Solar chargeable battery for portable devices
AssigneeSunCore, Inc.
InventorsPETER ENGLISH, Steven R. Brimmer
Life of this patent
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Abstract
A solar chargeable battery comprises a built-in photovoltaic array and a programmable battery charging circuit. The photovoltaic array provides a variable power source in response to light. The battery charging circuit receives the variable power source and operates in different modes to charge the battery over a range of lighting conditions. For example, the battery charging circuit charges the battery to a substantially fixed regulated voltage level in a first mode when a voltage level of the variable power source is above a predefined threshold. The battery charging circuit charges the battery to an adjustable regulated voltage level in a second mode when the voltage level of the variable power source is below the predefined threshold.
Claims17
A battery charging circuit for a portable device comprising:
- a switching regulator configured to receive a substantially DC power source from one or more photovoltaic cells at an input terminal and to charge a battery coupled to an output terminal;
- and
- a controller configured to monitor the substantially DC power source and to provide one or more control signals to the switching regulator to selectively operate the switching regulator in a first mode when a voltage level of the substantially DC power source is above a first predefined voltage threshold and in a second mode when the voltage level of the substantially DC power source is below the first predefined voltage threshold, wherein the switching regulator operates with a predetermined regulated voltage level in the first mode and operates with a variable regulated voltage level that tracks the voltage level of the substantially DC power source in the second mode.
A method to charge a battery from a variable DC power source, the method comprising:
- sensing a voltage level of the variable DC power source, wherein the variable DC power source is provided by a photovoltaic array;
- selectively operating in a first mode when the voltage level of the variable DC power source is above a predefined voltage threshold, wherein the variable DC power source charges the battery to a predetermined regulated voltage level in the first mode and the predetermined regulated voltage level is approximately 4.2 volts;
- and
- selectively operating in a second mode when the voltage level of the variable DC power source is below the predefined voltage threshold, wherein the variable DC power source charges the battery to an adjustable regulated voltage level in the second mode and the adjustable regulated voltage level is approximately equal to the voltage level of the variable DC power source less a predetermined amount.
A battery charger comprising:
- a power regulator configured to receive a variable DC power source and to charge a battery;
- and
- a controller configured to sense the variable DC power source, to operate the power regulator in a first mode when a voltage of the variable DC power source is above a predefined voltage level, and to operate the power regulator in a second mode when the voltage of the variable DC power source is below the predefined voltage level, wherein the power regulator charges the battery to a substantially fixed regulated voltage level in the first mode and to an adjustable regulated voltage level in the second mode.
Dependencies are inferred from the claim text.