Overcurrent detector
AssigneeTexas Instruments Incorporated
InventorGangqiang ZHANG
Life of this patent
Estimating the term…
Abstract
An overcurrent detector that includes a sense transistor connected to a sense resistor, a second transistor matched to the sense transistor and connected in parallel to a second resistor, and a voltage comparator coupled to the sense transistor and second resistor. The sense transistor is configured to connect in a same gate and source connection with a driver output transistor. The second transistor and second resistor are configured to receive a current reference and generate a voltage reference. The voltage comparator is configured to compare the voltage reference with a voltage drop across the sense resistor.
Claims20
An overcurrent detector comprising:
- a sense transistor connected to a sense resistor, the sense transistor configured to connect in a same gate and source connection with a driver output transistor;
- a second transistor matched to the sense transistor and connected in parallel to a second resistor, the second transistor and second resistor configured to receive a current reference and generate a voltage reference;
- and
- a voltage comparator coupled to the sense transistor and second resistor, the voltage comparator configured to compare the voltage reference with a voltage drop across the sense resistor.
A switch mode driver system comprising:
- a bootstrap regulator;
- a driver output transistor coupled to the bootstrap regulator;
- and
- an overcurrent detector coupled to the bootstrap regulator and driver output transistor, the overcurrent detector configured to generate an overcurrent output signal based on a current through the driver output transistor being above a threshold value;
- wherein the overcurrent detector includes a sense transistor coupled to a sense resistor and the driver output transistor, a voltage comparator, and a second transistor coupled in parallel to a second resistor and configured to receive a current reference and generate a voltage reference, the second transistor matched to the sense transistor;
- and
- wherein the voltage comparator is configured to compare the voltage reference with a voltage drop across the sense resistor.
An overcurrent detector, comprising:
- a sense transistor coupled with a driver output transistor and matched with a second transistor, the sense transistor configured to receive an output of the driver output transistor;
- a sense resistor matched with a second resistor, the sense resistor coupled in series with the sense transistor;
- a voltage reference duplication circuit;
- and
- a voltage comparator coupled to the sense transistor and voltage reference duplication circuit;
- wherein the second transistor is connected in parallel with the second resistor and configured to receive a current reference and generate a voltage reference;
- wherein the voltage reference duplication circuit is configured to receive and duplicate the voltage reference;
- and
- wherein the voltage comparator is configured to receive and compare the voltage reference and a voltage drop across the sense resistor and output an overcurrent signal based on the voltage reference being less than the voltage drop across the sense resistor.
Dependencies are inferred from the claim text.