Regarding the upper limit tolerance variation of the PWM frequency of the MP3301GJ.

Lighting Solutions
1

To whom it may concern.

I’m Shinichi Yamamoto.

I have a question about the MP3301GJ.

We can see LED Current Programming section on page 8 shows PWM max fewquency is 1kHz.

A question is regarding the acceptable PWM frequency of 1kHz.

What is the maximum usable percentage increase for a 1kHz frequency?

Can be 10% increase(1.1kHz) recommended?

2

Hi Shinichi,

Thank you for posting on the MPS Technical Forum.

According to the datasheet, you can use a PWM frequency above 1kHz as long as you include an RC filter with a cutoff frequency less than the PWM frequency divided by 10.

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What PWM frequency are you hoping to use? 1.1kHz?

Best,

Allison

3

Hi Allison
Thank you for your replay.
I want to drive the MP3301 at 1kHz, but due to variations, the PWM frequency may rise to 1.1kHz. I would like to ask if this 1.1kHz is acceptable or even recommended as a PWM frequency.
In this case off cource, is 1.1kHz drive available by not using cutoff filter ?

4

Hi Shinichi,

You should not need the RC filter.

Just to be safe, what is your PWM duty cycle range?

Thanks,

Allison

5

I’ve not decided dimming range yet.

The datasheet states that for PWM dimming, the DC voltage should be between 0.7V and 1.4V. Since I have 3.3V available for PWM, I’m considering using a duty cycle setting of 20% or higher. Is this possible?

6

Hi Shinichi,

Yes, this is possible.

To confirm your first question, you do not need an RC filter.

Best,

Allison

7

Thank you for your response.

I understand the content.