How is energy transferred in the voltage drop in a diode?

[swbluto]

If a diode causes a forward voltage drop when running current, then wouldn't that indicate power is lost through the diode and that it subsequently heats up(P=IV)? If, in the Schottky diode, they suggest that this voltage drop corresponds to the "band gap" that electrons have to cross, how is energy transferred from this "quantum leap" across the band-gap(as is projected by the part heating up)?

 

[ZapPat]

If a diode causes a forward voltage drop when running current, then wouldn't that indicate power is lost through the diode and that it subsequently heats up(P=IV)? If, in the Schottky diode, they suggest that this voltage drop corresponds to the "band gap" that electrons have to cross, how is energy transferred from this "quantum leap" across the band-gap(as is projected by the part heating up)?

Yes, a diode dissipates heat equivalent to it's instantaneous V * I drop as would any material in the universe. Maybe think of the diode as a highly non-linear resistance to work out it's power dissipation (check out their typical V vs I graphs in the datasheets for this).

I wish I could explain how a diode really works in terms of quantum physics, but I limit myself to practical knowledge about the way electronic parts work. I do know that schottkies switch states faster than conventionnal diodes and exhibit a lower Vdrop, but also have higher leakage currents.

 

[swbluto]

Maybe think of the diode as a highly non-linear resistance to work out it's power dissipation (check out their typical V vs I graphs in the datasheets for this).

Man, diodes don't seem easy to calculate when integrating in the circuit due to this non-linear behavior(is there an easier way?). The voltage drop is determined by the current through the diode, which itself is determined by the voltage "left over" and 'total resistance' afterwards and this reasoning sounds kind of recursive. It doesn't seem as easy to control what the current will be than a good old resistor over an arbitrary range of currents(Instead of, like, making sure to stay within a range of limits for a given diode so it's "intuitively predictable").

 

[fechter]

Here's an actual graph for a 48CTQ060 diode.

Note the temperature has a large effect on voltage drop.

 

[swbluto]

Here's an actual graph for a 48CTQ060 diode.

Note the temperature has a large effect on voltage drop.

On the suggesting that temperature effects the voltage drop, I took a quick guess as to which direction. Since higher temperatures cause a particle to have greater energy, it'd be "more spread out"(probabilistically) according to the shrodinger wave equation and so the effective distance of the band-gap would be reduced causing a reduction in the voltage drop.

The voltage drops seems decreased with increased temperature! Don't know about the hypothesis.