Low cell charge enable circuit
First Claim
1. A circuit for charging a deeply discharged battery cell comprising:
- a power switch having a control terminal, the power switch for coupling to the cell;
plus and minus battery pack terminals for coupling across the series-connected power switch and cell and for coupling to a charger or a load;
a transistor having a current path coupled between the plus terminal and the power switch control terminal and having a control terminal coupled to the minus terminal; and
a resistor coupled between the transistor control terminal and the minus terminal.
1 Assignment
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Accused Products
Abstract
A circuit and method of operating a circuit furnish a capability to connect a battery in a conduction mode to a battery pack and, therefore, to a charger. The circuit and method furnish this capability even when no power is available for driving normally active electronic circuits. The circuit includes passive-type components which sense for the presence of a charger and activate switches for connecting the battery to the charger. The circuit and method in these embodiments supply this capability by applying a voltage derived from the charger to a power switch connecting the battery to the battery pack. For example, for a battery pack utilizing a power switch including two power FETs connected back-to-back, the circuit pulls a gate potential of the power switch FETs as far as possible from the potential at the minus terminal of the power pack so that conduction through the FETs and battery accompanies attachment of the charger to the battery pack.
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Citations
45 Claims
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1. A circuit for charging a deeply discharged battery cell comprising:
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a power switch having a control terminal, the power switch for coupling to the cell; plus and minus battery pack terminals for coupling across the series-connected power switch and cell and for coupling to a charger or a load; a transistor having a current path coupled between the plus terminal and the power switch control terminal and having a control terminal coupled to the minus terminal; and a resistor coupled between the transistor control terminal and the minus terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A battery pack for charging a deeply discharged battery cell comprising:
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a power switch coupled to the cell and having a control terminal; plus and minus battery pack terminals for coupling across the series-connected power switch and cell and for coupling to a charger or a load; a transistor having a current path coupled between the plus terminal and the power switch control terminal and having a control terminal coupled to the minus terminal; a resistor coupled between the transistor control terminal and the minus terminal; and a controller having a control terminal coupled to the power switch control terminal. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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Specification