Figure 3-4 shows the logic of OOB behavior when the output voltage is larger than OV threshold (125%). When the output voltage is higher than 108% of target output value, the OOB function is activated, like Case1, the OOB_Output signal is triggered. After maximum 16-cycle NOC triggered, output voltage is still higher than target value, OOB_Output signal ends.

When Vout is increased to 125% of target value, the OV signal is pulled high, after a OVP deglitch time, the OV_Latch signal is on, the device enters OVP protection to discharge output by internal discharge resistor. Until the Vout is lower than 125%, OVP signal and OVP_latch signal is removed, OOB function works again.

Figure 3-5 shows the bench test waveform for TPS56C230, test conditions are 12Vin, 1.2Vout, Eco mode, force external 2V to Vout. In the zoom-in waveform of voltage rising Figure 3-6, 16-cycle NOC is triggered. Then, PG is pulled low due to output voltage higher than PGood Fault_Rising (115%). After external force power is removed, output is discharged as shown in Figure 3-7. Several cycles of NOC triggered PWM drive output voltage back to normal. After deglitch time of 64us, PG is back to high.