determines the output voltage to be a threshold or less, thereby detecting such a decrease in the remaining power.
- the GPIO 73 outputs an EN signal S 8 switched between the high level and the low level to the LED device 13 and, in a case where the output voltage of the primary battery 12 is a threshold or less, switches the EN signal S 8 to the high level.
- the LED device 13 When the EN signal S 8 is switched to the high level, the LED device 13 turns on the LED built in the LED device 13 , thereby allowing the user to recognize an alert for promoting the replacement of the primary battery 12 .
- the GPIO 73 switches the EN signal S 8 to the low level, thereby turning off the LED of the LED device 13 .
- the GPIO 73 switches the control signals S 31 , S 32 , and S 10 to the high level.
- the switching devices 81 a, 81 b, and 81 h are switched from the Off state or the second switching state to the On state illustrated in FIG. 8 or the first switching state.
- these switching devices 81 a, 81 b, and 81 h are switched to the On state illustrated in FIG.
- the LDO's 83 a and 83 b are caused not to be connected to the capacitor 6 and the primary battery 12 and are connected to the host device 2 through the SATA connector 3 , thereby receiving the supply of power from the host device 2 .
- the memory system 1 when the power supply cut-off state is detected, supplies power from the capacitor 6 or the primary battery 12 to the DRAM 5 .
- the memory system 1 not only has the same advantage as that of the first embodiment and, even when a transition to the power supply cut-off state is made, continuously maintains the data, which is stored in the DRAM 5 , in the DRAM 5 , thereby preventing loss of the data.
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Abstract
According to one embodiment, a memory system includes a volatile memory, a power supply circuit, and a controller. The power supply circuit includes a first power supply path in which power supplied from a host device is supplied to the volatile memory, a second, power supply path in which the power is supplied from the internal power supply to the volatile memory, and a switching device that switches between the first power supply path and the second power supply path. In response to an instruction for a transition to a low power consumption mode received from the host device, the controller outputs, to the switching device, an instruction to switch the power supply circuit from the first power supply path to the second power supply path.
Description
- This application is based upon and claims the benefit of priority from U.S. Provisional Application No. 62/048,959, filed on Sep. 11, 2014; the entire contents of which are incorporated herein by reference.
- Embodiments described herein relate generally to memory system.
- A memory system having a volatile memory such as a DRAM built therein maintains data in the volatile memory by supplying power to the volatile memory from an external power supply.
- However, there are cases where power cannot be supplied from an external power supply to the volatile memory such as a case where the memory system is operated in a low power consumption mode and a case where supply of power from an external power supply is cut off. In such cases, a structure for preventing loss of data stored in the volatile memory is necessary.
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FIG. 1 is a block diagram that illustrates the configuration of a memory system according to a first embodiment; -
FIG. 2 is a diagram that illustrates the configuration of a memory cell array; -
FIG. 3 is a flowchart that illustrates switching between a normal mode and a DEVSLP mode of the memory system; -
FIG. 4 is a diagram that illustrates power consumption in the normal mode and the DEVSLP mode of the memory system; -
FIG. 5 is a block diagram that illustrates the configuration of a memory system according to a second embodiment; -
FIG. 6 is a block diagram that illustrates the configuration of a memory system according to a third embodiment; -
FIG. 7 is a block diagram that illustrates the configuration of a memory system according to a fourth embodiment; and -
FIG. 8 is a block diagram that illustrates the configuration of a memory system according to a fifth embodiment. - In general, according to one embodiment, a memory system includes a non-volatile memory, a volatile memory, an internal power supply, a power supply circuit, and a controller. The non-volatile memory temporarily stores data to be written into the non-volatile memory or data read from the non-volatile memory. The power supply circuit includes a first power supply path in which power supplied from a host device is supplied to the volatile memory, a second power supply path in which the power is supplied from the internal power supply to the volatile memory, and a switching device that switches between the first power supply path and the second power supply path. In response to an instruction for a transition to a low power consumption mode received from the host device, the controller outputs, to the switching device, an instruction to switch the power supply circuit from the first power supply path to the second power supply path.
- Hereinafter, exemplary embodiments of the memory system will be explained below in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.
-
FIG. 1 is a block diagram that illustrates the configuration of amemory system 1 according to a first embodiment. Thememory system 1 serves as an external storage device of ahost device 2. Thememory system 1 includes: a serial ATA (SATA) connector 3 as a host interface; a NAND flash memory (hereinafter, referred to as a “NAND memory”) 4 as a non-volatile memory; aDRAM 5 as a volatile memory; acapacitor 6 as an internal power supply; acontroller 7; apower supply circuit 8; a voltage detector (hereinafter, referred to as a “V.DET”) 9 a; and afuse 10. The SATA connector 3 is connected to an SATA I/F 70 of thecontroller 7, performs a process according to an interface standard for thehost device 2, and outputs a read command, a write command, user data and the like received from thehost device 2 to the SATA I/F 70. In addition, the SATA connector 3 transmits user data read from theNAND memory 4, a response from thecontroller 7, and the like to thehost device 2. - The
NAND memory 4 is configured by one or more memory chips each having a memory cell array A1 illustrated inFIG. 2 . The memory cell array A1 is a NAND cell-type memory cell array and is configured to include a plurality of NAND cells in which the plurality ofmemory cells 41 are arranged in a matrix pattern. One NAND cell is configured by a memory string MS that is formed by thememory cells 41 connected in series and selection gates G1 and G2 that are connected to both ends thereof. The selection gate G1 is connected to bit lines BL0 to BLn-1, and the selection gate G2 is connected to a source line SRC. Control gates of thememory cells 41 arranged in the same row are connected to word lines WL0 to WLm-1 so as to be common thereto. In addition, the first selection gate G1 is commonly connected to a selection line SGD, and the second selection gate G2 is commonly connected to a selection line SGS. - The memory cell array A1 includes one or more planes P1. Each plane P1 includes a plurality of
blocks 42. Eachblock 42 is configured by a plurality of NAND cells and is a unit for data deletion. In addition, a plurality ofmemory cells 41 connected to one word line configure onephysical sector 43. Data is written and read for eachphysical sector 43. In the case of a two bits/cell writing system (quad values), in onephysical sector 43, for example, data corresponding to two pages is stored. On the other hand, in the case of a one bit/cell writing system (binary values), in onephysical sector 43, for example, data corresponding to one page is stored. In addition, in the case of a three bits/cell writing system (eight values), in onephysical sector 43, for example, data corresponding to three pages is stored. When a read operation, a program verification operation, or a program operation is performed, one word line is selected in accordance with a physical address received from the NAND I/F 74 of thecontroller 7, whereby thephysical sector 43 is selected. The conversion of a page into thephysical sector 43 is performed using the physical address. - The
memory system 1 illustrated inFIG. 1 , instead of theNAND memory 4, may include a magnetoresistive random access memory (MRAM) or a resistance random access memory (ReRAM) as the non-volatile memory. - The
DRAM 5 serves as a transmission buffer for writing data and read data between thehost device 2 and theNAND memory 4 and serves as a storage area of various kinds of management table data (hereinafter, referred to as “management data”). The management data is used for controlling the transmission of writing data and read data between thehost device 2 and theNAND memory 4. The management data, for example, includes mapping information that represents relation between a logical address designated by thehost device 2 and a storage position (physical address) on theNAND memory 4. TheDRAM 5, in order to maintain data, needs a refreshing operation rewriting (charging capacitors configuring the DRAM 5) the data on a regular basis. Thememory system 1, instead of theDRAM 5, may include a static random access memory (SRAM) as the volatile memory. - The
