ZHCS901E May 2012 – September 2021 TPS55340
PRODUCTION DATA
The TPS55340 provides cycle-by-cycle overcurrent protection that turns off the power switch once the inductor current reaches the overcurrent limit threshold. The PWM circuitry resets itself at the beginning of the next switch cycle. During an overcurrent event, the output voltage begins to drop as a function of the load on the output. When the FB voltage through the feedback resistors drops lower than 0.9 V, the switching frequency is automatically reduced to 1/4 of the normal value. Figure 6-8 shows the nonfoldback frequency with an 80-k? timing resistor and the corresponding foldback frequency. The switching frequency does not return to normal until the overcurrent condition is removed and the FB voltage increases above 0.9 V. The frequency foldback feature is disabled during soft-start.