A high-performance encoder with priority lookahead

In this brief, we introduce a priority encoder that uses a novel priority lookahead (PL) scheme to reduce delays associated with priority propagation. Two priority encoder approaches are presented, one without and the other with a PL scheme. For an N-bit encoder, the circuit with the PL scheme requires about 0.1 more transistors than the circuit without the scheme. However, a 32-bit very large scale integration (VLSI) encoder with the PL scheme is about 2.5 times faster than the other encoder. The worst case operation delay is 4.4 ns for this lookahead encoder using a 1 μm scalable complementary metal-oxide-semiconductor (CMOS) technology.