LM36923H: flickering issue on monitor

Hi Fred,

Could you please kindly ask our customer to share their schematic?

BR

Patrick

Hi Yao,

update schematic and code,

BTW, I repeat the frequency now is 800KHz, but they'll change to 150Hz.

not sure if this is the root cause. thanks

Hi Fred,

You mean this issue happened at PWM=150Hz, right?

Is this issue happened on all customer's boards or only one board? Have they tried ABBA test?

BR

Patrick

no,

this issue happens when PWM is 800KHz, which sounds weird I know,

they misunderstand the definition, so they use 800KHz

Hi Fred,

In figure 1 and figure 2, the time base is 1s and 100ms, I don't think this issue is happening with 800KHz PWM.

In figure 3, what's their oscilloscope probe bandwidth? The behavior seems fine in PWM dimming mode.

BR

Patrick

Hi Yao,

if it's not 800KHz , then what's the root cause?

after all, the  two terminal of LED are connecting to our Vout and LED pin respectively, so it's hard to think it's LED's problem.

do you think the flickering is caused by the behavior in red circle or something else normally?

Hi Fred,

1. What's the SW behavior at the red circle you placed?

2. Please make sure whether this issue is happened at 800kHz, if so, please let our customer send the waveforms again. Previous figures are not with 800kHz.

BR

Patrick