SLUAAM9 November   2022 TPS56C230

 

  1.   Abstract
  2.   Trademarks
  3. 1OOB Operation Principle
  4. 2Differences Between OOB and OVP
  5. 3OOB Operation Logic
    1. 3.1 Case 1: <OV Threshold, >OOB Threshold
    2. 3.2 Case2: >OV Threshold
  6. 4OOB Advantage in Load Transient
  7. 5Summary
  8. 6References

2 Differences Between OOB and OVP

OOB is an early non-fault overvoltage protection when output voltage is higher than OOB threshold. The OOB can help device fast recovery to normal operation. OVP is a fault protection when OVP threshold is triggered.

Taking TPS56C230 as an example, OOB threshold is 108% of output/reference voltage, while OVP threshold is 125% of output/reference voltage. When OOB is triggered, device is forced PWM controlled with maximum 16-cycle NOC triggered. PG will be high if output is lower than 115%. While, when OVP is triggered, the output will be discharged after a wait time of 120 µs and PG is low.

OOB operation only gains benefit in Eco-mode by forced PWM control with maximum 16-cycle NOC triggered. OOB operation is blanked in FCCM-mode. OVP is the protection no matter Eco-mode or FCCM-mode.

Table 2-1 summaries the differences between OOB and OVP based on TPS56C230.

Table 2-1 Differences Between OOB and OVP
OOBOVP
Triggered ThresholdFB>=108%*VrefFB>=125%*Vref
Triggered BehaviorForced PWM, maximum 16-cycle NOC triggered and PG High (FB<115%*Vref)Output discharge and PG Low
Fault BehaviorNon-faultFault
Operation ModeEco-modeBoth Eco-mode and FCCM-mode