Nonlinear control loop for DC-DC converters

A nonlinear DC-DC converter, comprising:

• a power stage configured to provide a coil current and an output voltage based on a PWM signal;
• and
• a nonlinear controller configured to receive the output voltage and the coil current from the power stage, and configured to generate the PWM signal based on:
• setting the DC-DC converter to a first phase associated with both buck and boost modes of the converter when a clock signal is asserted;
• and
• selecting a second phase associated with the buck mode of the DC-DC converter, if a sliding function signal achieves a first predetermined relationship with respect to a buck threshold before a next clock signal is asserted, or
• selecting a third phase associated with the boost mode of the DC-DC converter, if the sliding function signal achieves a second predetermined relationship with respect to a boost threshold before a next clock signal is asserted,
• wherein the sliding function signal is generated by a sliding function of the converter, the sliding function comprising a summation of feedback variables from the power stage,
• wherein the feedback variables comprise the output voltage, a coil current, and a processed value that is a function of the output voltage.

A nonlinear DC-DC converter, comprising:

• a power stage configured to provide a coil current and an output voltage based on a PWM signal;
• and
• a nonlinear controller configured to receive the output voltage and the coil current from the power stage, and configured to generate the PWM signal based on:
• setting the DC-DC converter to a first phase associated with both buck and boost modes of the converter when a clock signal is asserted;
• and
• selecting a second phase associated with the buck mode of the DC-DC converter, if a sliding function signal achieves a first predetermined relationship with respect to a buck threshold before a next clock signal is asserted, or
• selecting a third phase associated with the boost mode of the DC-DC converter, if the sliding function signal achieves a second predetermined relationship with respect to a boost threshold before a next clock signal is asserted,
• wherein the sliding function signal functions in accordance with a sliding function represented by:
• S(x)=(Vo−Vref)+α2iL+α3∫(Vo−Vref)dt
• where:
• S(x)=the sliding function,
• Vo=the output voltage from the power stage,
• Vref=a reference voltage,
• α2=a first multiplier coefficient,
• α3=a second multiplier coefficient,
• iL=the coil current from the power stage.

A nonlinear DC-DC converter, comprising:

• a measuring component configured and operable to measure a coil current and an output voltage during operation of the DC-DC converter;
• a first summing component operable to obtain the difference between the output voltage and a reference voltage;
• a first amplifier operable to scale the coil current, thereby providing a scaled coil current;
• a second amplifier operable to scale an integral of the difference between the output voltage and the reference voltage thereby providing an integral product;
• a second summing component operable to sum the difference between the output voltage and the reference voltage, the scaled coil current, and the integral product in order to provide a sliding function used by the DC-DC converter.