Vout and SENSE goes to a connector / switch. For some time, SENSE is not connected to Vout. It is open or pulled down to GND. Of couse, Vout runs away, but that doesn't matter. But would that cause any damage to thepart ?
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Vout and SENSE goes to a connector / switch. For some time, SENSE is not connected to Vout. It is open or pulled down to GND. Of couse, Vout runs away, but that doesn't matter. But would that cause any damage to thepart ?
Hi Dirk,
This is not a recommended way to operate.
Please add a resistor (100 Ohms) in between the SENSE pin and the VOUT pin at the module side.
This way, even when the connector/switch momentarily disconnects, VOUT does not run that far away and stays in the ballpark.
Regards,
Yitzhak Bolurian
Hi Yitzhak,
Unfortunately, it's not that easy. The sense line is connected to another circuit on the board which pulls it to GND as long as connector is not plugged.
So I would need to add some kind of switching circuit to connect it to Vout - only for the few milliseconds while the connection is open.
Hi Dirk,
Even if you don't implement this switch, there is a good possibility that a protection limit such as OCP is crossed and the device will not get damaged. But I can not guaranty that there will be no harm long term if the device operates like that.
You may want to run an automatic test and verify it at your end.
Regards,
Yitzhak Bolurian
Hi Dirk,
As you know 1 mS is a pretty long latency for protection purposes.
But I guess it is better than not having any protection.
Also, I am not sure how far is the voltage from the rating of your output caps.
Regards,
Yitzhak
Hello Yitzhak,
Thanks for the reply. As I said. I don't care for Vout going up to Vin (8V) for that time. It takes 300ms for the new device gets connected - plenty of time to turn the part off. Of course, all componets connected to Vout during that time can handle the higher voltage.
So, if the LMZ31710 doesn't get damaged, everything is fine :-)
Best Regards
Dirk