gopal_amlekar
Junior Member level 1
- Joined
- Jun 14, 2009
- Messages
- 17
- Helped
- 2
- Reputation
- 4
- Reaction score
- 2
- Trophy points
- 1,283
- Location
- Pune, India
- Activity points
- 1,468
Hello all,
I would like to get expert suggestions on whether it is possible to design a circuit for:
1. Temperature measurement using a NTC thermistor
2. 10-bit ADC (Max. input 3.3V)
3. Resolution of 0.1 degree celsius
4. Temperature range of -40 to +100 degree celsius
I studied a thermistor (10K, Beta value 2490) datasheet vishay.com/docs/29003/23816154.pdf.
If I use this thermistor in a voltage divider circuit biased from a 3.3V supply, I get a minimum step size of only 536uV for a 0.1 degree change in temperature.This step size varies through the range as the characteristics are nonlinear.
For a 10-bit ADC, minimum step size is 3.2mV.
Is there some way out or some other trick like amplifying voltage obtained across thermistor and / or changing gain of this amplifier dynamically etc. or some software manipulation / linearization etc.
Please guide..
Regards,
Gopal
I would like to get expert suggestions on whether it is possible to design a circuit for:
1. Temperature measurement using a NTC thermistor
2. 10-bit ADC (Max. input 3.3V)
3. Resolution of 0.1 degree celsius
4. Temperature range of -40 to +100 degree celsius
I studied a thermistor (10K, Beta value 2490) datasheet vishay.com/docs/29003/23816154.pdf.
If I use this thermistor in a voltage divider circuit biased from a 3.3V supply, I get a minimum step size of only 536uV for a 0.1 degree change in temperature.This step size varies through the range as the characteristics are nonlinear.
For a 10-bit ADC, minimum step size is 3.2mV.
Is there some way out or some other trick like amplifying voltage obtained across thermistor and / or changing gain of this amplifier dynamically etc. or some software manipulation / linearization etc.
Please guide..
Regards,
Gopal