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ADN8831 issue (probably with supply voltage drop)

Question asked by Oliver.Meier on Jan 29, 2015
Latest reply on Feb 17, 2015 by katout

Hello to all

 

We are trying to use an ADN8831 to drive a TE-module with up to 4V/4A, but it always turns off at ~3A (!standby-pin going low).

The circuit we're using is more or less the same as the eval board, except AVDD is connected via a 1Ohm (1.5kOhm@100MHz) bead to DVDD.

Because I put in a filter after the power supply the supply voltage drops ~250mV until the ADN8831 goes into standby mode (see attached "TEC2 Plots.png").

What causes !SB to go low? Is there some way to stop this behaviour?

 

Also is there maybe a replacement for the ADN8831 without the opamps built in? A (voltage controlled) H-bridge controller with similar behaviour?

 

Thanks for your help.

 

Oli

 

EDIT: I set the current limit a bit lower, now it looks like the "TEC2 fail.png" attachment. (-> the problem doesn't seem to be the voltage drop).

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