Description

AN4407

12/19

DocID025572 Rev 1

Figure 16. Impact of the parasitic effect during the turn-on operation

In this case, the real voltage across the gate and source pin becomes lower than the set

positive threshold necessary to fully turn-on the device because the extravoltage generates

a negative contribution. This aspect is confirmed by the waveform comparisons between the

standard 3-pin solution and the 4-pin alternative in Figure 17 and Figure 18.

1.3

Comparison analysis between 3-pin and 4-pin devices in

efficiency and temperature; turn-on and turn-off energy at

different output powers

The effect of the analyzed solution is the reduction of the overall power loss in the transistor,

which translates into lower operating temperatures and potentially more reliable and longer

lasting power systems. In the previous sections, we have seen the effects of the parasitic

inductance on the single switching instant. In order to understand the total effect on the

whole system, a deeper analysis has been performed on the system at different output

power levels for thermal and energy saving aspects.

The following graphs give the comparative switching energy data for different power levels,

using both the 3-pin and 4-pin solutions.

GIPG271120131048FSR