Method and apparatus for charging a battery
First Claim
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1. A DC-DC converter usable as a battery charger, comprising:
- current error amplifier means and voltage error amplifier means connected in parallel to control the charging phase of a battery, and a gradual turning off means gradually turning off said current error amplifier means in a battery charging end phase.
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Abstract
A DC-DC converter having a current error amplifier and a voltage error amplifier connected in parallel to control the charging of the battery and a gradual turning off circuit for turning off gradually the current error amplifier in a battery charging end phase. In this way, the DC-DC converter is able to supply to the battery a battery charging current that remains constant until the battery full charge voltage is reached.
51 Citations
22 Claims
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1. A DC-DC converter usable as a battery charger, comprising:
- current error amplifier means and voltage error amplifier means connected in parallel to control the charging phase of a battery, and a gradual turning off means gradually turning off said current error amplifier means in a battery charging end phase.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for charging a battery, comprising:
- supplying a current to said battery using a DC-DC converter comprising current error amplifier means and voltage error amplifier means connected in parallel to control charging of said battery, and gradually turning off said current error amplifier means in a battery charging end phase.
- View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A DC-DC converter usable as a battery charger, comprising:
current error amplifier means and a voltage error amplifier means connected in parallel to control the charging phase of a battery and a gradual turning off means gradually turning off the current error amplifier means in a battery charging end phase, the gradual turning off means comprising first current generating means supplying a first bias current for the current error amplifier means having decreasing amplitude in the battery charging end phase.
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17. A DC-DC converter usable as a battery charger, comprising:
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current error amplifier means and a voltage error amplifier means connected in parallel to control the charging phase of a battery, the voltage error amplifier means comprising an input stage including first and second transistor means connected in differential configuration; and
a gradual turning off means gradually turning off the current error amplifier means in a battery charging end phase, the gradual turning off means comprising first current generating means supplying a first bias current for the current error amplifier means having decreasing amplitude in the battery charging end phase, the first bias current comprising a function of the difference between the current flowing, in use, and the first and second transistor means.
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18. A DC-DC converter usable as a battery charger, comprising:
current error amplifier means and a voltage error amplifier means connected in parallel to control the charging phase of a battery, the current error amplifier means and the voltage error amplifier means sharing the same output stage, and a gradual turning off means gradually turning off the current error amplifier means in a battery charging end phase.
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19. A method for charging a battery comprising:
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supplying a current to the battery using a DC-DC converter comprising current error amplifier means and voltage error amplifier means connected in parallel to control charging of the battery; and
gradually turning off the current error amplifier means in a battery charging end phase by supplying to the current error amplifier means a first bias current having a decreasing amplitude in the battery charging end phase.
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20. A method for charging a battery, comprising:
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supplying a current to the battery using a DC-DC converter comprising current error amplifier means and a voltage error amplifier means connected in parallel to control charging of the battery, the voltage error amplifier means having an input stage including first and second transistor means connected in differential configuration;
generating a first bias current as a function of the difference between currents flowing, in use, in the first and second transistor means; and
gradually turning off the current error amplifier means in a battery charging end phase by supplying to the current error amplifier means the first bias current having a decreasing amplitude in the battery charging end phase.
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21. A battery charging regulation circuit, comprising:
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a voltage error amplifier having first and second differential inputs, the first differential input coupled to a reference voltage source, the second differential input adapted to be coupled to the battery, and an output stage having an output terminal;
an amplifier adapted to detect charging current delivered to the battery, the amplifier coupled to an adjustable bias current source and configured to deliver an output current to the output stage of the voltage error amplifier; and
a measuring stage coupled to the first and second differential inputs of the voltage error amplifier, and an output coupled to a control terminal of the adjustable bias current source, the measuring phase configured to generate a start-turning-off signal to the adjustable bias current source when the differential input to the voltage error amplifier is below a threshold value, the adjustable bias current source configured to provide a constant bias current to the amplifier during a charging phase and to provide a gradually reducing bias current to the amplifier in response to the start-turning-off signal. - View Dependent Claims (22)
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Specification