| 摘要 |
A field bus interface for connecting a device to a field bus, comprising communication circuitry for providing communication via the field bus, first power supply circuitry arranged to provide said communication circuit with a predefined communication power at a predefined drive voltage, and second power supply circuitry arranged to provide a processing circuitry with processing power at said bus voltage only when a power available from said field bus exceeds said communication power. More specifically, the power provided to the processing circuitry at a given bus current will be decided by the power actually available, instead of a power level decided by the lower limit of the voltage range of the field bus specification. The first circuitry and the communication circuitry will ensure that the field bus requirements are met in a case when the bus voltage falls close to the lower limit of the bus voltage range.
|
