This deadtime should allow for the turn on and turn off time of the transistors, especially when slowing them down with gate

resistors. This situation will be present when switching motor direction, or when sophisticated timing schemes are used for servo

systems such as locked antiphase PWM'ing for high bandwidth operation.

APPLICATION NOTES

BRIDGE DRIVE CONSIDERATIONS

It is important that the logic used to turn ON and OFF the various transistors allow sufficient "dead time" between a high side

transistor and its low side transistor to make sure that at no time are they both ON. When they are, this is called "shoot-through",

and it places a momentary short across the power supply. This overly stresses the transistors and causes excessive noise as well.

See Figure 1.

3

Figure 1

Rev. - 8/01