self-regulated PTC heater

R

Thread Starter

rialynn

Hi all,

I have a PTC heater that's self-regulated at 60C, rated at DC 24V20W. However this is still too hot for me, can I regulate it further? The ideal temperature would be around 40C.

I'm thinking about using PWM via MOSFET, and adjust the duty-cycle. But I'm not sure if the high frequency power cycle might harm the PTC.

Another option would be using a relay with a thermosensor, limiting the temperature in a window(say, 37C to 40C). But there could be delay between the PTC and sensor, and I would much prefer a more precise control(say, under 1C).

Anyway, any ideas?
 
PWM won't do any harm - your problem will be monitoring the temperature (feedback) in order to regulate it accurately as it will vary with ambient/contact with other items etc.
 
Thanks! sure I will monitor it, but it's a one-time thing I guess? Once the calibration is done, it will remain the temperature if I don't change the contact and ambient.

BTW, I'm also consider using the same method to control the speed of a 3-pin cpu fan. Some people told me the PWM signal will interfere with the intenal clock of the fan, and it won't work at all. Do you think it's doable?
 
Top