USB interface
地域：
Grenoble
摘要
In an embodiment, a USB interface includes a transformer, a primary winding of the transformer, and a first switch in series between a first and a second node, a secondary winding of the transformer and a component in series between a third and a fourth node, the fourth node configured to be set a first reference potential, a second switch connected between the third node and a first terminal, the first terminal configured to provide an output voltage of the USB interface; wherein the component is configured to avoid a current circulation in the secondary winding when the first switch is closed and a control circuit configured to compare a first voltage of an interconnection node between the secondary winding and the component to a first threshold and compare the first voltage to a second threshold when the first voltage is, in absolute values, above the first threshold.
說明書
This application is a continuation of U.S. application Ser. No. 17/373,881, filed on Jul. 13, 2021, which claims the benefit of French Patent Application No. 2008346, filed on Aug. 7, 2020, which applications are hereby incorporated reference herein in their entirety.
The present disclosure relates generally to interfaces for supplying power from a power supply source to a load. The disclosure more particularly relates to a Universal Serial Bus interface, or USB interface, connected between a source of power, such as the mains, and a USB connector; the USB connector is intended to be electrically coupled to a load to be supplied, in particular by a USB cable.
Although, currently, wireless connection is one of the main research axes in the field of power and data exchange, cables and connectors still seem to be the most reliable way to connect a plurality of electronic devices, be it to exchange data or power or charge one or a plurality of electronic devices.
Among the different types of cables and connectors of the USB standard, the USB type C enables the exchange of data and power. The USB-PD technology (“USB Power Delivery”) is a technology that adapts to USB type C cables and connectors. Such a technology enables the management of the power of electronic devices.
Embodiments provide an improved USB interface powering a load from a power source, in particular of USB interfaces adapted to the USB-PD technology.
權(quán)利要求
What is claimed is:1. A method for operating a universal serial bus (USB) interface, the method comprising:receiving, at an input terminal, an AC input voltage; controlling, by a control circuit, a first switch such that a voltage at a first terminal of a second switch equals a set point value, the first switch having a first terminal coupled to a primary winding of a transformer, the first switch having a second terminal coupled to reference ground, the first terminal of the second switch coupled to a secondary winding of the transformer, the second switch having a second terminal coupled to an output terminal of the USB interface; comparing, by the control circuit, a first voltage to a first threshold, the first voltage being a voltage at the secondary winding and representative of the AC input voltage; comparing, by the control circuit, the first voltage to a second threshold in response to the first voltage being greater than the first threshold in absolute values; and communicating, by the control circuit, a message with a load coupled to the output terminal of the USB interface based on the result of the comparison of the first voltage to the first threshold, the second threshold, or both. 2. The method of claim 1 , wherein the first threshold is based on a set point value of a voltage at the output terminal. 3. The method of claim 1 , wherein the second threshold is determined by a nominal value of the AC input voltage. 4. The method of claim 1 , wherein a relative polarity of a voltage on the primary winding is opposite to a relative polarity of the first voltage. 5. The method of claim 1 , where communicating the message is based on an absolute value of the first voltage being below the second threshold. 6. The method of claim 1 , wherein the message indicates that the USB interface will stop providing power supply. 7. The method of claim 1 , wherein the message is an ALERT message according to USB Power Delivery Specification Revision 3.0. 8. A universal serial bus (USB) interface, comprising:an input terminal configured to receive an AC input voltage; a transformer having a primary winding and a secondary winding; a first switch having a first terminal coupled to the primary winding, the first switch having a second terminal coupled to reference ground; a second switch having a first terminal coupled to the secondary winding, the second switch having a second terminal coupled to an output terminal of the USB interface; and a control circuit configured to:control the first switch such that a voltage at the first terminal of the second switch equals a set point value, compare a first voltage to a first threshold, the first voltage being a voltage at the secondary winding and representative of the AC input voltage, compare the first voltage to a second threshold in response to the first voltage being greater than the first threshold in absolute values, and communicate a message with a load coupled to the output terminal of the USB interface based on the result of the comparison of the first voltage to the first threshold, the second threshold, or both. 9. The USB interface of claim 8 , wherein the first threshold is based on a set point value of a voltage at the output terminal of the USB interface. 10. The USB interface of claim 8 , wherein the second threshold is determined by a nominal value of the AC input voltage. 11. The USB interface of claim 8 , wherein a relative polarity of a voltage on the primary winding is opposite to a relative polarity of the first voltage. 12. The USB interface of claim 8 , where communicating the message is based on an absolute value of the first voltage being below the second threshold. 13. The USB interface of claim 8 , wherein the message indicates that the USB interface will stop providing power supply to the load. 14. The USB interface of claim 8 , wherein the message is an ALERT message according to USB Power Delivery Specification Revision 3.0. 15. A method for operating a universal serial bus (USB) interface, the method comprising:preventing current circulation, by a first circuit, in a secondary winding of a transformer in response to a first switch being in a closed configuration, the first switch coupled between a first node and a second node, the first circuit coupled in series between a third node and reference ground, the transformer having a primary winding and a secondary winding; comparing, by a control circuit, a first voltage to a first threshold, the first voltage corresponding to a voltage at an interconnection node between the secondary winding and the control circuit; comparing, by the control circuit, the voltage to a second threshold in response to the first voltage being greater than the first threshold in absolute values; and providing an output voltage of the USB interface at a first terminal, a second switch coupled between the first terminal and the third node. 16. The method of claim 15 , wherein the first threshold is based on a set point value of the output voltage. 17. The method of claim 15 , wherein the second threshold is determined by a nominal value of an AC input voltage to the USB interface. 18. The method of claim 15 , wherein a relative polarity of a voltage on the primary winding is opposite to a relative polarity of a voltage on the secondary winding. 19. The method of claim 15 , further comprising communicating, by the control circuit, a message with a load coupled to an output terminal of the USB interface based on an absolute value of the first voltage being below the second threshold. 20. The method of claim 19 , wherein the message indicates that the USB interface will stop providing power supply to a load at an output of the USB interface.
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