Omron: MEMS absolute pressure sensor low current consumption
Omron Corporation has developed a new type of "absolute pressure sensor" (※ 1), which can accurately detect changes in air pressure within a height range of 50 cm. The absolute pressure sensor uses MEMS technology, one of Omron's core technologies, to achieve the world's top level of high precision and low current consumption, and will be released in January 2013.
The absolute pressure sensor realizes the process integration of the CMOS circuit and the MEMS sensor, and realizes a small package of 3.8 mm long x 3.8 mm wide and 0.92 mm thick, which is easier to apply to small devices such as mobile phones.
It is suitable for battery-driven parts of devices such as smartphones and exercise gauges (* 2), which helps to extend battery life. When this sensor is applied to a motion meter, it can measure up and down stairs and other types of motion data with height differences, which solves the long-standing problems. When applied to car navigation systems, it can ensure the accuracy of navigation in a three-dimensional parking lot and identify general roads and elevated roads. In addition, it can also be used in the field of security because it can measure changes in air pressure when the door is opened or the window is broken.
(※ 1) The thermal sensor can sense the energy radiated by the object through the hot spot stack structure, thereby realizing non-contact temperature measurement. Omron combined the hot spot stack structure using MEMS technology with ASIC to create an ultra-small non-contact temperature sensor.
(※ 2) BEMS and HEMS are divided into abbreviations of Building Energy Management System and Home Energy Management System, which refer to energy-saving and energy-creating systems used in buildings, office spaces and homes.
In addition, CMOS and MEMS integrated chips can also be sold to meet the needs of mounting other sensors on the same motherboard.
In the future, Omron will continue to contribute to society with its unique MEMS technology.
This product will be exhibited at the "23rd Micromechanical / MEMS Exhibition" held at the Tokyo International Exhibition Center from July 11 (Wednesday) to July 15 (Friday).
(※ 1) Absolute pressure sensor refers to a pressure detection sensor that uses vacuum as a reference.
(※ 2) Unlike ordinary pedometers, it can measure not only the number of steps, but also the amount of medium-intensity, low-intensity exercise and daily exercise (used in sweepers, light-weight items, cooking, etc.). instrument.
■ Features
1. Small package: length 3.8mm width 3.8mm height 0.92mm.
2. Small chip: CMOS circuit integrated with MEMS sensor, length 1.9mm, width 1.9mm, thickness 0.5mm.
3. A wide measuring range of 300 ～ 1100hPa
4． The relative pressure accuracy is equivalent to a pressure change of 6pa caused by a height difference of about 50cm.
5. Low current consumption of 0.5 ~ 9.5uA is conducive to prolong battery life. (※ 3)
6. A temperature sensor is included to assist in correcting changes in air pressure caused by temperature changes around the sensor.
7. Adopt I2C output mode, can communicate in series.
(※ 3) The current consumption depends on the measurement conditions and operation mode.
1. Detection principle
The company's MEMS absolute pressure sensor uses a varistor method developed for the pressure sensor in the sphygmomanometer. The varistor method uses the piezoelectric effect, which is a change in resistance caused by a change in the force applied to the resistive element, and uses this principle to convert pressure into a current signal.
Furthermore, in order to measure changes in atmospheric pressure, the absolute pressure sensor uses MEMS bonding technology to vacuum seal the inside of the sensor chip. Therefore, it is possible to perceive the value of atmospheric pressure compared with the vacuum state, that is, the absolute pressure value.
2. technical expertise
The sensor integrates various technical functions developed by the company for many years into a single chip, including semiconductor circuit design technology, CMOS process technology, MEMS technology, pressure sensor, analog amplifier circuit, digital processing circuit, non-volatile storage, etc. Therefore, the miniaturization, high performance and noise resistance of the chip have been improved.
In addition, the sensor uses MEMS bonding technology to expand the capacity of the vacuum chamber inside the sensor chip and maximize the input dynamic range of the sensor. Thereby achieving high precision.
3. The measurement results
The result can reach the discrimination of 50cm.