Battery fuel gauge
First Claim
1. A circuit for providing a signal representative of the capacity of a battery, the circuit comprising:
- means for sensing the electrical current supplied from a battery in a predetermined circuit;
means for integrating said electrical current for a predetermined amount of time, said integrating means including means for resetting said integrating means;
means for determining the elapsed time for said resetting means to reset said integrating means; and
means responsive to said time determining means for providing a signal representative of the capacity of the battery.
6 Assignments
0 Petitions
Accused Products
Abstract
A power supply system, for example, for use with a portable personal computer, includes a smart battery pack and a charging system. The smart battery pack is provided with a dedicated microcontroller for controlling the charging level of the battery charger system. In particular, the status of the battery including the voltage and temperature of the battery is applied to the microcontroller along with a signal representative of the current load demand of the computer system. The microcontroller, in turn, provides a control signal in the form of fixed frequency, variable duty cycle pulse width modulated (PWM) signal for controlling the charging level of the battery charger system. The duty cycle of the PWM signal is used to regulate the charging current supplied by the battery charger. In particular, the DC value of the PWM signal is used as a reference to control the charging current of the regulator to provide a variable output charging current with a relatively wide current range. As such, the battery charger is adapted to efficiently utilize the residual capacity of the battery charger system for optimizing charging of the battery packs during all operating conditions of the computer system. Moreover, the use of a PWM signal from the battery pack to control the battery charger enables a single type of battery charger to be utilized for various battery technologies.
62 Citations
27 Claims
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1. A circuit for providing a signal representative of the capacity of a battery, the circuit comprising:
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means for sensing the electrical current supplied from a battery in a predetermined circuit; means for integrating said electrical current for a predetermined amount of time, said integrating means including means for resetting said integrating means; means for determining the elapsed time for said resetting means to reset said integrating means; and means responsive to said time determining means for providing a signal representative of the capacity of the battery. - View Dependent Claims (2, 3, 4, 5)
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6. A circuit for providing a signal representative of the capacity of a battery, the circuit comprising:
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means for sensing the electrical current supplied from a battery in a predetermined circuit; and means responsive to said sensing means for providing a signal representative of the capacity of the battery, said sensing means includes means for providing an electrical voltage signal representative of the current being supplied from the battery, said electrical voltage signal providing means includes a predetermined analog to digital converter (ADC) electrically coupled to said sensing means for providing a digital representation of said battery circuit, said predetermined ADC being a dual slope ADC having an inverting input and a non-inverting input, said digital representation providing means including means for comparing the output of said ADC with a predetermined reference voltage which switches states as a function of whether said ADC output voltage is more or less than said predetermined reference voltage. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A circuit for determining the remaining capacity of a battery, the circuit comprising:
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means sensing the current supplied by said battery and providing a signal representative of the battery current; means responsive to said providing means for generating a signal representative of the remaining capacity of said battery, said generating means including means for converting said battery current representative signal to a digital value, said converting means including a predetermined dual slope analog to digital converter. - View Dependent Claims (18, 19, 20)
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21. A circuit for determining the remaining capacity of a battery, the circuit comprising:
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means sensing the current supplied by said battery and providing a signal representative of the battery current; means responsive to said providing means for generating a signal representative of the remaining capacity of said battery, said generating means including means for accumulating the battery current representative signal, said accumulating means including means for converting said battery current representative signal to a digital value, said converting means includes a predetermined analog to digital converter (ADC), said predetermined ADC being a dual slope ADC with an inverting input and a non-inverting input. - View Dependent Claims (22, 23)
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24. A computer system comprising:
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a portable personal computer means for providing a portable source of direct current (DC) electrical power to said personal computer; means for integrating an electrical voltage for a predetermined amount of time, said integrating means including means for integrating a predetermined value having polarity opposite to said direct current until said integrating means is reset; means for determining the elapsed time for said integrating means to integrate from said predetermined value to reset; and means responsive to said elapsed time for generating a signal representative of the remaining capacity of said portable source of DC power. - View Dependent Claims (25, 26)
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27. A method for determining the remaining capacity of a battery, the method comprising the steps of:
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(a) sensing the current supplied by the battery; (b) integrating said current for a predetermined amount of time and then integrating a predetermined value until said integrated value is zero; (c) determining the elapsed time for said integrating step to integrate from said predetermined value to zero; and (d) determining the remaining capacity of the battery based on said elapsed time.
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Specification