Peltier cooling module circuit
sheonbanks2
Posts: 2
I bought a peltier cooling module(tec 101706, 2V DCm 3.79V). I would like to set up a circuit with it using the basic stamp to control the module. Is this possible? If so, can someone provide the components and/or schematic. I am a newbie to circuits and I don't know much about circuits but I am willing to try. I have access to a propellor module as well but it is not as readily available.
Sheon
Sheon
Comments
A Stamp or a Propeller (or even an LM339 comparator) could be used. You'll need a thermistor or other temperature sensor.
The more details of your application you provide will expedite a useful answer.
Next, you want to see the temp of the item being cooled. This is where the thermistor comes in. The thremistor is read using another io on the micro controller.
Thermal mass is about how big the item being cooled, and how much cooling power is available. A small item is easy to cool with a lot of power, a larger item is hard to cool with little power. If you can tell us something about what you are cooling and how its being heated, we could try to dete3rmine how much is enough and how long it takes.
Its a whole bunch of small, easy steps. If you do them in a good order, its not too hard, and folks will help.
Don't forget, peltiers are semiconductor products, so they are subject to thermal runaway. So you should feed them with fixed current, not voltage.
In that case, I guess just a transistor won't do it? Would someone suggest a link to a simplest fixed current circuit thast might work?
Linear (simple to use, requires less parts and less knowledge, but in most cases will be VERY ineffective, generating way too much heat). One of the thousands of solutions is Onsemi's CAT4101 - perfectly compatible with basic stamp, tested by myself. But current will be limited to 1A. If you need more current, you can use Linear Technology's LT1185. A bit harder to adjust current using basic stamp, but total current can be up to 3A.
DC/DC converter, such as buck/boost/etc (A bit harder to do, requires inductor, more external components and specific PCB design, but can have 94% efficiency). Again, there are a lot of solutions, and one of them is Maxim's MAX16832, for currents up to 1A. If you need higher currents, you'll have to use solution with external mosfet, like Linear technology's LT3791 (This one may be an overkill for beginner, but it gives you good idea about these circuits).
If you want just simplest (fixed) set and forget solution, just get bunch of ONsemi's NSI50350 chip. It is fixed 350ma current led driver, connects in series with load, no other components required. You can connect parallel as many of them as you like, to get the desired current.
I am no expert with transistors which causes me to read so...
Bipolar Transistor Configurations
As the Bipolar Transistor is a three terminal device, there are basically three possible ways to connect it within an electronic circuit with one terminal being common to both the input and output. Each method of connection responding differently to its input signal within a circuit as the static characteristics of the transistor vary with each circuit arrangement.
Common Base Configuration - has Voltage Gain but no Current Gain.
Common Emitter Configuration - has both Current and Voltage Gain.
Common Collector Configuration - has Current Gain but no Voltage Gain.
The explanation is here.
The Common Collector (CC) Configuration
In the Common Collector or grounded collector configuration, the collector is now common through the supply. The input signal is connected directly to the base, while the output is taken from the emitter load as shown. This type of configuration is commonly known as a Voltage Follower or Emitter Follower circuit. The emitter follower configuration is very useful for impedance matching applications because of the very high input impedance, in the region of hundreds of thousands of Ohms while having a relatively low output impedance.
The Common Collector Transistor Circuit
The common emitter configuration has a current gain approximately equal to the β value of the transistor itself. In the common collector configuration the load resistance is situated in series with the emitter so its current is equal to that of the emitter current. As the emitter current is the combination of the collector AND the base current combined, the load resistance in this type of transistor configuration also has both the collector current and the input current of the base flowing through it. Then the current gain of the circuit is given as:
The Common Collector Current Gain
This type of bipolar transistor configuration is a non-inverting circuit in that the signal voltages of Vin and Vout are "in-phase". It has a voltage gain that is always less than "1" (unity). The load resistance of the common collector transistor receives both the base and collector currents giving a large current gain (as with the common emitter configuration) therefore, providing good current amplification with very little voltage gain.
I have not tried it but it looks like you can control the current with the value of the base resistor with this setup. I found this here.