Motorola Corporation

Motorola Mobility LLC

Sameh W Tawadrous

Thomas E Voor

Ronald H Deck

Brian E Brucknor

The invention concerns a method () and system () for selective control of charging a power source (). The method can include the steps of charging () the power source of an electronic device () in which the electronic device also includes a global positioning system unit () and conducting () a session for the global positioning system unit. The method can also include the step of&#x2014;in response to the session&#x2014;selectively throttling () the flow of current to the power source of the electronic device to reduce the effect of thermal variation on the operation of the global positioning system unit.

Method and system for selective control of charging a power source

A frequency management scheme for a hybrid communications/positioning device, such as a cellular/GPS or other combined device, generates a local clock signal for the communications portion of the device, using a crystal oscillator or other part. The oscillator output may be delivered to a phase locked loop to drive a high-frequency clock for the cellular or other communications portion of the hybrid device. A processor may determine frequency error between the phase locked loop and base station or other reference, to derive a digital frequency tracking message. A Doppler search or other logical control message may likewise be communicated from the processor to a GPS or other positioning receiver. The GPS receiver circuitry may consequently adjust Doppler center, window width or other parameters to enhance time to first fix or other performance. The architecture eliminates the need for a second crystal or other direct oscillator in the GPS receiver portion of the hybrid device, while still maintaining GPS performance. The architecture of the design also eliminates the need for frequency correcting elements in the crystal oscillator or other base reference oscillator or clock. The invention can furthermore be used in any system, radio, modem, transceiver, or receiver that has two or more receivers that share one reference or base oscillator or clock.

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Coral Springs, FL, United States of America

Sameh W Tawadrous