controller 7 controls a write command and a read command transmitted from thehost device 2. Thecontroller 7 includes: a SATA interface (hereinafter, referred to as a “SATA I/F”) 70; aprocessor 71; a system 72 (logic circuit) and a general purpose input output (GPIO) 73 as interfaces; a NAND interface (hereinafter, referred to as a “NAND I/F”) 74; a DRAM interface (hereinafter, referred to as a “DRAM I/F”) 75; and an internal bus B1. The SATA I/F 70, theprocessor 71, thesystem 72, the GPIO 73, the NAND I/F 74, and the DRAM I/F 75 are interconnected through the internal bus B1. The SATA I/F 70 is connected to the SATA connector 3, converts a write command, a read command, or the like, which is transmitted from thehost device 2, received through the SATA connector 3 into an internal signal of thecontroller 7, and outputs the internal signal to the internal bus B1. In addition, the SATA I/F 70 converts a command or the like received from the inside of thecontroller 7 through the internal bus B1 into an external signal of thecontroller 7, and transmits the external signal to the SATA connector 3. - When a write command transmitted from the
host device 2 is received through the SATA I/F 70 and the internal bus B1, theprocessor 71 uses theDRAM 5 as a buffer for writing data and writes the writing data into theNAND memory 4 based on the write command, management data stored in theDRAM 5, and the like. When a read command transmitted from thehost device 2 is received through the SATA I/F 70 and the internal bus B1, theprocessor 71 reads data from theNAND memory 4 based on the read command, the management data stored in theDRAM 5, and the like and transmits the read data to thehost device 2 using theDRAM 5 as a buffer for the read data. - The
system 72 is connected to the SATA connector 3 in addition to the internal bus B1 and, as will be described later, controls thepower supply circuit 8. In addition, theGPIO 73, as will be described later, controls thepower supply circuit 8. The NAND I/F 74 directly controls writing data into theNAND memory 4 and reading data from theNAND memory 4 based on a command transmitted from theprocessor 71. The DRAM I/F 75 directly controls wiring data into theDRAM 5 and reading data from theDRAM 5 based on a command transmitted from theprocessor 71. - The
capacitor 6 can supply power to theDRAM 5 through thepower supply circuit 8. Thecapacitor 6 is charged by receiving supply of power from any other power supply. In the first embodiment, the static capacitance of thecapacitor 6, for example, is about 0.01 to 0.047 (F). - The
power supply circuit 8 is connected to thehost device 2 through the SATA connector 3 and thefuse 10 and receives the supply of power from thehost device 2 in a series of flow (in order of thehost device 2=>the SATA connector 3=>thefuse 10=>the power supply circuit 8) illustrated inFIG. 1 . In addition, thepower supply circuit 8 is also connected to theNAND memory 4, theDRAM 5, thecapacitor 6, and thecontroller 7 and can supply the power delivered from thehost device 2 to theNAND memory 4, theDRAM 5, thecapacitor 6, and thecontroller 7. In this way, in the example illustrated inFIG. 1 , thehost device 2 serves as an external power supply for thememory system 1. Hereinafter, thepower supply circuit 8 is assumed to be in a state (power supply steady state) in which power is supplied from thehost device 2 unless otherwise mentioned. In addition, thepower supply circuit 8 can supply power from thecapacitor 6 to theDRAM 5. - The
power supply circuit 8 includes: switchingdevices DC converters input resistor 84. - The switching
device 81 a, as illustrated inFIG. 1 , is interposed between thecapacitor 6 and the SATA connector 3. The switchingdevice 81 a, in an On state illustrated inFIG. 1 , connects thecapacitor 6 and the SATA connector 3. To the contrary, the switchingdevice 81 a, in an Off state, causes thecapacitor 6 and the SATA connector 3 not to be connected to each other. - The switching
device 81 b, as illustrated inFIG. 1 , is interposed between thecapacitor 6, the DC/DC converter 82 a, and theLDO 83 a. The switchingdevice 81 b, in a first switching state illustrated inFIG. 1 , connects the DC/DC converter 82 a and theLDO 83 a and causes thecapacitor 6 and theLDO 83 a not to be connected to each other. To the contrary, the switchingdevice 81 b, in a second switching state not illustrated inFIG. 1 , causes the DC/DC converter 82 a and theLDO 83 a not to be connected to each other and connects thecapacitor 6 and theLDO 83 a. - The DC/
DC converter 82 a is connected to the SATA connector 3 through thefuse 10. The DC/DC converter 82 a monitors the level of an enable signal (hereinafter, referred to as an “EN signal”) S1 to be described later and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S1. The DC/DC converter 82 a, in the conductive state, supplies power delivered from thehost device 2 to the NAND I/F 74, each component (theprocessor 71, the DRAM I/F 75, and the like; here, thesystem 72, theGPIO 73, and the NAND I/F 74 are excluded; hereinafter, referred to as “the other components”) of thecontroller 7, and theLDO 83 a. This DC/DC converter 82 a converts the output voltage of thehost device 2 into a predetermined voltage that is required for the NAND I/F 74 and the other components of thecontroller 7 and outputs the predetermined voltage. In addition, the DC/DC converter 82 a, in the non-conductive state, cuts off the supply of power delivered from thehost device 2 to the NAND I/F 74, the other components of thecontroller 7, and theLDO 83 a. - The DC/
DC converter 82 b is connected to the SATA connector 3 through thefuse 10. The DC/DC converter 82 b monitors the level of an EN signal S2 to be described later and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S2. The DC/DC converter 82 b, in the conductive state, supplies power delivered from thehost device 2 to theNAND memory 4. This DC/DC converter 82 b converts the output voltage of thehost device 2 into a predetermined voltage that is required for theNAND memory 4 and outputs the predetermined voltage. In addition, the DC/DC converter 82 b, in the non-conductive state, cuts off the supply of power delivered from thehost device 2 to theNAND memory 4. - The
LDO 83 a is connected to thecapacitor 6 and the DC/DC converter 82 a through the switchingdevice 81 b. TheLDO 83 a monitors the level of an EN signal S4 to be described later and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S4. TheLDO 83 a, in the conductive state, supplies power delivered from thehost device 2 or power supplied from thecapacitor 6 to theDRAM 5 through the DC/DC converter 82 a in accordance with switching of theswitching devices LDO 83 a converts the output voltage of the DC/DC converter 82 a and the output voltage of thecapacitor 6 into a predetermined voltage that is required for theDRAM 5 and outputs the predetermined voltage. In addition, theLDO 83 a, in the non-conductive state, cuts off the supply of power delivered from thehost device 2 or thecapacitor 6 to theDRAM 5. - The
LDO 83 b is connected to the SATA connector 3 through thefuse 10. TheLDO 83 b monitors the level of an EN signal S5 to be described later and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S5. TheLDO 83 b, in the conductive state, supplies power delivered from thehost device 2 to theGPIO 73 and theLDO 83 c. TheLDO 83 b converts the output voltage of thehost device 2 into a predetermined voltage that is required for theGPIO 73 and outputs the predetermined voltage. In addition, theLDO 83 b, in the non-conductive state, cuts off the supply of power delivered from thehost device 2 to theGPIO 73 and theLDO 83 c, Furthermore, the DC/DC converters LDO 83 b are connected to a branch point BP and are connected to thefuse 10 through the branch point BP. - The
LDO 83 c is connected to the SATA connector 3 through theLDO 83 b and thefuse 10. TheLDO 83 c, in the conductive state, supplies power delivered from thehost device 2 through theLDO 83 b to thesystem 72. ThisLDO 83 c converts the output voltage of theLDO 83 b into a predetermined voltage required for thesystem 72 and outputs the predetermined voltage. - An
input resistor 84 is connected to thecapacitor 6 in series and suppresses a current input to thecapacitor 6 when thecapacitor 6 is charged. - A
V.DET 9 a is connected between theinput resistor 84 of thepower supply circuit 8 and thecapacitor 6, monitors the output voltage of thecapacitor 6, and outputs a result of the monitoring to theGPIO 73. - The
fuse 10 is interposed between the SATA connector 3 and thepower supply circuit 8 and blows so as to protect thepower supply circuit 8 in a case where an excessive current is supplied from thehost device 2. - In a state in which the transmission of writing data and read data between the
host device 2 and theNAND memory 4 is completed, as a low power consumption instruction (device sleep (DEVSLP) instruction) is received from thehost device 2, thememory system 1 transits to a low power consumption mode (DEVSLP mode) in which the supply of power from thehost device 2 for the operation is suppressed, for example to be 5 (mW) or less. The SATA connector 3 outputs a DEVSLP signal S0 for switching thememory system 1 between the DEVSLP mode and a normal mode (a state in which the DEVSLP mode is disabled) to thesystem 72. When a DEVSLP instruction is received from thehost device 2, the SATA connector 3 switches the DEVSLP signal S0 to a high level. When a DEVSLP mode disabling signal is received from thehost device 2, the SATA connector 3 switches the DEVSLP signal S0 to a low level. -
