LM3435: The LED current setting range

Shoji Nakayama

Prodigy 90 points

Part Number: LM3435

Dear customer support staff,

The data sheet has the following description, and so is Figure 7.

"The LED current setting can be in the range of 0.5A up to 2A maximum."

I would like to set the current to a maximum of 0.2A. Is it possible?

When the maximum current is 200mA, the resistance value will be calculated to be 123.75kohm (24.75 / 0.2).

It can be set, but does it mean that the current variation will be large?

Best regards,

Nakayama

over 3 years ago

0 Aaron Bing over 3 years ago

TI__Expert 4160 points

Hi Nakayama-san,

As also what explained in this thread LM3435: Can LM3435 provide LED current less than 20mA, a 123.75kohm Rref cannot properly reduce the max current to 0.2A. The current variation will go larger in this case.

Best Regards,

Aaron

0 Shoji Nakayama over 3 years ago in reply to Aaron Bing

Prodigy 90 points

Hi Aaron-san,

Thank you for your reply.

Since the maximum rating of the driving LED is 200mA, I want to limit the driver side so that it does not exceed this regardless of the register value.

Is it possible to estimate the current variation with 123.75kohm Rref?

Best Regards,

Nakayama

0 Aaron Bing over 3 years ago in reply to Shoji Nakayama

TI__Expert 4160 points

Hi Nakayama-san,

We don’t have a precise estimation of current variation with 123.75kohm Rref, but it should be somehow larger than 3%.

Best Regards,

Aaron

0 Shoji Nakayama over 3 years ago in reply to Aaron Bing

Prodigy 90 points

Hi Aaron-san,

Thank you for your reply.

I will replace the resistors of LM3435EVAL / NOPB and check the current value.

Best regards,

Nakayama

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LM3435: The LED current setting range