Integrated temperature sensor PC616 and application
The integrated temperature sensor of PN junction utilizes the transistor-resistor logic there’s different current density that work on different temps badly. Its output form could be split into voltagetype and 2 kinds of current model, included in this the quality of sensitivity from the voltagetype is usually 10mV / ?, the quality of sensitivity of the present model is 1 A / ?. Still it has got the sign of outputting the electrical quantity as zero during the time of absolute zero, utilizes this characteristic, can appraise the absolute temperature value effortlessly. PC616 is really a current output type integrated temperature sensor of PN junction. ? /p>
Structure and operating principle of PC616
The integrated temperature sensor of PN junction has good output linearities, output impedence is low, likely to interface with controlling circuit, the measurement employed for temperature and controlling, respects for example temperature compensation and ventilation rate recognition of cold junction employed for thermocouple,etc.. The sensor of series PC may be the items of NEC Company, PC616 is among the typical items, its principle, internal structure are proven in Fig. 1, Fig. 2.
40 – +125 ? in measurement limit of PC616A, and 25 – +85 ? in measurement limit in PC616C. PC616A utilizes a set of transistor-resistor logics matched up greatly, make sure they are work under different current density, utilize difference ? VBE and temperature (T) from the transistor-resistor logic VBE Linear relationship come temperature measurement. In Fig. 1, emitter and difference ? VBE from the terminal current of group could be expressed as:
Within the type: K is really a Boltzman constant, I1, I2 are transistor-resistor logics G1 and collector current of G2, q is definitely an electronic charge, r is perfect for G1 and G2 emitter area than,it is among constants.
By aboving and knowing, if I1/ I2 within the plethora of wider temperature constant, ? VBE and absolute temperature T become linear associations then. Fig. 3 is PN junction temperature (?) of PC616A And it is output current (V) Between history,will find outing, present between they could it be spanking linear relationship.
Could be discovered from Fig. 2, PC616 circuit could be split into a part of a temperature sensor, current regulation part and operation amplifier part. Negligence the temperature sensor has temperature coefficient of 10mV/K, the complete worth of its output current is within T =At 25 ? for just two.982V (correspondent to 298.2K) ,So PC616 can convert its output value towards the absolute temperature value very easily. Have compensator circuit of temps within the current regulation part, therefore result in the output current very steady, the entire circuit characteristic is steady, reliable with higher repeatability, this a part of a circuit becomes equivalently a spark-over current is really a zener diode of 6.85V. The operation amplifier has two functions within the circuit, first when PC616 can be used in temperature measurement, the oppisite phase input finish from the operation amplifier connects and becomes the voltagefollower using the Ausgang, outcoming signal and absolute temperature (K) examined Match, output current and corresponding worth of the temperature are 100K/ V The 2nd function is the fact that input terminuses of the oppisite phase are utilized singly, because the input finish of set point during the time of temperature control. ?
Use of the integrated temperature sensor PC616
The applying circuit of PC616 really is easy, it’s 2 kinds of fundamental circuits employed for temperature measurement that Fig. 4 shows, a feet within the circuit, 2 ft connect, the 3rd feet and 1, have temperature coefficient of 10mV/K between 2 ft, and output current V0 =(10mV/ K) Communication Center News Information world wide web.CCNinfo.com