公开(公告)号：US4654870A

公开(公告)日：1987-03-31

申请号：US733304

申请日：1985-05-13

申请人： Richard N. Brooksbank

发明人： Richard N. Brooksbank

IPC分类号： H04M9/00 ,  H04M19/00

CPC分类号： H04M9/003

摘要： In a telephone key system including a central branch exchange and a plurality of key stations, each key station includes a switch-mode power supply unit and derives logic circuit drive power by converting unregulated high tension d.c. voltage power from the exchange to regulated low tension logic level voltage. In the preferred arrangement each key station includes WAL II code signalling receive and transmit circuits and burst mode signalling is adopted. The transformers of these circuits are center-tapped for transformer phantom coupling to the switch-mode power supply unit, and are connected to the exchange by a 2-way 4-wire line. The switch-mode power supply unit is preferably of flyback configuration and includes thus a controlled transistor switch, a transformer, a rectifier, and a switch-mode power supply controller to control on/off operation of the switch for voltage regulation.

摘要翻译： 在包括中央分支交换机和多个关键站的电话密钥系统中，每个关键站包括开关模式电源单元，并通过转换未调节的高压直流电压来导出逻辑电路驱动功率。 电压从交流电到稳压低电平的逻辑电平。 在优选布置中，每个关键站包括WAL II码信令，接收和发送电路和突发模式信令被采用。 这些电路的变压器中心抽头用于变压器幻像耦合到开关模式电源单元，并通过双向4线制线路连接到交换机。 开关模式电源单元优选地具有回扫配置，并且包括受控晶体管开关，变压器，整流器和开关模式电源控制器，用于控制用于电压调节的开关的开/关操作。