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ADuM4223 Start Conditions

Question asked by Ralf.M on May 25, 2013
Latest reply on May 28, 2013 by RSchnell

Dear Guys,

i use an ADumM 4223 for a 2 phase motor driver and found a problematic start condition.

 

The AD is powered like this: VDD1 = +5V, VDDB = 15V  and VDDA = 15V with out switching (bootstrap).

GND1 and GNDB are tight together for test purpose.

 

The power suppy comes from a fast starting test modul.

All supplies starting together (within 2ms).

 

2.) VIA = 0V, VIB = 0V, DISABLE = 0V

All Inputs (e.g. VIA, VIB, DISABLE) have never been toggled since the start of the power supplies.

 

Obeservation:

Output VOB is +15V !   But it should be 0V

 

If the inputs are toggled once then everything is correct (e.g. VOA = 0V => VOB = 0V).

 

Could any body give me an hint about the problem.

I could not find any restrictions about an "power-up" schedule in the data sheets or app's on analog.com

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