LM3410: Could it support 1A and Vin = 3.3V application?

Teresa Chiu

Prodigy 690 points

Part Number: LM3410

Hi Sir,

May I have your help to check does LM3410 support below condition? If not, do you have another recommend solution?

If yes, could you help to check the

1. Vin:3.3V

2. Current limit: 1.5A

3. 4 LED in serial

a. Vf = 2.9V

b. If = 1A

over 6 years ago

0 Irwin Nederbragt over 6 years ago

TI__Mastermind 28655 points

Hello Teresa,

If Vout is 2.9V * 4 = 11.6V and Iout is 1A, Pout is 11.6W. Assuming 100% efficiency Iin at 3.3V would be 11.6W/3.3V = 3.87A, this won't work. I don't understand what 1.5A current limit is?

At 3.3V input we don't have another solution.

Best Regards,

0 Sanjay B C over 6 years ago in reply to Irwin Nederbragt

Prodigy 70 points

Hello Irwin,

You reply has provided good insight about led driver, would you explain further why input current cannot be 3.87 A ?

Also, what is the restricting factor for input current?

Thank you.

0 Irwin Nederbragt over 6 years ago in reply to Sanjay B C

TI__Mastermind 28655 points

Hello Teresa,

On page 5 of the datasheet: "ICL Switch current limit 2.1 2.8 A"

The minimum specification for switch current limit is 2.1A. This means, for design purposes, the maximum designed input current for the LM3410 MOSFET needs to be below 2.1A including inductor ripple, efficiency and input voltage with output power. 3.87A is well beyond this and it doesn't include any of this.

Best Regards,

0 Sanjay B C over 6 years ago in reply to Irwin Nederbragt

Prodigy 70 points

Hello Irwin,

Thank you for the clarification regarding current limit switch.

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LM3410: Could it support 1A and Vin = 3.3V application?