LT3966 and max channel current

Hi Zefram,

May I know your input voltage range for this application? Does 1.8A pertain to your load current?

Regards,

Xian

Hi Xian,

the input voltage is 12V and yes, 1.8A is the load current for each channel.

Thank you

Hello Zefram,

this won't work. The switch in a boost regulator does 'see' the input current. To obtain 31V and 1,8A as output load you demand for 56W/channel(!!)

To deliver 56W with 12V input you end up at 4.65A input current. And this simplified calculation does not take <100% efficiency or ripple current into account. But your app is far beyond the capabilities of the LT3966.

If I take the 12V Vin and 31VLED as fixed I think a LED current of 400mA is achievable with careful design and good thermals

The examples in the ds show 25W/channel. Take this values as guidance what is possible with our parts.

kind regards

Markus

Thanks for the answer,
do you have any advice on which driver i can use for such application? May be LT8391 a good alternative (I'd be using 4 of them to control the strips, each one with 43.5v, 800mA (totalling at 34W per Channel))?

Thank you again

Thanks for the answer,
do you have any advice on which driver i can use for such application? May be LT8391 a good alternative (I'd be using 4 of them to control the strips, each one with 43.5v, 800mA (totalling at 34W per Channel))?

Thank you again

Yes, the LT8391 is a part which can deliver the desired power. Maybe the LT8391A is ok as well and saves some space as higher switching frequency allows smaller inductor.

For sure a much bigger design than one LT3966, but your power level does not allow for a simpler solution.

kind regards

Markus