What IC structure can I use to design temperatur sensor?

[aaronwlee]

Hi All

Right now, I am considering to desing an IC which could sense the temperature. I only have access to common process like TSMC 0.18, thus I can only use techniques within the chip. Can you give me some suggestion?

Thanks

Aaron

 

[drabos]

by using temperature dependent element like voltage of diode or PTAT current.
As a starting point I would suggest to check the bandgap voltage reference, I would simply modify a basic bandgap....

 

[jiangxb]

hi aaronwlee,

a method is to measure the ratio of PTAT voltage to bandgap reference voltage using an adc.

see this paper:
A CMOS Smart Temperature Sensor With a 3σ Inaccuracy of +/-0.1°C From -55°C to 125°C - Michiel A. P. Pertijs

 

[aaronwlee]

Thank you guys.

Aaron

 

[jgrant3]

It depends on how accurately you would like to sense the temperature and also what temperature range you are interested in. The other posters in this thread have suggested some good ideas (I myself use a PTAT temperature sensor).

 

[kytan]

If it is silicon based you can use the vertical or lateral parasitic bipolar to generate a PTAT signal and the reference is from the bandgap reference signal. In addition you might want to interface a first order sigma delta converter for digital readout. Depending on your accuracy requirements you might need additional front end circuitry and higher order modulators for the Delta Sigma ADC

 

[duet12]

The issue with PTAT signal is the process variation is significant. Usually two-points calibration is needed.

 

[electronrancher]

PTAT using two diodes is not process sensitive. You cancel out the process variation by using two junctions very close to one another.