Apparatus and method for signal handling on gtl-type buses

Abstract

Transceivers for bus communications using GTL-type transmission-line bus structures provide improved clamping of an initially ON output pulse of a communication bus driver and adds an active pull-up function inside the integrated circuit that does not change the external circuit nor require additional functional external circuit corrections. Receivers may contain an active pull-up for added signal quality improvement Improved clamping and active pull-up allow reduced width of the channel of the N-channel CMOS output transistor. A drive/receive clamp may be added to a sequential pull-up circuit and an active pull-up circuit for better performance at higher frequencies. A related method may comprise first switching OFF an active pull down circuit and switching ON an active pull-up circuit, where the active pull-up circuit clamps the driver output voltage from falling below a first voltage. Then switching OFF a first clamping circuit, where the first clamping circuit clamps the driver output voltage from exceeding a second voltage when the first damping circuit is ON, and where the second voltage is greater than the first voltage. And then switching OFF a second clamping circuit, where the second clamping circuit clamps the driver output voltage from exceeding a third voltage when the second clamping circuit is ON, and where the third voltage is greater than the second voltage.