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Researchers Submit Patent Application, "Startup Boot Cycle Testing of a Mobile Device at Diminished Power Supply Current", for Approval

August 21, 2014

By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventor Tam, Ching-Yu John (Los Gatos, CA), filed on August 21, 2013, was made available online on August 7, 2014.

The patent's assignee is Apple Inc.

News editors obtained the following quote from the background information supplied by the inventors: "Mobile multi-function devices include a main system processor that runs the operating system and performs the basic arithmetical, logical, and input/ output operations of the mobile device. Generally mobile devices are powered by an integrated battery, but are sometimes capable of being powered by external power sources. In some situations the battery may be depleted (e.g. zero charge or low charge) and cannot power the device during startup boot procedures. In these situations, the mobile device must rely on an external source to power the mobile device during boot procedures.

"While performing boot procedures, a current limiter in the mobile device restricts the flow of current to the device from an external source. This current limit is raised after the mobile device has successfully booted. Manufactures often set this current limit as low as possible while booting to ensure the draw of current by the mobile device does not damage or negatively affect the external power source or the mobile device. Since this current limit is low and at the edge of what is necessary to boot the mobile device, manufacturers seek to test the ability of their processors to boot using these lower current levels."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventor's summary information for this patent application: "There is a need for a system and method for testing the tolerance of the default low current startup condition of a mobile multi-function device. By stealing current provided by an external power source, less power is available to startup the device. The amount of current stolen that stills allows the main system of the device to startup is the power margin available.

"An embodiment relates to a startup boot cycle test system for testing a mobile multi-function device under test (DUT) that has a power manager and a main system processor. The system includes an external power source and a tester device. The external power source provides an input current to the power manager. The power manager has an integrated current limiter that limits the amount of current drawn by the DUT from the external power source during boot/ startup and provides power to the main system and charging circuits of the DUT. The tester device connects to a test point in the DUT using a contact test probe to steal current from the boot current provided to the main system of the DUT. The resulting diminished boot current is used by the system to boot. The tester device detects whether the processor successfully boots using the diminished boot current using a data input connector connected between the DUT and the tester device. In another embodiment, the processor may itself determine it has successfully booted using the diminished boot current and report the results to the tester device or directly to a test engineer. By drawing the margin current, the tester device determines whether the processor can boot solely using a low/diminished current that falls below the current level set by a current limiter in the DUT. If the processor is able to boot using this diminished current, the processor will likely boot using the higher current set by the current limiter during normal operation of the DUT.

"The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary.


"The embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to 'an' or ' one' embodiment of the invention in this disclosure are not necessarily to the same embodiment, and they mean at least one.

"FIG. 1 shows a human user holding different types of mobile multi-function communications devices, namely a smart phone and a tablet-like personal computer.

"FIGS. 2A and 2B show functional unit block diagrams and some constituent hardware components of a startup boot cycle test systems for testing the mobile multi-function communications devices with a tester device.

"FIG. 3 shows a partial diagram of display driver circuitry of a mobile multi-function communications device with a test point as arranged in FIG. 2B.

"FIG. 4 shows a functional unit block diagram and some constituent hardware components of the tester device.

"FIG. 5 shows a method for testing the tolerance of a processor in a mobile multi-function communications device according to one embodiment."

For additional information on this patent application, see: Tam, Ching-Yu John. Startup Boot Cycle Testing of a Mobile Device at Diminished Power Supply Current. Filed August 21, 2013 and posted August 7, 2014. Patent URL:

Keywords for this news article include: Apple Inc.

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Source: Politics & Government Week

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