of a Laboratory Benchtop Power Supply
Commercial Cooler Power Supply
TEC to Controller's Capability
Power Supply to Controller
Match Power Supply to TEC
Notes: Using Multiple Power Supplies
Information About Power Supplies
Precautions and Warnings
Using Multiple Power Supplies in Parallel
We do not recommend specific power supplies unless
we are preforming
the design and engineering of the entire project, however, here are
notes we put together about some power supply sources.
Note: "TEC" stands for Thermoelectric
is a Peltier module.
OF A LABORATORY BENCHTOP
For working with low power TECs we use a TENMA
Laboratory DC Power Supply
72-2005. It has over current protection so that it shuts off if the
goes too high. It also has coarse and fine adjust with meters for the
and voltage. It is a nice general purpose power supply for up to about
20 vdc and 3 amps. There are other TENMA benchtop power supplies with
power. These are available from
Your local electronics store may have TENMA or
other power supplies.
COOLER POWER SUPPLY
If you are working with a commercial TEC based
"cooler" (such as Igloo)
it will have its own power supply. You may not be able to find the
you need, though, on the power supply or TEC. Be careful that you
the operating voltage and the Imax (max current draw) and that these
match your temperature controller's capability.
MATCH TEC TO
These two examples use a Model
controller: 9-24 vdc, 7.5 amperes max (heatsink recommended for 3A or more).
Note that the Model 5R7-350
requires at least 9 vdc for its own operation, but can be configured
use two power sources. For TECs that have a Vmax less than 9 vdc use
power source for the controller and a second for the low voltage TEC.
This first one is OK for the 5R7-350.
#1) Imax 3.1
amps, Vmax 15.7 vdc (OK. Heatsink recommended.)
#2) Imax 5.6
amps, Vmax 16.1
vdc (OK. Heatsink recommended.)
You would need a more powerful controller, such as our Model 5R7-001
this next one because of the higher Imax. Or, in the case of the
controller, you would need additional heatsinking for the controller.
#3) Imax 5.6 amps, Vmax 7.9 vdc (OK. Heatsink recommended. Requires 2 power supplies.)
#4) Imax 2.7 amps, Vmax 12 vdc. (OK.)
#5) Imax 8
amps, Vmax 16.1 vdc (Amperage is too high for 5R7-350)
#6) Imax 12.4
amps, Vmax 15.9
vdc (Amperage is too high for 5R7-350)
the point is that you want to match the pelter specifications to the
specifications of the temperature controller, or Vice-versa.
SUPPLY TO CONTROLLER
If you can run the load with the same voltage that
is used to run
the controller itself, a single output power supply
Controllers such as the 5R7-001 can also run low
TE modules, but still require 12 or more volts for the controller
itself. In this
case you can use one power supply for the controller and one for the
or dual output power supply. Usually the power supply for the
would be 12 vdc and 1 amp - but the current draw is less than 500
and the Model 5R7-350 can optionally go down to 9 vdc, and so smaller
supplies or even batteries could be used for the controller itself.
We can and do build controllers that run on 5 vdc
or some other custom
voltage or voltage range for our OEM customers.
SUPPLY TO TEC
The power supply must be able to supply the Imax
of the TEC. It should
be rated for the TEC's Imax or more.
The power supply must be able to supply
"sufficient" voltage. It should
be rated for the TEC's Vmax or less. It may be possible to have optimal
operation of the TEC at 75% of the Vmax. A power supply with an
voltage may be useful, especially for odd Vmax values such as 4.75 vdc.
If powering the controller and TEC from the same
power output, add the
requried milliamps of the controller to the Imax of the TEC to
the power supply requirement.
For a module with these
Vmax 16.1 vdc
Imax 5.6 amps
We can run this with a
controller from one power
supply. If the controller requires 250 milliamps, we should add 0.25
to the Imax and that gives us 5.85 amps maximum.
So then, the power supply
we select may be 12
to 16 vdc, with a capacity to handle 5.85 or more amperes.
INFORMATION ABOUT POWER SUPPLIES
We buy power supplies on-line and just about any
will probably be OK.
We have no particular recommendations, though. We use switching power
not linear. They are generally lighter, less expensive, hold to the
voltage better, and dissipate less heat.
You need to multiply the voltage you are using by
the maximum amperage that mght be drawn in order to determine the
maximum watts required, and then use a power supply that is capable of
supplying that many watts.
If a module has an Imax of 5A and a Vmax of 16v
and if you are going to run it at 16v, then the power supply should be
able to supply 5 x 16 = 80W or more.
Matching the right power supply (considering
economics as well as power)
is an area that requires some research and design experimentation on
Some power supplies from other manufacturers may
be smaller or lighter.
Also, usually, the less power you need the smaller the power supply can
Note if they are single or multiple output, also.
