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

[gary239955_stm1_stmicro_com]

Posted on March 30, 2016 at 10:29

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. 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''.
3. Table 11 on page 17 says the Sense output goes to VSenseH after a short to ground.
4. Table 9 on page 12 reports that VSenseH in a fault condition lies between 7.5 and 9.5 V when RSense = 3.9k.
5. 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.

#high-side-driver-overcurrent #support

[gary239955_stm1_stmicro_com]

Posted on March 30, 2016 at 12:39

Correction:  Change that second assertion to:

• My colleagues think that CSn stays a current source, in which case

  statement 5 trumps statement 4.

[gary239955_stm1_stmicro_com]

Posted on September 14, 2016 at 14:45

I originally posted this question 6 months ago and it remains unanswered. In fact,

so far the only person to follow up was when I corrected a typo in my original post.

Now I am looking at the big board for ''Motor Driver ICs and Boards'' and estimate

that 80% of the posts have 0 follow-up, which begs the question:

        ''Does anyone from ST ever look at these requests for support?''

(If you're not there, please don't answer.)