ZHCSCL9A July 2014 – September 2021 TPS55340-EP
PRODUCTION DATA
The TPS55340-EP provides cycle-by-cycle overcurrent protection that turns off the power switch when 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 droop 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 7-7 shows the non-foldback 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.