Propagation delay reduction (PDR) control has two primary functions, a pre-charge propagation delay reduction function and a post-charge acceleration function. The PDR control function is only available in the Half-Bridge Control PWM mode and on SPI device variants.
The propagation delay reduction (PDR) primary goal is to reduce the turn on and turn off delay of the external MOSFET by using dynamic pre-charge and pre-discharge currents before the MOSFET QGD miller region. This can enable the driver to achieve higher and lower duty cycle resolution while still meeting difficult EMI requirements.
The post-charge acceleration function allows for the MOSFET to more quickly reach its low resistive or off state to minimize power losses by increasing the post-charge and post-discharge gate current after the MOSFET QGD miller region.
An example of the MOSFET pre-charge and post-charge current profiles are shown in Figure 8-13. The same control loop is repeated for the MOSFET pre-discharge and post-discharge as shown in Figure 8-14. Several examples of the full control loop in different PWM and motor cases are shown in Figure 8-15 and Figure 8-16.