FIG. 3 is a flowchart that illustrates switching between the normal mode and the DEVSLP mode of thememory system 1. Thesystem 72 illustrated inFIG. 1 monitors the DEVSLP signal S0 transmitted from the SATA connector 3 at a predetermined interval in Step S1 and determines whether or not thememory system 1 is in the normal mode based on the level of the DEVSLP signal S0 in Step S2. In a case where the DEVSLP signal S0 is in the low level, thesystem 72 determines that thememory system 1 is in the normal mode (Yes in Step S2) and monitors whether or not the DEVSLP signal S0 is switched to the high level in Step S3. Then, when the DEVSLP signal S0 is switched to the high level, thesystem 72 executes a transition from the normal mode to the DEVSLP mode in Step S4. On the other hand, in Step S3, in a case where the DEVSLP signal S0 is determined to be in the low level without being switched to the high level (No in Step S3), thesystem 72 does not execute the transition to the DEVSLP mode. In addition, in Step S2, in a case where the DEVSLP signal S0 is in the high level, thesystem 72 determines thememory system 1 to be not in the normal mode but in the DEVSLP mode (No in Step S2) and monitors whether or not the DEVSLP signal S0 is switched to the low level in Step S5. Then, when the DEVSLP signal S0 is switched to the low level (Yes in Step S5), thesystem 72 executes a transition from the DEVSLP mode to the normal mode in Step S6. On the other hand, in Step S5, in a case where the DEVSLP signal S0 is determined to be in the high level without being switched to the low level (No in Step S5), thesystem 72 does not execute a transition from the DEVSLP mode to the normal mode. - The
system 72 illustrated inFIG. 1 outputs an EN signal S1 switched between the high level and the low level to the DC/DC converter 82 a and, when the DEVSLP signal S0 is switched from the low level to the high level (corresponding to Yes in Step S3 illustrated inFIG. 3 ), thesystem 72 switches the EN signal S1 to the low level. The DC/DC converter 82 a outputs an EN signal S2 switched between the high level and the low level to the DC/DC converter 82 b and, when an EN signal S1 is switched to the low level, switches the EN signal S2 to the low level and transits to the non-conductive state, thereby cutting out the supply of power from thehost device 2 to the NAND I/F 74 and the other components of thecontroller 7. When the EN signal S2 is switched to the low level, the DC/DC converter 82 b transits to the non-conductive state, thereby cutting off the supply of power from thehost device 2 to theNAND memory 4. Here, the EN signal S2 may be configured to be directly output from thesystem 72 to the DC/DC converter 82 b. - The
GPIO 73 outputs control signals S31 and S32 switched between the high level and the low level to theswitching devices FIG. 3 ), thesystem 72 switches the control signals S31 and S32 from the high level to the low level. When the control signal S31 is switched to the low level, the switchingdevice 81 a is switched from the On state illustrated inFIG. 1 to the Off state. When the control signal S32 is switched to the low level, the switchingdevice 81 b is switched from the first switching state illustrated inFIG. 1 to a second switching state. When these switchingdevices capacitor 6 and theLDO 83 a are connected to each other, and accordingly, theLDO 83 a receives the supply of power from thecapacitor 6. Even when thememory system 1 transits to the DEVSLP mode, theLDO 83 a maintains to be in the conductive state, and accordingly, theDRAM 5 receives supply of power from thecapacitor 6. Accordingly, when the transition to the DEVSLP mode is made, the power supply source of theDRAM 5 is switched from thehost device 2 to thecapacitor 6. As long as the supply of power is continued from thecapacitor 6, theDRAM 5 performs a refreshing operation using the power and continues to maintain the management data, whereby loss of the data in the DEVSLP mode can be prevented. - Even when the
memory system 1 transits to the DEVSLP mode, the LDO's 83 b and 83 c maintain the conductive state. Accordingly, thesystem 72 and theGPIO 73 receive the supply of power from thehost device 2 through the LDO's 83 b and 83 c. - As described above, when the DEVSLP signal S0 is switched from the high level to the low level (corresponding to Yes in Step S5 illustrated in
FIG. 3 ), thesystem 72 causes thememory system 1 to transit from the DEVSLP mode to the normal mode (corresponding to Step S6 illustrated inFIG. 3 ). At this time, thesystem 72 and theGPIO 73 perform a control process that is reverse to the control process performed in the DEVSLP mode. - When the DEVSLP signal S0 is switched from the high level to the low level (corresponding to Yes in Step S5 illustrated in
FIG. 3 ), thesystem 72 switches the EN signal S1 to the high level. When the EN signal S1 is switched to the high level, the DC/DC converter 82 a transits to the conductive state, supplies power supplied from thehost device 2 to the NAND I/F 74 and the other components of thecontroller 7, and switches the EN signal S2 to the high level. When the EN signal S2 is switched to the high level, the DC/DC converter 82 b transits to the conductive state and supplies power supplied from thehost device 2 to theNAND memory 4. - In addition, when the DEVSLP signal S0 is switched from the high level to the low level (corresponding to Yes in Step S5 illustrated in
FIG. 3 ), thesystem 72 switches the control signals S31 and S32 output from theGPIO 73 from the low level to the high level. When the control signals S31 and S32 are switched to the high level, theswitching devices FIG. 1 or the first switching state. When these switchingdevices FIG. 1 or the first switching state, thecapacitor 6 and theLDO 83 a are in the non-conductive state, and theLDO 83 a and the DC/DC converter 82 a are connected to each other, whereby theLDO 83 a receives the supply of power from thehost device 2 through the DC/DC converter 82 a. - When the
memory system 41 transits to the normal mode, the switchingdevice 81 a is in the On state, and thecapacitor 6 and thehost device 2 are connected to each other. Accordingly, thecapacitor 6 receives the supply of power from thehost device 2 and is charged. According to such charging, thecapacitor 6, in the DEVSLP mode, can recover the power that is reduced due to the supply of power to theDRAM 5. - Even when the
memory system 1 transits to the normal mode, the LDO's 83 a to 83 c maintain the conductive state. Accordingly, even when thememory system 1 transits to the normal mode, theDRAM 5 receives the supply of power from thehost device 2 through theLDO 83 a. In addition, thesystem 72 and theGPIO 73 receive the supply of power from thehost device 2 through the LDO's 83 b and 83 c. - In addition, the LDO's 83 a and 83 b can be caused to the non-conductive state in accordance with the EN signals S4 and S5. The EN signal S4 is output from the
GPIO 73 and is switched between the high level and the low level. When the EN signal S4 is switched to the low level, theLDO 83 a transits to the non-conductive state and cuts off the supply of power to theDRAM 5. The EN signal S5 is an input voltage of theLDO 83 b and is switched between the high level and the low level in accordance with an input voltage. When the EN signal S5 is switched to the low level, theLDO 83 b transits to the non-conductive state and cuts off the supply of power to theGPIO 73 and theLDO 83 c. In order to return these LDO's 83 a and 83 b from the non-conductive state to the conductive state, the EN signals S4 and S5 may be switched to the high level. -
FIG. 4 is a diagram that illustrates power consumption in the normal mode and the DEVSLP mode of thememory system 1. InFIG. 4 , the horizontal axis represents the time. In addition, the vertical axis represents power (power consumption of the memory system 1) supplied from thehost device 2 to thememory system 1. - In the normal mode, the
memory system 1, as described above, supplies power delivered from thehost device 2 to theNAND memory 4, theDRAM 5, thecapacitor 6, and thecontroller 7. Accordingly, the power consumption of thememory system 1 in the normal mode, for example, is about 50 to 100 (mW). - When a transition from the normal mode to the DEVSLP mode is made, the
memory system 1, as described above, limits the supply of power from thehost device 2 to thesystem 72 and theGPIO 73. Accordingly, the power consumption of thememory system 1 in the DEVSLP mode is lower than the power consumption of thememory system 1 in the normal mode, for example, to be 5 (mW) or less as represented by a dashed line K0 inFIG. 4 . - In the DEVSLP mode, power is supplied from the
capacitor 6 to theDRAM 5. However, when the remaining power of thecapacitor 6 is lowered too much, there is a possibility that supply of power from thecapacitor 6 to theDRAM 5 cannot be continued. Thus, theGPIO 73 illustrated inFIG. 1 receives a monitoring result of the output voltage of thecapacitor 6 from theV.DET 9 a and notifies thesystem 72 of the monitoring result. In a case where the output voltage is determined to be a threshold or less, thesystem 72 detects such a decrease in the remaining power, outputs a control signal (not illustrated in the figure) of the high level to theswitching device 81 a even in the DEVSLP mode, and turns on theswitching device 81 a so as to connect thehost device 2 and thecapacitor 6, thereby charging thecapacitor 6. During the charging process, power is supplied from thehost device 2 to thecapacitor 6, and accordingly, even in the DEVSLP mode, the power consumption of thememory system 1 temporarily increases as denoted as periods T1 and T2 inFIG. 4 . - As a comparative example, a case will be described in which, when the
