Low-side physical interface driver circuit for microcomputer date transmission applications

摘要

Low-side driver circuit (200) for data transmission applications includes external connection (202) for connecting and providing drive current to an external physical interface circuit. Sink transistor (210) forms an isolation from the physical interface circuit, and channels low-side drive current to external connection (202). Sink transistor (210) includes base (216), collector (208), and emitter (224). Emitter follower transistor (228) associates with sink transistor (210), and in conjunction with "A" input to the gate of transistor (228), sink transistor (210) controls the state of emitter follower transistor (228). Blocking transistor (206) associates with base (216) of sink transistor (210) to block the base of sink transistor (210) in the off state of sink transistor (210). Pull-down diodes (218) and (220) associate with base (216) of sink transistor (210) to pull down the voltage of the base when sink transistor (210) is in an off state.