Auto mode change in buck-boost converter

A buck-boost converter having a buck mode of operation, a boost mode of operation, and a buck-boost mode of operation, comprising:

• an H-bridge including a first high-side transistor (HS1), a first low-side transistor (LS1), a second high-side transistor (HS2), and a second low-side transistor (LS1);
• a first driver configured to drive HS1 and LS1;
• a second driver configured to drive HS2 and LS2;
• a phase controller configured to produce phase control signals including a first driver control signal and a second driver control signal to control switching of HS1, LS1, HS2, and LS2, wherein the phase control signals are based on a mode of operation of the buck-boost converter;
• and
• an automatic mode selector configured to indicate to the phase controller the mode of operation of the buck-boost controller based upon a buck on-time TON_bk or a buck off-time TOFF_bk, a boost on-time TON_bst or boost off-time TOFF_bst, and a control configuration on-time TPI3, wherein TON_bk is an on-time during the buck mode of operation, TOFF_bk is the off-time during the buck mode operation, TON_bst is an on-time during the boost mode of operation, TOFF_bk is the off-time during the boost mode operation, and TPI3 is a time where a HS2 is on and a LS1 is on.