在高压恶劣环境下，我们需要很多压力传感器来测量气体或流体压力。例如，有些动力总成系统需要测量缸内、变速箱油、柴油共轨、GDI燃油、柴油微粒滤清器(DPF)和废气再循环系统(EGR)的压力。安全应用包括制动液和乘客检测系统的重量或压力。高压恶劣环境应用要求传感器元件(容性或压阻)必须与信号调理芯片分隔开。例如，压阻(应变片)解决方案可以测量最高达到2,800 bar的压力。应变片技术基于电阻电桥。四个应变片附加到一个薄膜上，形成薄膜式压力传感器。输出信号小至10 mV。系统误差包括机械输出、热输出、容差和应变系数误差。总误差可以达到最高100%的FSR。因此，调理电路必须高度精确，具有低漂移。另外还需要基于增益、失调、温度和线性度相关的多变量补偿。压力传感器主要放置在恶劣环境中。典型工作温度范围为?40°C至+125°C，在某些情况下高达150°C。这些传感器还需要高抗电磁干扰能力和诊断功能。
To improve fuel economy and energy management, the position of the solenoid valve in the fuel injection system and the automatic transmission must be precisely controlled. In addition, the motor current of the "on demand" power must be monitored more accurately. The design challenges we typically encounter include high accuracy, low offset in harsh environments (offset must be less than 5 mV, offset drift must be less than 20 μV), high bandwidth (up to 500 kHz in some cases), wide common-mode voltage range ( Up to 65 V), wide operating temperature range (up to 125 ° C).
Capacitive sensors offer several advantages, such as low system cost, different shape feasibility, and low power consumption. They are typically used in keyless entry gating system proximity sensors, rain detectors, humidity sensors, fuel level/quality sensors. Capacitive sensors are sensitive to environmental changes and must have high resolution, accuracy, adjustable common mode capacitance, and immunity to electromagnetic interference.
Position and speed sensor
ADI has a broad product portfolio and a long history in the Rotary Digital Converter (RDC) market. The AD2S1205 and AD2S1210 are capable of handling trace rates up to 3,125 RPS. Their accuracy can reach ±2.5 arc minutes. The AD2S1205 is a 12-bit RDC and the 10/12/14/16-bit resolution of the AD2S1210 can be set by the user. The chip features differential input and incremental encoder outputs, as well as programmable fault detection thresholds. They are used for motor shaft angle and speed measurements in gearbox, EPS and HEV/EV motors.
ADI's TMP36 has an accuracy of ±2°C over full scale and a linearity of 0.5°C over full scale with a temperature range of ?40°C to +125°C with analog output. ADI's ADT7311 and ADT7312 are accurate to ±1°C full scale and temperature range from ?40°C to +150°C with digital SPI output. Based on the die package, the temperature range of the ADT7312 can be increased to -40 to +175 °C.
ADI has long-standing relationships with leading automotive suppliers and has a proven track record in high-performance signal processing, high reliability and high quality product development to provide optimized solutions to meet these challenges.