When the EN voltage goes High, the device starts loading the default values into the device registers. This action typically is done within 120 μs. After that, the internal soft-start circuitry controls the output voltage during start-up. This control avoids excessive inrush current and makes sure of a controlled output voltage ramp. This control also prevents unwanted voltage drops from high-impedance power sources or batteries. Finally, the PG signal has a delay up to 180 μs at start-up. Figure 7-5 shows a start-up sequence, where the EN pin is pulled up to VIN.

Figure 7-3 Start-Up Timing When EN is Pulled Up to VIN

Figure 7-4 shows a start-up sequence, where an external signal is connected to the EN pin.

Figure 7-4 Start-Up Timing When an External Signal is Connected to the EN Pin

The TPS62830x can start into a prebiased output if enabled for the first time. For a new prebiased operation, a power cycle is needed to disable the active output discharge. Figure 7-5 shows a start-up into a prebiased output voltage.

Figure 7-5 Start-Up into a Prebiased Output