Patent ID: 8780055

Claim:
A portable electronic device, comprising: a housing; a controller received within the housing; a touch-sensitive display having a touch-sensitive overlay, the touch-sensitive display being mechanically constrained by the housing; a plurality of force sensing resistors located below the touch-sensitive display on an opposite side to the touch-sensitive overlay, the plurality of force sensing resistors being connected to the controller and measuring forces applied to the touch-sensitive display; and a multi-port switch having a switch for each of the force sensing resistors, the multi-port switch being controlled by the controller, the multi-port switch summing force data measured by the plurality of force sensing resistors; wherein the controller is configured for: initiating a sleep mode of the electronic device from a full power mode of the electronic device, in response to a trigger; when in the sleep mode, reading a sum of the force data measured by the plurality of force sensing resistors at a reduced duty cycle relative to the full power mode, comparing the sum of force data to a wakeup force threshold, and returning to the full power mode from the sleep mode when the sum of force data is greater than the wakeup force threshold; wherein, in the multi-port switch, a respective switch for each of the force sensing resistors is closed during an active portion of the sleep duty cycle in which force data is read, and wherein the respective switch for each of the force sensing resistors is open during the inactive portion in which force data is not read.