Method and apparatus for automatically switching and charging multiple batteries
First Claim
1. A battery charging and selecting system coupled to a terminal of a voltage supply for charging at least first and second batteries and for selecting at least one of at least first and second batteries to deliver power to an electrical component, the first and second batteries having respective first and second voltages, the system comprising:
- a battery charger coupled to the terminal of the voltage supply and selectively coupled to the first and second batteries, the battery charger selectively providing a first mount of current to the first and second batteries;
a battery selector for selectively coupling the first and second batteries to the electrical component, the battery selector having a first state that couples at least one of the first and second batteries to the electrical component to supply power thereto and a second state that uncouples both of the first and second batteries from the electrical component;
a battery voltage monitoring circuit coupled to the first and second batteries and outputting first and second voltage signals representing the first and second voltages, respectively; and
a control circuit coupled to the battery charger, the battery selector and the battery voltage monitoring circuit, the control circuit determining in which state the battery selector is, and, if the battery selector is in the first state, then the control circuit(i) directs the battery selector to couple the first battery to the electrical component,(ii) compares the first voltage signal to a threshold voltage value,(iii) directs the battery selector to couple the second battery to the electrical component when the first voltage signal is less than the threshold voltage value,(iv) compares the second voltage signal to the threshold voltage value, and(v) directs the battery selector to couple both of the first and second batteries to the electrical component when the second voltage signal is less than the threshold voltage value, and if the battery selector is in the second state, the control circuit then(i) compares the first and second voltage signals before the battery charger provides the first amount of current to either one of the first and second batteries,(ii) determines that the first voltage signal corresponding to the first voltage on the first battery is greater than the second voltage signal corresponding to the second voltage on the second battery,(iii) causes the battery charger to provide the first amount of current to the first battery, and(iv) thereafter causes the battery charger to provide the first amount of current to the second battery.
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Accused Products
Abstract
A battery selecting and charging system forms part of a portable electronic device, preferably a portable medical device. When the device is powered up, a selecting circuit selects one of two rechargeable batteries to power the device until it is depleted, and then automatically switches to the other battery. When the second battery is depleted, both batteries are selected to power the device. When the device is powered down, a battery charging circuit, having both a high and low charge section, provides a high charge to the battery having the greatest terminal voltage. Thereafter, the high charge is applied to the other battery, the low charge is applied to the first battery, and then the low charge is applied to the second battery. The battery charging circuit monitors the terminal voltage to prevent any damage to the batteries or the device.
159 Citations
12 Claims
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1. A battery charging and selecting system coupled to a terminal of a voltage supply for charging at least first and second batteries and for selecting at least one of at least first and second batteries to deliver power to an electrical component, the first and second batteries having respective first and second voltages, the system comprising:
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a battery charger coupled to the terminal of the voltage supply and selectively coupled to the first and second batteries, the battery charger selectively providing a first mount of current to the first and second batteries; a battery selector for selectively coupling the first and second batteries to the electrical component, the battery selector having a first state that couples at least one of the first and second batteries to the electrical component to supply power thereto and a second state that uncouples both of the first and second batteries from the electrical component; a battery voltage monitoring circuit coupled to the first and second batteries and outputting first and second voltage signals representing the first and second voltages, respectively; and a control circuit coupled to the battery charger, the battery selector and the battery voltage monitoring circuit, the control circuit determining in which state the battery selector is, and, if the battery selector is in the first state, then the control circuit (i) directs the battery selector to couple the first battery to the electrical component, (ii) compares the first voltage signal to a threshold voltage value, (iii) directs the battery selector to couple the second battery to the electrical component when the first voltage signal is less than the threshold voltage value, (iv) compares the second voltage signal to the threshold voltage value, and (v) directs the battery selector to couple both of the first and second batteries to the electrical component when the second voltage signal is less than the threshold voltage value, and if the battery selector is in the second state, the control circuit then (i) compares the first and second voltage signals before the battery charger provides the first amount of current to either one of the first and second batteries, (ii) determines that the first voltage signal corresponding to the first voltage on the first battery is greater than the second voltage signal corresponding to the second voltage on the second battery, (iii) causes the battery charger to provide the first amount of current to the first battery, and (iv) thereafter causes the battery charger to provide the first amount of current to the second battery. - View Dependent Claims (2, 3, 4)
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5. A method of controlling a battery charging and selecting system, the system having a battery selector having first and second states, the method comprising:
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selecting at least one of at least first and second batteries to deliver power to an electrical component when the battery selector is in the first state by; selecting the first battery to deliver power to the electrical component; comparing the voltage output of the first battery to a first threshold voltage value; selecting the second battery to power the electrical component if the output voltage of the first battery is less than the first threshold voltage value; comparing the voltage output of the second battery to the first threshold voltage value; and selecting both of the first and second batteries to supply power to the electrical component if the voltage output of the second battery is less than the first threshold voltage value; and charging at least the first and second batteries when the battery selector is in the second state by; comparing the output voltages of the first and second batteries before charging either one of the first and second batteries; and if the output voltage of the first battery is greater than the output voltage of the second battery, charging the first battery with a first amount of current; and
thereafter charging the second battery with the first amount of current. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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Specification