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Why the coil get so hot?

Question asked by yigal on Jun 14, 2018
Latest reply on Jun 14, 2018 by ARad

 Hello,

 

We have designed a board based upon an LT3795 application note.

We are using the circuit to boost to 54 Volts from 24V. I am getting a relatively high ripple (0.5V). The surrounding of the coil is very hot (gets up to 80 degrees). I have taken a lot of spares and I'm using a 22uH 7mohm(15 Amps).

As far as I understand it should not be so hot. I would like to reduce the ripple to ~200mV.

Rt--> 10Kohm(700Khz switching frequency) instead of currently 23.K(i.e. 320KHz)  that I'm using now. The inductor according to the calculation should be 8uH.

 

Before these changes can you approve my estimation and check the values of the design?

 

Do have any recommendation for switching frequency? are you familiar with the heating problem how can it be solved? 

The diode, capacitor and the Fet near the coil are getting pretty hot. I assume the coil is the reason.

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