Mode-transition Architecture for Buck-boost converter

An integrated circuit (IC) controller for a Universal Serial Bus (USB) Type-C device, the IC controller comprising:

• a current sense amplifier (CSA) to measure an input current of a buck-boost converter;
• a slope compensation circuit coupled to an output of the CSA;
• and
• a controller coupled to the slope compensation circuit, wherein the controller is operable to:
• cause the slope compensation circuit to apply a first slope compensation to the input current in a first mode in which the buck-boost converter is operating in a discontinuous conduction mode (DCM), the first mode having a first duty cycle;
• detect a transition of the buck-boost converter from a first mode having a first duty cycle to a second mode having a second duty cycle that is less than the first duty cycle;
• and
• cause the slope compensation circuit to apply a second slope compensation to the input current, wherein the second slope compensation starts at a maximum offset of the first slope compensation.

A Universal Serial Bus (USB) device comprising:

• a buck-boost converter comprising an input terminal and an output terminal;
• a USB Type-C connector comprising a VBUS line;
• and
• an integrated circuit (IC) controller comprising:
• a VBUS terminal coupled to the VBUS line of the USB Type-C connector and the output terminal of the buck-boost converter;
• a current sense amplifier (CSA) to measure an input current at the input terminal;
• a slope compensation circuit coupled to an output of the CSA;
• and
• a controller coupled to the slope compensation circuit, wherein the controller is operable to:
• cause the slope compensation circuit to apply a first slope compensation to the input current in a first mode in which the buck-boost converter is operating in a discontinuous conduction mode (DCM), the first mode having a first duty cycle;
• detect a transition of the buck-boost converter from a first mode having a first duty cycle to a second mode having a second duty cycle that is less than the first duty cycle;
• and
• cause the slope compensation circuit to apply a second slope compensation to the input current, wherein the second slope compensation starts at a maximum offset of the first slope compensation.