TPS60255: LED blinking when Iout>100mA

Sara Jia

Expert 2975 points

Part Number: TPS60255

Dear TIs,

I used TPS60255 as our LED driver, the total Iout is set to 100mA,5P2S LED

But LED is blinking, But reducing Iout, the phenomenon is disappearing.,The sch as follow:

over 6 years ago

0 Hak-Leong Ng over 6 years ago

TI__Intellectual 1985 points

Hi Sara,

I think VF = 6.2 +/- 0.4V might be a little too high for this device. As the led current increase, Vf increases as well. I suspect you are hitting the overvoltage limit of the charge pump (typ. 6.6V) when you increase the led current to the point when LED starts to blink.

What is your input voltage to VIN pin? If you can , you should check VOUT waveform with a scope as well.

Regards
H L

0 Sara Jia over 6 years ago in reply to Hak-Leong Ng

Expert 2975 points

Hi H L,
Thanks a lot,.
We use Li battery as supply power(3.7-4.2V). I will check the Vout waveform.

0 Hak-Leong Ng over 6 years ago in reply to Sara Jia

TI__Intellectual 1985 points

Hi Sara,

Any update on this issue? I still believe VF = 6.2 +/- 0.4V is a little too high for this device and causing the problem you are seeing. Do you have a chance to take a look at the output waveform?

Regards
H L

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TPS60255: LED blinking when Iout>100mA