Microsoft Technology Licensing, LLC

Junius Mark Penny

Agustya Ruchir Mehta

David Simon Lukofsky

Jonathan Alan Dutra

Eugene Lvovich Shoykhet

David C Wyland

Scott Fullam

Julian Arlo Binder

David Paul Wunsch Desrosiers

Scott Francis Fullam

David Carl Wyland

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

A dynamic power control circuit is provided. The control circuit can detect the presence of the external power source as well as detect one or more conditions of the device. For instance, the control circuit can detect a voltage difference between a first node coupling a first power output and a system circuit and a second node coupling a second power output and the batteries. The control circuit can also detect the activation or deactivation of the external power source. Based on the inputs, the control circuit can cause the controlled resistor to dynamically adjust a level of impedance between the first node and the second node. The controlled impedance between the first node and the second node enables the system circuit to dynamically utilize power supplied by the external power source as well as power supplied by the batteries.

Dynamic power control circuit

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, excess heat, etc. Individual 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 triggers one or more associated switches to shut down one or more components. In addition, by the use of the techniques disclosed herein, the individual PCM can also trigger switches that are controlled by other PCMs. Configurations disclosed herein mitigate occurrences where a multi-PCM device is operating after at least one PCM has shut down. Configurations disclosed herein provide safeguards and redundant protection in scenarios where a fault event is detected by one PCM and not detected by another PCM in a parallel configuration.

Enhanced parallel protection circuit

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

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Ben Lomond, CA, United States of America

Junius Mark Penny