Current feedback output circuit

Patent metadata

Field	Value
Publication number	US-9692371-B2
Application number	US-201514733402-A
Country	US
Kind code	B2
Filing date	Jun 8, 2015
Priority date	Dec 18, 2012
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

The current feedback output circuit includes first and second transistors. The current feedback output circuit includes a current amplifier that has a non-inverting input terminal, an inverting input terminal, a first output terminal and a second output terminal, an input impedance of the non-inverting input terminal being higher than an input impedance of the inverting input terminal, and flows a current obtained by amplifying the difference between a current of an input signal to the non-inverting input terminal and a current input to the inverting input terminal between the first output terminal and the second output terminal. The current feedback output circuit includes first to sixth current mirror circuits. The current feedback output circuit includes a current feedback circuit that supplies a current responsive to a voltage at the signal output terminal to the inverting input terminal.

First claim

What is claimed is:

1. A power amplifying circuit comprising:
an input terminal;
a signal output terminal;
a voltage feedback circuit configured to generate a voltage in accordance with a voltage at the signal output terminal;
a current feedback circuit configured to generate a current in accordance with the voltage at the signal output terminal;
a first amplifier circuit, a voltage from the input terminal being inputted to a non-inverting terminal thereof, the voltage generated by the voltage feedback circuit being inputted to an inverting terminal thereof, and an input voltage being outputted therefrom; and
a second amplifier circuit, the input voltage being inputted to a non-inverting terminal thereof, the current generated by the current feedback circuit being inputted to an inverting terminal thereof, and an output signal therefrom being outputted to the signal output terminal,
wherein the second amplifier circuit includes a current amplifier configured to generate a current in accordance with the input voltage.

2. The power amplifying circuit according to claim 1 , wherein the current feedback circuit includes a first resistor that is connected, at a first end of a current path thereof, to the inverting terminal of the second amplifier circuit, and connected, at a second end of the current path thereof, to a reference terminal to which a reference voltage is applied.

3. The power amplifying circuit according to claim 2 , wherein the current feedback circuit includes a second resistor that is connected, at a first end of a current path thereof, to the first end of the first resistor, and connected, at a second end of the current path thereof, to the signal output terminal.

4. The power amplifying circuit according to claim 2 ,
wherein the second amplifier circuit includes:
a first transistor of a first conductivity type that is connected, at a first end of a current path thereof, to a first power supply rail to which a first voltage is applied, and connected, at a second end of the current path thereof, to the signal output terminal; and
a second transistor of a second conductivity type that is connected, at a first end of a current path thereof, to a second power supply rail to which a second voltage that is lower than the first voltage is applied, and connected, at a second end of the current path thereof, to the signal output terminal, and
wherein the reference voltage is lower than the first voltage and higher than the second voltage.

5. The power amplifying circuit according to claim 4 , wherein the reference voltage is an intermediate voltage between the first voltage and the second voltage.

6. The current feedback output circuit according to claim 1 , wherein the current amplifier comprises:
a current source that is connected to the first power supply rail at a first end thereof and outputs a current;
a third transistor of the second conductivity type that is connected to a second end of the current source at a first end thereof and is diode-connected;
a fourth transistor of the first conductivity type that is connected to a second end of the third transistor at a first end thereof and to the non-inverting input terminal at a second end thereof and is diode-connected;
a fifth transistor of the second conductivity type that is connected to a first output terminal at a first end thereof, to the inverting input terminal at a second end thereof and to a control terminal of the third transistor at a control terminal thereof; and
a sixth transistor of the first conductivity type that is connected to the inverting input terminal at a first end thereof, to a second output terminal at a second end thereof and to a control terminal of the fourth transistor at a control terminal thereof;
wherein the current amplifier is configured to pass a current obtained by amplifying a difference between a current inputted to the non-inverting terminal and a current inputted to the inverting terminal as the difference of the current between the first output terminal and the second output terminal.

7. The power amplifying circuit according to claim 6 , wherein an area ratio between the third transistor and the fifth transistor is identical to an area ratio between the fourth transistor and the sixth transistor.

8. The power amplifying circuit according to claim 7 , wherein the fifth transistor is larger in area than the third transistor, and the sixth transistor is larger in area than the fourth transistor.

9. The power amplifying circuit according to claim 6 , wherein the third transistor and the fifth transistor form a first current mirror circuit and the fourth transistor and the sixth transistor form a second current mirror circuit, a mirror ratio of the first current mirror circuit being identical to a mirror ratio of the second current mirror circuit.

Assignees

• Toshiba Kk

Inventors

• Yamauchi Akira
• Tsurumi Hiroyuki

Classifications

• H03F2203/21181

  the supply current of a power amplifier being continuously controlled, e.g. by controlling current sources or resistors · CPC title

• H03F3/45475

  using IC blocks as the active amplifying circuit · CPC title

• H03F3/211 Primary

  using a combination of several amplifiers (H03F3/60 takes precedence) · CPC title

• H03F2200/91

  the amplifier has a current mode topology · CPC title

• H03F1/342 Primary

  in field-effect transistor amplifiers · CPC title