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Cyclone III FPGA Temperature Measurement.....

Altera_Forum
Honored Contributor II
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Hi All, 

 

I want to measure the temperature across the cyclone III fpga. 

 

Is there any inbuilt sensor is available for the temperature measurement? 

If yes please let me know the procedure to measure using in built mega functions.  

 

If in built sensor is not there then how can we measure the temperature across the fpga? 

 

Please guide me. 

 

Thanks for your replies. 

 

Regards, 

Venkatesh V.
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Altera_Forum
Honored Contributor II
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The pin connection guidelines for the Cyclone III: 

 

http://www.altera.com/literature/dp/cyclone3/pcg-01003.pdf 

 

Do not list THERM_P/THERM_N pins. This means there is no thermal diode. 

 

You could check the pinout for your specific part (which you did not state): 

 

http://www.altera.com/literature/lit-dp.jsp?category=cyc%203&showspreadsheet=y 

 

However, you're probably not going to be able to measure the die temperature. The best you can do is measure the case temperature using an external device. 

 

Cheers, 

Dave
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Altera_Forum
Honored Contributor II
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You can measure temperature by forward biasing a substrate or PCI clamp diode.

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Altera_Forum
Honored Contributor II
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Hi Frank, 

 

--- Quote Start ---  

You can measure temperature by forward biasing a substrate or PCI clamp diode. 

--- Quote End ---  

 

 

Have you ever implemented such a circuit? Any details? 

 

An FPGA thermal diode is usually a diode-connected transistor, which can be sensed by say an ADM1032 I2C device 

 

http://www.onsemi.com/pub/collateral/adm1032-d.pdf 

 

I thought I'd read a warning not to use regular diodes for this application ... 

 

How would you use a clamp diode in this manner? You'd have to raise the current-source voltage above VCCIO so that the diode conducted right? 

 

Cheers, 

Dave
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Altera_Forum
Honored Contributor II
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Hi Dave, 

 

Thanks for your reply. 

I think, the in built temperature sensor is not available in the CycloneIII devices.  

But I have seen, some one posted in the altera forum, he did the i2c communication with the 

temperature sensor from the DE0 in CyloneIII fpga. 

 

Do you have any idea about it? 

 

We are planning to measure the board temperature instead of measuring the die. 

 

Thanks for your replies. 

 

Regards, 

Venkatesh
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Altera_Forum
Honored Contributor II
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--- Quote Start ---  

 

We are planning to measure the board temperature instead of measuring the die. 

 

--- Quote End ---  

 

 

Then that is fairly simple. 

 

Are you designing a board, or do you already have a board? If the board has a board-level temperature sensor, then all you need is the read the sensor, eg., using I2C or SPI (two common interfaces for sensors). 

 

Provide a little more detail, and I'll point you in the right direction. 

 

Cheers, 

Dave
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Altera_Forum
Honored Contributor II
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The suggeston to use substrate or clamp diode for temperature measurement isn't but a reminder to a general method used in semiconductor testing. The details have to be worked out. You are right, that we can't expect a similar ideal behavior as with a dedicated sensor diode built into Stratix devices. The diode characteristic must be possibly calibrated and we should be aware of supply rail voltage drops. Needless to say that the test current should be choosen with respect to maximum ratings. 

 

I imagine, that the methode can be useful at least during development, not necessarily for regular operation due to possibly limited reproducibility.  

 

Regards, 

Frank
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Altera_Forum
Honored Contributor II
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Thanks Dave. 

 

We have already designed Board is available. In the Board schematics we don't have a on-board sensor(LM Series etc).  

But some one told me that, we can measure temperature using the on-board transistor(transistor acts as a diode 

(Like MMBT3904)). 

We are checking for such type of transistor is available in our board or not? 

 

Do you have any idea about this type measurement and devices used for the temperature measurement? 