memory system 1 transits to the DEVSLP mode, management data stored in theDRAM 5 is copied to theNAND memory 4 so as to be stored therein, and thereafter, the supply of power from thehost device 2 to theNAND memory 4, theDRAM 5, the NAND I/F 74, and the other components of thecontroller 7 is cut off. In the case of the comparative example, when the management data is copied, as denoted by a dotted line K1 inFIG. 4 , power higher than the power consumed in the normal mode described above is temporarily consumed. In addition, in the case of the comparative example, when thememory system 1 is returned to the normal mode, it is necessary to copy the management data copied to theNAND memory 4 to theDRAM 5 again, and, also at this time, as denoted by a dotted line K2, power higher than the power consumed in the normal mode described above is consumed. In addition, since such a copy operation is stress for theNAND memory 4, in the case of the comparative example, there is a possibility that the life of theNAND memory 4 decreases. - According to the first embodiment, when transiting to the DEVSLP mode, the
memory system 1 stops the supply of power from thehost device 2 to theDRAM 5, theNAND memory 4, the NAND I/F 74, and the other components of thecontroller 7 and supplies power from thecapacitor 6 to theDRAM 5. Accordingly, in order to suppress the power consumption of thehost device 2, even when the supply of power from thehost device 2 to theDRAM 5 is cut off, thememory system 1 maintains the management data stored in theDRAM 5 continuously in theDRAM 5, whereby loss of the data can be prevented. - In addition, according to the first embodiment, even when transiting to the DEVSLP mode, the
memory system 1 continuously maintains the management data stored in theDRAM 5 in theDRAM 5 without copying the management data to theNAND memory 4. Accordingly, differently from the comparative example, thememory system 1 does not consume much power according to the copying process. In addition, according to thememory system 1, differently from the comparative example, since stress according to the copying process is not applied to theNAND memory 4, a decrease in the life of theNAND memory 4 can be suppressed. -
FIG. 5 is a block diagram that illustrates the configuration of amemory system 1 according to a second embodiment. According to the second embodiment, thememory system 1 not only responds to a DEVSLP mode but appropriately protects data stored in aDRAM 5 even when a transition to a state in which the supply of power from an external power supply (host device 2) to apower supply circuit 8 is completely cut off is made. Hereinafter, the same reference numeral will be assigned to the same configuration as that of the first embodiment, and duplicate description thereof will not be presented. - As illustrated in
FIG. 5 , thememory system 1 according to the second embodiment includes a super capacitor 11 and aV.DET 9 b. The super capacitor 11 serves as an internal power supply replacing thecapacitor 6 according to the first embodiment. The super capacitor 11, for example, has static capacitance of about 1 (F) and has a power supply capability that is superior to thecapacitor 6 according to the first embodiment as an internal power supply and has capacitance enabling writing data temporarily stored in theDRAM 5 and management data stored in theDRAM 5 to be copied to aNAND memory 4. The super capacitor 11 is charged by receiving supply of power from another power supply. - A
V.DET 9 b is connected between afuse 10 and a power supply circuit 8 (between thefuse 10 and aswitching device 81 c to be described later), monitors an output voltage of thehost device 2 for thepower supply circuit 8, and transmits a monitoring result thereof to aGPIO 73. TheV.DET 9 b, based on the monitoring result, outputs a control signal S70 switched between the high level and the low level to switchingdevices converter 86 to be described later. TheV.DET 9 b controls theswitching devices converter 86 using the control signal S70 and the EN signal S71. - The
V.DET 9 a according to the second embodiment is connected between thepower supply circuit 8 and the super capacitor 11, monitors an output voltage of the super capacitor 11, and outputs a monitoring result thereof to theGPIO 73. - The
power supply circuit 8 according to the second embodiment includes: switchingdevices 81 c to 81 f replacing theswitching device 81 a according to the first embodiment; acharger 85 replacing theinput resistor 84; and newly theconverter 86. - The switching
device 81 c is interposed in a first path. This first path is a section from thefuse 10 to a branch point BP. In the On state illustrated inFIG. 5 , the switchingdevice 81 c connects DC/DC converters LDO 83 b to a SATA connector 3 through thefuse 10. To the contrary, in the Off state, the switchingdevice 81 c causes the DC/DC converters LDO 83 b not to be connected to the SATA connector 3. -
Switching devices 81 d to 81 f are interposed in a second path. This second path is connected to the first path in parallel between the switchingdevice 81 c and the branch point BP. Theswitching devices 81 d to 81 f are in mutually-serial relation in the second path. In the second path, between the switchingdevice 81 d and theswitching device 81 e, thecharger 85 is interposed. In the second path, between the switchingdevice 81 e and theswitching device 81 f, theconverter 86 is interposed. In the second path, between the switchingdevice 81 e and theconverter 86, a first electrode of the super capacitor 11 is connected. - In the On state, the switching
device 81 d, as illustrated inFIG. 5 , connects thecharger 85 to the first path. To the contrary, in the Off state, the switchingdevice 81 d causes thecharger 85 not to be connected to the first path. In the On state illustrated inFIG. 5 , the switchingdevice 81 e connects thecharger 85 to the super capacitor 11 and theconverter 86. To the contrary, in the Off state, the switchingdevice 81 e causes thecharger 85 not to be connected to the super capacitor 11 and thecharger 85. In the On state, the switchingdevice 81 f connects the super capacitor 11 to the first path through theconverter 86. To the contrary, in the Off state as illustrated inFIG. 5 , the switchingdevice 81 f causes theconverter 86 and the super capacitor 11 not to be connected to the first path. - In a first switching state illustrated in
FIG. 5 , the switchingdevice 81 b connects the DC/DC converter 82 a and theLDO 83 a and causes the super capacitor 11 and theLDO 83 a not to be connected to each other. To the contrary, in a second switching state not illustrated inFIG. 5 , the switchingdevice 81 b causes the DC/DC converter 82 a and theLDO 83 a not to be connected to each other and connects the super capacitor 11 and theLDO 83 a. - The
charger 85 is connected to the super capacitor 11 through the switchingdevice 81 e. Thecharger 85 improves the charging efficiency of the super capacitor 11 by controlling the charging of the super capacitor 11. - The
converter 86 is connected to the super capacitor 11 and performs control such that the output voltage of the super capacitor 11 is the same as the output voltage of thehost device 2 and outputs the output voltage. Theconverter 86 monitors the level of the EN signal S71 and is switched between a conductive state and a non-conductive state in accordance with the level of the EN signal S71. In the conductive state, theconverter 86 outputs power supplied from the super capacitor 11 to the DC/DC converters LDO 83 b. To the contrary, in the non-conductive state, theconverter 86 cuts off such an output. - When the
memory system 1 according to the second embodiment transits to the DEVSLP mode, the DC/DC converters - The
GPIO 73 outputs a control signal S61 that is switched between the high level and the low level to theswitching device 81 b. In addition, theGPIO 73 outputs a control signal S62 that is switched between the high level and the low level to theswitching devices memory system 1 transits to the DEVSLP mode, asystem 72 switches theswitching devices FIG. 5 or the first switching state to the Off state or the second switching state by switching the control signals S61 and S62 output from theGPIO 73 to the low level. - When these switching
devices LDO 83 a are connected, and theLDO 83 a receives the supply of power from the super capacitor 11. Accordingly, the power supply source of theDRAM 5 that receives the supply of power through theLDO 83 a is switched from thehost device 2 to the super capacitor 11. As long as the supply of power from the super capacitor 11 is received, theDRAM 5 performs a refreshing operation using the supplied power and continuously maintains management data, thereby preventing loss of the management data in the DEVSLP mode. - Even in the DEVSLP mode, since the switching
device 81 c is controlled to be in the On state, thesystem 72 and theGPIO 73 receives supply of power from thehost device 2 through the LDO's 83 b and 83 c. In addition, in the DEVSLP mode, the switchingdevice 81 f is controlled to be in the Off state illustrated inFIG. 5 . Furthermore, in the DEVSLP mode, the DC/DC converters host device 2 or the super capacitor 11, the DC/DC converters host device 2 and the super capacitor 11 to theNAND memory 4, the NAND I/F 74, theLDO 83 a, and the other components of thecontroller 7. - In the DEVSLP mode, when the remaining power of the super capacitor 11 for the
DRAM 5 is lowered too much, there is a possibility that supply of power from the super capacitor 11 to theDRAM 5 cannot be continued. Thus, in a case where the output voltage of the super capacitor 11 is determined to be a threshold or less, thememory system 1 detects a decrease in the remaining power and, even in the DEVSLP mode, switches the control signal S62 to the high level and causes theswitching devices host device 2 and the super capacitor 11, thereby charging the super capacitor 11. - For example, in a case where the
