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LM5118, how to set 32V/4A out?

Nicola Fiorucci

Intellectual 300 points

Other Parts Discussed in Thread: LM5118

Hi, i'm tryong to configure the LM5118 to output 32V and 4A max current. I can't find a solution in WEBENCH. I tried to calculate the components value from datasheet and put them into Evaluation board. I notice high current absorption and the board doesn't work (i destroyed something).

Can you help me?

Thanks

over 11 years ago

0 EricLee over 11 years ago

TI__Guru 58171 points

Hi

What's your input voltage range ?

Regards,

0 Nicola Fiorucci over 11 years ago in reply to EricLee

Intellectual 300 points

Hi,

minimum input voltage is about 8 to 10V

maximum input voltage is 36V

Thanks

Regards

0 EricLee over 11 years ago in reply to Nicola Fiorucci

TI__Guru 58171 points

Hi

WEBENCH could not find a suitable MOSFET/Diode in WEBENCH database for your design because 128W was too much for LM5118 to handle.

Please contact your local FAE to see what is available in TI's road map.

Regards,

0 Nicola Fiorucci over 11 years ago in reply to EricLee

Intellectual 300 points

Hi and thanks for your help.

This 32V is used as a main voltage of a mosfet H-bridge. The effective power delivered is about 70W. There is no DC absorption from the 32V.

However even if the power was 128W why the LM5118 can't handle this?

The load current and volatge are in charge of mosfets and diodes, the LM5118 act only as a controller. Am i wrong?

Thanks and regards

0 EricLee over 11 years ago in reply to Nicola Fiorucci

TI__Guru 58171 points

Hi

You are right. Since LM5118 is a controller, there is no direct relationship with output power.

Practically, diode temperature will be very high, it will be hard to find suitable inductor, it will be hard to minimize current sense noise.

Regards,