Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

bandgap chip temp detectors

Status
Not open for further replies.

amic

Member level 5
Member level 5
Joined
Aug 30, 2005
Messages
91
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
2,069
how are the present chip temp detectors for voltage regulators designed these days ?
do we need to essentially use both BGR voltage and PTAT voltage ? or since PTAT is already an indication of chip tempreture, could it simply be buffered and sent to an A-D converter to get tempreture digital readout ( or control signal )

thanks.

Sachin
 

You can use both. But if you use ADC that means you use bandgap also.
For the best resolution you should adjust temperature sensor output voltage to ADC input range.
 

Fom said:
You can use both. But if you use ADC that means you use bandgap also.
For the best resolution you should adjust temperature sensor output voltage to ADC input range.

thanks fom, but could u explain why use of ADC necessitates use of BGR voltage ? can't PTAT voltage be directly the input for ADC ?
 

Sorry I meant IC implementation.
If you are going to implement both on the same chip you need precise voltage reference for ADC. Usually it is bandap.
 

    amic

    Points: 2
    Helpful Answer Positive Rating
Fom said:
Sorry I meant IC implementation.
If you are going to implement both on the same chip you need precise voltage reference for ADC. Usually it is bandap.

But Fom, My Vdd is 1.8 V which I was planning to use as referance voltage for the ADC ( as opposed to 1.2 V BGR voltage ). If I use lower Vref for ADC then it would reduce the input dynamic range and increse noise sensitivity. wouln't it ??

attached is the architecture, I had in mind ....any suggestions on how should I go about ?
 

Using Vdd is a bad idea in production chips, as Vdd usually varies 10-20% from board to board. But you're right, a higher reference voltage is always nicer. If you're only going to use this chip in the lab, then using Vdd as a reference is fine else you probably do need an internal reference.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top