LM5022: Could it do 15V->40V and -15V->-40V?

Hello Victoria,

Thanks for reaching out to us via e2e.

I understand that you have a symmetric +-15V supply and want to connect a symmetric +-40V load.

Is it necessary to distribute the load current across positive and negative supply?
Or could the symmetric +-40V output be connected to +15V input only?

Our Boost converters cannot be used to create a negative output voltage when used in a Boost topology.
You may use a Buck converter to convert e.g. +15V to -40V.

Or else you could use a flyback with two output windings on the transformer (driven by a single +15V input volage)
Or, if necessary two flyback converters with a single output each, which would be the most complex constellation.

Best regards
Harry

Hi Hofner,

Thanks for your detailed reply! Customer wants non-iso topo. 

That's a great idea both ±40V come from +15V! What's the difference between 2 solutions: 15->40, -15->-40 ; 15->±40？ I think both of 2 solution need one boost one buck. And 15V->-40V will need higher voltage buck, which will be more expensive. 

BR,

Victoria 

Hello Victoria,

We have not talked about the power level yet.
If it is low enough for a flyback solution and if generating both output voltages from the +15V rail is acceptable, why would the customer insist on a non-isolated solution?
You could use one single flyback controller and a transformer with two similar output windings to create the +-40V.
It does not need to be really/completely isolated. You can connect the GND potential from the input to the output side and you can use a simple feedback divider (no opto-coupler).
So, you basically have one converter which gives you the second output for a minimal adder (the additional winding of the transformer, a diode and some output capacitors).

Best regards
Harry