Two types of low-power asynchronous comparators named asynchronous ripple comparator and pre-stop asynchronous comparator are proposed based on the statistical characteristic of input data in the paper.The asynchronous ripple comparator stops computing at the first unequal bit

but it has to deliver the result to the LSB.The pre-stop asynchronous comparator is proposed by revising the truth table based on the new 2-bit comparison unit and stop judgment circuit.It can stop comparing at the first unequal bit and obtain the result immediately.The proposed and contrastive comparators (BCL comparator and clock-gating comparator) are implemented with SMIC 0.18 m process.Simulation results show that the proposed pre-stop asynchronous comparator features the lowest power.It saves 87.1%

84.5% and 37.5%

28.6% power respectively compared to the synchronous BCL comparator and clock-gating comparator with random data and data from LDPC decoder.