Electrical Isolation Technique for Tree Branches in CVS Circuit Family
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
In this publication a technique is described wherein the performance of a CVS tree is greatly enhanced by electrically isolating the loading of the "off" tree branches within the tree from its output node. A design problem in the SCVS/DCVS circuit family greatly affects its performance. This may be explained, utilizing a DCVS design (the same explanation is also valid for SCVS trees), as follows: Fig. 1 shows an example of a DCVS tree with inputs A, AN, B, Bn, C, CN,..... and outputs NT and NC. A tree branch is defined as a combination of series and/or parallel n-channel devices (performing a specific Boolean expression) connecting node NC or NT to ground. (Image Omitted) In the standby state, PC is low, turning off device TG and enabling nodes NT and NC to charge to full VDD through P-channel devices TV1 and TV2.