The propagation delay is defined as the time taken for changing input logic edges INHx and INLx (whichever changes first, if MCU dead time is added) to change the half-bridge output voltage (OUTx). Driver propagation delay (t_PD) and dead time (t_dead) are specified with a typical and maximum value, but not with a minimum value. This is because the propagation delay can be smaller than typical depending on the direction of current at the OUTx pin during synchronous switching. Driver propagation delay and dead time can be more than typical values due to slower internal turn-on of the high-side or low-side internal MOSFETs to avoid parasitic dV/dt coupling.

For more information and examples of how propagation delay and dead time differs for input PWM and output configurations, refer to Delay and Dead Time in Integrated MOSFET Drivers.

The dead time from the external microcontroller’s (MCU) PWM inputs (INHx, INLx) can be used as an extra precaution in addition to the DRV8317 internal shoot-through (cross conduction) protection. If the MCU dead time is less than the DRV8317 driver dead time, actual output (OUTx voltage) dead time will be decided by the DRV8317 dead time (t_DEAD). If the MCU dead time is larger than the driver dead time, actual output (OUTx voltage) dead time will be decided by the MCU dead time.

A summary of the DRV8317 delay times with respect to synchronous inputs INHx and INLx, OUTx current direction, and MCU dead time are listed in Table 9-2.