• Resolved

# LM5022: LM5022 PMP9446 Reference Design Question

Dear Team,

My customer is looking for Vin=12V and Vo=54V, Io=0.5A isolated circuit.

So I suggest PMP9446:

But the customer thinks the current transformer's cost is too high.

Can they get rid of this transformer and use a smaller resistor? ( Or you have another reference design)

I check this transformer's turn ratio is 100:1.

This transformer's only purpose is to reduce Rsense loss right?

If they want to remove this transformer, what is the resistor value they should use for Rsense?

BR

Kevin

• Hi Kevin,

The engineer supporting this device is out of office. He will reply you next week.

Best Regards

Jasper Li
Boost Converter Solution

• Hi Kevin,

If the customer wants to remove the transformer that is no problem. The way to calculate this resistor is to divide the value of R8 by the turns ratio of the transformer. The the calculation is 3Ohm/100. This provides a current sense resistor value of 30mOhm. The reason for place the current sense transformer is to reduce the power losses of the current sense circuit.

Thanks,

Garrett