Transmit and receive unit for semi-passive transponder to control tire pressure in motor vehicle, uses contactless data transfer with series capacitors between contacts, one of capacitors is MOS varactor

摘要

IC for control of back scattered part of inquiry signal has series circuit of three capacitors (C1,C2,C3) with one MOS varactor (C2), located between contact surfaces (A1,A2). Effective phase modulation is created by voltage (Vmod) fed to varactor (C2). Range of signal is increased as signal absorption is done by rectifier (GL) and not in series of capacitors. INDEPENDENT claim for transmit and receive unit containing sensors for ambient conditions, for use of transmit and receive unit to construct communication unit with passive or semi-passive transmit and receive and for use of unit to control tire pressure.