In developed countries such as Europe and the United States, TPMS is a standard product of automobiles, so TPMS is growing rapidly in terms of product variety and production output. The technology development of MEMS chips and IC chips used is very fast, and TPMS final product technology is also improved. Therefore, it has developed rapidly.
TPMS is the abbreviation of “TIre Pressure Monitoring System†for automobile tire pressure monitoring system. It is mainly used for automatic monitoring of tire air pressure in real time when the car is running, alarming for tire leakage and low air pressure to ensure driving safety, driving The life safety guarantee system for passengers and occupants.
The TPMS tire pressure monitoring module consists of five parts: (1) a smart sensor SoC with pressure, temperature, acceleration, voltage detection and post-signal processing ASIC chip combination; (2) 4-8 bit microcontroller (MCU); (3) ) RF RF transmitter chip; (4) Lithium-ion battery; (5) Antenna. See Figure 1, Figure 2 is a physical map of the finished product. The housing is made of high-strength ABS plastic. All devices and materials must meet the automotive temperature range of -40 ° C to +125 ° C.
Figure 1 TPMS transmitter consists of five parts
Figure 2 Physical map of the finished tire pressure monitoring module of TPMS
The smart sensor is a pressure sensor integrated with silicon micromachining (MEMS) technology, an accelerometer chip and a temperature sensor, battery voltage detection, internal clock and analog-to-digital converter (ADC), sampling/holding (S/H) ), SPI port, sensor data calibration, data management, ID code and other functions of digital signal processing ASIC chip. With mask programmability, it can be configured with customer-specific software. It is made up of several chips from MEMS sensors and ASIC circuits in an integrated circuit process (Figure 3). A pressure/temperature inlet (Figure 4) is placed over the package to introduce pressure directly into the stress film of the pressure sensor (Figure 5), which also directs the ambient temperature directly to the semiconductor temperature sensor.
The MEMS silicon piezoresistive pressure sensor adopts a circular fixed stress silicon film inner wall fixed around the periphery, and uses MEMS technology to directly inscribe four high-precision semiconductor strain gauges on the surface stress, forming a Wheatstone measuring bridge as a power Transforming the measuring circuit, the physical quantity of pressure is directly converted into electric quantity, and the measuring precision can reach 0.01-0.03% FS. The structure of the silicon piezoresistive pressure sensor is shown in Figure 5. The upper and lower layers are glass and the middle is a silicon wafer. The upper part of the stress silicon film has a vacuum chamber, making it a typical absolute pressure sensor.
To facilitate identification of the TPMS receiver, each pressure sensor has a unique 32-bit ID code that produces 400 million unique numbers.
Figure 3 Pressure, acceleration and ASIC/MCU combination packaged in one package
Figure 4 pressure / temperature inlet hole
Figure 5 Silicon piezoresistive pressure sensor structure
Figure 6 Acceleration sensor plane structure diagram
Figure 7 Acceleration sensor cut-off structure diagram Similarly, the acceleration sensor is also made by MEMS technology, Figure 6 is the MEMS acceleration sensor plane structure diagram, Figure 7 is the acceleration sensor section structure diagram, the middle of the figure is made of MEMS technology, with the movement A silicon island mass that can swing freely up and down, a strain gauge is engraved on the silicon beam connected to the peripherally fixed silicon, and a strain gauge formed on the other three fixed silicon is used to form a Wheatstone measurement. The bridge, as long as the mass swings with the acceleration force, the balance of the Wheatstone measuring bridge is destroyed, and the Wheatstone measuring bridge outputs a varying voltage ΔV that is linear with the force.
The pressure sensor, accelerometer, and ASIC/MCU are three separate bare chips that are integrated into a packaged unit by the chip's integrated manufacturer. Figure 8 shows the US GE NPX2. Figure 9 shows the clear removal of the package material. Seeing these three bare chips, the connection and matching between the three chips are also done.
Figure 8 US GE company NPX2
Figure 9 is after removing the packaging material
The accelerometer can make the transmitting module have automatic wake-up function. The SP12/30 and NPX2 series of smart sensors all contain acceleration sensors. The accelerometer uses its mass to sensitivity to motion, realizes instant movement of the car, and enters the system self-test and automatic. Wake up, press speed when driving at high speed
Automatically determine the detection time period, and set the safety period, sensitive period and dangerous period with software to gradually shorten the inspection cycle, improve the early warning capability, and save energy. The acceleration sensor + MCU + software can be used to design the wake-up function, no need to use other chips, so as not to increase the cost.
Figure 10 SP30 integrates P2SC using PHILPS
Figure 11 NPX2 integrates P2SC using PHILPS
The smart sensor module also integrates the ASIC/MCU. The NPX2 and SP30 are PIC chips that use PHILPS' P2SC sensor signal conditioning (Figure 10, Figure 11). This unit can be clearly seen in the NPX2 electrical schematic. Includes an 8-bit RISC microcontroller for arithmetic processing control, 4K EROM or FLASH for system firmware setup, 4K ROM for customer applications, 128Byte EEPROM for storing sensor calibration parameters and user-defined data, RAM , timing modulator, interrupt controller, RC oscillator, and low noise amplifier LNA that amplifies sensor signals, ADC that converts sensor signals into digital signals, I/O ports that communicate with the outside world, power management, and viewing Door dog, intermittent timer, 1-3 interface LF interface.
Figure 12 TPMS sensor module technology development trend
The trend of TPMS sensor module technology is to develop the transmitter module into a highly integrated, singular, wireless passive (Figure 12). With the high integration and high reliability requirements of the TPMS product market, there are already intelligent sensor modules such as Infineon SP12/SP30 and GE NPX that combine the sensors and MCUs required to test each physical quantity. In the next few years, a three-in-one module containing RF transmitter chips will be developed, including a four-in-one module that uses self-powered mechanical energy. At that time, the tire pressure monitoring transmitter consists of only one module and one antenna. The secondary design is very simple.
The elecric mini food processors have many fuctions. Some are usually used to chop the vegatable and spice. Such as onion, cabbage, carrot, garlic and clove etc.. Some can mix the vegatable and meat. They are usually small size, but mini style with multifunction. Mostly use stainless stell blade in "S " shape, sharp enough to chop. Some model also have an egg beater attahed, can use to whip eggs. They are all detachable parts, easy to stroe and clean. They are not only the helper for cooking in the kitchen, but also can make your daily life more simple.
Blender Food Processor,Food Blender,Kitchenaid Food Processor,Small Food Processor,Kitchenaid Food Chopper,Food Processor,Electric Food Chopper,Electric Vegetable Chopper
Jiangmen Yingxiang Motor Manufacturer Co., Ltd. , http://www.yingxiang-blender.com