LOW POWER PHYSICAL LAYER FOR A BUS IN AN INDUSTRIAL TRANSMITTER

摘要

A process variable transmitter (200) connects a serial bus (232) to an accessory load. A supply limiter circuit (234) provides a first supply current limit and provides a stored energy output (236). A recessive driver circuit (238) draws a drive current from the stored energy output (236) and couples the drive current to the serial bus (232). The recessive driver circuit (238) provides a drive current limit. A dominant driver circuit (242) has a dominant state in which it conducts the drive current, and an inactive state in which the drive current is available to the accessory load.