# US 12,117,887 B2 · Slave device and host device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,117,887 B2 - Document ID: US12117887B2 - Status: Granted - Kind: B2 - Application number: 18/122,977 - Filed: 2023-03-17 - Published: 2023-07-13 - Granted: 2024-10-15 - Earliest claimed: 2020-09-25 - Assignees: Panasonic Intellectual Property Management Co., Ltd. - Applicants: Panasonic Intellectual Property Management Co., Ltd. - Inventors: Tadashi Ono; Yoshihisa Inagaki - Web page: https://patentgrep.com/patent/US12117887B2 ## CPC - G06F 1/3296: by lowering the supply or operating voltage - G11C 5/14: Power supply arrangements {, e.g. power down, chip selection or deselection, layout of wirings or power grids, or multiple supply levels} - G06F 1/04: Generating or distributing clock signals or signals derived directly therefrom - G06F 1/266: {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} - G06F 1/3275: {Power saving in memory, e.g. RAM, cache} - G11C 5/04: Supports for storage elements {, e.g. memory modules}; Mounting or fixing of storage elements on such supports - G11C 16/30: Power supply circuits - G11C 2207/2227: Standby or low power modes - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G11C: STATIC STORES (semiconductor memory devices H10B) ## Abstract When a host-slave system including a host device and a slave device transitions to a power-down mode, the host device drives a CMD line in order of a high level, a low level, and a high level, and stops supplying a clock signal after a predetermined time elapses. During a power-down mode period, the slave device stops supplying a power to a back-end module. When the host device resumes the supply of the clock signal, the host-slave system returns from the power-down mode. ## Claims ### Claim 1 A slave device that is connected to a host device via a plurality of signal lines including a first signal line and a second signal line, comprising: a controller; and a back-end module, wherein: in a case where the slave device is in a first mode in which a clock signal supplied from the host device is received via the first signal line and a power supplied from the host device is supplied to both the controller and the back-end module, when the controller receives a first predetermined signal pattern via the second signal line and does not receive the clock signal via the first signal line, the slave device transitions to a second mode in which the power supplied to the back-end module is stopped, and in a case where the slave device is in the second mode, when the controller receives the clock signal via the first signal line, the slave device transitions to the first mode and transmits a second predetermined signal pattern via the second signal line. ### Claim 2 (depends on 1) The slave device according to claim 1, wherein the first predetermined signal pattern includes a signal of a first voltage level, a signal of a second voltage level, and a signal of the first voltage level in this order. ### Claim 3 (depends on 1) The slave device according to claim 1, wherein the first predetermined signal pattern indicates a predetermined command. ### Claim 4 (depends on 1) The slave device according to claim 1, wherein the second predetermined signal pattern includes a signal of a second voltage level and a signal of a first voltage level in this order. ### Claim 5 (depends on 1) The slave device according to claim 1, wherein the second predetermined signal pattern indicates a predetermined response. ### Claim 6 (depends on 2) The slave device according to claim 2, wherein the first voltage level is higher than 0 V, and the second voltage level is 0 V. ### Claim 7 (depends on 1) The slave device according to claim 1, wherein the back-end module has a function of recording data transmitted from the host device. ### Claim 8 (depends on 1) The slave device according to claim 1, wherein the back-end module has a function of transmitting and receiving data to and from a device other than the host device via a wireless interface. ### Claim 9 (depends on 4) The slave device according to claim 4, wherein the first voltage level is higher than 0 V, and the second voltage level is 0 V. ### Claim 10 A host device that is connected to a slave device via a plurality of signal lines including a first signal line and a second signal line, comprising: a controller; and a power supply unit that supplies a power to the slave device, wherein: in a first mode in which the power is supplied to the slave device via a power supply line by the power supply unit and a clock signal is supplied via the first signal line from the controller, after the controller transmits a first predetermined signal pattern via the second signal line, the host device transitions to a second mode in which the clock signal is not supplied from the controller via the first signal line, and in the second mode, after the controller supplies the clock signal via the first signal line and receives a second predetermined signal pattern via the second signal line, the host device transmits a signal to the slave device. ### Claim 11 (depends on 10) The host device according to claim 10, wherein, in the second mode, the power supply unit does not supply the power to the slave device via the power supply line. ### Claim 12 (depends on 10) The host device according to claim 10, wherein the first predetermined signal pattern includes a signal of a first voltage level, a signal of a second voltage level, and a signal of the first voltage level in this order. ### Claim 13 (depends on 10) The host device according to claim 10, wherein the first predetermined signal pattern indicates a predetermined command. ### Claim 14 (depends on 10) The host device according to claim 10, wherein the second predetermined signal pattern includes a signal of a second voltage level and a signal of a first voltage level in this order. ### Claim 15 (depends on 10) The host device according to claim 10, wherein the second predetermined signal pattern indicates a predetermined response. ### Claim 16 (depends on 12) The host device according to claim 12, wherein the first voltage level is higher than 0 V, and the second voltage level is 0 V. ### Claim 17 (depends on 14) The host device according to claim 14, wherein the first voltage level is higher than 0 V, and the second voltage level is 0 V.