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What happens to VND5T050AK-E CSn output when you overload the output?

Question asked by lynch.gary on Mar 30, 2016
Latest reply on Sep 14, 2016 by lynch.gary

We need to settle a difference of opinion interpreting the data sheet for the VND5T050AK-E, dual channel high-side driver IC.

We agree that when you provide a normal load, the CSn output acts as a current source whose current is a rough fraction of the actual output current on channel n.

When you overload the output however, the channel switches into fault mode and the CSn output does something else.

       
  1. I thought I read somewhere that after a fault the CSn output assumes a voltage which is distinguishable from any valid current reading, but today I cannot find this statement anywhere in the data sheet.
  2.    
  3. A block diagram on page 5 of the data sheet shows a switch changing the source of the CSn output from the "Current sense" amplifier to a block labeled "VSenseH".
  4.    
  5. Table 11 on page 17 says the Sense output goes to VSenseH after a short to ground.
  6.    
  7. Table 9 on page 12 reports that VSenseH in a fault condition lies between 7.5 and 9.5 V when RSense = 3.9k.
  8.    
  9. The same table indicates that ISenseH in the same state is between 4.9 & 12 mA when VSense = 5 V.
       
  • I interpret this to mean that after a fault the CSn output changes to a voltage source, in which case statement 4 trumps statement 5.
  •    
  • My colleagues think that CSn stays a current source, in which case statement 4 trumps statement 5.

Does anybody know for sure? Is it somewhere in the data sheet and I just can't find it?

Thanks.

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