Battery protection system and process for charging a battery
First Claim
1. A battery protection system having a first terminal, a second terminal, a first battery electrode, and a second battery electrode, comprising:
- a first switch having a control electrode, a first current conducting electrode coupled to the first terminal of the battery protection system, and a second current conducting electrode;
an inductor having a first electrode coupled to the second current conducting electrode of the first switch and a second electrode coupled to the first battery electrode of the battery protection system;
a resistor having a first electrode coupled to the second battery electrode of the battery protection system and a second electrode coupled to the second terminal of the battery protection system;
a rectifier having a first electrode coupled to the second electrode of the resistor and a second electrode coupled to the first electrode of the inductor;
a first comparator having a first input coupled to the first electrode of the resistor, a second input coupled to the second electrode of the resistor, and an output coupled to the control electrode of the first switch; and
a battery monitoring circuit having a plurality of inputs and a first output, a first input of the plurality of inputs being coupled to the second electrode of the inductor, a second input of the plurality of inputs being coupled to the first electrode of the resistor, and the first output being coupled to the control electrode of the first switch.
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Accused Products
Abstract
A battery protection system (20) controls a process for charging a battery pack (15). A hysteresis comparator (54) senses a charging current flowing through the battery pack (15) and switches off a charging switch (31) to interrupt the charging current when the charging current reaches an upper limit. A transient current is then generated by an inductor (34). The hysteresis comparator (54) senses the transient current flowing through the battery pack (15) and switches on the charging switch (31) to regenerate the charging current when the transient current decreases substantially to zero. Periodically, a battery monitoring circuit (40) switches off the charging switch (31) and measures an open circuit voltage across each battery cell in the battery pack (15). In response to the open circuit voltage of a battery cell reaching a fully charged voltage, the battery monitoring circuit (40) switches off the charging switch (31) to terminate the charging process.
82 Citations
15 Claims
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1. A battery protection system having a first terminal, a second terminal, a first battery electrode, and a second battery electrode, comprising:
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a first switch having a control electrode, a first current conducting electrode coupled to the first terminal of the battery protection system, and a second current conducting electrode; an inductor having a first electrode coupled to the second current conducting electrode of the first switch and a second electrode coupled to the first battery electrode of the battery protection system; a resistor having a first electrode coupled to the second battery electrode of the battery protection system and a second electrode coupled to the second terminal of the battery protection system; a rectifier having a first electrode coupled to the second electrode of the resistor and a second electrode coupled to the first electrode of the inductor; a first comparator having a first input coupled to the first electrode of the resistor, a second input coupled to the second electrode of the resistor, and an output coupled to the control electrode of the first switch; and a battery monitoring circuit having a plurality of inputs and a first output, a first input of the plurality of inputs being coupled to the second electrode of the inductor, a second input of the plurality of inputs being coupled to the first electrode of the resistor, and the first output being coupled to the control electrode of the first switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A rechargeable battery system, comprising:
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a rechargeable battery pack having a first terminal and a second terminal; an inductor having a first electrode coupled to the first terminal of the rechargeable battery pack, and a second electrode; a first field effect transistor having a gate electrode, a source electrode, and a drain electrode coupled to the second electrode of the inductor; a current sensing element having a first electrode coupled to the second terminal of the rechargeable battery pack, and a second electrode; a rectifier having a first electrode coupled to the second electrode of the current sensing element and a second electrode coupled to the second electrode of the inductor; a hysteresis comparator having a first input coupled to the first electrode of the current sensing element, a second input coupled to the second electrode of the current sensing element, and an output; a battery monitoring circuit having a plurality of inputs and a first output, a first input of the plurality of inputs being coupled to the first terminal of the rechargeable battery pack, and a second input of the plurality of inputs being coupled to the second terminal of the rechargeable battery pack; and a transistor driver having a first input coupled to the output of the hysteresis comparator, a second input coupled to the first output of the battery monitoring circuit, and an output coupled to the gate electrode of the first field effect transistor. - View Dependent Claims (12, 13, 14, 15)
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Specification