ZHCSB48B May 2013 – January 2019 TPS55330
PRODUCTION DATA.
The TPS55330 provides cycle-by-cycle over-current protection that turns off the power switch once the inductor current reaches the over-current limit threshold. The PWM circuitry resets itself at the beginning of the next switch cycle. During an over-current 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 8 shows the non-foldback frequency with an 80kΩ timing resistor and the corresponding foldback frequency. The switching frequency does not return to normal until the over-current condition is removed and the FB voltage increases above 0.9 V. The frequency foldback feature is disabled during soft-start.