Buck Converter efficiency

[eegchen]

buck converter efficiency

hi,

Buck converter example.
if we increase the frequency, delta I will decrease, so the delta V will.

But why the efficiency is decreasing?

best
gang

 

[dick_freebird]

improving buck converter efficiency

Switching losses

 

[eegchen]

buck efficiency

thanks.

why is switch loss increasing in high frequency?

 

[lemonhead]

efficiency buck converter

Power elements will need more driving current since they need to be turned on faster (Q = I * t), since t goes down cause f goes up, I needs to increase, Q is a "constant" dependent on the power device.

 

[dick_freebird]

buck converter efficiency

The power MOSFET gate charge is shuttled once a cycle,
ditto the loss-slug as the FET transitions through the
dissipative region (zero voltage, zero current schemes
are for this). More cycles per second, more joules per
second (i.e. loss watts).