Multi-phase switching regulator and control circuit and control method thereof

Patent metadata

Field	Value
Publication number	US-10097092-B1
Application number	US-201815911125-A
Country	US
Kind code	B1
Filing date	Mar 4, 2018
Priority date	Jul 21, 2017
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A multi-phase switching regulator includes: a plurality of power stages, a plurality of pulse width modulation (PWM) controllers and a ramp signal setting circuit. The PWM controllers generate corresponding PWM signals for controlling corresponding power stages respectively according to an error signal related to an output voltage and a plurality of ramp signals corresponding to corresponding power stages respectively. The ramp signal setting circuit adjusts the ramp signal of the phase that is to be enabled or disabled according to the phase adjustment signal. Under a phase-cut operation, the ramp signal setting circuit causes a basis level of the ramp signal corresponding to the phase to be disabled to gradually change, thereby decreasing a duty ratio of the PWM signal corresponding to the phase to be disabled.

First claim

What is claimed is:

1. A multi-phase switching regulator, comprising:
a plurality of power stages configured to operably convert an input voltage to an output voltage, wherein each power stage is one phase; wherein at least one of the power stages is configured to be enabled (phase-add) or disabled (phase-cut) according to a phase adjustment signal; and, wherein each power stage controls at least one power transistor in the corresponding power stage according to a corresponding pulse width modulation (PWM) signal, so that the plurality of power stages together convert the input voltage to the output voltage, while each phase generates a respective phase output current;
a plurality of PWM controllers, which are configured to operably generate the PWM signals for controlling the corresponding power stages according to an error signal which is related to an output voltage and a plurality of ramp signals corresponding to the plurality of PWM controller; and
a ramp signal setting circuit, which is configured to operably adjust the ramp signal of the phase that is to be enabled or disabled according to the phase adjustment signal; wherein, under a phase-cut operation, the ramp signal setting circuit causes the ramp signal of the phase to be disabled to gradually change, such that a duty ratio of the PWM signal of the phase to be disabled gradually decreases.

2. The multi-phase switching regulator of claim 1 , wherein under a phase-cut operation in which two or more phases are cut, the phases to be disabled are turned OFF sequentially and are not turned OFF at the same time.

3. The multi-phase switching regulator of claim 2 , wherein under a phase-cut operation in which two or more phases are cut, the ramp signal corresponding to one phase to be disabled is first caused to gradually change, and thereafter, the ramp signal corresponding to another phase to be disabled is caused to gradually change.

4. The multi-phase switching regulator of claim 1 , wherein the ramp signal setting circuit includes:
an adjustable offset voltage source, which is configured to operably adjust an offset thereof according to the phase adjustment signal; and
an adder circuit, which is configured to add the offset onto an initial ramp signal corresponding to the phase to be enabled or disabled, so as to generate the ramp signal corresponding to the phase to be enabled or disabled, whereby a basis level of the ramp signal is changed.

5. The multi-phase switching regulator of claim 4 , wherein the initial ramp signal corresponding to each phase is generated based upon a clock circuit or the corresponding phase output current.

6. The multi-phase switching regulator of claim 1 , wherein when it is under a phase-cut operation, in at least one of the power stages that is not to be disabled, a basis level of the ramp signal remains unchanged or is caused to gradually decrease with a constant or variable slope.

7. The multi-phase switching regulator of claim 1 , wherein when it is under a phase-add operation, the ramp signal setting circuit causes the ramp signal of the phase to be enabled to gradually change, such that a duty ratio of the PWM signal of the phase to be enabled gradually increases.

8. The multi-phase switching regulator of claim 7 , wherein under a phase-add operation in which two or more phases are added, the ramp signal corresponding to one phase to be enabled is first caused to gradually change, and thereafter, the ramp signal corresponding to another phase to be enabled is caused to gradually change.

9. The multi-phase switching regulator of claim 1 , wherein when it is under a phase-add operation, in at least one of the power stages that is already active, a basis level of the ramp signal remains unchanged or is caused to gradually increase with a constant or variable slope.

10. The multi-phase switching regulator of claim 1 , wherein a slope of a basis level of the ramp signal corresponding to the phase to be disabled is adjustable.

11. The multi-phase switching regulator of claim 7 , wherein a slope of a basis level of the ramp signal corresponding to the phase to be enabled is adjustable.

12. A control circuit of a multi-phase switching regulator, the multi-phase switching regulator comprising: a plurality of power stages configured to operably convert an input voltage to an output voltage, wherein each power stage is one phase; wherein at least one of the power stages is configured to be enabled (phase-add) or disabled (phase-cut) according to a phase adjustment signal; and, wherein each power stage controls at least one power transistor in the corresponding power stage according to a corresponding pulse width modulation (PWM) signal, so that the plurality of power stages together convert the input voltage to the output voltage, while each phase generates a respective phase output current; the control circuit comprising:
a plurality of PWM controllers, which are configured to operably generate the PWM signals for controlling the corresponding power stages according to an error signal which is related to an output voltage and a plurality of ramp signals corresponding to the plurality of PWM controller; and
a ramp signal setting circuit, which is configured to operably adjust the ramp signal of the phase that is to be enabled or disabled according to the phase adjustment signal; wherein, under a phase-cut operation, the ramp signal setting circuit causes the ramp signal of the phase to be disabled to gradually change, such that a duty ratio of the PWM signal of the phase to be disabled gradually decreases.

13. The control circuit of a multi-phase switching regulator of claim 12 , wherein under a phase-cut operation in which two or more phases are cut, the phases to be disabled are turned OFF sequentially and are not turned OFF at the same time.

14. The control circuit of a multi-phase switching regulator of claim 13 , wherein under a phase-cut operation in which two or more phases are cut, the ramp signal corresponding to one phase to be disabled is first caused to gradually change, and thereafter, the ramp signal corresponding to another phase to be disabled is caused to gradually change.

15. The control circuit of a multi-phase switching regulator of claim 12 , wherein the ramp signal setting circuit includes:
an adjustable offset voltage source, which is configured to operably adjust an offset thereof according to the phase adjustment signal; and
an adder circuit, which is configured to add the offset onto an initial ramp signal corresponding to the phase to be enabled or disabled, so as to generate the ramp signal corresponding to the phase to be enabled or disabled, whereby a basis level of the ramp signal is changed.

16. The control circuit of a multi-phase switching regulator of claim 15 , wherein the initial ramp signal corresponding to each phase is generated based upon a clock circuit or the corresponding phase output current.

17. The control circuit of a multi-phase switching regulator of claim 12 , wherein when it is under a phase-cut operation, in at least one of the power stages that is not to be disabled, a basis level of the ramp signal remains unchanged or is caused to gradually decrease with a constant or variable slope.

18. The control circuit of a multi-phase switching regulator of claim 12 , wherein when it is under a phase-add operation, the ramp signal setting circuit causes the ramp signal of the phase to be enabled to gradually change, such that a duty ratio of the PWM signal of the phase to be enabled gradually increases.

19. The contr

Assignees

• Richtek Technology Corp

Inventors

• Ho Jyun-Che
• Chen Yu-Chang
• Wang Jo-Yu
• Lee Yi-Wei
• Chen Isaac Y

Classifications

• H02M3/1584 Primary

  with a plurality of power processing stages connected in parallel · CPC title

• H02M2003/1586

  Electricity · mapped topic

• H02M3/1586

  switched with a phase shift, i.e. interleaved · CPC title