Method for balancing power sources and structure therefor
First Claim
1. A method for balancing power sources, comprising the steps of:
- generating a first current by applying a voltage of a first power source across a first resistor having a predetermined resistance value;
generating a second current by applying a voltage of a second power source across a second resistor having the predetermined resistance value;
discharging the first power source in response to the first current being greater than the second current by a first amount, the first amount being more than a first predetermined current value; and
discharging the second power source in response to the second current being greater than the first current by a second amount, the second amount being more than a second predetermined current value.
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Accused Products
Abstract
A power source balancing circuit (10) balances two power sources such as two battery cells (12 and 42). When the power source balancing circuit (10) is enabled, it compares a current flowing through the first battery cell (12) and a first resistor (22) with a current flowing through the second battery cell (42) and a second resistor (52). Because the resistance of the first resistor (22) is equal to that of the second resistor (52), a difference between the two currents indicates a difference between the voltages of the two battery cells (12 and 42). If a current difference larger than a predetermined limit is detected, the battery cell (12 or 42) with a higher voltage is discharged through a corresponding discharge resistor (14 or 44) by switching on a corresponding switch (16 or 46). The corresponding switch (16 or 46) is controlled by a corresponding flip-flop (32 or 62).
67 Citations
20 Claims
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1. A method for balancing power sources, comprising the steps of:
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generating a first current by applying a voltage of a first power source across a first resistor having a predetermined resistance value; generating a second current by applying a voltage of a second power source across a second resistor having the predetermined resistance value; discharging the first power source in response to the first current being greater than the second current by a first amount, the first amount being more than a first predetermined current value; and discharging the second power source in response to the second current being greater than the first current by a second amount, the second amount being more than a second predetermined current value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A power source balancing circuit, comprising:
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a first discharge switch having a control electrode, a first current conducting electrode, and a second current conducting electrode; a first discharge resistor having a first electrode and a second electrode, wherein the second electrode is coupled to the second current conducting electrode of the first discharge switch; a second discharge switch having a control electrode, a first current conducting electrode, and a second current conducting electrode; a second discharge resistor having a first electrode and a second electrode, wherein the first electrode is coupled to the first current conducting electrode of the first discharge switch and the second electrode is coupled to the second current conducting electrode of the second discharge switch; a sensing element having a first input, a second input, a common input, a first output, and a second output, wherein the first input is coupled to the first electrode of the first discharge resistor, the second input is coupled to the first current conducting electrode of the second discharge switch, and the common input is coupled to the first electrode of the second discharge resistor; and an control element having, a first input, a second input, a first output, and a second output, wherein the first input is coupled to the first output of the sensing element, the second input is coupled to the second output of the sensing element, the first output is coupled to the control electrode of the first discharge switch, and the second output is coupled to the control electrode of the second discharge switch. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A battery balancing circuit, comprising:
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a first battery cell having a positive electrode and a negative electrode; a second battery cell having a positive electrode and a negative electrode, wherein the positive electrode is coupled to the negative electrode of the first battery cell; a first discharge resistor having a first electrode and a second electrode, wherein the first electrode is coupled to the positive electrode of the first battery cell; a first discharge switch having a control electrode, a first current conducting electrode, and a second current conducting electrode, wherein the first current conducting electrode is coupled to the second electrode of the first discharge resistor and the second current conducting electrode is coupled to the negative electrode of the first battery cell; a second discharge resistor having a first electrode and a second electrode, wherein the first electrode is coupled to the positive electrode of the second battery cell; a second discharge switch having a control electrode, a first current conducting electrode, and a second current conducting electrode, wherein the first current conducting electrode is coupled to the second electrode of the second discharge resistor and the second current conducting electrode is coupled to the negative electrode of the second battery cell; and a balancing element having a clock input, a first input, a second input, a common input, a first output, and a second output, wherein the clock input is coupled for receiving a clock signal, the first input is coupled to the positive electrode of the first battery cell, the second input is coupled to the negative electrode of the second battery cell, the common input is coupled to the negative electrode of the first battery cell, the first output is coupled to the control electrode of the first discharge switch, and the second output is coupled to the control electrode of the second discharge switch. - View Dependent Claims (19, 20)
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Specification