| 摘要 |
PURPOSE:To perform the integration of office termination circuits and to share it in the both of a telephone service and an ISDN service by providing a normal reverse switch generating positive or negative voltage and changing the polarity. CONSTITUTION:A power source circuit has a transformer T1, a first switch S1 which is serially connected to the primary coil of the transformer T1 and controls a voltage level by changing the time ratio of on and off and a rectifier circuit which is connected to the secondary coil of the transformer T1 and generating positive voltage by the voltage level controlled by the change of the time ratio of on and off by the first switch S1. This circuit is also provided with normal reverse switches (sr1, sr2, sn1, sn2) which are connected to this rectifier circuit and generates positive or negative voltage and changes polarity by the positive voltage generated by the rectifier circuit. The voltage and current values outputted by a power feeding circuit are measured, the values are inputted in a microprocessor for control, the power feeding circuit is controlled by the calculation within the microprocessor, and power supply is increased by +DELTAE and the power supply is decreased by -DELTAE. |
