Inquiry regarding LM3404HV output protection

Atsushi Okui

Other Parts Discussed in Thread: LM3404HV

Hello, all

Now we are evaluating LM3404HV for our next trial.

On our configuration, the maximum drive current to LED is 800mA, and the cable length from system board (LM3404HV mounted) to LED is 0.4meter.

When considering this configuration, we assume that we need to protect the output on system board by rectifier diode or etc.

Please let us clarify whether such protection would be necessary or not, if necessary please advice us some recommended parts number.

We thank you in advance for your information.

Best regards,

over 12 years ago

0 Mike Kosteva over 12 years ago

TI__Intellectual 2590 points

Can you post your propsed schematic or email to mkosteva@ti.com

0 Atsushi Okui over 12 years ago in reply to Mike Kosteva

Genius 4015 points

Hello, thank you for your prompt reply.

We haven't prepared any proposed schematic for this device yet.

Instead of that, we are evaluating LM3404HVEVAL Board and the schematic would be same as this EVM design.

We are evaluating this EVM on following conditions;

Vin: 48V

Vout: 40V

Iout: 800mA

Thank you once again for your information.

Best regards,

0 Mike Kosteva over 12 years ago in reply to Atsushi Okui

TI__Intellectual 2590 points

The evm as configured provides for open circuit protection with the addition of Z1 and change of value for Rz to a 1kohm. Z1 value needs to to greater than 40 vdc and less than the 48 vdc and should have a tight tolerance due to your voltage string voltage of 40 vdc. Please read pages 13,19,20, and 21 that discuss this.

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Inquiry regarding LM3404HV output protection