Design And Implementation Of A Power Amplifier In Wireless Tire Pressure System

With the rapid development of society, road traffic accidents haveresulted a significant loss in life and property security andsocio-economic development. So, we should pay more and more attentionto highway traffic safety. Puncture car traffic accident is one of the mainreasons for road traffic accidents. So maintaining the standard tire airpressure traveling is the key to prevent puncture. The tire pressuremonitoring system (TPMS) comes into being to protect car security. Thetire pressure monitoring system is mainly used for real-time detection oftire pressure and temperature in the vehicle, which the real-time detectionmethod is the using of RFID technologies. The system alarms when theabnormal tire pressure and tire temperature inside, in order to protect thesafety of the occupants of the lane.In the tire pressure monitoring system, the RFID transmitter-end iscomposed of two parts, a phase-locked loop and a power amplifier. In thisarticle, we have designed a high-efficiency power amplifier which meetsthe requirements of the tire pressure monitoring system.The design applied the process of Hua Hong NEC CMOS0.35μm forthe power amplifier with the input frequency is433MHz. We discuss howto design the whole power amplifier, including EAC, input and outputmatching networks, step of computing device parameters. When the gate-source voltage is3.5V, and the drive power is25dBm, the drainvoltage is6V, the maximum DC conversion efficiency is77.28%andmaximum PAE is57.86%, the output power is34.21dBm and the gain is11.21dB. We analyze the two aspects of the simulation results, shows thatwhen the input signal transistor overdrive to make it work in the stronglynonlinear region as well as the input frequency is consistent with thematching networks in order to achieve optimum output power and PAEAt the layout step, we discuss some of the key points and precautionsof layout steps. With the non-ideality factor in power amplifier, wediscussed the attenuation of the power amplifier efficiency with theparasitic inductance, as well as bond wire inductance as inductivecomponents instead of using planar spiral inductors to increase theefficiency of the power amplifier output because the bond wire has alarger Q value. We also verify the accuracy of the empirical formula ofthe length of bond wire.