This　paper　presents　an　implantable　pressure　sensor　readout　system　(IPRO)　which　can　work　at　low　voltage　and　does　not　need　internal　low　dropout　regulator　(LDO).　This　paper　has　made　a　series　of　optimizations　for　power　consumption.　The　power　supply　of　IPRO　uses　434　MHz　energy　harvesting　(EH),　which　only　uses　two-stage　rectification　and　is　equipped　with　corresponding　ultra-low　power　undervoltage　locking　(UVLO)　circuit.　The　analog　front-end　(AFE)　and　signal　processing　parts　use　current　mode　and　differential　pseudo　phase　locked　loop　(DPPLL),　which　can　work　stably　under　low　voltage　and　maintain　a　certain　degree　of　accuracy　and　power　rejection　ability.　The　wireless　data　transmission　part　adopts　the　impulse　ultra-wide　band　(IR-UWB)　scheme.　Its　ultra-low　power　consumption　allows　it　to　be　powered　by　a　charge　pump,　which　is　the　first　time　it　has　been　proposed　in　implantable　systems.　In　order　to　further　optimize　power　consumption,　a　simplest　encoding　circuit　suitable　for　the　front-end　output　form　was　proposed,　and　a　power　oscillator　(PO)　with　accelerated　start-up　was　used　to　optimize　area　and　power　consumption.　The　system　is　implemented　in　180　nm　Complementary　Metal　Oxide　Semiconductor　(CMOS)　process,　with　a　chip　area　of　1.1　∗　1.0　mm2.　The　measurement　results　indicate　that　the　typical　working　voltage　of　the　IPRO　is　0.8　V,　the　typical　power　consumption　is　11.8　μW,　and　the　accuracy　is　1.11　mmHg.　Compared　with　existing　designs,　there　is　a　significant　optimization　in　supply　voltage　and　power　consumption.　　©　2001-2012　IEEE.