| 摘要 |
PURPOSE:To limit the power consumption of a call IC, etc., to within an allowable value by providing a clamping means for generating a current corresponding to a DC component of a line voltage generated by a line current applied from a telephone circuit, and keeping the line voltage constant even if the line current is varied by controlling a voltage/current converting means. CONSTITUTION:The DC output voltage of a voltage generating means 50 corresponding to the DC component of a line voltage generated by a line current applied from the telephone circuit 6 is converted to a current by the voltage/ current converting means 60. In this state, when the line voltage is boosted, the DC voltage is also boosted, therefore, the output current of a clamping means 70 is increased, and the output current of the voltage/current converting means 60 is increased and works in the direction for lowering the line voltage. As a result, the boosting of the line voltage is negated, and it is held in a constant voltage. In such a manner, the power consumption of the inside of an IC can be limited to an allowable value or below. |
