Clamp control circuit having current feedback
AssigneeTexas Instruments Incorporated
InventorsErhan Ozalevli, Luthuli Dake, Rashed Anam
Life of this patent
Estimating the term…
Abstract
In accordance with an aspect of the present invention, an external FET driving circuit includes a driving portion, a drain-to-gate clamp portion and a current feedback portion. The driving portion provides a driving signal to the external FET. The drain-to-gate clamp portion protects the external FET from flyback current, when the external FET is quickly turned OFF. The current feedback portion controls the driving signal provided by the driver.
Claims20
A circuit operable to receive an input signal and to provide a driving voltage, based on the input signal, to an external FET having a gate, a drain and a source, said circuit comprising:
- a driving portion operable to receive the input signal, said driving portion comprising a positive current source, a negative current source, a first current mirror associated with said positive current source and a second current mirror associated with said negative current source, said positive current source being operable to provide a positive voltage to the gate of the external FET via said first current mirror, said negative current source being operable to provide a first voltage to the gate of the external FET via said second current mirror;
- an inductive load portion;
- a drain-to-gate clamp portion;
- and
- a current feedback portion comprising a third current mirror and a fourth current mirror, said third current mirror being associated with said negative current source, said fourth current mirror being associated with said positive current source.
A circuit operable to receive an input signal, said circuit comprising:
- a FET having a gate, a drain and a source;
- a driving portion operable to receive the input signal, said driving portion comprising a positive current source, a negative current source, a first current mirror associated with said positive current source and a second current mirror associated with said negative current source, said positive current source being operable to provide a positive voltage to said gate of said FET via said first current mirror, said negative current source being operable to provide a first voltage to said gate of said FET via said second current mirror;
- an inductive load portion;
- a drain-to-gate clamp portion;
- and
- a current feedback portion comprising a third current mirror and a fourth current mirror, said third current mirror being associated with said negative current source, said fourth current mirror being associated with said positive current source.
A circuit operable to receive an input signal, said circuit comprising:
- a FET having a gate, a drain and a source;
- a driving portion operable to receive the input signal, said driving portion comprising a positive current source, a negative current source, a first current mirror associated with said positive current source and a second current mirror associated with said negative current source, said positive current source being operable to provide a positive voltage to said gate of said FET via said first current mirror, said negative current source being operable to provide a first voltage to said gate of said FET via said second current mirror;
- an inductive load portion;
- a drain-to-gate clamp portion;
- and
- a current feedback portion comprising a third current mirror and a fourth current mirror, said third current mirror being associated with said negative current source, said fourth current mirror being associated with said positive current source;
- wherein said third current mirror comprises a third current mirror input FET and a third current mirror output FET,
- wherein said fourth current mirror comprises a fourth current mirror input FET and a fourth current mirror output FET,
- wherein said third current mirror output FET is in electrical connection with said first current mirror,
- wherein said fourth current mirror output FET is in electrical connection with said second current mirror,
- wherein said first current mirror has an input-to-output ratio of 1:N,
- wherein said second current mirror has an input-to-output ratio of 1:N,
- wherein said third current mirror has an input-to-output ratio of 1:M
- wherein said fourth current mirror has an input-to-output ratio of 1:M, and
- wherein M≧N.
Dependencies are inferred from the claim text.