Power amplifier

Patent metadata

Field	Value
Publication number	US-9647614-B2
Application number	US-201514802412-A
Country	US
Kind code	B2
Filing date	Jul 17, 2015
Priority date	Jul 18, 2014
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A power amplifier includes a class D amplification section and a load current feedback circuit. The class D amplification section includes an input section and a switching section serving as an output stage and switched depending on a signal input to the input section, and outputs current from a power source to a load via the switching section. The load current feedback circuit negatively feeds back the current flowing in the load to the input section of the class D amplification section.

First claim

What is claimed is:

1. A power amplifier comprising:
a class D amplification section that includes an input section and a switching section serving as an output stage and switched depending on a signal input to the input section, and that outputs current from a power source to a load via the switching section;
a load current feedback circuit that feeds back a current flowing in the load to a negative terminal of the input section of the class D amplification section; and
a filter current feedback circuit that feeds back a current flowing in a filter to the negative terminal of the input section of the class D amplification section;
wherein the filter is interposed between the output stage of the class D amplification section and the load;
wherein the filter comprises an inductor and a capacitor;
wherein the inductor is inserted between an output terminal of the output stage and the load so as to be connected in series to the output stage and the load; and
wherein one terminal of the capacitor is connected to a node between the inductor and the load.

2. The power amplifier according to claim 1 , wherein the load current feedback circuit comprises:
a negative feedback amount adjustor which adjusts a balance between a feedback amount of a voltage for the load to be fed back to the negative terminal of the input section of the class D amplifier and a feedback amount of the current flowing in the load to be fed back to the negative terminal of to the input section of the class D amplifier.

3. The power amplifier according to claim 1 , wherein a variable element configured to adjust electric characteristics is located in a path of the load current feedback circuit.

4. The power amplifier according to claim 1 , wherein the class D amplification section is a self-oscillating amplifier.

5. The power amplifier according to claim 1 , wherein the class D amplification section is a separately-excited oscillating amplifier.

Assignees

• Yamaha Corp

Inventors

• Otani Yohei
• Noro Masao

Classifications

• H03F2200/546

  A tunable capacitance being present in an amplifier circuit · CPC title

• H03F2200/171

  A filter circuit coupled to the output of an amplifier · CPC title

• H03F2203/45528

  the FBC comprising one or more passive resistors and being coupled between the LC and the IC · CPC title

• H03F2203/45526

  the FBC comprising a resistor-capacitor combination and being coupled between the LC and the IC · CPC title

• H03F2200/153

  Feedback used to stabilise the amplifier · CPC title