An adjustable gate-drive current control to the MOSFETs of half-bridges is implemented to achieve the slew rate control. The MOSFET VDS slew rates are a critical factor for optimizing radiated emissions, energy and duration of diode recovery spikes, and switching voltage transients related to parasitics. These slew rates are predominantly determined by the rate of gate charge to internal MOSFETs as shown in Figure 8-16.

Figure 8-16 Slew Rate Circuit Implementation

The slew rate can be adjusted by the SLEW pin in hardware variant or by using the SLEW bits in SPI variant. Four slew rate settings are available : 25-V/µs, 50-V/µs, 125-V/µs or 200-V/µs. The slew rate is calculated by the rise time and fall time of the voltage on OUTx pin as shown in Figure 8-17.

Figure 8-17 Slew Rate Timings