Patent ID: 6320408
Filing Date: 2001-11-20
Classification: H03K

Abstract:
A bus switch with undershoot protection on both ports comprising:a bus-switch transistor controlled by a gate node that controls current conduction between a first port and a second port;a first detector, coupled to the first port, for activating a first signal in response to a low-going transition detected on the first port;a first fixed-gate transistor coupled to conduct an undershoot on the first port to a first node;a first connecting transistor coupled to conduct the undershoot from the first node to the gate node when the first signal is activated;an enable gate, receiving an enable signal, for driving an enabling voltage onto the gate node to enable conducting by the bus-switch transistor, and for driving a disabling voltage onto the gate node to isolate the first port from the second port;a second detector, coupled to the second port, for activating a second signal in response to a low-going transition detected on the second port;a second fixed-gate transistor coupled to conduct an undershoot on the second port to a second node; anda second connecting transistor coupled to conduct the undershoot from the second node to the gate node when the second signal is activated, whereby undershoots are conducted through fixed-gate and connecting transistors to the gate node to prevent channel conduction by the bus-switch transistor.