USB power delivery interface

1 . A method for operating a universal serial bus (USB) power delivery (PD)-type interface, the method comprising:

receiving a first power supply potential at a first node of the USB PD-type interface;

delivering a second power supply potential at a second node of the USB PD-type interface;

setting a third node of the USB PD-type interface to be at a reference potential;

delivering, by a first circuit, a control potential to a base of a bipolar transistor, the bipolar transistor having a collector coupled to a gate of a first metal-oxide-semiconductor (MOS) transistor, an emitter of the bipolar transistor coupled to a fourth node coupled to the first node, the first MOS transistor coupled between a fifth node and the second node, the control potential determined based on a current at a first resistor coupled between the fourth node and the fifth node; and

delivering a floating ground to an operational amplifier of the first circuit from a node of connection of a diode and a second resistor of the first circuit in series between the fourth node and the third node,

wherein the operational amplifier includes a first input coupled to the fourth node, a second input coupled to the fifth node, an output coupled to the base of the bipolar transistor, and

wherein a gain of the operational amplifier is variable and determinable by the first power supply potential.

2 . The method of claim 1 , further comprising determining, by the first circuit, the control potential to limit the current in the first resistor with respect to a current threshold.

3 . The method of claim 1 , further comprising increasing, by the first circuit, a base-emitter voltage of the bipolar transistor in response to the current in the first resistor increasing above a current threshold.

4 . The method of claim 1 , further comprising:

delivering, by a second circuit, a binary signal in a first binary state in response to the second power supply potential being greater than the first power supply potential; and

coupling, by a switch, the second node to the third node in response to the binary signal being in its first state.

5 . The method of claim 1 , further comprising discharging a capacitive element in response to the second power supply potential being greater than the first power supply potential.

6 . The method of claim 1 , wherein the first MOS transistor is a P-channel MOS (PMOS) transistor, and the bipolar transistor is a PNP transistor.

7 . The method of claim 1 ,

wherein the emitter of the bipolar transistor is coupled to the fourth node and the first circuit includes a direct connection between the base of the bipolar transistor and the fifth node; or

wherein the first circuit comprises an NPN transistor having an emitter coupled to the third node and a collector coupled to the fourth node by a voltage dividing bridge comprising an intermediate node, and

wherein the method further comprises:

supplying the control potential by the intermediate node

supplying a potential to a base of the NPN transistor by a second circuit, the potential determined from a voltage across the first resistor, a gain between the voltage across the first resistor and the control potential being variable and determined by the first power supply potential.

8 . A method for operating a universal serial bus (USB) power delivery (PD)-type interface, the method comprising:

receiving a first power supply potential from a USB connector at a first node of the USB PD-type interface;

delivering a second power supply potential at a second node of the USB PD-type interface;

receiving a reference potential from the USB connector at a third node of the USB PD-type interface;

delivering, by a first circuit, a control potential to a base of a bipolar transistor determined from a current in a first resistor, the first resistor coupled between a fourth node and a fifth node, the fourth node coupled to the first node, the bipolar transistor having a collector coupled to a gate terminal of a first metal-oxide-semiconductor (MOS) transistor, an emitter of the bipolar transistor coupled to the fourth node or the fifth node, the first MOS transistor coupled between the fifth node and the second node;

controlling the first MOS transistor by a second circuit comprising an NPN transistor and a voltage dividing bridge having an intermediate node coupled to the gate terminal of the first MOS transistor, the NPN transistor having a conduction terminal coupled to the third node and another conduction terminal coupled to the fourth node or the fifth node by the voltage dividing bridge, a second voltage dividing bridge coupling the fourth node or the fifth node to the third node and having an intermediate node coupled to the base of the NPN transistor; and

powering a circuit or an application coupled to a USB PD-type interface.

9 . The method of claim 8 , further comprising determining, by the first circuit, the control potential to limit the current in the first resistor with respect to a current threshold.

10 . The method of claim 8 , further comprising increasing, by the first circuit, a base-emitter voltage of the bipolar transistor in response to the current in the first resistor increasing above a current threshold.

11 . The method of claim 8 , wherein the first MOS transistor is a P-channel MOS (PMOS) transistor, and the bipolar transistor is a PNP transistor.

12 . The method of claim 8 , further comprising:

delivering, by the second circuit, a binary signal in a first binary state in response to the second power supply potential being greater than the first power supply potential; and

coupling, by a switch, the second node to the third node in response to the binary signal being in its first state.

13 . The method of claim 8 , further comprising discharging a capacitive element in response to the second power supply potential being greater than the first power supply potential.

14 . The method of claim 8 ,

wherein the emitter of the bipolar transistor is coupled to the fourth node and the first circuit includes a direct connection between the base of the bipolar transistor and the fifth node, or

wherein the first circuit comprises an NPN transistor having an emitter coupled to the third node and a collector coupled to the fourth node by the voltage dividing bridge comprising an intermediate node, and

wherein the method further comprises:

supplying the control potential by the intermediate node; and

supplying a potential to the base of the NPN transistor by the second circuit, the potential determined from a voltage across the first resistor, a gain between the voltage across the first resistor and the control potential being variable and determined by the first power supply potential.

15 . A method for operating a universal serial bus (USB) power delivery (PD)-type interface, the method comprising:

receiving a first power supply potential at a first node of the USB PD-type interface;

delivering a second power supply potential at a second node of the USB PD-type interface;

setting a third node of the USB PD-type interface to be at a reference potential;

coupling a first resistor between a fourth node and a fifth node, wherein the fourth node is coupled to the first node;

coupling a first metal-oxide-semiconductor (MOS) transistor between the fifth node and the second node;

coupling a collector of a bipolar transistor to a gate of the first MOS transistor;

coupling an emitter of the bipolar transistor to the fourth node;

delivering, by a first circuit, a control potential to a base of the bipolar transistor, the control potential determined based on a current in the first resistor; and

determining the control potential to limit the current in the first resistor with respect to a current threshold, wherein the first circuit comprises a direct connection between the base of the bipolar transistor and the fifth node.

16 . The method of claim 15 , further comprising increasing, by the first circuit, a base-emitter voltage of the bipolar transistor in response to the current in the first resistor increasing above the current threshold.

17 . The method of claim 15 , wherein the first MOS transistor is a P-channel MOS (PMOS) transistor, and the bipolar transistor is a PNP transistor.

18 . The method of claim 15 , further comprising:

delivering, by a second circuit, a binary signal in a first binary state in response to the second power supply potential being greater than the first power supply potential increased by a margin; and

coupling, by a switch, the second node to the third node in response to the binary signal being in its first state.

19 . The method of claim 18 , further comprising:

coupling a base of a PNP transistor of the second circuit to the fourth node;

coupling a collector of the PNP transistor to the third node through a resistor;

coupling an emitter of the PNP transistor to the second node; and

delivering the binary signal from the collector of the PNP transistor.

20 . The method of claim 15 , further comprising:

coupling a capacitive element between the second node and the third node; and

discharging the capacitive element in response to detecting that the second power supply potential is greater than the first power supply potential.