CPC H02M 3/1582 (2013.01) [H02M 1/08 (2013.01); H02M 1/0009 (2021.05)] | 18 Claims |
1. An apparatus comprising:
a buck converter portion of a buck-boost converter configured to operate under a constant on-time control scheme, wherein an on-time of a high-side switch of the buck converter portion is determined by a buck on-time timer, wherein the buck on-time timer is configured to determine a turn-off edge of a gate drive signal applied to the high-side switch of the buck converter portion of the buck-boost converter, wherein a comparator of the buck on-time timer comprises a first input configured to receive a first ramp, and a second input configured to receive a first threshold voltage, and wherein the first ramp is generated by a first current source having a current level proportional to an input voltage of the buck-boost converter, and the first threshold voltage is proportional to an output voltage of the buck-boost converter; and
a boost converter portion of the buck-boost converter configured to operate under a constant off-time control scheme, wherein an off-time of a low-side switch of the boost converter portion is determined by a boost off-time timer.
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