Constant-current/constant-voltage circuit architecture
AssigneeLinear Technology Corporation
InventorsTrevor W. Barcelo, Robert L. Reay, David M. Dwelley
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Abstract
Methods and circuits implementing a constant-current/constant-voltage circuit architecture are provided. The methods and circuits preferably provide a charging system that provides current to a load using a fixed current until the load is charged. When the load is charged, the methods and circuits preferably provide a variable current to the load in order to maintain the voltage level across the load. This variable current varies according to the voltage across the load. In one embodiment of the invention, a constant power current may also be used as one of the load charging currents. The constant power current may act as a limit on the charging circuit's power output.
Claims8
A circuit for providing current to a load, comprising:
- a first current source coupled to provide a constant current or a variable current to said load;
- a second current source coupled to a resistor;
- a constant current amplifier that controls application of said constant current to the load when the voltage across said load is below a predetermined voltage level, wherein the output of said constant current amplifier is coupled to control said first and second current sources;
- and
- a constant voltage amplifier that controls application of said variable current to said load when the voltage across said load is at or above said predetermined voltage level, wherein the output of said constant voltage amplifier is coupled to control said first and second current sources.
Dependencies are inferred from the claim text.