To　reduce　the　power　consumption　of　a　bio-electrical　signal　detection　system,　a　level-crossing　analog-to-digital　converter　(LC-ADC)　with　low　power　consumption　was　proposed　for　biomedical　signal　detection.　An　adaptive　resolution　sampling　mode　is　also　designed　to　reduce　power　consumption　on　the　original　basis.　The　level-crossing　ADC　is　designed　and　simulated　using　a　180-nm　CMOS　process.　The　measurement　results　show　that　the　power　consumption　is　only　197　nW,　the　effective　number　of　bits　is　6.4　bits　and　the　signal-to-noise　and　distortion　ratio　is　41.6　dB　under　0.8　V　power　supply　voltage.　The　proposed　LC-ADC　uses　a　chip　area　of　0.147　mm2　and　the　FOM　is　278　fJ/conversion.