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.

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.

Abstract: This specification relates to a method and a system for detecting light emitting diode (LED) short circuit in a plurality of LED strings or detecting matching among the plurality of LED strings, wherein one end of each of the plurality of LED strings is connected to a same output end of a power supply, and the other end is respectively connected to a corresponding switch. According to the present invention, first current of each of LED strings is obtained when the output end of the power supply outputs a first voltage; differences between the minimum of the first currents of LED strings and other first currents are calculated; the differences are compared with a comparing threshold; it is determined that the LED strings corresponding to the other currents for which differences are larger than the comparing threshold include short circuit or mismatch with the LED string corresponding to the minimum current. Accordingly, it is possible to reduce the number of pins and area of a control chip.

Abstract: This specification relates to a method and a system for detecting light emitting diode (LED) short circuit in a plurality of LED strings or detecting matching among the plurality of LED strings, wherein one end of each of the plurality of LED strings is connected to a same output end of a power supply, and the other end is respectively connected to a corresponding switch. According to the present invention, first current of each of LED strings is obtained when the output end of the power supply outputs a first voltage; differences between the minimum of the first currents of LED strings and other first currents are calculated; the differences are compared with a comparing threshold; it is determined that the LED strings corresponding to the other currents for which differences are larger than the comparing threshold include short circuit or mismatch with the LED string corresponding to the minimum current. Accordingly, it is possible to reduce the number of pins and area of a control chip.