Robust current sensing during inverse current load conditions
AssigneeInfineon Technologies AG
InventorsIoan-Alexandru Tranca, Florian Brugger, Alexander Mayer
Life of this patent
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Abstract
A current sensing circuit includes load transistors having a current path coupled between a power terminal and corresponding load terminals, sense transistors having a current path coupled between the power terminal and corresponding sense terminals, each sense transistor being coupled to a respective load transistor, N-channel transistors having a current path coupled between a respective sense transistor and a respective sense terminal, an amplifier for selectively equalizing the voltages across one of the load transistors and one of the sense transistors, and bypass circuits coupled to a bulk terminal of the N-channel transistors.
Claims21
A current sensing circuit comprising:
- a load transistor having a current path coupled between a power terminal and a load terminal, and a control terminal;
- a sense transistor having a current path coupled between the power terminal and a sense terminal, and a control terminal coupled to the control terminal of the load transistor;
- a P-channel transistor having a current path coupled between the sense transistor and the sense terminal, and a control terminal;
- an N-channel transistor having a current path coupled between the sense transistor and the sense terminal, and a control terminal for receiving a control voltage;
- an amplifier for equalizing the voltages across the load transistor and the sense transistor, having an output coupled to the control terminal of the P-channel transistor;
- and
- a bypass circuit directly connected to a bulk terminal of the N-channel transistor, and wherein the bulk terminal of the N-channel transistor is separate from a source terminal of the N-channel transistor.
A current sensing circuit comprising:
- a plurality of load transistors having a current path coupled between a power terminal and a plurality of load terminals;
- a plurality of sense transistors having a current path coupled between the power terminal and a sense terminal, each sense transistor being coupled to a respective load transistor;
- a plurality of N-channel transistors having a current path coupled between a respective sense transistor and a respective sense terminal;
- an amplifier for selectively equalizing the voltages across one of the load transistors and one of the sense transistors;
- and
- a plurality of bypass circuits coupled to a bulk terminal of the plurality of N-channel transistors.
A current sensing method, the method comprising:
- providing a load current in a first current path;
- sensing the load current to provide a sense current in a second current path;
- passing the sense current through an N-channel transistor in the second current path;
- and
- bypassing a parasitic current flowing out of a bulk terminal of the N-channel transistor so that it is not added to the sense current in the second current path, wherein the parasitic current is bypassed through a bypass circuit directly coupled to the bulk terminal, and wherein the bulk terminal of the N-channel transistor is separate from a source terminal of the N-channel transistor.
Dependencies are inferred from the claim text.