Under normal linear operation, the PWM on- and off-times are generated by the control loop. To improve noise immunity, the controller forces a minimum on-time whenever the PWM pins pulse high. The off-time for any phase is limited by a forced minimum off-time. Although TI smart power stage devices have built-in protection from glitches on the PWM pins also, this feature provides redundant protection against cross-conduction issues.

The controller also limits the time between sending pulses to any two adjacent phases. This is referred to as the leading-edge blanking time, t_BLANK. Increase the leading edge blanking time to prevent over-compensation (or "ring-back") by the controller during heavy load transient events. The minimum on-time, minimum off-time, and leading edge blanking time are programmable by the NONLINEAR_CONFIG PMBus command. Refer to the Technical Reference Manual for a register map of this command.

For multiphase designs, the maximum per-phase switching frequency during transients, is limited by the leading edge blanking time parameters as shown in Equation 35. The controller also forces a minimum-off-time per phase. The greater of the two limits the maximum frequency.

where

• N_Φ is the number of active phases
• t_BLANK is the leading edge blanking time in seconds