Back to results
US 7,443,699 B2Granted
Negative current compensation method and circuit
AssigneeSemiconductor Components Industries, LLC
InventorFrancois Lhermite
Life of this patent
Estimating the term…
Abstract
A power supply controller (10, 60, 70) uses a negative current (36) of a power transistor (16, 71) to detect the valley point for enabling the power transistor when driving an inductor (17). The negative current occurs when the inductor is de-magnetized and can be used for controlling the time to enable the power transistor.
Claims20
A method of compensating a negative current flow comprising:
- providing a first transistor having a negative current flow into a control electrode of the first transistor;
- coupling a driver transistor to a voltage return to drive the control electrode of the first transistor;
- coupling a first current carrying electrode of a detector transistor to the control electrode of the first transistor;
- blocking the negative current from flowing from the voltage return through the driver transistor;
- and
- enabling the detector transistor to conduct a positive compensation current from a supply voltage input to the control electrode of the first transistor when a voltage at the first current carrying electrode of the detector transistor is no less than a first voltage.
3 more elements
A negative current detection circuit comprising:
- a driver transistor having a first current carrying electrode coupled to provide a positive current flow from a second current carrying electrode of the driver transistor to a voltage return;
- a first transistor having a control electrode coupled to be driven by the second current carrying electrode of the driver transistor;
- a detector transistor having a first current carrying electrode coupled to the second current carrying electrode of the driver transistor to provide a positive compensation current to the control electrode of the first transistor, the detector transistor having a threshold voltage;
- and
- a current mirror coupled to conduct the positive compensation current from a voltage input to the detector transistor and coupled to generate an output current representative of the positive compensation current.
2 more elements
A method of forming a negative current compensation circuit comprising:
- coupling a first transistor to generate a negative current into a control electrode of the first transistor;
- forming a driver transistor having a first current carrying electrode coupled to drive the control electrode of the first transistor, and a second current carrying electrode coupled to block the negative current from flowing from a voltage return through the driver transistor to the control electrode of the first transistor;
- and
- forming a detector transistor having a first current carrying electrode coupled to generate a positive compensation current that flows from a voltage input to the control electrode of the first transistor responsively to the negative current producing a first voltage at the first current carrying electrode of the detector transistor wherein the positive compensation current is representative of at least a portion of the negative current.
1 more element
Dependencies are inferred from the claim text.