LM3435: About turning off the all LED

Hi Kato-san,

In the design, CTRL low makes LED turned off but the VOUT still has voltage.

How much LED current / brightness do you see when CTRL turned low?

Thanks!

Hello Issac-san,

LED continues to light up even when the G/B/RCTRL pin is set to LOW.
The current / voltage of the G/B/RLED pin at that time is below.

　GLED : 3.7mA/4.68V
　BLED : 11mA/4.84V
　RLED : 18.8mA/5.5V

　Vin：4.3V

The LED used is below.
It is 3 color LED which lights at min 5mA.

　OSRAM : LRTB GVSG
　www.osram-os.com/.../LRTB GVSG - MULTILED.pdf

The current will flow at CTRL pin = LOW, so the color will not be as expected.

Even if the CTRL pin = LOW, is the specification that the current flows to the LED?
Is there countermeasure to prevent current from flowing?

Best regards,
Kato

Hi Kato-san,

I doubt the device might be damaged during the evaluations.
Can you please re-check the phenomenon by replacing a new LM3435 on board?

Thank you!

Best Regards,
Issac.

Hello Issac-san,


The customer replaced the new device, but the state did not change.
Is it expected that current will not flow with CTRL = LOW?

Also, large switching noise is output because customer's layout is bad.
Is this related to the phenomenon?


Best regards,
Kato

Hi Kato-san,

It is expected that the current will not flow once CTRL = LOW.
I am not sure if the residual current issue is due to the bad layout or not.

Best Regards,
Issac.