If you are going to
run fans you may want a multiple output supply that also provides the
needed for the fans.
When building a product for process control, note
that 24 vdc is considered
by some to be the current "standard" for industrial applications, and
you may want to consider using 24 vdc for the controller and TEC. If
a transportable product you may want to use 12 vdc, as provided by an
battery, for the controller and TEC.
SOME PRECAUTIONS AND WARNINGS
These precautions and warnings should not
be used in lieu of
those provided by the controller, TEC and power supply manufacturers.
- Heatsink or Cool if Necessary: Be
to note the cooling requirements
of the power supply. You may see a power supply that provides the
and amperage you need but then there will be a note to the effect that
the power supply requires certain ambient temperature conditions, or
air cooling, or similar.
- Supply Sufficient Amperage: Do not
connect an output that sources
less amperage than the the maximum current draw of the devices you are
powering. If powering the controller and TEC add about 0.5 amps (check
with us for the current draw of a specific controller model) to the
of the TEC to determine the maximum current draw you should allow for.
- Supply Sufficient Voltage: Do not use
linear power supply for
the controller unless you are sure it will provide the required voltage
under load. For example, the 5R7-001 series of controllers require 12
minimum for communications to operate normally.
- Avoid Shorts and Sparks and Miswiring:
Always have the supply power
OFF when making or changing connections. Double-check your connections.
- Prevent Thermal Runaway, Note 1: Have
thermometer or other way
to test the TEC to see if the working side is heating when you expect
to heat, or cooling when you expect it to cool, so that you can be sure
you hooked up the TEC with the appropriate polarity. If the TEC is
up with the wrong polarity you could experience thermal runaway and
out the sensor or TEC or attached equipment/devices.
- Prevent Thermal Runaway, Note 2: If
controller has a alarm
settings with "power out shutdown if alarm" use this to prevent your
from thermal runaway.
We can supply the
following Single Output Switching
Power Supplies. Contact us for more
Dimensions: 199x110x50mm (5.1"x2.8"x1.3")
Model S-150-12: 12V, 0~12.5A, $41.90,
DC adjustment range), 150W.
Model S-150-24: 24V, 0~6.5A, $41.90,
DC adjustment range), 150W.
- AC input rangeselectable
- Protections:Short circuit / Overload / Over
- Fixed switching frequency at 25KHz
- Approvals: UL / CUL / TUV / CB / CE / BSMI
- Cooling by free air convection
- 100% full load burn-in test
- AC input voltage range......88~132VAC
/ 176~264VAC selectable by switch
- DC adjustment range......±10%
rated output voltage
- Overload protection......105%~150%
shut off, AC recycle to re-start
- Over voltage protection.....115%~145% rated
- Setup, rise, hold up time......100ms,
50ms, 28ms at full load and 230VAC
- Withstand voltage......I/P-O/P:3KVAC,
- Working temperature......-10~60OC(refer
to output derating curve)
- Safety standards......UL1012,
UL60950-1, TUV EN60950-1 approved
- EMC standards......EN55022
class B, EN61000-3-2,-3 EN61000-4-2,3,4,5,6,8,11, ENV50204
9.5mm pitch terminal blockPacking 0.8kg ; 16pcs /
13.8kg / 0.95CUFT
Dimensions: 215x115x50mm (5.5"x3"x1.3")
S-320-12: 12V, 0~25A, $95.45,
(±10% DC adjustment range), 320W.
24V, 0~12.5A, $95.45,
DC adjustment range), 320W.
You may have several power supplies that
you would like to
use to simultaneously power and control multiple TECs. The power
of a commercial cooler, for instance, are usually meant to supply power
for the one TE module in the cooler - but what if you have several and
want to use their combined power for temperature control.
What if you want to use one temperature
controller with multiple TE
modules using multiple power supplies?
The following discussion assumes that all power
supplies are the same
model/manufacturer with the same ratings of voltage and maximum
for the VDC outputs, and it assumes that all the TE modules are meant
be used with those power supplies.
You could purchase a new power supply that will
handle the required
load, or you may be able to connect multiple power supplies from the
Some power supplies can be connected in a
similar manner as batteries
- in series or parallel. Connecting each power supply's (+) to the (+)
of one or more additional power supplies, and similarly the (-) to the
(-), results in no change in the voltage but an increase in the
amount of amperage. You would have to ask the power supply manufacturer
if the type of power supply, and the number of power supplies, you want
to connect together can be connected in parallel. CAUTION: Do not
power supplies in series or parallel unless you know for certain they
capable of being connected and used in such a configuration safely!
If they can be connected in parallel, you could
use one controller with
multiple power supplies that are connected in parallel. CAUTION: Be
sure the temperature controller is rated for the total Imax amperage
current draw) of all the TE modules being powered.