Control of four-switch, single inductor, non-inverting buck-boost converters

A system, comprising:

• a voltage source;
• and
• a power converter configured to receive input from the voltage source at a voltage input of the power converter, the power converter comprising:
• a buck leg circuit connected between the voltage input of the power converter and ground;
• a boost leg circuit connected between a voltage output of the power converter and ground;
• an inductor connected between the buck leg circuit and the boost leg circuit;
• an error amplifier configured to compare the voltage output of the power converter against a reference voltage to yield a feedback signal;
• and
• a control circuit configured to:
• generate a reference buck ramp configured to be compared against the feedback signal to determine whether to operate the buck leg circuit in buck mode;
• and
• generate a reference boost ramp by superposing a variable boost ramp portion on to the reference buck ramp, the reference boost ramp configured to be compared against the feedback signal to determine whether to operate the boost leg circuit in boost mode.

A method of converting power, comprising:

• receiving input from a voltage source at a voltage input of a power converter;
• with a buck leg circuit connected between the voltage input of the power converter and ground, operating the power converter in buck mode;
• with a boost leg circuit connected between a voltage output of the power converter and ground, operating the power converter in boost mode;
• connecting an inductor between the buck leg circuit and the boost leg circuit;
• with an error amplifier, comparing the voltage output of the power converter against a reference voltage to yield a feedback signal;
• and
• with a control circuit:
• generating a reference buck ramp configured to be compared against the feedback signal to determine whether to operate the buck leg circuit in buck mode;
• and
• generating a reference boost ramp by superposing a variable boost ramp portion on to the reference buck ramp, the reference boost ramp configured to be compared against the feedback signal to determine whether to operate the boost leg circuit in boost mode.