Abstract:
As more features are being integrated into mobile platforms, the demand for
long battery life during standby mode has been increasing. Light load efficiency
becomes one of essential features in today's DC-DC converter. The most effective
method to improve light load efficiency is to operate the DC-DC converter under
pulse-frequency-modulation (PFM) to reduce the switching loss. However, using such
architecture could also have the switching frequency get into the band of interest, and
requires large off-chip components to filter unwanted signal. In this research, an
efficient PFM with frequency limiting is designed. It has similar efficiency profile as
the single pulse PFM by utilizing width switching and frequency control techniques. It
operates in between 1~2 MHz switching frequency under light load condition.
