Apple Inc.

Microsoft Technology Licensing, LLC

Eugene Lvovich Shoykhet

Yehonatan Perez

Stephen J Hrinya

Julian Arlo Binder

Rajarshi Paul

Agustya Ruchir Mehta

David Simon Lukofsky

Junius Mark Penny

Christoph Horst Krah

Martin Paul Grunthaner

Jahan C Minoo

Joseph R Fisher, Jr

Kevin M Keeler

Brian C Menzel

Daniel Chian

Ruchi Jagdish Parikh

David Paul Wunsch Desrosiers

Stephen Hrinya

Ruchi Parikh

The uneven charge and discharge from non-collocated batteries within an HMD can be solved by monitoring the DC current on the paths coupled to the first battery and the second battery and making an adjustment in the path resistance to equalize, or at least reduce, the difference between the currents on the two paths. Aspects of the technology described herein monitor current on paths from two or more non-collocated batteries. When the currents are different, resistance is dynamically added to the path with the higher current to equalize the current in the two paths. The monitoring and resistance adjustment can occur during discharge from a battery to a load and during battery recharge.

Automatic DC resistance compensation

An enhanced parallel protection circuit is provided. A system using separate battery packs in a parallel configuration is arranged with multiple protection circuit modules (PCMs). The PCMs are configured to detect fault conditions, such as over voltage, under voltage, excess current, etc. The PCMs can be configured to control associated switches and/or other components. When a fault condition is detected by an individual PCM, the individual PCM transitions to a fault state, and the PCM triggers an output causing one or more actions, e.g., causing a device to shut down or isolate one or more components. In addition, by the use of the techniques disclosed herein, the individual PCM can generate a control signal that causes other PCMs to transition to a fault state. The individual PCM can also receive a control signal from another PCM to cause the individual PCM to transition to a fault state.

Enhanced parallel protection circuit

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.

Electronic device power protection circuitry

An electronic device is configured with sub-assemblies including a main logic board, flexible printed circuit, and dual battery packs that are assembled together with electrical connectors to enable power from the battery packs to flow over a power bus that is distributed along the flexible printed circuit and main logic board. A protection circuit module (PCM) in each battery pack is configured to determine a state of each of the connections among the sub-assemblies (i.e., whether or not properly assembled to provide electrical continuity through the connector) so that power from the battery packs is switched on to the power bus only when electrical continuity is verified at each of the connectors. In the event that any connection is faulty, for example due to a misalignment of a connector during assembly that prevents electrical continuity to be established through a connector, neither PCM will switch power on to the power bus.

Enablement of device power-on with proper assembly

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.

Electronic device with connector fault protection circuitry

Techniques for detecting mating and un-mating of a first connector with a second connector include providing a pulsed voltage signal at a contact of the second connector and measuring a rate of rise of voltage at the contact. If the measured voltage at the contact exceeds a threshold voltage during the time the pulsed voltage signal is applied, then it is concluded that the first connector is not present and not mated with the second connector. If the measured voltage is lower than or equal to the threshold voltage during the time of application of the voltage pulse, it is concluded that the first connector is present and mated with the second connector.

Using pulsed DC to detect connector mating and unmating

A force sensor interface in a touch controller of a touch sensitive device is disclosed. The force sensor interface can couple to touch circuitry to integrate one or more force sensors with touch sensors of the device. The force sensor interface can include one portion to transmit stimulation signals generated by the touch circuitry to the force sensors to drive the sensors. The interface can also include another portion to receive force signals, indicative of a force applied to the device, from the force sensors for processing by the touch circuitry. The device can use the touch circuitry to concurrently and seamlessly operate both the force sensors and the touch sensors.

Force sensor interface for touch controller

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San Jose, CA, United States of America

Eugene Lvovich Shoykhet