When current is going out of the phase, propagation delay and driver dead time is determined by whether INHx is rising or falling.

In Figure 2-3, when INLx goes low (green), current is momentarily pulled through the body diode (purple) of the low-side (LS) FET to continue sourcing current out of OUTx (red). The duration the body diode of the LS FET conducts is the dead time. When the body diode stops conducting (dead time is over), the high-side (HS) FET begins to conduct (blue).

Figure 2-3 Current Switching With INHx Rising, INLx Falling, and Current Out of OUTx

Note how the current direction is opposite internally between the body diode of the LS FET and the conduction path of the HS FET. To reduce a large change of current, the device waits until the LS body diode fully conducts and then turns on the HS FET, which lengthens propagation delay to the typical or maximum value as specified in the data sheet.

The example waveform in Figure 2-4 shows INHx rising and INLx falling and current is going out of the phase (positive current in green) for the DRV8316 with a slew rate of 200 V/µs and sinusoidal commutation. The dead time and propagation delay typical values in the DRV8316 data sheet specifications are 500 ns and 700 ns, respectively, with maximums included as well. Note how internal dead time is included into the propagation delay.

Figure 2-4 Waveforms of Dead Time and Propagation Delay When INHx is Rising, INLx is Falling, and Current Flows Out of OUTx