Patent ID: 8296492

Claim:
A power supply circuit for IEEE 1394 interface, comprising: an IEEE 1394 interface control chip capable of outputting transmission protocol signals; wherein the IEEE 1394 interface control chip comprises a first differential signal output terminal, a second differential signal output terminal, a third differential signal output terminal, and a fourth differential signal output terminal; an interface circuit electrically connected to the IEEE 1394 interface control chip by a number of differential signal transmission lines; wherein the interface circuit is capable of receiving the transmission protocol signals and exchanging data with a peripheral device according to the received transmission protocol signals; a power circuit, having a voltage decreasing circuit, capable of providing working voltage to the interface circuit; wherein the voltage decreasing circuit is capable of receiving a DC voltage and converting the received DC voltage to the working voltage; and a filter circuit electrically connected to the IEEE 1394 interface control chip and the interface circuit; wherein the filter circuit comprises a first common mode choke and a second common mode choke; each of the first common mode choke and the second common mode choke comprises a first differential signal input terminal, a second differential signal input terminal, a first differential signal output terminal and a second differential signal output terminal; and the first differential signal output terminal, the second differential signal output terminal, the third differential signal output terminal and the fourth differential signal output terminal of the IEEE 1394 interface control chip are respectively electrically connected to the first differential signal input terminals and the second differential signal input terminals of the first common mode choke and the second common mode choke by the number of differential signal transmission lines.