 

 

Regards, 

Venkatesh
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Altera_Forum
Honored Contributor II
666 Views

 

--- Quote Start ---  

The suggeston to use substrate or clamp diode for temperature measurement isn't but a reminder to a general method used in semiconductor testing. The details have to be worked out. You are right, that we can't expect a similar ideal behavior as with a dedicated sensor diode built into Stratix devices. The diode characteristic must be possibly calibrated and we should be aware of supply rail voltage drops. Needless to say that the test current should be choosen with respect to maximum ratings. 

 

I imagine, that the methode can be useful at least during development, not necessarily for regular operation due to possibly limited reproducibility.  

 

--- Quote End ---  

 

 

Ok, thanks! 

 

Cheers, 

Dave
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Altera_Forum
Honored Contributor II
666 Views

 

--- Quote Start ---  

 

We have already designed Board is available. In the Board schematics we don't have a on-board sensor(LM Series etc).  

But some one told me that, we can measure temperature using the on-board transistor(transistor acts as a diode 

(Like MMBT3904)). 

We are checking for such type of transistor is available in our board or not? 

 

Do you have any idea about this type measurement and devices used for the temperature measurement? 

 

--- Quote End ---  

 

 

You are the one with the schematic, so it should be easy for you to see. 

 

If the board designer intended you to be able read temperature, and there is a remote diode-connected-transistor placed near the Cyclone III, then there needs to be an ADM1032 or similar sensor connected to that transistor. Read the data sheet for the ADM1032 - it outputs two different currents, averages the voltage measurements for each current, and then calculates an estimate of the temperature. If you do not have that logic built into your board, you will not be able to measure the temperature using any logic on your board.  

 

You could measure the temperature using an external device, eg., an IR gun or an iButton temperature sensor. 

 

Cheers, 

Dave
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Altera_Forum
Honored Contributor II
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Thanks for your reply Dave. 

In our board schematics, we don't have a on-board temperature sensing device. 

We have only one component ADM1185, which is a supply monitor and sequencer. 

then we dont have any option to measure even on-board temperature also. 

So we are planning to go for some external to measure it. 

 

Thanks for your guidance. 

 

Regards, 

Venkatesh
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Altera_Forum
Honored Contributor II
666 Views

 

--- Quote Start ---  

 

In our board schematics, we don't have a on-board temperature sensing device. 

 

--- Quote End ---  

 

Ok. 

 

 

--- Quote Start ---  

 

We have only one component ADM1185, which is a supply monitor and sequencer. 

 

--- Quote End ---  

 

I looked at the data sheet. If it had an unused ADC channel, I was going to suggest using a voltage output temperature sensor, however, the ADM1185 uses comparators for voltage monitoring. 

 

 

--- Quote Start ---  

 

then we dont have any option to measure even on-board temperature also. 

So we are planning to go for some external to measure it. 

 

--- Quote End ---  

 

 

If you have some FPGA pins available for GPIO (that you can access with a soldering iron :) ), then an I2C sensor or SPI sensor could be added to the design easily. There are adhesive SMT footprints that you can stick to the PCB, and then solder an ADM1032 I2C sensor, or AD7814 SPI temperature sensor. If you use the ADM1032 sensor, then it has local and remote sensing, so you could bond a diode-connected-transistor to the FPGA (or its heatsink). 

 

Cheers, 

Dave
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Altera_Forum
Honored Contributor II
666 Views

Thanks for your reply Dave. 

 

What you mentioned things were discussed with my team. 

Finally We decided that, we don't want to do any modifications on board(Soldering etc). 

I have checked the FPGA schematics,we don't have any available pins in FPGA. 

 

So we are planning to keep some External device near to FPGA. So it will do the measurement.  

 

Regards, 

Venkatesh
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Altera_Forum
Honored Contributor II
666 Views

 

--- Quote Start ---  

 

What you mentioned things were discussed with my team. 

Finally We decided that, we don't want to do any modifications on board(Soldering etc). 

I have checked the FPGA schematics,we don't have any available pins in FPGA. 

 

So we are planning to keep some External device near to FPGA. So it will do the measurement. 

--- Quote End ---  

 

 

Great! It always helps to weight out the different options. 

 

Cheers, 

Dave
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