fuse 10 blows or a power failure occurs, there are cases where thememory system 1 according to the second embodiment transits to a state (power supply cut-off state) in which the supply of power from thehost device 2 as an external power supply to thepower supply circuit 8 is completely cut off. TheV.DET 9 b, in a case where the output voltage of thehost device 2 for thepower supply circuit 8 is determined to be a threshold or less, detects such a power supply cut-off state. In such a case, theV.DET 9 b switches the control signal S70 and the EN signal S71 to the low level and transmits a result of the detection of the power supply cut-off state to theGPIO 73. - When the control signal S70 is switched to the low level, the
switching devices FIG. 5 to the Off state. When the control signal S70 is switched to the low level, the switchingdevice 81 f is switched from the Off state illustrated inFIG. 5 to the On state. When the EN signal S71 is switched to the low level, theconverter 86 is switched to the conductive state. Thus, the super capacitor 11 and theLDO 83 b are connected, and the power supply source of thesystem 72 and theGPIO 73 to which power is supplied through theLDO 83 b is switched from thehost device 2 to the super capacitor 11. For this reason, even when thememory system 1 transits to the power supply cut-off state, thesystem 72 and theGPIO 73 continue to operate, the remaining power of the super capacitor 11 is monitored by theGPIO 73, and the DC/DC converters system 72. - In the normal mode, when the power supply cut-off state is detected, the
memory system 1 according to the second embodiment operates to copy the management data from theDRAM 5 to theNAND memory 4. Even when thememory system 1 transits to the power supply cut-off state as above, thesystem 72 performs control of the DC/DC converters NAND memory 4, the other components (theprocessor 71, the DRAM I/F 75, and the like) of thecontroller 7, the NAND I/F 74, and theDRAM 5 operate by receiving the supply of power from the super capacitor 11. In addition, theGPIO 73 transmits a result of the detection of the power supply cut-off state that is transmitted from theV.DET 9 b to theprocessor 71 through the internal bus B1. When a notification of the detection of the power supply cut-off state is received, theprocessor 71 transmits a data copy command for copying data (the writing data, the management data, and the like) stored in theDRAM 5 to theNAND memory 4 to the NAND I/F 74 and the DRAM I/F 75. When the command is received, the NAND I/F 74 and the DRAM I/F 75 copies the data from theDRAM 5 to theNAND memory 4 in accordance with the command. When the copy operation is completed, thesystem 72 stops the supply of power from the super capacitor 11 to theNAND memory 4, the other components (theprocessor 71, the DRAM I/F 75, and the like) of thecontroller 7, the NAND I/F 74 and theDRAM 5 by performing control of the DC/DC converters - On the other hand, when the power supply cut-off state is detected in the DEVSLP mode, the
memory system 1 maintains the supply of power from the super capacitor 11 to theDRAM 5 by performing control of theswitching device 81 b to be in the second switching state, thereby continuously maintaining the management data in theDRAM 5 using the power supplied from the super capacitor 11. - When the output voltage from the
host device 2 for thepower supply circuit 8 is detected to have exceeded the threshold, theV.DET 9 b determines that the power supply cut-off state is released and switches the control signal S70 and the EN signal S71 to the high level. When the control signal S70 is switched to the high level, theswitching devices FIG. 5 . When the control signal S70 is switched to the high level, the switchingdevice 81 f is switched from the On state to the Off state illustrated inFIG. 5 . When the EN signal S71 is switched to the high level, theconverter 86 is switched to the non-conductive state. Accordingly, the power supply source of thesystem 72 and theGPIO 73 is switched from the super capacitor 11 to thehost device 2. - When the power supply cut-off state is detected in the DEVSLP mode, the
memory system 1 according to the second embodiment, in order to appropriately protect the management data stored in theDRAM 5, can operate to copy the management data from theDRAM 5 to theNAND memory 4 by consuming the power of the super capacitor 11. More specifically, in a case where output voltage information of the super capacitor 11 is received from theV.DET 9 a in the middle of the power supply cut-off state in the DEVSLP mode, theGPIO 73 outputs the voltage information to thesystem 72 through the internal bus B1. In a case where the output voltage of the super capacitor 11 is determined to be the threshold or less based on the voltage information, thesystem 72 switches the EN signal S1 to the high level so as to cause the DC/DC converter 82 a to be in the conductive state. When the EN signal S1 is switched to the high level, the DC/DC converter 82 a switches the EN signal S2 to the high level so as to cause the DC/DC converter 82 b to be in the conductive state. In the power supply cut-off state in the middle of the DEVSLP mode, as described above, theconverter 86 is in the conductive state, and theswitching device 81 f is in the On state. Accordingly, theNAND memory 4, the other components (theprocessor 71, the DRAM I/F 75, and the like) of thecontroller 7, and the NAND I/F 74 are connected to the super capacitor 11 through the DC/DC converters processor 71 transmits a data copy command for copying the management data stored in theDRAM 5 to theNAND memory 4 to the NAND I/F 74 and the DRAM I/F 75. When the command is received, the NAND I/F 74 and the DRAM I/F 75 copy the management data from theDRAM 5 to theNAND memory 4 in accordance with the command. - The threshold of the output voltage of the super capacitor 11 is set to a voltage value for which the management data stored in the
DRAM 5 can be copied to theNAND memory 4 using the remaining power of the super capacitor 11. For this reason, the management data can be appropriately protected before the management data cannot be maintained in theDRAM 5 due to a decrease in the remaining power of the super capacitor 11 as the power supply cut-off state lasts for a long time. - When the
memory system 1 transits to the normal mode, the DC/DC converters memory system 1 transits from the DEVSLP mode to the normal mode, thesystem 72 switches theswitching devices FIG. 5 or the first switching state by switching the control signals S61 and S62 output from theGPIO 73 to the high level. When these switchingdevices LDO 83 a is caused not to be connected to the super capacitor 11 but is connected to the DC/DC converter 82 a, and similar to the first embodiment, receives the supply of power from thehost device 2 through the DC/DC converter 82 a. Also in the normal mode, the switchingdevice 81 c is controlled to be in the On state and enables the supply of power from thehost device 2 to the DC/DC converters LDO 83 b. In addition, also in the normal mode, the switchingdevice 81 f is controlled to be in the Off state. - In the normal mode, since the
switching devices 81 c to 81 e are controlled to be in the On state, the super capacitor 11 is connected to thehost device 2 through thecharger 85 and is charged by receiving the supply of power from thehost device 2. Through such a charging process, the super capacitor 11 can recover the remaining power lowered in the DEVSLP mode or the like. - According to the second embodiment, when transiting to the DEVSLP mode, the
memory system 1 stops the supply of power from thehost device 2 to theDRAM 5, theNAND memory 4, the NAND I/F 74, and the other components of thecontroller 7 and supplies power from the super capacitor 11 to theDRAM 5. Accordingly, similar to the first embodiment, in order to suppress the power consumption of thehost device 2, even when the supply of power from thehost device 2 to theDRAM 5 is cut off, thememory system 1 maintains the management data continuously in theDRAM 5 without copying the management data stored in theDRAM 5 into theNAND memory 4, whereby loss of the data can be prevented. - In addition, according to the second embodiment, when the power supply cut-off state is detected in the DEVSLP mode, the
memory system 1 supplies power from the super capacitor 11 to theGPIO 73 and thesystem 72. Accordingly, even when transiting to the power supply cut-off state, thememory system 1 monitors the remaining power of the super capacitor 11 by operating thesystem 72 and theGPIO 73, whereby the DC/DC converters - Furthermore, according to the second embodiment, in a case where the output voltage of the super capacitor 11 that is monitored through the
V.DET 9 a is determined to be the threshold or less even when thememory system 1 transits to the power supply cut-off state, thememory system 1 copies the management data stored in theDRAM 5 into theNAND memory 4 by consuming the power of the super capacitor 11. Accordingly, even in a case where the power supply cut-off state lasts for a long time, thememory system 1 can appropriately protect the management data stored in theDRAM 5 before the remaining power of the super capacitor 11 becomes insufficient. -
FIG. 6 is a block diagram that illustrates the configuration of amemory system 1 according to a third embodiment. According to the third embodiment, while thememory system 1 does not respond to a DEVSLP mode but protects data stored in aDRAM 5 even when a transition to a state in which the supply of power from an external power supply to apower supply circuit 8 is completely cut off is made. Hereinafter, the same reference numeral will be assigned to the same configuration as that of the first embodiment, and duplicate description thereof will not be presented. - As illustrated in
