ADN8831 no cooling mode

[dongtao1010]

I am working on a new hardware design using ADN8831 TEC controller.
i have a problem with the ADN8831 going into a cooling mode.when the temperature of TEC that i set is below the environment temperature, the chip ADN8831 does not go into cooling mode.
In my design, PVDD=5.02 volts.
Heating mode seems to work as my expect.

Has anyone use the ADN8831 to control the TEC temperature successfully?
Any ideas why it will not cool?
Thanks
Dylan.
Email: removed by Harald kapp (mod)

 

[Harald Kapp]

Welcome to our forum. I removed your E-Mail address since it is our policy not to make E-Mail addresses public to prevent users from spam. YOu can be contacted using the forum's conversation feature - although we very much prefer and encourage posting messages within a thread so other users can see them as well.

A schematic would be very helpful in understanding your circuit.

 

[dongtao1010]

This is my Schematic.

 

[KrisBlueNZ]

OK, try again. This time, post the schematic with the TEC in it!