SLUSES3B October 2023 – July 2024 UCC25660
PRODUCTION DATA
UCC25660x family burst mode algorithm minimizes audible noise, while improving light load efficiency. This is accomplished by maintaining the burst packet frequency to either be above the audible range (>25kHz) or to maintain the burst packet frequency to be at the very low end of the audible region (<400Hz). UCC25660x family employs two burst mode patterns; high-frequency (HF) pulse skip and low-frequency (LF) burst.
HF burst packet includes a fixed number of LO and HO pulses. The purpose of HF burst is to maintain the burst frequency higher than the audible frequency range. In the below image, the low-side gate is enabled on the 2nd valley of the switch node to begin delivery of the next HF burst packet.
LF burst includes a number of HF burst packets and a LF burst off period.
The number of HF burst packet is calculated to maintain the LF burst frequency within a frequency range. A set of target frequency range is internally provided, the default option is to regulate the LF burst around 200Hz.