Motorola Corporation

Thomas E Voor

Ronald H Deck

Sameh W Tawadrous

Joseph Patino

Stephen J Oglesby

Brian E Brucknor

A device () contains a battery () which is recharged under control of a charge controller (). An external power supply () provides charging current and voltage (). A linear regulator () regulates the raw voltage provided by the external power supply. The device () also contains a heat-generating sub-system (). To prevent excess heat generation while charging the battery, the battery charging regime is altered from a conventional regime when the heat-generating sub-system is active. Once the battery voltage reaches a charge limit (), charge current is ceased () until the battery voltage falls to a lower limit (), at which time the charging current is recommenced.

Method and apparatus for charging a battery using a threshold to cease charging

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.

System and method for frequency management in a communications positioning device

A global positioning system (GPS) receiver ( ) has a reference oscillator ( ) for use in synthesizing signals for use in receiving and acquiring GPS satellite signals by a GPS downconverter ( ). Upon manufacture of the receiver ( ), the receiver is tested and a factory frequency offset of the oscillator is determined ( ). It has been found that the heat used in reflowing the solder used to attach receiver components causes the operating frequency of oscillator devices, such as crystals, to shift considerably. In addition, during a brief period after manufacture of the receiver, the frequency of the oscillator shifts back towards its original operating frequency, and so much so that the narrow search window used to search for a GPS carrier is inadequate, and it is likely that the receiver would not locate the desired carrier signal. The invention takes advantage of the time period after manufacture, when the frequency of the oscillator settles, and the first time unit is turned on, the receiver is used proactively with a wide search window ( ) to determine an operating frequency offset. Then, for subsequent location determination operations, a narrow search window is used ( ).

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Parkland, FL, United States of America

Thomas E Voor