LP5810: LP5810: Current leak in out0 when LEDs are powered but VCC is down v2

Hi Francols,

Do you mean that the LED will be turned on once the VLED is power up?

BR, Jared

VCPU is ON, VLED is ON, all good.  Then we remove the battery for the system, VCPU falls first as less capacitors on it.  Since VLED is still higher, the LED will blink once, until the VLED drop enough.  Does on a RED led, as the V Forward is lower.

Hi Francols,

Do all the IC have this behavior or only 1 IC has this problem?

BR, Jared

At first I was suspecting a layout issue, it just turn out that we were testing more those LEDs...  I have 3 bank of 4 drivers.  So it can happen on any of those.

Hi Francols,

Do you mean that you have total 12pcs LP5810 and all the IC have this problem?

Does the problem occur when you first test or after some testing?

BR, Jared

Sorry I'm on 2 issues at the same time.  This happen all the time when removing battery.  VLed got more capacitors and stay ON a bit longer.  The Red Leds flash once.  Maybe IR as well, harder to see.

Hi Francois,

Our expert is currently out of office and will reply to you next Monday. Thanks for your understanding.

Best Regards,

Steven

Hi Francois,

Let me clarify your problem here.

The LED will be lighted up when you only power the VLED and leave the VCC open. Am I right?

If in this way, I think the IC might be broken since on my EVM, the good unit doesn't have this behavior like you.

BR, Jared

No I said it will blink for a very short moment when removing VCPU as VLED stay On a little longer.  The other user seems to have the same issue on Drive 1, for me it's hard to know what drive as all 4 are connected...

Hi Francois,

Do you have any waveform to describe this phenomenon? Actually, this is the first time to meet such problem. It will be better if there is a waveform.

BR, Jared

Sure I will ask my technicien to record one.  Only does that with red leds as the V forward is lower.

Hi Francois,

Thanks for understanding! Since I will be OoO tomorrow. I have looped in my manager to follow up. Let's follow up on email in case I can't reply you on time. My manager will be backup.

BR, Jared

Here is the traces when removing VCC and V Led is dropping slower (More caps on it.)

A Red Led will flash for a moment.

Top trace is VLed

Bottom is the other side of the led (chip side)

Gray trace is the Math difference between the two.  Difference get between 1.6V to 1.9V, the red led start at 1.6V of V Forward. 

Hi Francois,

Jared is currently out of office. I will ask another expert to help on this thread. He will respond to you later. Thanks for your understanding.

Best Regards,

Steven