| 摘要 |
Known is a wire bound telecommunications device to be coupled to telecommunication lines comprising a transmission circuit coupled between the telecommunications lines, which transmission circuit comprises a power supply circuit for forming a supply voltage from a telecommunications line voltage, whereby the power supply circuit comprises sensing means for sensing a telecommunications line current and adjustment means for adjusting the supply voltage, a supply voltage terminal being coupled to the sensing means. In the known device, no optimal matching is obtained for the load line of the power supply to a DC-mask for line voltages as a function of a line current as prescribed for a given country. A more optimal matching is proposed. Hereto, the power supply circuit comprises a controllable current source coupled to an adjustment terminal of the adjustment means and that a control input of the controllable current source is coupled to the sensing means, whereby the power supply is arranged such that the adjustment means operates as current sinking or current sourcing means, respectively, so as to cause the supply voltage to increase or decrease, respectively, in accordance with a predetermined function. |
