DocID025572 Rev 1

9/19

AN4407

Description

19

Equation 3

The second method involves estimating the value of Ls using a simulation tool. A HFSS

Electromagnetic simulator tool gave the following results after factoring in the data regarding

the length and section of a wire bonding:

Figure 10. Wires bonding for the HFSS tool

In this case, the simulations return a value of 8.9 nH.

This data is confirmed by the measurements performed on the bench. Figure 11 shows the

computation of the parasitic inductance at around 4 nH because, in this case, the source

path is realized using two wires in parallel.

Figure 11. Wires bonding for the HFSS tool

Given this data, we can proceed with the study of its impact on the system.

Before looking at the influence of the parasitic inductance on the switching commutations,

consider a commutation on the inductive load: the influence of the inductive parasitic effect

is associated with the slope of the current during the switching phase as well as the time of

the commutation.

nH

2

,

9

10

×

200

×

)

1

d

l

4

(ln

l

=

L

GIPG261120131457FSR