Bootstrap voltage refresh for buck-boost converter

A system comprising:

• a gate driver buck converter comprising:
• a first high-side driver of a buck-boost converter, the first high-side driver powered between a first bootstrap voltage (VBST1) and a first output voltage of a first high-side switch driven by the first high-side driver;
• a first comparator to detect VBST1 drop below a threshold value with respect to the first output voltage when the buck-boost converter is in boost mode;
• and
• a first leakage control circuit to boost, using VBST1 as a voltage source, a second bootstrap voltage (VBST2) each cycle of buck mode in which an output of a second comparator is enabled;
• and
• a gate driver boost converter comprising:
• a second high-side driver of the buck-boost converter, the second high-side driver powered between a second bootstrap voltage (VBST2) and a second output voltage of a second high-side switch driven by the second high-side driver;
• the second comparator to detect VBST2 drop below the threshold value with respect to the second output voltage when the buck-boost converter is in buck mode;
• and
• a second leakage control circuit to boost, using VBST2 as a voltage source, VBST1 each cycle of boost mode in which an output of the first comparator is enabled.

A Universal Serial Bus (USB) Type-C controller comprising:

• a gate driver buck converter comprising:
• a first high-side driver configured for a buck-boost converter, the first high-side driver powered between a first bootstrap voltage (VBST1) of a first capacitor and a first output voltage of a first high-side switch of the buck-boost converter driven by the first high-side driver;
• a first comparator to detect VBST1 drop below a threshold value with respect to the first output voltage when the buck-boost converter is in boost mode;
• and
• a first low-side driver to drive a first low-side switch of the buck-boost converter;
• a gate driver boost converter comprising:
• a second high-side driver configured for the buck-boost converter, the second high-side driver powered between a second bootstrap voltage (VBST2) of a first capacitor and a second output voltage of a second high-side switch of the buck-boost converter driven by the second high-side driver;
• a second comparator to detect VBST2 drop below the threshold value with respect to the second output voltage when the buck-boost converter is in buck mode;
• and
• a second low-side driver to drive a second low-side switch of the buck-boost converter;
• and
• control logic coupled to the gate driver buck converter and the gate driver boost converter, wherein the control logic is to:
• detect an output enabled of one of the first comparator or the second comparator;
• and
• cause each of the first high-side driver, the first low-side driver, the second high-side driver, and the second low-side driver to toggle an output in response to the detection.