Method and system for operating a camera flash on a mobile device
First Claim
1. A method of operating a camera flash on a mobile device powered by a battery module, wherein upon determination that the camera flash needs to be activated the method comprises:
- measuring battery parameters of the battery module without operating the camera flash;
determining an equivalent series resistance (ESR) of the battery module based on one of the measured battery parameters;
determining a maximum flash current based on the measured battery parameters, the ESR of the battery module, potential current loads that may occur during the operation of the camera flash and a minimum battery voltage for operation of the mobile device; and
generating a camera flash current while drawing a current from the battery module with an amplitude less than or equal to the maximum flash current;
wherein the measured battery parameters comprise a battery voltage and a battery temperature of the battery module;
wherein the method comprises using a look-up table of battery temperature values and associated ESR values of the battery module to determine the ESR of the battery module from the measured battery temperature; and
wherein the method further comprises using additional look-up tables for different pulse lengths in the camera flash current.
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Accused Products
Abstract
Various embodiments are described herein for a method and related apparatus for safely operating a camera flash on a mobile device powered by a battery module. Upon determination that the camera flash needs to be activated the method comprises measuring several battery parameters including the voltage and temperature of the battery module. An equivalent series resistance (ESR) of the battery module is determined based on the battery temperature. The maximum flash current is then determined based on the battery voltage, and ESR along with potential current loads that may occur during operation of the camera flash, and a minimum battery voltage for safe operation of the mobile device where the battery voltage has been adjusted if needed. The device is then configured to draw a current from the battery module that is not greater than the maximum flash current.
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Citations
20 Claims
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1. A method of operating a camera flash on a mobile device powered by a battery module, wherein upon determination that the camera flash needs to be activated the method comprises:
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measuring battery parameters of the battery module without operating the camera flash; determining an equivalent series resistance (ESR) of the battery module based on one of the measured battery parameters; determining a maximum flash current based on the measured battery parameters, the ESR of the battery module, potential current loads that may occur during the operation of the camera flash and a minimum battery voltage for operation of the mobile device; and generating a camera flash current while drawing a current from the battery module with an amplitude less than or equal to the maximum flash current; wherein the measured battery parameters comprise a battery voltage and a battery temperature of the battery module; wherein the method comprises using a look-up table of battery temperature values and associated ESR values of the battery module to determine the ESR of the battery module from the measured battery temperature; and wherein the method further comprises using additional look-up tables for different pulse lengths in the camera flash current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A mobile device comprising:
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a microprocessor configured to control the operation of the mobile device; a battery module configured to provide power to the mobile device; and a camera unit configured to take pictures, the camera unit comprising a camera flash sub-unit having a camera flash and a current drive unit configured to provide a camera flash current to the camera flash sub-unit for activation of the camera flash; wherein, upon determination that the camera flash needs to be activated the microprocessor is adapted to determine a maximum flash current based on measured battery parameters obtained without operating the camera flash, an equivalent series resistance (ESR) of the battery module determined from one of the measured battery parameters, potential current loads that may occur during the operation of the camera flash and a minimum battery voltage for operation of the mobile device; wherein the measured battery parameters comprise a battery voltage and a battery temperature of the battery module; wherein a look-up table of battery temperature values and associated ESR values of the battery module is used to determine the ESR of the battery module from the measured battery temperature; wherein additional look-up tables are used for different pulse lengths in the camera flash current; and wherein the current drive unit is adapted to generate the camera flash current while drawing a current from the battery module with an amplitude less than or equal to the maximum flash current. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification