# US 2020/0401295 A1 · System and method of controlling an electropermanent magnet at a trackpad > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0401295 A1 - Document ID: US20200401295A1 - Status: Published application - Kind: A1 - Application number: 16/450,269 - Filed: 2019-06-24 - Published: 2020-12-24 - Earliest claimed: 2019-06-24 - Assignees: Dell Products L.P. - Applicants: Dell Products, LP - Inventors: Jason S. Morrison; Laurent A. Regimbal - Web page: https://patentgrep.com/patent/US20200401295A1 ## CPC - G06F 3/04186: {Touch location disambiguation} - G06F 1/169: {the I/O peripheral being an integrated pointing device, e.g. trackball in the palm rest area, mini-joystick integrated between keyboard keys, touch pads or touch stripes (G06F1/1643 takes precedence; constructional details of pointing devices G06F3/033)} - G06F 3/044: by capacitive means - G06F 3/045: using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact - H01F 7/0231: {Magnetic circuits with PM for power or force generation} - H01F 7/04: Means for releasing the attractive force - H01H 21/24: biased to return to normal position upon removal of operating force - H03K 17/962: {Capacitive touch switches} - G06F 1/1616: {with folding flat displays, e.g. laptop computers or notebooks having a clamshell configuration, with body parts pivoting to an open position around an axis parallel to the plane they define in closed position} - G06F 3/016: {Input arrangements with force or tactile feedback as computer generated output to the user} - G06F 3/03547: {Touch pads, in which fingers can move on a surface} - H01H 2003/008: {with a haptic or a tactile feedback controlled by electrical means, e.g. a motor or magnetofriction} - H01H 2215/05: electromechanical - H01H 2221/032: adjustable - H01H 2239/03: Avoiding erroneous switching - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract An information handling system may include a processor to receive input from a trackpad at the information handling system, from a user; and an electropermanent magnet control system to control the activation of an electropermanent magnet (EPM) magnetically couplable to the trackpad to influence the force of actuation. ## Claims ### Claim 1 An information handling system, comprising: a processor to receive user input from a trackpad at the information handling system; and an electropermanent magnet control system to control the activation of an electropermanent magnet (EPM) magnetically couplable to a diveboard structure of the trackpad to set a resistive actuation force for a click input to the trackpad. ### Claim 2 (depends on 1) The information handling system of claim 1, wherein the EPM is a multi-level EPM comprising a high-coercivity magnet and a plurality of lower coercivity magnets. ### Claim 3 (depends on 1) The information handling system of claim 1, wherein the electropermanent magnet control system receives user input descriptive of a setting for the resistive actuation force of the trackpad used by the user to actuate the trackpad. ### Claim 4 (depends on 1) The information handling system of claim 1, wherein the electropermanent magnet control system controls the resistive actuation force of the trackpad used by the user to actuate the trackpad by selectively aligning each of a magnetic field of a plurality of low-coercivity magnets with a magnetic field of a high-coercivity magnet within the EPM to generate a magnetic field over the trackpad. ### Claim 5 (depends on 1) The information handling system of claim 1, wherein the trackpad comprises a permanent magnet operatively coupled to a flange formed on the trackpad such that the permanent magnet is disposed over the EPM by the flange. ### Claim 6 (depends on 1) The information handling system of claim 1, wherein the EPM is a multi-level EPM comprising a plurality of low-coercivity magnet to set polarity levels of the EPM to magnetically interact with the trackpad comprising a permanent magnet having a permanent magnet polarity. ### Claim 7 (depends on 1) The information handling system of claim 1, wherein the electropermanent magnet control system detects an errant touch of the trackpad and selects a magnetic level of a multi-level EPM to interact with the diveboard structure of the trackpad such that the resistive actuation force increases to prevent inadvertent click inputs. ### Claim 8 A trackpad system, comprising: a substrate having a touch sensing layer to receive input from a user; a switch to detect deflective movement of the substrate as a user actuates the trackpad system; a permanent magnet operatively coupled to a portion of the substrate having a permanent magnet polarity; and an electropermanent magnet (EPM) including a low-coercivity magnet having an electrically conductive wire coiled around the low-coercivity magnet to receive a first electrical current pulse to adjust the polarity of the low-coercivity magnet relative to the permanent magnet to generate an EPM magnetic flux to interact with the permanent magnet to set a resistive actuation force for a click input to the trackpad. ### Claim 9 (depends on 8) The trackpad system of claim 8 further comprising: the EPM having a plurality of low-coercivity magnets each having an electrically conductive wire coiled around the low-coercivity magnet to receive electrical current pulses to adjust the polarity of the low-coercivity magnets relative to the permanent magnet polarity. ### Claim 10 (depends on 9) The trackpad of claim 9, wherein the polarities of the low-coercivity magnets are selectively aligned opposite to the permanent magnet polarity in order to increase, incrementally, the resistive actuation force used by the user to actuate the trackpad depending on the number of low-coercivity magnets oppositely aligned. ### Claim 11 (depends on 8) The trackpad system of claim 8 further comprising: a flange formed on the substrate onto which the permanent magnet is operatively coupled to dispose the permanent magnet to magnetically interface with the EPM. ### Claim 12 (depends on 8) The trackpad system of claim 8, wherein the EPM is coupled to a chassis of an information handling system associated with the trackpad. ### Claim 13 (depends on 8) The trackpad system of claim 8, comprising a number of flanges formed on the substrate onto which the permanent magnets are operatively coupled wherein the flanges overhang a past an edge of a housing of the trackpad to prevent the trackpad from rising above the housing. ### Claim 14 A method of controlling a multilevel electro-permanent magnet (EPM) of a trackpad assembly of an information handling system, comprising: at the multilevel EPM comprising a plurality of low-coercivity magnets and a plurality of electrically conductive wires each coiled around a low-coercivity magnet: selecting a magnetic level from a plurality of magnetic levels for the multilevel EPM by applying a selected number of current pulses to the plurality of electrically conductive wires to select a number of low-coercivity magnets for polarity alignment with a high coercivity magnet or the EPM or to oppose polarity alignment of a permanent magnet disposed on the trackpad assembly to set the magnetic level of the multilevel EPM, where the selected magnetic level may be used to adjust resistive actuation force for a click input to the trackpad assembly. ### Claim 15 (depends on 14) The method of claim 14, comprising determining if an intentional touch is detected at the trackpad assembly and: when an intentional touch is detected, receiving input from the trackpad assembly at a processor of the information handling system; and when an errant touch is detected, preventing any input from the trackpad assembly to be received at a processor of the information handling system. ### Claim 16 (depends on 15) The method of claim 15, wherein detecting the errant touch occurs when a sensor in a palm rest near the trackpad assembly detects a touch or proximity of a user's hand. ### Claim 17 (depends on 14) The method of claim 14, wherein application of any current to any electrically conductive wire causes an attractive force to be exerted onto a diveboard structure of the trackpad assembly to generate the resistive actuation force when the multilevel EPM is disposed under the c-cover of an information handling system. ### Claim 18 (depends on 15) The method of claim 15, wherein detecting the errant touch occurs when a touch sensor layer of the trackpad assembly detects a touch indicating a palm or side of user's hand. ### Claim 19 (depends on 15) The method of claim 15, wherein detecting the errant touch causes a selection of a magnetic level of the multi-level EPM to lock the trackpad assembly in an up position to prevent an errant click. ### Claim 20 (depends on 15) The method of claim 15, wherein detecting the errant touch causes the multi-level EPM to set the polarity of the plurality of low-coercivity magnets to oppose a permanent magnet disposed on the trackpad assembly to lock in an up position.