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US 5,672,952 AGranted
Controller for battery charger with reduced reverse leakage current
AssigneeAnalog Devices, Inc.
InventorThomas S. Szepesi
Life of this patent
Estimating the term…
Abstract
A battery charger controller monitors the voltage across an associated battery charger's power element and opens a switch which inhibits current flow through the controller whenever the voltage across the pass element is substantially equal to zero.
Claims18
A battery charging controller which limits reverse leakage current through a power transistor from a battery to which an associated battery charger is connected, comprising:
- battery charging control circuitry having an electrical return path,
- a comparator connectable to an associated power transistor having two conducting terminals, said comparator having noninverting and inverting inputs for connection to the conducting terminals of said associated power transistor and an output that is responsive to a voltage imposed across said inputs, and
- a current control switch having a control terminal connected to the output of the comparator and two conduction terminals connected between the controller's return path and an associated negative reference terminal such that, when closed, the switch forms a low-impedance path between said return path and negative reference terminal.
A battery charger which limits reverse leakage current, comprising:
- a power input,
- a power switch connected between said power input and a battery being charged, said power switch arranged to control the flow of a charging current from the power input to the battery being charged, said power switch being subject to a reverse bias leakage current,
- a controller arranged to determine a charge state for the battery being charged and which operates the power switch in response to the charge state, said controller being subject to a reverse bias leakage current through the power switch,
- a current control switch connected to inhibit the flow of reverse bias leakage current through the controller, and
- a sensor connected to sense the proximity of a reverse bias leakage condition for said power switch, and in response to open said current control switch.
2 more elements
A battery charger which limits reverse leakage current, comprising:
- a power input,
- a power switch connected to control the flow of charging current from the power input to a battery being charged, said battery being charged having a respective voltage, said power switch being subject to a reverse bias leakage current,
- a controller arranged to determine a charge state for the battery being charged and which operates the power switch in response to the charge state, said controller being subject to a reverse bias leakage current through the power switch,
- a current control switch connected to inhibit the flow of reverse bias leakage current through the controller,
- circuitry connected to sense the voltage of the battery being charged,
- a second current control switch connected to inhibit the flow of current through said battery voltage sensing circuitry, and
- a sensor connected to sense the proximity of a reverse bias leakage condition for said power switch, and in response to open said current control switch.
4 more elements
A battery operated device including a battery charger controller which limits reverse leakage current from a battery, comprising:
- a battery charger comprising
- a power input,
- a power switch connected to control the flow of charging current from the power input to a battery being charged, said power switch being subject to a reverse bias leakage current,
- a controller arranged to determine a charge state for the battery being charged and which operates the power switch in response to the charge state of the battery being charged, said controller being subject to a reverse bias leakage current through the power switch,
- a current control switch connected to inhibit the flow of reverse bias leakage current through the controller,
- a sensor connected to sense the proximity of a reverse bias leakage condition for said power switch, and in response to open said current control switch,
- a battery having two terminals and connected to receive charging current from said charger, and
- electronic application circuitry connected to receive operational power through said battery terminals.
5 more elements
A voltage regulator which limits reverse leakage current, comprising:
- a power input,
- a power switch connected to control the flow of current from the power input to a power consuming circuit having an associated voltage, said power switch being subject to a reverse bias leakage current,
- circuitry connected to sense the voltage of the power consuming circuitry,
- a controller which operates the power switch in response to the voltage of the power consuming circuitry, said controller being subject to a reverse bias leakage current through the power switch,
- a current control switch connected to inhibit the flow of reverse bias leakage current through the controller, and
- a sensor connected to sense the proximity of a reverse bias leakage condition for said power switch, and in response to open said current control switch.
3 more elements
Dependencies are inferred from the claim text.