Development Trend of Intelligent Temperature Sensor
1.1 intelligent temperature sensor to improve temperature accuracy and resolution:
The first launch of the intelligent temperature sensor, Its temperature accuracy is low, Resolution can only reach 1 ° C. At present, China has launched a variety of high-precision, High-resolution intelligent temperature sensor, Using a 9 to 12 A / D converter, Resolution is generally up to 0.5 ~ 0.0625 ° C. By the United States DALLAS semiconductor company developed a new DS1624 high-resolution intelligent temperature sensor, Can output 13-bit binary data, The resolution of up to 0.03125 ° C, Temperature accuracy is ± 0.2 ° C.
1.2 intelligent temperature sensor to improve multi-channel conversion speed:
In order to improve the conversion rate of multi-channel intelligent temperature sensor, Some chips also use high-speed successive approximation A / D converters. Taking AD7817 5-channel intelligent temperature sensor as an example, It is on the local sensor. The conversion time of each remote sensor is only 27us, 9us. In addition, the intelligent temperature sensor is from single channel to multi-channel direction. This is for the development and development of multi-channel temperature measurement and control system to create a good condition.
1.3 intelligent temperature sensor to increase the multi-functional:
The versatility of the new intelligent temperature sensor is also increasing. Multifunctional products:
1,> DS1629 single-line intelligent temperature sensor to increase the real-time calendar clock (RTC)Make its function more perfect.
2,> DS1624 also increased the storage function, Using the chip internal 256 bytes of E2PROM memory, Can store the user's short message.
3, the latest development of intelligent temperature sensors (such as MAX6654, LM83) also increased the sensor fault detection function. Can automatically detect the external transistor temperature sensor (also known as remote sensor) open or short circuit fault.
4,> MAX6654 has a choice of "parasitic impedance offset" (PArAsitic ResistAnce CAncellAtion, abbreviated as prc) Can offset the remote sensor lead impedance caused by the temperature error. Even if the lead impedance reaches 100 ohms, It will not affect the measurement accuracy.
5,> TCN75 intelligent temperature sensor serial interface, Interrupt / comparator signal output and address input can withstand 1000V electrostatic discharge voltage. LM83 intelligent temperature sensor can withstand 4000V electrostatic discharge voltage.
Intelligent temperature sensors have a variety of operating modes to choose from. Mainly including single conversion mode, Continuous conversion mode, Standby mode, And some also increased the low temperature limit expansion mode, Operation is very simple. For some intelligent temperature sensors, The host (external microprocessor or microcontroller) can also set its A / D conversion rate (typical MAX6654) through the corresponding registers, Resolution and maximum conversion time (typical product DS1624).
1.4 Intelligent temperature sensor bus technology standardization and standardization
At present, the intelligent temperature sensor bus technology also achieved a standardized, standardized, The main bus used is a single wire (1-Wire) bus, I2C bus, SMBus bus and spI bus. The temperature sensor as a slave can communicate with the host via a dedicated bus interface.