HV9821 LED driver current sense resistor conenction is wrong?

[treez]

On page 3 of the HV9821 LED driver datasheet, howcome on page 3, the high side current sense resistor is connected to ground?

HV9821
**broken link removed**

So there could be 700V one side of this resistor, and then ground on the other side of this resistor?

 

[FvM]

the high side current sense resistor is connected to ground?

I don't see a ground connection of Rs.

 

[treez]

on the "functional block diagram...inside the controller there is a ground symbol.

 

[FvM]

But the IC hasn't a ground pin. The block diagram clarifies that the ground symbol refers to the OUT pin.

 

[treez]

But the IC hasn't a ground pin. The block diagram clarifies that the ground symbol refers to the OUT pin.

I agree, but why is the Rs connected to it?

 

[FvM]

Output current is sensed at the OUT pin, I think. So what's strange about it?

 

[treez]

So what's strange about it?

The buck freewheel diode cathode is grounded in their diagram

 

[FvM]

The buck freewheel diode cathode is grounded in their diagram

May be I didn't yet get your point, but the diode connection is also typical for a buck converter.

 

[treez]

the diode connection is also typical for a buck converter

Buck freewheel diode cathode should never be grounded

 

[FvM]

I really don't get your point. :?:

Very regularly, the cathode is grounded. The anode is not grounded.

 

[treez]

but your picture shows the anode of D1 directly connected to ground , as it should be.

If you open out that picture above, you would see the cathode of D1 has got a ground connection , which it shouldnt have.

 

[FvM]

You are confusing the substrate connection inside the chip with a ground connection. See my post #4.