Voltage regulator control systems and methods

1. A buck-boost control system configured to control a buck-boost converter to operate in either a buck mode or a boost mode, the buck-boost control system comprising:

compensator circuitry configured to:

determine a target current based on a difference between a target voltage and a regulated output voltage of the buck-boost converter;

determine a tolerance current, wherein the tolerance current is offset from the target current by a predetermined offset and, with the target current, defines a range of expected coil current for a first operating mode; and

based on the difference between the target voltage and the regulated output voltage, generate a charge control signal or a discharge control signal for the buck-boost converter for the coil current to reach the target current; and

mode control circuitry configured to switch the buck-boost converter from the first operating mode to a second operating mode when the coil current reaches the tolerance current.

2. The buck-boost control system of claim 1 , wherein the mode control circuitry comprises a tolerance current sensor configured to:

receive the coil current;

compare the coil current to the tolerance current; and

generate a tolerance hit signal when the coil current is equivalent to the tolerance current.

3. The buck-boost control system of claim 1 wherein the mode control circuitry comprises a mode select circuitry configured to, in response to the coil current reaching the tolerance current, generate a buck or boost mode selection signal to control buck-boost switches in the buck-boost converter based on a selected one of a buck mode switching scheme or a boost mode switching scheme.

4. The buck-boost control system of claim 3 , wherein the mode select circuitry is configured to generate a peak or valley switching mode selection signal that selects either a peak switching mode or a valley switching mode for the buck-boost switches based on a relative duration of a variable phase of the coil current as compared to a duration of a fixed phase of the coil current.

5. The buck-boost control system of claim 4 , further comprising mapper circuitry configured to translate the charge control signal and the discharge control signal into control signals for the buck-boost switches based on the operating mode and the selected peak or valley switching mode.

6. The buck-boost control system of claim 1 , further comprising:

a voltage sensor configured to:

compare the regulated output voltage with a supply voltage; and

generate a difference signal indicative of a difference between the regulated output voltage and the supply voltage, and

wherein the mode control circuitry is configured to refrain from switching the buck-boost converter to the second operating mode when the difference signal exceeds a switching threshold.

7. A method configured to control a buck-boost converter to operate in either a buck mode or a boost mode, the method comprising:

determining a target current based on a difference between a target voltage and a regulated output voltage of the buck-boost converter;

determining a tolerance current, wherein the tolerance current is offset from the target current by a predetermined offset and, with the target current, defines a range of expected coil current for a first operating mode; and

switching the buck-boost converter from the first operating mode to a second operating mode when the coil current reaches the tolerance current.

8. The method of claim 7 , further comprising generating a mode selection signal to control buck-boost switches in the buck-boost converter based on a selected one of a buck mode switching scheme or a boost mode switching scheme in response to the coil current reaching the tolerance current.

9. The method of claim 7 , further comprising generating a peak or valley switching mode selection that selects either a peak switching mode or a valley switching mode for buck-boost switches in the buck-boost converter based on a relative duration of a variable phase of the coil current as compared to a duration of a fixed phase of the coil current.

10. The method of claim 7 , further comprising:

translating a charge control signal into control signals for buck-boost switches in the buck-boost converter based on the first operating mode; and

translating a discharge control signal into control signals for the buck-boost switches based on the first operating mode.

11. The method of claim 7 , further comprising:

comparing the regulated output voltage with a supply voltage; and

generating a difference signal indicative of a difference between the regulated output voltage and the supply voltage;

refraining from switching the buck-boost converter to the second operating mode when the difference signal exceeds a switching threshold.

12. A buck-boost system, comprising:

a buck-boost converter configured to operate in either a buck mode or a boost mode; and

a buck-boost control system, comprising:

compensator circuitry configured to:

determine a target current based on a difference between a target voltage and a regulated output voltage of the buck-boost converter;

determine a tolerance current, wherein the tolerance current is offset from the target current by a predetermined offset and, with the target current, defines a range of expected coil current for a first operating mode; and

based on the difference between the target voltage and the regulated output voltage, generate a charge control signal or a discharge control signal for the buck-boost converter for the coil current to reach the target current; and

mode control circuitry configured to switch the buck-boost converter from the first operating mode to a second operating mode when the coil current reaches the tolerance current.

13. The buck-boost system of claim 12 , wherein the mode control circuitry comprises a tolerance current sensor configured to:

receive the coil current;

compare the coil current to the tolerance current; and

generate a tolerance hit signal when the coil current is equivalent to the tolerance current.

14. The buck-boost system of claim 12 , wherein the mode control circuitry comprises a mode select circuitry configured to, in response to the coil current reaching the tolerance current, generate a buck or boost mode selection signal to control buck-boost switches in the buck-boost converter based on a selected one of a buck mode switching scheme or a boost mode switching scheme.

15. The buck-boost system of claim 14 , wherein the mode select circuitry is configured to generate a peak or valley switching mode selection signal that selects either a peak switching mode or a valley switching mode for the buck-boost switches based on a relative duration of a variable phase of the coil current as compared to a duration of a fixed phase of the coil current.

16. The buck-boost system of claim 15 , further comprising mapper circuitry configured to translate the charge control signal and the discharge control signal into control signals for the buck-boost switches based on the operating mode and the selected peak or valley switching mode.

17. The buck-boost system of claim 12 , further comprising:

a voltage sensor configured to:

compare the regulated output voltage with a supply voltage; and

generate a difference signal indicative of a difference between the regulated output voltage and the supply voltage, and

wherein the mode control circuitry is configured to refrain from switching the buck-boost converter to the second operating mode when the difference signal exceeds a switching threshold.