Base drive circuit design

AN2528

10/21

Figure 5.

DC current gain

Figure 6.

Dynamic collector-source saturation voltage

Note that, using the driving network shown in Figure 4, a quasi total recovery of energy to

drive the base is achieved. During the storage time the collector current comes out from the

base and is stored in the base capacitor. If the capacitor is small enough, the voltage across

To set the time duration of the base current spike, the following approximate formula is

useful:

Equation 12

Equation 13

chosen as a compromise between a damping effect and additional power dissipation on it.

t

peak

3R

B

•

C

B

•

=

C

B

t

peak

3R

B

•

-----------------

10nF

=

=