Hybrid switched mode amplifier

Patent metadata

Field	Value
Publication number	US-9906196-B2
Application number	US-201615270631-A
Country	US
Kind code	B2
Filing date	Sep 20, 2016
Priority date	Jan 18, 2016
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A switching power stage for producing a load voltage may include a first processing path having a first output, a second processing path having a second output, a first plurality of switches comprising at least a first switch coupled between the first output and a first load terminal and a second switch coupled between the first output and the second load terminal, a second plurality of switches comprising at least a third switch coupled between the second output and the first load terminal and a fourth switch coupled between the second output and the second load terminal, and a controller configured to control switches in order to generate the load voltage as a function of an input signal such that one of the first switch and the second switch operates in a linear region of operation and one of the third switch and the fourth switch operates in a saturated region of operation for a predominance of a dynamic rage of the load voltage.

First claim

What is claimed is:

1. A switching power stage for producing a load voltage at a load output of the switching power stage, the load output comprising a first load terminal having a first load voltage and a second load terminal having a second load voltage such that the load voltage comprises a difference between the first load voltage and the second load voltage, the switching power stage comprising:
a power converter comprising a power inductor and a first plurality of switches, wherein the power converter is configured to drive a power converter output terminal coupled to the first load terminal in order to drive the first load terminal;
a linear amplifier configured to drive a linear amplifier output terminal coupled to the second load terminal in order to drive the second load terminal;
a second plurality of switches, comprising at least a first switch coupled between the power converter output terminal and the first load terminal and a second switch coupled between the power converter output terminal and the second load terminal such that the power converter output terminal and the first load terminal are coupled via the first switch and the power converter output terminal and the second load terminal are coupled via the second switch;
a third plurality of switches, comprising at least a third switch coupled between the linear amplifier output terminal and the first load terminal and a fourth switch coupled between the linear amplifier output terminal and the second load terminal such that the linear amplifier output terminal and the first load terminal are coupled via the third switch and the linear amplifier output terminal and the second load terminal are coupled via the fourth switch; and
a controller configured to control the first plurality of switches, the second plurality of switches, the third plurality of switches, and the linear amplifier in order to generate the load voltage as a function of an input signal to the controller such that energy delivered to the load output is supplied predominantly by the power converter, and such that one of the first switch and the second switch operates in a linear region of operation and one of the third switch and the fourth switch operates in a saturated region of operation for a predominance of a dynamic range of the load voltage.

2. The switching power stage of claim 1 , further comprising a capacitor coupled between the first load terminal and the second load terminal.

3. The switching power stage of claim 1 , further comprising a capacitor coupled between the first load terminal and one of a first supply terminal having a first voltage and a second supply terminal having a second voltage.

4. The switching power stage of claim 3 , wherein a second terminal of the power inductor is coupled to the power converter output terminal.

5. The switching power stage of claim 3 , wherein the first plurality of switches comprises:
a first switch coupled between a second terminal of the power inductor and the power converter output terminal; and
a second switch coupled between the second terminal of the power inductor and the second supply terminal.

6. The switching power stage of claim 1 , further comprising:
a first capacitor coupled between the power converter output terminal and one of a first supply terminal having a first voltage and a second supply terminal having a second voltage; and
a second capacitor coupled between the second load terminal and one of the first supply terminal and the second supply terminal.

7. The switching power stage of claim 1 , wherein the first plurality of switches comprises:
a fifth switch coupled between a first terminal of the power inductor and a first supply terminal having a first voltage; and
a sixth switch coupled between the first terminal of the power inductor and a second supply terminal having a second voltage.

8. The switching power stage of claim 7 , wherein the first plurality of switches further comprises:
a seventh switch coupled between a second terminal of the power inductor and the power converter output terminal; and
an eighth switch coupled between the second terminal of the power inductor and the second supply terminal.

9. The switching power stage of claim 1 , wherein the controller further controls the first plurality of switches to drive the first load voltage as a function of a target output voltage which is a function of the input signal.

10. The switching power stage of claim 9 , wherein the function of the target output voltage includes a magnitude of the target output voltage.

11. The switching power stage of claim 9 , wherein the function of the target output voltage includes a lower saturation limit of the power converter output terminal.

12. The switching power stage of claim 11 , wherein the controller further controls the linear amplifier to drive a non-zero voltage as the second load voltage in order to increase a common mode voltage of the first load terminal and the second load terminal when the power converter output terminal is driven to the lower saturation limit in order to produce the output voltage as a function of an input signal to the controller while minimizing non-linearities of the output voltage as a function of the input signal.

13. The switching power stage of claim 1 , wherein the controller further controls the linear amplifier to drive the second load voltage as a function of a target output voltage which is a function of the input signal.

14. A method for producing a load voltage at a load output of the switching power stage, the load output comprising a first load terminal having a first load voltage and a second load terminal having a second load voltage such that the load voltage comprises a difference between the first load voltage and the second load voltage, wherein the switching power stage comprises:
a power converter comprising a power inductor and a first plurality of switches, wherein the power converter is configured to drive a power converter output terminal coupled to the first load terminal in order to drive the first load terminal;
a linear amplifier configured to drive a linear amplifier output terminal coupled to the second load terminal in order to drive the second load terminal;
a second plurality of switches, comprising at least a first switch coupled between the power converter output terminal and the first load terminal and a second switch coupled between the power converter output terminal and the second load terminal such that the power converter output terminal and the first load terminal are coupled via the first switch and the power converter output terminal and the second load terminal are coupled via the second switch; and
a third plurality of switches, comprising at least a third switch coupled between the linear amplifier output terminal and the first load terminal and a fourth switch coupled between the linear amplifier output terminal and the second load terminal such that the linear amplifier output terminal and the first load terminal are coupled via the third switch and the linear amplifier output terminal and the second load terminal are coupled via the fourth switch;
wherein the method comprises controlling the first plurality of switches, the second plurality of switches, the third plurality of switches, and the linear amplifier in order to generate the load voltage as a function of an input signal to the controller such that energy delivered to the load output is supplied predominantly by the power converter, and such that one of the first switch and the second switch operates in a linear region of operation and one of the third switch and the fourth swi

Assignees

• Cirrus Logic Int Semiconductor Ltd
• Cirrus Logic Inc

Inventors

• He Zhaohui
• King Eric J
• Maru Siddharth
• Melanson John L

Classifications

• H03F2200/351

  Pulse width modulation being used in an amplifying circuit · CPC title

• H03F3/2171

  with field-effect devices (H03F3/2173 - H03F3/2178 take precedence) · CPC title

• H03F2200/432

  Two or more amplifiers of different type are coupled in parallel at the input or output, e.g. a class D and a linear amplifier, a class B and a class A amplifier · CPC title

• H03F3/185

  with field-effect devices (H03F3/187 takes precedence) · CPC title

• H04R3/12

  for distributing signals to two or more loudspeakers {(specially adapted for hearing aids H04R25/407)} · CPC title