AN3152

Measurements on the BOOST stage

Doc ID 17056 Rev 1

11/17

Figure 8.

Table 1 summarizes the results of the measurements performed by varying the R

resistor value. Please note that we use a gate resistor just for turn-on. For turn-off, a simple

diode is used, connected in parallel to the gate resistor. It should be highlighted that lower

time this means higher spike voltage and current during commutation. By using a lower gate

resistor you get better efficiency, but also higher peak recovery current and higher di/dt. This

could be a problem for EMI irradiation and reliability, so an 8.2

Ω and 1400 A di/dt should be

a good compromise.

Although designers strive to keep all board parasitic influences to a minimum, they cannot

be eliminated completely due to the physical limitations related to component dimensions.

The copper tracks on the board must be as short as possible, but in any case must be long

Table 1.

Efficiency @

3.9

2200

26.6

98.52

5.6

2000

24.7

98.40

8.2

1400

20.6

98.27

15

800

17.4

98.14