FIG. 6 , thememory system 1 according to the third embodiment includes: aprimary battery 12 as an internal power supply; aV.DET 9 c; and anLED device 13 as an alert display unit. Theprimary battery 12 serves as an internal power supply replacing thecapacitor 6 according to the first embodiment. For example, theprimary battery 12 is a button-type battery. Theprimary battery 12 is not connected to a SATA connector 3. - The
V.DET 9 c is connected between afuse 10 and a power supply circuit 8 (a path connecting DC/DC converters LDO 83 b to the fuse 10), monitors the output voltage of ahost device 2 for thepower supply circuit 8, and outputs a monitoring result thereof to theGPIO 73. - The
LED device 13 has an LED built therein and, when an EN signal S8 to be described later is switched to the high level, turns on the LED so as to display an alert for promoting the replacement of theprimary battery 12. The LED is attached to a position that is viewable from a user, and theLED device 13 turns off the LED when the EN signal S8 is switched to the low level. - The
power supply circuit 8 according to the third embodiment includes aswitching device 81 g replacing theswitching device 81 a according to the first embodiment in addition to aswitching device 81 b. The switchingdevice 81 g is interposed between a branch point BP and theLDO 83 b and theprimary battery 12. The switchingdevice 81 g connects theLDO 83 b and the SATA connector 3 in a first switching state illustrated inFIG. 6 and causes theLDO 83 b and theprimary battery 12 not to be connected to each other. To the contrary, in a second switching state not illustrated inFIG. 6 , the switchingdevice 81 g causes theLDO 83 b and the SATA connector 3 not to be connected to each other and connects theLDO 83 b and theprimary battery 12. - In the first switching state illustrated in
FIG. 6 , the switchingdevice 81 b according to the third embodiment connects theLDO 83 a and the DC/DC converter 82 a and causes theLDO 83 a and theprimary battery 12 not to be connected to each other. To the contrary, in a second switching state not illustrated inFIG. 6 , the switchingdevice 81 b causes theLDO 83 a and the DC/DC converter 82 a not to be connected to each other and connects theLDO 83 a and theprimary battery 12. - The
V.DET 9 a according to the third embodiment is connected between thepower supply circuit 8 and theprimary battery 12, monitors the output voltage of theprimary battery 12, and outputs a monitoring result thereof to theGPIO 73. - There are cases where the
memory system 1 transits to a state (power supply cut-off state) in which the supply of power from thehost device 2 to thepower supply circuit 8 is cut off. In such cases, it is necessary to protect data (writing data, management data, and the like) stored in theDRAM 5. When the power supply cut-off state is detected, thememory system 1 according to the third embodiment switches the power supply source of theNAND memory 4, theDRAM 5, and thecontroller 7 from thehost device 2 to theprimary battery 12, thereby protecting the data stored in theDRAM 5. TheGPIO 73 outputs a control signal S9 switched between the high level and the low level to theswitching devices host device 2 for thepower supply circuit 8 that is monitored through theV.DET 9 c is determined to be a threshold or less, theGPIO 73 detects the power supply cut-off state and switches the control signal S9 to the low level. - When the control signal S9 is switched to the low level, the
switching devices FIG. 6 to the second switching state. When theswitching devices primary battery 12 and receive supply of power from theprimary battery 12. Accordingly, when the supply of power is received through the LDO's 83 a and 83 b, the power supply source of theDRAM 5, thesystem 72, and theGPIO 73 is switched to theprimary battery 12. - Even in the power supply cut-off state, the
LDO 83 a maintains the conductive state and supplies power delivered from theprimary battery 12 to theDRAM 5. Thus, as long as the supply of power is received from theprimary battery 12, theDRAM 5 performs a refreshing operation using the power, the data stored in theDRAM 5 is continuously maintained, whereby loss of the data can be prevented. In addition, even in the power supply cut-off state, the LDO's 83 b and 83 c maintain the conductive states. - Accordingly, the
system 72 and theGPIO 73 operate by receiving the supply of power from theprimary battery 12. - As the
primary battery 12 supplies the power to theDRAM 5, thesystem 72, and theGPIO 73, the remaining power thereof is lowered. TheGPIO 73 receives a monitoring result of the output voltage of theprimary battery 12 from theV.DET 9 a and determines the output voltage to be a threshold or less, thereby detecting a decrease in the remaining power. TheGPIO 73 outputs an EN signal S8 switched between the high level and the low level to theLED device 13 and, in a case where the output voltage of theprimary battery 12 is a threshold or less, switches the EN signal S8 to the high level. When the EN signal S8 is switched to the high level, theLED device 13 turns on the LED built in theLED device 13, thereby allowing the user to recognize an alert for promoting the replacement of theprimary battery 12. When the output voltage of theprimary battery 12 is above the threshold, theGPIO 73 switches the EN signal S8 to the low level, thereby turning off the LED of theLED device 13. - When the output voltage of the
host device 2 for thepower supply circuit 8 that is monitored through theV.DET 9 c is determined to be above the threshold, theGPIO 73 determines that the power supply cut-off state is released and switches the control signal S9 to the high level. When the control signal S9 is switched to the high level, theswitching devices FIG. 6 . When these switchingdevices primary battery 12 and are connected to thehost device 2 through the SATA connector 3. In the state in which the power supply cut-off state is released, the LDO's 83 a to 83 c and the DC/DC converters NAND memory 4, theDRAM 5, and thecontroller 7 receive the supply of power from thehost device 2. - According to the third embodiment, when the power supply cut-off state is detected, the
memory system 1 supplies power from theprimary battery 12 to theDRAM 5. Thus, even when a transition to the power supply cut-off state is made, thememory system 1 continuously maintains the data, which is stored in theDRAM 5, in theDRAM 5, thereby preventing loss of the data. -
FIG. 7 is a block diagram that illustrates the configuration of amemory system 1 according to a fourth embodiment. Thememory system 1 according to the fourth embodiment, compared to thememory system 1 according to the third embodiment, has a superior power supply capability of the internal power supply. Hereinafter, the same reference numeral will be assigned to the same configuration as that of the first or third embodiment, and duplicate description thereof will not be presented. - As illustrated in
FIG. 7 , thememory system 1 according to the fourth embodiment includes: a plurality ofprimary batteries 12 connected in parallel as internal power supplies; a plurality ofdiodes 87; and a plurality of V.DET's 9 a, which is different from thememory system 1 according to the third embodiment. - Each
diode 87 is connected to a correspondingprimary battery 12 in series. Eachdiode 87 serves to enable the supply of power from aprimary battery 12 that is connected thereto in series to LDO's 83 a and 83 b and to cut off the supply of power from aprimary battery 12 connected thereto in parallel to theprimary battery 12 connected thereto in series. Accordingly, even when the output voltages of theprimary battery 12 are different from each other, thememory system 1 can appropriately supply power to the LDO's 83 a and 83 b without consuming power of theprimary batteries 12 inside the plurality ofprimary batteries 12. - Each
V.DET 9 a is connected between thediode 87 and theprimary battery 12 that are connected in series, monitors the output voltage of eachprimary battery 12, and outputs a monitoring result thereof to theGPIO 73. - When it is determined that any one of the output voltages of the plurality of the
primary batteries 12, which are monitored through the plurality of V.DET's 9 a, is determined to be a threshold or less, theGPIO 73 switches the EN signal S8 to the high level. When the EN signal S8 is switched to the high level, theLED device 13 turns on an LED built in theLED device 13, thereby allowing the user to recognize an alert for promoting the replacement of theprimary battery 12. On the other hand, in a case where the output voltages of all theprimary batteries 12 are above the threshold, theGPIO 73 switches the EN signal S8 to the low level, thereby turning off the LED of theLED device 13. - In a range illustrated in
FIG. 7 , while twoprimary batteries 12, twodiodes 87, and two V.DET's 9 a appear, thememory system 1 may be configured to include three or moreprimary batteries 12, three ormore diodes 87, and three or more V.DET's 9 a. - In the first switching state illustrated in
FIG. 7 , the switchingdevice 81 g connects theLDO 83 b and the SATA connector 3 and causes theLDO 83 b and the plurality of theprimary batteries 12 not to be connected to each other. To the contrary, in the second switching state not illustrated inFIG. 7 , the switchingdevice 81 g causes theLDO 83 b and the SATA connector 3 not to be connected to each other and connects theLDO 83 b and the plurality of theprimary batteries 12. - In the first switching state illustrated in
FIG. 7 , the switchingdevice 81 b connects theLDO 83 a and the DC/DC converter 82 a and causes theLDO 83 a and the plurality of theprimary batteries 12 not to be connected to each other. To the contrary, in the second switching state not illustrated inFIG. 7 , the switchingdevice 81 b causes theLDO 83 a and the DC/DC converter 82 a not to be connected to each other and connects theLDO 83 a and the plurality of theprimary batteries 12. - According to the fourth embodiment, since the
