一种用于TPMS的新型环振式数字压力传感器

A New Digital Ring Oscillating Pressure Sensor for TPMS Application

研制了一种新型环振式数字压力传感器,它可应用于汽车轮胎压力监测报警系统(TPMS)。采用硅薄膜上的PMOS环形振荡器作为压力敏感元件,两个反方向变化的环振输出信号通过集成在片内的混频器实现频率相减。该传感器具有准数字输出、温度系数低、灵敏度高以及制作工艺简单等特点。分析并设计了压力传感器的环形振荡器电路、混频器电路、物理结构。分析了环形振荡器的频率特性、环形振荡器的谐振频率与压力的关系,以及制作工艺,并制作了样品,其灵敏度为5.12 kHz/Bar。

A novel digital pressure sensor using ring oscillators（RO）and mixer was presented,which is applicable for tire pressure monitoring system（TPMS）.The sensitive unit of this novel pressure sensor is PMOS ring oscillator located on silicon membrane.There are two different ring oscillators on this pressure sensor.The output signal was achieved by subtracting syntonic frequency of one ring oscillator from that of the other,which was realized by a mixer located on the bulk silicon.The digital pressure sensor had many advantages,such as digital output,low temperature coefficient,high sensitivity and simple fabrication process.The physical structure and circuits of ring oscillator and mixer were designed.Frequency characteristics of PMOS ring oscillator and its relationship with pressure were described.Samples of RO pressure sensor were fabricated,which has a sensitivity of 5.12 kHz/Bar.