Hi everyone,

I have a battery (Li-Ion ) operated boost circuit which drives a BDLC fan rated at 300mA at 12V. The battery is rated at 7.4V, 4400 mAH. The fan drive circuit fails frequently because the wires running to the fan, mounted on a separate piece hardware, break and get shorted.

There is a fuse in series with the battery and the fan, but the fuse rarely ever blows. It is a standard 750mA, glass fuse. It is rated at 750mA to be able to handle any surges during starting and stopping of the fan motor.

I want to introduce an electronic short-circuit protection circuit in here to prevent these field failures.

What suggestions do the the experts have for me? I have one other constraint. I may not be able to add too many devices in this circuit. It should be cost effective.

Thanks in advance for all your help.

Regards
Atanu

 

I would address this issue first:

"The fan drive circuit fails frequently because the wires running to the fan, mounted on a separate piece hardware, break and get shorted."

After you fix that issue, there is no need for an additional safety.

I mean, you want to "introduce an electronic short-circuit protection circuit in here to prevent these field failures", but that does not prevent a field failure. It just gives you a non working device, which is a field failure.

 

Hi Gibson,

I agree wholeheartedly with your suggestion. That aspect has been taken care of. The assembly has been improved, but as a learned friend of mine used to say .. sometimes it is important to "idiot proof" systems such that it does not fail, however badly it may be used.

To provide a little more context to this scenario, it would suffice to say that users of this equipment are first time users of any sophisticated equipment. This would be the first time they are exposed to electronics, other than the mobile phone! Hope this helps.

Rgds
-Atanu