jrz126
Active Member
I'm working on a DC-DC buck converter for work (so I cant post a schematic) and I had some questions about calculating the losses.
Its a 20-80V input and an isolated 12V,5A output (60W). It will typically be running at 74VDC in. When starting the engine, the voltage will drop to 25-35V while cranking.
When running at 80V in, 5A out, I am putting in 133W and getting 65W out. I'm losing 68W somewhere, and I'd like to figure out why.
First off, what is the typical efficiency of a buck converter? It seems to me that 50% is pretty low, concidering my boss was talking about reaching 90%, but we could be wrong.
It is more efficent at lower input voltages too, at 35Vin 5A out, I'm putting in 87W and getting 65W out. thats about 73%.
Also, how significant are the switching losses? Its currently switching at 225kHz.
Finally, is there an easy way to calculate the power lost in the fets and diode?
Its a 20-80V input and an isolated 12V,5A output (60W). It will typically be running at 74VDC in. When starting the engine, the voltage will drop to 25-35V while cranking.
When running at 80V in, 5A out, I am putting in 133W and getting 65W out. I'm losing 68W somewhere, and I'd like to figure out why.
First off, what is the typical efficiency of a buck converter? It seems to me that 50% is pretty low, concidering my boss was talking about reaching 90%, but we could be wrong.
It is more efficent at lower input voltages too, at 35Vin 5A out, I'm putting in 87W and getting 65W out. thats about 73%.
Also, how significant are the switching losses? Its currently switching at 225kHz.
Finally, is there an easy way to calculate the power lost in the fets and diode?