memory system 1 includes the plurality of theprimary batteries 12, there are more power supply sources of theDRAM 5, thesystem 72, and theGPIO 73 than those of thememory system 1 according to the third embodiment, and, even in the power supply cut-off state, power can be supplied to theDRAM 5, thesystem 72, and theGPIO 73 for a long time. In addition, since thememory system 1 includes the plurality of theprimary batteries 12, theprimary batteries 12 are replaced in turns, and accordingly, the power supply cut-off state can be further continued. -
FIG. 8 is a block diagram that illustrates the configuration of amemory system 1 according to a fifth embodiment. Thememory system 1 according to the fifth embodiment not only responds to a DEVSLP mode but protects data stored in aDRAM 5 even when a transition to a state in which the supply of power from an external power supply (host device 2) to apower supply circuit 8 is completely cut off is made. Hereinafter, the same reference numeral will be assigned to the same configuration as that of the first embodiment, and duplicate description thereof will not be presented. - As illustrated in
FIG. 8 , thememory system 1 according to the fifth embodiment additionally includes aprimary battery 12, V.DET's 9 c and 9 d, and anLED device 13 as an alert display unit in addition to thememory system 1 according to the first embodiment. - The
primary battery 12 serves as an internal power supply of thememory system 1 and is connected to acapacitor 6 in parallel. For example, theprimary battery 12 is a button-type battery. The output voltage of theprimary battery 12 is lower than the output voltage of thecapacitor 6 that is sufficiently charged. - The
V.DET 9 c is connected between afuse 10 and a power supply circuit 8 (a path connecting DC/DC converters LDO 83 b to the fuse 10), monitors the voltage that is supplied from ahost device 2 for thepower supply circuit 8, and outputs a monitoring result thereof to theGPIO 73. - The
V.DET 9 d is connected between thepower supply circuit 8 and theprimary battery 12, monitors the output voltage of theprimary battery 12, and outputs a monitoring result thereof to theGPIO 73. - The
LED device 13 has an LED built therein and, when an EN signal S8 to be described later is switched to the high level, turns on the LED so as to display an alert for promoting the replacement of theprimary battery 12. The LED is attached to a position that is viewable from a user, and theLED device 13 turns off the LED when the EN signal S8 is switched to the low level. - The
power supply circuit 8 according to the fifth embodiment, compared to that of the first embodiment, additionally includes aswitching device 81 h and adiode 87. The switchingdevice 81 h is interposed between theLDO 83 b and thecapacitor 6 and theprimary battery 12 and a branch point BP. In a first switching state illustrated inFIG. 8 , the switchingdevice 81 h connects theLDO 83 b and the SATA connector 3 and causes theLDO 83 b not to be connected to thecapacitor 6 and theprimary battery 12. To the contrary, in a second switching state not illustrated inFIG. 8 , the switchingdevice 81 h causes theLDO 83 b and the SATA connector 3 not to be connected to each other and connects theLDO 83 b to thecapacitor 6 and theprimary battery 12. The switchingdevice 81 h is switched between the first switching state and the second switching state in accordance with the level of a control signal S10 that is output from theGPIO 73. The switchingdevice 81 h is in the first switching state illustrated inFIG. 8 in accordance with the control signal S10 of the high level and is in the second switching state in accordance with the control signal S10 of the low level. In the DEVSLP mode and the normal mode, the switchingdevice 81 h is in the first switching state in accordance with the control signal S10 of the high level. - In the On state illustrated in
FIG. 8 , the switchingdevice 81 a connects thecapacitor 6 and theprimary battery 12 to the SATA connector 3. To the contrary, in the Off state, the switchingdevice 81 a causes thecapacitor 6 and theprimary battery 12 not to be connected to the SATA connector 3. - In the first switching state illustrated in
FIG. 8 , the switchingdevice 81 b connects theLDO 83 a and the DC/DC converter 82 a and causes theLDO 83 a not to be connected to thecapacitor 6 and theprimary battery 12. To the contrary, in the second switching state not illustrated inFIG. 8 , the switchingdevice 81 b causes theLDO 83 a and the DC/DC converter 82 a not to be connected to each other and connects theLDO 83 a to thecapacitor 6 and theprimary battery 12. - The
diode 87 is connected to theprimary battery 12 in series. Thediode 87 serves to enable the supply of power from theprimary battery 12 to the LDO's 83 a and 83 b and to cut off the supply of power from thecapacitor 6 connected thereto in parallel to theprimary battery 12. Accordingly, even when the output voltage of thecapacitor 6 connected in parallel is higher than the output voltage of theprimary battery 12, the power of thecapacitor 6 is not consumed by theprimary battery 12 but is appropriately supplied to the LDO's 83 a and 83 b. - When the
memory system 1 transits to the DEVSLP mode, the DC/DC converters - In addition, when the
memory system 1 transits to the DEVSLP mode, control signals S31 and S32, similar to the first embodiment, are in the low level and causes theswitching devices FIG. 8 or the first switching state to the Off state or the second switching state. - When the
switching devices capacitor 6 and theprimary battery 12 are connected to theLDO 83 a. As described above, the output voltage of theprimary battery 12 is lower than the output voltage of thecapacitor 6 that is sufficiently charged. Thus, until the output voltage of thecapacitor 6 is lowered to be the output voltage of theprimary battery 12 or less, theprimary battery 12 does not serve as a power supply source of theLDO 83 a and does not consume power. Accordingly, in a state in which thecapacitor 6 is sufficiently charged, theDRAM 5 receives the supply of power from thecapacitor 6 through theLDO 83 a. By receiving the supply of power as above, theDRAM 5, in the DEVSLP mode, performs a refreshing operation using the power and continuously maintains the management data without copying the management data to theNAND memory 4, thereby preventing loss of the data. - In the DEVSLP mode, in a case where the output voltage of the
capacitor 6 that is monitored through theV.DET 9 a and theGPIO 73 is determined to be a threshold or less, thesystem 72 outputs a control signal (not illustrated in the figure) of the high level to theswitching device 81 a so as to cause theswitching device 81 a to be in the On state and connects thehost device 2 and thecapacitor 6, thereby charging thecapacitor 6. By employing a value above the output voltage of theprimary battery 12 as such a threshold, in the DEVSLP mode, thememory system 1 can maintain the output voltage of thecapacitor 6 to be higher than the output voltage of theprimary battery 12, whereby unnecessary power consumption of theprimary battery 12 not corresponding to charging can be prevented. - When the
memory system 1 transits to the normal mode, the DC/DC converters memory system 1 transits to the normal mode, theswitching devices FIG. 8 or the first switching state in accordance with the control signals S31 and S32. When these switchingdevices LDO 83 a is caused not to be connected to thecapacitor 6 and theprimary battery 12 and is connected to the DC/DC converter 82 a. Accordingly, theDRAM 5 receives the supply of power from thehost device 2 through theLDO 83 a and the DC/DC converter 82 a. By causing theswitching device 81 a to be in the On state, thecapacitor 6 and thehost device 2 are connected to each other, and thecapacitor 6 is charged by receiving the supply of power from thehost device 2. - There are cases where the
memory system 1 transits to a state (power supply cut-off state) in which the supply of power from thehost device 2 to thepower supply circuit 8 is cut off. In such cases, it is necessary to protect data (writing data, management data, and the like) stored in theDRAM 5. When the power supply cut-off state is detected, thememory system 1 according to the fifth embodiment switches the power supply source of theDRAM 5, thesystem 72, and theGPIO 73 from thehost device 2 to thecapacitor 6 and theprimary battery 12, thereby protecting the data stored in theDRAM 5. In a case where the output voltage of thehost device 2 for thepower supply circuit 8 that is monitored through theV.DET 9 c is determined to be a threshold or less, theGPIO 73 detects the power supply cut-off state, switches the control signals S31 and S32 to the low level, outputs the control signals S31 and S32 to theswitching devices switching device 81 h. - When the control signals S31, S32, and S10 are switched to the low level, the
switching devices FIG. 8 or the first switching state to the Off state or the second switching state. In the case of the DEVSLP mode, theswitching devices switching devices switching devices capacitor 6 and theprimary battery 12. The LDO's 83 a and 83 b receive the supply of power from one, of which the output voltage is higher, out of thecapacitor 6 and theprimary battery 12. Accordingly, the power supply source of theDRAM 5, thesystem 72, and theGPIO 73 that receive the supply of power through the LDO's 83 a and 83 b is switched to thecapacitor 6 or theprimary battery 12. In addition, as described above, in the state in which thecapacitor 6 is sufficiently charged, the output voltage of thecapacitor 6 is higher than the output voltage of theprimary battery 12. Accordingly, until the output voltage of thecapacitor 6 is lowered to be the output voltage of theprimary battery 12 or less, the LDO's 83 a and 83 b receive the supply of power from thecapacitor 6. - Even in the power supply cut-off state, the
