| 摘要 |
A Subscriber Line Interface Circuit (SLIC) having a voltage regulator (5) for application thereto of a DC supply voltage VB and connected at the output terminals to an audio transmission line (3,4) to provide a line current IL and voltage VL for a given resistance load RL on the line, is provided with a control circuit (2) which, by picking up appropriate current and voltage values from the interface circuit, outputs a voltage value which is the equal of the difference between an optimum supply voltage VBF and the supply voltage VB. The control circuit (2) output is connected to the voltage regulator (5) to minimize the voltage VBFK applied to the interface circuit (1) as the transmission line (3,4) resistance load RL varies, thus minimizing the power dissipated through the interface circuit. |
