Buck-boost converter for an audio amplifier with multiple operations modes

Patent metadata

Field	Value
Publication number	US-10116215-B2
Application number	US-201514612889-A
Country	US
Kind code	B2
Filing date	Feb 3, 2015
Priority date	Feb 4, 2014
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A switching power stage for producing an output voltage to a load may include a power converter and a controller. The power converter may include a power inductor and plurality of switches arranged to sequentially operate in a plurality of switch configurations. The controller may be configured to, based on a measured parameter associated with the switching power stage, select a selected operational mode of the power converter from a plurality of operational modes, and sequentially apply switch configurations from the plurality of switch configurations to selectively activate or deactivate each of the plurality of switches in order to transfer electrical energy from an input source of the power converter to the load in accordance with the selected operational mode.

First claim

What is claimed is:

1. A switching power stage for producing an output voltage to a load, comprising:
a power converter comprising:
a power inductor;
a plurality of switches arranged to sequentially operate in a plurality of switch configurations;
an output for producing the output voltage as an amplified version of a time-varying input signal, the output comprising a first output terminal and a second output terminal, wherein a first switch of the plurality of switches is coupled between the power inductor and the first output terminal and a second switch of the plurality of switches is coupled between the power inductor and the second output terminal; and

at least one of: a first capacitor coupled to the first output terminal and a second capacitor coupled to the second output terminal; and
a controller configured to:
based on a measured parameter associated with the switching power stage and indicative of the time-varying input signal, select a selected operational mode of the power converter from a plurality of operational modes as a function of the time-varying input signal; and
sequentially apply switch configurations from the plurality of switch configurations to selectively activate or deactivate each of the plurality of switches in order to transfer electrical energy from a substantially constant input source of the power converter to the load in accordance with the selected operational mode.

2. The switching power stage of claim 1 , wherein the measured parameter is an error between a signal indicative of the output voltage and the time-varying input signal.

3. The switching power stage of claim 2 , wherein the time-varying input signal is an audio signal.

4. The switching power stage of claim 2 , wherein the controller further implements a loop filter to generate a quantized output indicative of the selected operational mode in order to minimize the error.

5. The switching power stage of claim 1 , wherein the load is an acoustic transducer.

6. The switching power stage of claim 1 , wherein the plurality of switch configurations comprises at least one charging configuration wherein the power converter charges a first terminal of the load through the power inductor during a charging phase of the power converter.

7. The switching power stage of claim 6 , wherein the plurality of operational modes comprises:
at least one buck configuration wherein charge is transferred from the first terminal of the load to a second terminal of the load during a transfer phase of the power converter and a switch between the input source and the power inductor is deactivated; and
at least one boost configuration wherein charge is transferred from the first terminal of the load to the second terminal of the load during the transfer phase of the power converter and the switch between the input source and the power inductor is activated;
wherein the switch configuration applied during a transfer phase of the power converter is selected from the at least one buck configuration and the at least one boost configuration based on the selected operational mode.

8. The switching power stage of claim 7 , wherein a duration of the transfer phase is based on the selected operational mode.

9. The switching power stage of claim 1 , wherein the measured parameter is a parameter indicative of the output voltage.

10. The switching power stage of claim 1 , wherein the measured parameter is an input signal indicative of a target voltage for the output voltage.

11. The switching power stage of claim 1 , wherein at least one of the plurality of operational modes comprises a converter mode.

12. The switching power stage of claim 11 , wherein the converter mode comprises one of a boost mode, a buck mode, and a buck-boost mode.

13. A method for producing an output voltage to a load, comprising in a power converter comprising a power inductor, a plurality of switches arranged to sequentially operate in a plurality of switch configurations, an output comprising a first output terminal and a second output terminal, wherein a first switch of the plurality of switches is coupled between the power inductor and the first output terminal and a second switch of the plurality of switches is coupled between the power inductor and the second output terminal; and at least one of a first capacitor coupled to the first output terminal and a second capacitor coupled to the second output terminal:
producing at an output of the power converter the output voltage as an amplified version of a time-varying input signal;
based on a measured parameter associated with the switching power stage and indicative of the time-varying input signal, selecting a selected operational mode of the power converter from a plurality of operational modes as a function of the time-varying input signal; and
sequentially applying switch configurations from the plurality of switch configurations to selectively activate or deactivate each of the plurality of switches in order to transfer electrical energy from a substantially constant input source of the power converter to the load in accordance with the selected operational mode.

14. The method of claim 13 , wherein the measured parameter is an error between a signal indicative of the output voltage and the time-varying input signal.

15. The method of claim 14 , wherein the time-varying input signal is an audio signal.

16. The method of claim 14 , further comprising generating, with a loop filter, a quantized output indicative of the selected operational mode in order to minimize the error.

17. The method of claim 13 , wherein the load is an acoustic transducer.

18. The method of claim 13 , wherein the plurality of switch configurations comprises at least one charging configuration wherein the power converter charges a first terminal of the load through the power inductor during a charging phase of the power converter.

19. The method of claim 18 , wherein the plurality of operational modes comprises:
at least one buck configuration wherein charge is transferred from the first terminal of the load to a second terminal of the load during a transfer phase of the power converter and a switch between the input source and the power inductor is deactivated; and
at least one boost configuration wherein charge is transferred from the first terminal of the load to the second terminal of the load during the transfer phase of the power converter and the switch between the input source and the power inductor is activated;
wherein the switch configuration applied during a transfer phase of the power converter is selected from the at least one buck configuration and the at least one boost configuration based on the selected operational mode.

20. The method of claim 19 , wherein a duration of the transfer phase is based on the selected operational mode.

21. The method of claim 13 , wherein the measured parameter is a parameter indicative of the output voltage.

22. The method of claim 13 , wherein the measured parameter is an input signal indicative of a target voltage for the output voltage.

23. The method of claim 13 , wherein at least one of the plurality of operational modes comprises a converter mode.

24. The method of claim 23 , wherein the converter mode comprises one of a boost mode, a buck mode, and a buck-boost mode.

25. A switching power stage for producing an output voltage to a load as an amplified version of a time-varying input signa

Assignees

• Cirrus Logic Inc

Inventors

• Swanson Eric
• Melanson John L
• Tucker John C
• King Eric J

Classifications

• H03F3/217 Primary

  Class D power amplifiers; Switching amplifiers · CPC title

• H02M3/1582 Primary

  Buck-boost converters (H02M3/1584 takes precedence) · CPC title

• H03F1/0227 Primary

  using supply converters · CPC title

• H03F3/181

  Low-frequency amplifiers, e.g. audio preamplifiers · CPC title

• H02M3/1588

  comprising at least one synchronous rectifier element (H02M3/1582, H02M3/1584 take precedence) · CPC title