SWCS142 July 2018 TPS650861
PRODUCTION DATA.
In addition to DVS, BUCK1–BUCK6 can decay down to a lower voltage when BUCKx_DECAY bit in BUCKxCTRL register is set to 1. Decay mode is only used in a downward direction of VID. The VR does not control slew rate. As both high-side and low-side FETs stop switching, the output voltage ramps down naturally, dictated by current drawn from the load and output filtering capacitance. When the VR is in the middle of decay down its PGOOD is masked until VOUT falls below the over-voltage (OV) threshold of the set VID value. Figure 5-7 shows two cases that differ from each other as to whether VOUT has reached the target voltage corresponding to a new VID when the VR is commanded to slew back up to a higher voltage. In case that VOUT has not decayed down below VID as denoted case 2, the VR will wait for VID to catch up, and then VOUT will start ramping up to keep up with the VID ramp.