Abstract:
A host electronic device may be coupled to an accessory electronic device. During normal operation, the host device may supply the accessory device with power over a power supply line. Back-powering events in which the accessory device delivers power to the host device may be prevented by interposing a protection transistor in the power supply line. A current mirror may be formed using the protection transistor and an additional transistor that produces a sense current proportional to the amount of current that is flowing through the power supply line. A current-to-voltage amplifier may produce a sense voltage that is proportional to the sense current. A bias circuit may be used to bias the sense current through the current mirror. A control circuit may compare the sense voltage to one or more reference voltages and turn off the protection transistor when appropriate to prevent back-powering of the host device.
Abstract:
A transmitter device for an inductive energy transfer system can include a DC-to-AC converter operably connected to a transmitter coil, a first capacitor connected between the transmitter coil and one output terminal of the DC-to-AC converter, and a second capacitor connected between the transmitter coil and another output terminal of the DC-to-AC converter. One or more capacitive shields can be positioned between the transmitter coil and an interface surface of the transmitter device. A receiver device can include a touch sensing device, an AC-to-DC converter operably connected to a receiver coil, a first capacitor connected between the receiver coil and one output terminal of the AC-to-DC converter, and a second capacitor connected between the receiver coil and another output terminal of the AC-to-DC converter. One or more capacitive shields can be positioned between the receiver coil and an interface surface of the receiver device.
Abstract:
An electronic device may include protection circuitry coupled to a connector port. The connector port may be a reversible connector port that receives a mating reversible connector plug with either first or second orientations. The connector port may include contacts for receiving and/or transmitting signals during communications between the electronic device and the accessory device. The protection circuitry may monitor signals received at the contacts to determine whether transient or permanent connection faults exist. In response to determining that a connection fault exists at any of the contacts, the protection circuitry may electrically disconnect the faulty contacts from processing circuitry in the electronic device.
Abstract:
An inductor coil includes a wire which is wound in alternating layers such that the surface area of the wire in each winding viewed from above or below the coil is substantially equal in each half of the coil defined by a line bisecting the center point in each layer. The layers are also wound in a serpentine fashion to balance the capacitance between layers. The substantially equal surface area of wire in each half of a coil layer and in adjacent coil layers results in a balanced capacitance of the coil which, in turn, results in reduced common mode noise.
Abstract:
Methods for operating a portable electronic device to conduct a mobile payment transaction at a merchant terminal are provided. The electronic device may verify that the current user of the device is indeed the authorized owner by requiring the current user to enter a passcode. If the user is able to provide the correct passcode, the device is only partly ready to conduct a mobile payment. In order for the user to fully activate the payment function, the user may have to supply a predetermined payment activation input such as a double button press that notifies the device that the user intends to perform a financial transaction in the immediate future. The device may subsequently activate a payment applet for a predetermined period of time during which the user may hold the device within a field of the merchant terminal to complete a near field communications based mobile payment transaction.
Abstract:
An inductor coil includes a wire which is wound in alternating layers such that the surface area of the wire in each winding viewed from above or below the coil is substantially equal in each half of the coil defined by a line bisecting the center point in each layer. The layers are also wound in a serpentine fashion to balance the capacitance between layers. The substantially equal surface area of wire in each half of a coil layer and in adjacent coil layers results in a balanced capacitance of the coil which, in turn, results in reduced common mode noise.
Abstract:
A transmitter device for an inductive energy transfer system can include a DC-to-AC converter operably connected to a transmitter coil, a first capacitor connected between the transmitter coil and one output terminal of the DC-to-AC converter, and a second capacitor connected between the transmitter coil and another output terminal of the DC-to-AC converter. One or more capacitive shields can be positioned between the transmitter coil and an interface surface of the transmitter device. A receiver device can include a touch sensing device, an AC-to-DC converter operably connected to a receiver coil, a first capacitor connected between the receiver coil and one output terminal of the AC-to-DC converter, and a second capacitor connected between the receiver coil and another output terminal of the AC-to-DC converter. One or more capacitive shields can be positioned between the receiver coil and an interface surface of the receiver device.
Abstract:
Implementations described and claimed herein provide systems and methods for supplying voltage to a load and battery. In one implementation, a first regulated DC-to-DC converter is electrically connected to a first energy source to down convert a first voltage supplied by the first energy source. A load is electrically connected to the first regulated DC-to-DC converter to receive the down converted first voltage. A second regulated DC-to-DC converter is electrically connected to the first regulated DC-to-DC converter to regulate the down converted first voltage to a second voltage. A second power source is electrically connected to the second regulated DC-to-DC converter to charge the second power source using the second voltage, and the second power source is switchably connectable to the load.
Abstract:
Methods for operating a portable electronic device to conduct a mobile payment transaction at a merchant terminal are provided. The electronic device may verify that the current user of the device is indeed the authorized owner by requiring the current user to enter a passcode. If the user is able to provide the correct passcode, the device is only partly ready to conduct a mobile payment. In order for the user to fully activate the payment function, the user may have to supply a predetermined payment activation input such as a double button press that notifies the device that the user intends to perform a financial transaction in the immediate future. The device may subsequently activate a payment applet for a predetermined period of time during which the user may hold the device within a field of the merchant terminal to complete a near field communications based mobile payment transaction.
Abstract:
Methods, structures, and apparatus that are able to detect the presence of a connection to a device contact of an electronic device and are also able to detect the presence of contamination at the device contact. A host device includes a connection detection circuit and a contamination detection circuit connected to the device contact. The connection detection circuit includes a pull-up resistor that is pulled down by a pull-down resistor in an accessory device following a connection. The contamination detection circuit includes a current source to provide a current at the device contact and measurement circuitry to measure a resulting voltage.