LDO 83 a maintains to be in the conductive state and supplies power supplied from one, of which the output voltage is higher, out of thecapacitor 6 and theprimary battery 12 to theDRAM 5. As above, as long as the supply of power is received, theDRAM 5 performs a refreshing operation using the supplied power and continuously maintains data stored in theDRAM 5, thereby preventing loss of the management data. At this time, since the switchingdevice 81 a is in the Off state, the supply of power from thecapacitor 6 or theprimary battery 12 to thehost device 2 is cut off, and unnecessary power consumption of thecapacitor 6 and theprimary battery 12 is prevented. - As the
primary battery 12 supplies the power to theDRAM 5, thesystem 72, and theGPIO 73, the remaining power thereof is lowered. TheGPIO 73 receives a monitoring result of the output voltage of theprimary battery 12 from theV.DET 9 d and determines the output voltage to be a threshold or less, thereby detecting such a decrease in the remaining power. TheGPIO 73 outputs an EN signal S8 switched between the high level and the low level to theLED device 13 and, in a case where the output voltage of theprimary battery 12 is a threshold or less, switches the EN signal S8 to the high level. When the EN signal S8 is switched to the high level, theLED device 13 turns on the LED built in theLED device 13, thereby allowing the user to recognize an alert for promoting the replacement of theprimary battery 12. In addition, when the output voltage of theprimary battery 12 is above the threshold, theGPIO 73 switches the EN signal S8 to the low level, thereby turning off the LED of theLED device 13. - When the output voltage of the
host device 2 for thepower supply circuit 8 that is monitored through theV.DET 9 c is determined to be above the threshold, theGPIO 73 switches the control signals S31, S32, and S10 to the high level. When the control signals S31, S32, and S10 are switched to the high level, theswitching devices FIG. 8 or the first switching state. When these switchingdevices FIG. 8 or the first switching state, the LDO's 83 a and 83 b are caused not to be connected to thecapacitor 6 and theprimary battery 12 and are connected to thehost device 2 through the SATA connector 3, thereby receiving the supply of power from thehost device 2. - According to the fifth embodiment, when the power supply cut-off state is detected, the
memory system 1 supplies power from thecapacitor 6 or theprimary battery 12 to theDRAM 5. Thus, thememory system 1 not only has the same advantage as that of the first embodiment and, even when a transition to the power supply cut-off state is made, continuously maintains the data, which is stored in theDRAM 5, in theDRAM 5, thereby preventing loss of the data. - While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Claims (20)
1. A memory system comprising:
a non-volatile memory;
a volatile memory that temporarily stores data to be written into the non-volatile memory or data read from the non-volatile memory;
an internal power supply;
a power supply circuit that includes a first power supply path in which power supplied from a host device is supplied to the volatile memory, a second power supply path in which the power is supplied from the internal power supply to the volatile memory, and a switching device that switches between the first power supply path and the second power supply path; and
a controller that, in response to an instruction for a transition to a low power consumption mode received from the host device, outputs, to the switching device, an instruction to switch the power supply circuit from the first power supply path to the second power supply path.
2. The memory system according to claim 1 , wherein the controller does not copy data stored in the volatile memory to the non-volatile memory in response to the instruction for the transition to the low power consumption mode.
3. The memory system according to claim 2 , further comprising a connector that supplies power input from the host device to the power supply circuit and transmits, to the controller, the instruction for the transition to the low power consumption mode received from the host device.
4. The memory system according to claim 3 ,
wherein the internal power supply is chargeable, and
wherein the power supply circuit supplies the power supplied from the connector to the internal power supply.
5. The memory system according to claim 4 , wherein the internal power supply includes a capacitor.
6. The memory system according to claim 5 , wherein the controller monitors an output voltage of the internal power supply, and controls the power supply circuit to supply the power supplied from the host device to the internal power supply when the output voltage is a threshold or less.
7. The memory system according to claim 6 , wherein the controller includes a voltage detector that monitors the output voltage of the internal power supply.
8. The memory system according to claim 7 ,
wherein the controller includes a volatile memory interface and a logic circuit that receives a first signal from the connector,
wherein the power supply circuit includes a converter that converts a voltage supplied from the host device and supplies the converted voltage to the volatile memory interface, and
wherein the logic circuit transmits a second signal to the converter based on the received first signal.
9. The memory system according to claim 8 ,
wherein the second signal includes a high level and a low level, and the logic circuit switches the second signal when the first signal includes the instruction for the transition to the low power consumption mode, and
wherein the converter cuts off the supply of power to the volatile memory interface in accordance with the switching of the second signal.
10. The memory system according to claim 9 ,
wherein the non-volatile memory is a NAND type flash memory, and
wherein the volatile memory is a DRAM.
11. The memory system according to claim 4 , wherein the controller copies data stored in the volatile memory to the non-volatile memory when an output voltage of the internal power supply becomes a threshold or less after the instruction for the transition to the low power consumption mode is received.
12. A memory system comprising:
a non-volatile memory;
a volatile memory that temporarily stores data to be written into the non-volatile memory or data read from the non-volatile memory;
an internal power supply;
a power supply circuit that includes a first power supply path in which power supplied from a host device is supplied to the volatile memory, a second power supply path in which the power is supplied from the internal power supply to the volatile memory, and a switching device that switches between the first power supply path and the second power supply path; and
a controller that, when power supply is cut off, outputs, to the switching device, an instruction to switch the power supply circuit from the first power supply path to the second power supply path, and does not copy the data stored in the volatile memory to the non-volatile memory.
13. The memory system according to claim 12 , further comprising a connector that supplies power input from the host device to the power supply circuit.
14. The memory system according to claim 13 , wherein the controller monitors an output voltage from the connector to the power supply circuit and determines that the power supply is cut off when the output voltage is a first threshold or less.
15. The memory system according to claim 14 , wherein the internal power supply includes a primary battery.
16. The memory system according to claim 15 , wherein the primary battery is a button-type battery.
17. The memory system according to claim 16 , further comprising a display unit,
wherein the controller monitors an output voltage of the primary battery and displays an alert for urging to replace the primary battery on the display unit when the output voltage of the primary battery is a second threshold or less.
18. The memory system according to claim 16 , wherein the internal power supply includes a capacitor and supplies power from the capacitor to the second power supply path when an output voltage of the capacitor is the output voltage of the primary battery or more.
19. The memory system according to claim 18 , wherein the power supply circuit includes a third power supply path in which the power supplied from the connector is supplied to the capacitor.
20. The memory system according to claim 19 ,
wherein the non-volatile memory is a NAND type flash memory, and
wherein the volatile memory is a DRAM.
Priority Applications (2)
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US14/632,297 US20160077561A1 (en) | 2014-09-11 | 2015-02-26 | Memory system |
US15/706,293 US10656692B2 (en) | 2014-09-11 | 2017-09-15 | Memory system |
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US201462048959P | 2014-09-11 | 2014-09-11 | |
US14/632,297 US20160077561A1 (en) | 2014-09-11 | 2015-02-26 | Memory system |
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US15/706,293 Continuation US10656692B2 (en) | 2014-09-11 | 2017-09-15 | Memory system |
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US20180004267A1 (en) | 2018-01-04 |
US10656692B2 (en) | 2020-05-19 |
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