# US 2014/0153025 A1 · Method of sensing connection of usb device in power save mode and image forming apparatus for performing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153025 A1 - Document ID: US20140153025A1 - Status: Published application - Kind: A1 - Application number: 13/938,390 - Filed: 2013-07-10 - Published: 2014-06-05 - Earliest claimed: 2012-12-03 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Byung-sun MIN; Si-nae Choi - Web page: https://patentgrep.com/patent/US20140153025A1 ## CPC - G06F 1/3215: Monitoring of peripheral devices - 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 1/3206: Monitoring of events, devices or parameters that trigger a change in power modality - G06F 1/3234: Power saving characterised by the action undertaken - G06F 1/3278: {Power saving in modem or I/O interface} - G06F 1/3284: {Power saving in printer} - G06F 1/3287: by switching off individual functional units in the computer system - G06K 15/406: {Wake-up procedures (start-up of a laser scanner G06K15/1219)} - H04N 1/00896: {using a low-power mode, e.g. standby} - H04N 2201/0081: Image reader (H04N2201/0091 - H04N2201/0094 take precedence) - Y02D 10/00: Energy efficient computing, e.g. low power processors, power management or thermal management - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract An image forming apparatus includes a main controller, a universal serial bus (USB) interface to which an external USB device is connected, a voltage bus (VBUS) power supply to supply power to the USB interface through the VBUS line, a voltage change detector to output a wake-up signal to the main controller if a voltage change occurs on the VBUS line, a USB host controller to perform data communication with the USB device connected through the USB interface, and an image forming job performing unit to perform an image forming job according to control by the main controller. ## Claims ### Claim 1 An image forming apparatus comprising: a main controller; a universal serial bus (USB) interface; a voltage bus (VBUS) power supply to supply power to the USB interface through the VBUS line; a voltage change detector to output a wake-up signal to the main controller if a voltage change occurs on the VBUS line; a USB host controller to perform data communication with a USB device connected through the USB interface; and an image forming job performing unit to perform an image forming job according to control by the main controller, wherein the main controller turns off the USB host controller when the image forming apparatus enters a power save mode, and the main controller turns on the USB host controller when the wake-up signal is received from the voltage change detection unit. ### Claim 2 (depends on 1) The image forming apparatus of claim 1, wherein the voltage change detector comprises: a resistor on the VBUS line; and a comparator for outputting the wake-up signal if a voltage difference occurs between a first end and a second end of the resistor. ### Claim 3 (depends on 2) The image forming apparatus of claim 2, wherein a voltage value of the first end of the resistor is input to a non-inverting input port of the comparator, and a voltage value of the second end of the resistor is input to an inverting input port of the comparator. ### Claim 4 (depends on 2) The image forming apparatus of claim 2, wherein the resistor is implemented as a poly switch or a switching transistor. ### Claim 5 (depends on 1) The image forming apparatus of claim 1, wherein the main controller comprises: a general purpose input/output (GPIO) to manage an input and output of a signal; and a power save mode manager to manage a power supply when the image forming apparatus is in a power save mode, wherein the power save mode manager turns off the USB host controller when the image forming apparatus enters the power save mode, and turns on the USB host controller when a wake-up signal is received through the GPIO. ### Claim 6 (depends on 5) The image forming apparatus of claim 5, wherein the power save mode manager is a micro kernel operated when the image forming apparatus is in the power save mode. ### Claim 7 (depends on 1) The image forming apparatus of claim 1, wherein the USB host controller is located in the main controller. ### Claim 8 (depends on 7) The image forming apparatus of claim 7, further comprising: a USB hub to perform data communication with the USB host controller, wherein the USB hub is located outside the main controller, wherein the main controller blocks power supplied to the USB hub when the image forming apparatus enters the power save mode. ### Claim 9 (depends on 1) The image forming apparatus of claim 1, wherein the USB host controller is located outside the main controller, and the main controller blocks power supplied to the USB controller when the image forming apparatus enters the power save mode. ### Claim 10 A method of sensing connection of a universal serial bus (USB) device when an image forming apparatus is in a power save mode, the method comprising: turning off a USB host controller of the image forming apparatus when the image forming apparatus enters the power save mode; outputting a wake-up signal to a main controller of the image forming apparatus when a USB device is connected to a USB port of the image forming apparatus and a voltage change occurs on a voltage bus (VBUS) line that supplies power to the USB port; receiving the wake-up signal by the main controller; and turning on the USB host controller by the main controller. ### Claim 11 (depends on 10) The method of claim 10, wherein the outputting of the wake-up signal amplifies a voltage difference between first and second ends of a resistor on the VBUS line, and outputs the amplified voltage difference. ### Claim 12 (depends on 11) The method of claim 11, wherein the resistor is implemented as a poly switch or a switching transistor. ### Claim 13 (depends on 10) The method of claim 10, wherein the main controller operates a micro kernel if the image forming apparatus enters the power save mode, wherein the receiving of the wake-up signal comprises receiving the wake-up signal through a general purpose input/output (GPIO) of the main controller; and wherein the turning on of the USB host controller turns on the USB host controller when the micro kernel receives the wake-up signal from the GPIO. ### Claim 14 (depends on 10) A non-transitory computer-readable recording medium having recorded thereon a program for executing the method of claim 10 in a computer. ### Claim 15 An image forming apparatus comprising: a main controller; an external device interface; a power supply to supply power to the external device interface through a power supply line; a voltage change detector to output a wake-up signal to the main controller if a voltage change occurs on the power supply line; wherein the main controller turns off one or more components of the image forming apparatus when the image forming apparatus enters a power save mode, and the main controller turns on one or more components of the image forming apparatus when the wake-up signal is received from the voltage change detection unit. ### Claim 16 (depends on 15) The image forming apparatus of claim 15, wherein the power supply is a voltage bus (VBUS) power supply an power is supplied to the external device interface through a VBUS line. ### Claim 17 (depends on 16) The image forming apparatus of claim 16, wherein the voltage change detector comprises: a resistor on the VBUS line; and a comparator for outputting the wake-up signal if a voltage difference occurs between a first end and a second end of the resistor. ### Claim 18 (depends on 17) The image forming apparatus of claim 17, wherein a voltage value of the first end of the resistor is input to a non-inverting input port of the comparator, and a voltage value of the second end of the resistor is input to an inverting input port of the comparator. ### Claim 19 (depends on 17) The image forming apparatus of claim 17, wherein the resistor is implemented as a poly switch or a switching transistor. ### Claim 20 (depends on 15) The image forming apparatus of claim 15, wherein the external device interface is a universal serial bus (USB) interface. ### Claim 21 (depends on 1) The image forming apparatus of claim 1, wherein the main controller further turns off the image forming job performing unit.