Electricity: battery or capacitor charging or discharging – Battery or cell charging
Reexamination Certificate
1998-04-30
2001-04-24
An, Meng-Al T. (Department: 2154)
Electricity: battery or capacitor charging or discharging
Battery or cell charging
C320S134000, C320S164000
Reexamination Certificate
active
06222347
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to portable computing devices and, more particularly, to charging batteries of portable computing devices.
2. Description of the Related Art
A computing device often includes one or more batteries to supply power to the computing device. Those computing devices that use batteries to supply power to operate are referred to as portable computing devices. Portable computing devices pertain to a wide range of devices, including portable computers (various sizes), portable game apparatuses, personal digital assistants (PDAs), etc.
Normally, these portable computing devices use rechargeable batteries as the primary source of power to the device. The portable computing devices typically are also able to couple to an alternating current (AC) power source with an AC adapter. The AC adapter plugs into a electric wall socket and converts incoming AC power into DC power which is used to power the portable computing device and/or charge the rechargeable batteries within the portable computing device.
Conventionally, these batteries take a considerable amount of time to fully charge. One reason is that the amount of power made available for charging is determined based on a worst case power budget such that the power used to charge a battery tends to be low. As such, the power used to charge the battery is low when the portable computing device is active. Another reason why conventional charging is so slow is that the amount of power varies over the charging cycle as the battery voltage changes but the charging current remain fixed at a safe level. With this approach, the fixed current level is set to a rather low level so that when the portable computing device is active it will not be starved for power by the charging of the battery. If the portable computing device were to be starved for power during its operation, then the portable computing device would fail, crash or otherwise cease to operate.
Thus, there is a need for charging techniques that are able to better utilize available power to charge batteries.
SUMMARY OF THE INVENTION
Broadly speaking, the invention relates to improved techniques for charging batteries within portable computing devices. The improved techniques operate to charge a battery at dynamically determined power levels. The power levels for charging the battery are dynamically determined by monitoring the power consumption of the portable computing device. When subsystems of the portable computing device are determining to be consuming less power than has been allocated thereto, higher levels of power from a power source are made available for charging the battery. As a result, the battery is able to be charged at a rate that is significantly faster than previously performed. Also, by dynamically monitoring the power consumption of the portable computing device, the improved techniques also ensure that the portable computing device will not be starved for power during its operation even as its subsystem's switch between normal (active) modes and low power modes.
The invention can be implemented in numerous ways, including as a method, an apparatus, and a computer system. Several embodiments of the invention are discussed below.
As a method for charging a battery of a portable computing device from a power supply, one embodiment of the invention includes the acts of: determining an amount of power available for charging the battery from the power supply depending on power being consumed by subsystems of the portable computing device; and charging the battery in accordance with the determined amount of power, such that the battery is charged with an increased amount of power from the power supply when one or more of the subsystems of the portable computing device are in a low power mode.
As a method for charging a battery of a portable computing device having peripheral subsystems, another embodiment of the invention includes the acts of: periodically monitoring a state of the peripheral subsystems, the state including an active state and an inactive state; periodically determining a power available amount for charging the battery based on the state of the peripheral subsystems; and charging the battery in accordance with the power available amount.
As a computer system, still another embodiment of the invention includes: a power supply for providing DC power to the computer system from an AC power source; a battery for providing DC power to the computer system; a plurality of peripheral subsystems, each of the peripheral subsystems having a low-power state and an active state; a processor for performing computations and controlling the system; a power management unit for monitoring status of the battery, monitoring the state of the peripheral subsystems, and determining an amount of power available for charging based at least in part on those of the peripheral subsystems that are in the inactive state; and a battery charge circuit for delivering power from the power supply to the battery in accordance with the power charge level.
The advantages of the invention are numerous. One advantage of the invention is that a battery are able to be charged significantly faster than previously. Another advantage of the invention is that the charging of the battery is safely performed regardless of the amount of power being consumed by the operation of the portable computing device.
Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
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An Meng-Al T.
Apple Computer Inc.
Beyer Weaver & Thomas LLP
Chang Jung-won
LandOfFree
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