Can a Thermostat Considerate as Forced Air Convecting Tool?

A thermostat is a switch.

The principal forced air convection tool is a fan. (A thermostat might turn it on and off.) (And if it does so politely, that would be considerate.)

1. There are many types of thermostat

2. Most of them will be much more expensive than cooling fan.

3. cooling is calculable. Starting from collection of required data:

P = Power generated by chip,

Tj max = allowable junction temperature,

Rth j-c = Thermal resistance junction to case,

Ta = ambient temperature.

delta T junction to case = P x Rth j-c.

delta T case to ambient = Tj max - delta T junction to case

You have to apply such a cooler that will have

Thermal resistance <= delta T case to ambient / P [deg/W]

If radiator + cooling fan is too weak, You may have to use heat pipe.

Whatsa DUT?? Forced air convection is a continuous process used to provide uniformity of temperature in a defined space...A thermostat is a temperature controlled switch used to control the source of the cooling or heating ...A fan is a device used to move air.... er,,,ah,,,, what was the question again? Oh yeah,,,,no, it's part of a system...

thank you very much to all of you..

DUT means device under test. The thermostat that I mean here is the peltier-cell cooled dry thermostat (one of the mentor graphics product which come along with T3Ster)

http://www.mentor.com/products/mechanical/products/t3ster/options-accessories

It is controlled by the measurement software and can be used as a single-side cold plate as well.

When I compare the thermal behaviors of micro devices in still air chamber and using the thermostat , the results differs. The cold plate in the dry thermostat maintains the device temperature through out the experiments.

If It is not applicable for forced convection, can it be considerate as natural convection tool?

This statement makes no sense..." can it be considerate as natural convection tool"

If you mean, "can it be considered a natural convection tool?" I would say no....a thermal convection enabler? maybe....A heat transfer device? yes...

you wrote

When I compare the thermal behaviors of micro devices in still air chamber and using the thermostat , the results differs. The cold plate in the dry thermostat maintains the device temperature through out the experiments.

Are you only measuring the temp of device or are you seeing if the device is performing during test cycle?

If you are really using a thermostat, it will trip the power supply of device at set point. I hope you understand that, without power your device will not do any work. And no work means no heat generation

1. t3ster is a tool for research of thermal behavior of DUT. It allows to record temperature change at choosen point (or more points). It allows to control amount of heat generated at DUT (P(time).

2. Peltier element - thermostat is an additional tool, with programmable temperature of it's plate. It's fan is needed for proper operation of mentioned thermostat. It is a part of tool.

Using this programmable thermostat, You can calibrate Your *temperature sensor . You can also use this thermostat to force Tcase to desired temperature, if You will mount Your Chip-s case to the plate of thermostat.

3. To make experiments with cooling fan, You have to make Your own setup: chip mounted on radiator, and fan blowing air towards this radiator. Probably regulated power supply, to be able to controll speed of rotation of fan. And another setup to supply Your DUT, (with possibility control generated heat, if allowed).

4.* temperature sensor.

To make temperature measurements, You must have temperature sensor.

If chip under test has built in sensor, You can use it. Sometimes it is possible to find p-n junction diode within structure, which can be used as temperature sensor(sometimes only temporarily = time sharing - once chip works in normal mode, another time supplied so , that temperature can be measured). Search for keywords: diode as temperature sensor. Transistor as temperature sensor.

If You cannot find sensor inside of Your chip, You can use thermocouple, attached to Your chip. Or more thermocouples to get more data; for example :on the hottest point on the chip, (above area, where heat is generated), on side of the chip, between chip and radiator, on the top of radiator, on the side of radiator, thermocouple to measure ambient temperature, to track temperature distribution along heat flow path.

All this is just a rough description. For details , use keywords: junction temperature measurement, temperature distribution in semiconductors, thermal resistance, thermal impedance.

Your language is curiously stilted, and your terminology does not conform to normal usage. In particular, you seem quite confused about the term "thermostat", which is just a switch that changes state when the ambient temperature crosses the setpoint.

If you are using a Peltier module to cool some electronic components, it can work in these three ways:

1) heat conduction from the electronics to the cold side of the Peltier module,
2) natural convection of air around both the electronics and the Peltier module,
3) forced air convection around both, via a fan.

The most effective is a combination of (1) and (3).