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FEATURES

? The world¡¯s first window based TEC controller: stands

by automatically when the target object temperature is

within a pre-set temperature window.

? Programmable set-point temperature window

? High efficiency: ¡Ý90

? Seebeck voltage available

? Switching frequency synchronizable to an external signal

? Programmable maximum output current: 0 to 3A

? Programmable maximum output voltage: 0 to VVPS

? Actual object temperature monitoring

? Completely shielded: zero EMI

? Compact size

? DIP and SMT packages available

? 100 lead (Pb)-free and RoHS compliant

DESCRIPTIONS

The ATW3A314 is a compact high efficiency electronic

module designed to control TECs (Thermo-Electric Coolers)

for regulating a target object temperature to be within a preset

temperature window. When the target object temperature

falls within the pre-set temperature window range, the

controller puts itself into a standby mode, decreasing energy

consumption to a minimum level; when the target object

temperature reaches the upper bound of the temperature

window, the controller cools down the target object so that

its temperature regulated to be equal to the upper bound of

the window temperature; when the target object temperature

reaches the lower bound of the window, the controller heats

up the target object so that its temperature remains to be

equal to the lower bound of the window temperature, as

shown in Figure 3.

The output stage of the ATW3A314 utilizes a patented

PWM-Linear topology, resulting in a high efficiency and

small size. The output pins to the TEC terminals are filtered

from PWM to a low frequency signal, thus eliminating the

heating effect and the interference to other electronics, as

opposed to driving the TEC with the PWM signal directly.

Figure 1 is the photo of an actual ATW3A314D.

The ATW3A314 TEC controller module provides interface

ports for setting the desired target object temperature

window range; the maximum output current; the maximum

output voltage across the TEC; shutdown control, standby

indication, and switching frequency synchronization

input/output. The shut down pin shuts down the whole

controller and cuts the power supply current to < 10¦ÌA. This

shut down pin can also be used to force the controller into

standby mode, which only shuts down the output stages,

leaving the rest of the circuit active.

The sensing temperature range can be configured by the user

conveniently by using 3 external resistors.

The TEC¡¯s voltage is monitored in real time. It is worth

mentioning that the Seebeck voltage (which is generated by

the temperature difference between the 2 TEC plates) can be

detected under standby mode, it can be used to measure the

temperature difference between the 2 TEC plates.

The TEC¡¯s actual current can also be monitored in real time.

In addition, the controller has many other functions:

temperature measurement and monitoring, TMO;

temperature control loop status indication, TGD; TEC

voltage monitoring, VTEC; and current monitoring, ITEC;

current limit settings, ILM; synchronization input and output,

soft start, and shut down.

The window TEC controller ATW3A314 comes with a high

stability low noise 2.5V voltage reference which can be used

for setting the output voltage and current limits, and the

desired target object temperature window by using POTs

(Potentiometers) or a DACs (Digital to Analog Converters).

When using this reference for setting the set-point window

temperatures, the error in the actual target object temperature

is independent of this reference voltage. This is because the

internal temperature measurement network also uses the

reference voltage as the reference, the errors in setting the

temperature and measuring the temperature cancel with each

other. This reference can also be utilized by external ADCs

(Analog to Digital Converters). For the same reason, the

measurement error will also be independent of the reference

voltage change, resulting in a more accurate measurement.

The ATW3A314 is packaged in a 6 sided metal enclosure

with the case connected to the ground node of the circuit,

which blocks EMIs (Electro-Magnetic Interferences) to

prevent the controller and other electronics from interfering

with each other.