US Patent 11682973 Advanced constant off-time control for four-switch buck-boost converter

An apparatus includes a first timer configured to determine a turn-off time of a first high-side switch of a buck-boost converter, and a second timer configured to determine a turn-off time of a second low-side switch of the buck-boost converter based on a comparison between a first signal and a second signal, the first signal being proportional to an input voltage of the buck-boost converter, and the second signal being generated based on a signal proportional to an output voltage of the buck-boost converter.