Usb data pin impedance detection
AssigneeDialog Semiconductor GmbH
InventorsFuqiang Shi, Jianming Yao, Weihai Huang, Yong Li, John William Kesterson
Life of this patent
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Abstract
A device for determining impedance at a data pin of a communication interface. In one embodiment, the device includes a current source configured to selectively inject a test current to the data pin. The device also includes a sensing circuit for sensing a first test voltage corresponding to a voltage at the data pin without the test current injected, and a second test voltage corresponding to another voltage at the data pin with the test current injected. The sensing circuit determines the impedance at the data pin based on the first test voltage and the second test voltage.
Claims21
A device for determining impedance at a data pin of a communication interface, the device comprising:
- a current source coupled between the data pin and a first voltage, the current source configured to selectively inject a test current to the data pin;
- and
- a sensing circuit to sense a first test voltage corresponding to a voltage at the data pin without the test current injected and a second test voltage corresponding to another voltage at the data pin with the test current injected and to determine the impedance at the data pin based on the first test voltage and the second test voltage.
A method of determining impedance at a data pin of a communication interface, the method comprising:
- sensing a first test voltage corresponding to a voltage at the data pin without a test current injected to the data pin;
- injecting the test current to the data pin;
- sensing a second test voltage corresponding to another voltage at the data pin with the test current injected;
- and
- determining the impedance at the data pin based on a comparison of the first test voltage with the second test voltage.
Dependencies are inferred from the claim text.