# US 9,438,186 B2 · Power amplifier with envelope injection

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- Number: US 9,438,186 B2
- Document ID: US9438186B2
- Status: Granted
- Kind: B2
- Application number: 14/266,451
- Filed: 2014-04-30
- Published: 2015-11-05
- Granted: 2016-09-06
- Earliest claimed: 2014-04-30
- Assignees: Freescale Semiconductor, Inc.
- Applicants: Ramanujam Srinidhi Embar; Abdulrhman M. S Ahmed; Roy McLaren; Sarmad K. Musa; Joseph Staudinger
- Inventors: Ramanujam Srinidhi Embar; Abdulrhman M. S Ahmed; Roy McLaren; Sarmad K. Musa; Joseph Staudinger
- Web page: https://patentgrep.com/patent/US9438186B2

## CPC

- H03F 3/245: {with semiconductor devices only}
- H03F 1/0222: {by using a signal derived from the input signal}
- H03F 1/0266: {by using a signal derived from the input signal}
- H03F 1/0288: {using a main and one or several auxiliary peaking amplifiers whereby the load is connected to the main amplifier using an impedance inverter, e.g. Doherty amplifiers}
- H03F 3/195: in integrated circuits
- H03F 3/21: with semiconductor devices only {(H03F3/245 takes precedence)}
- H03F 3/211: {using a combination of several amplifiers (H03F3/60 takes precedence)}
- H03F 2200/102: A non-specified detector of a signal envelope being used in an amplifying circuit
- H03F 2200/405: the output amplifying stage of an amplifier comprising more than three power stages
- H03F: AMPLIFIERS

## Abstract

A device and a method for an amplifier having reduced intermodulation (IM) distortion output products are presented. An amplifier has an output, and at least one of a gate bias input and a drain supply input. The amplifier is configured to receive an input signal and output an amplified signal at the output of the amplified. An input is configured to receive an envelope signal. The input is connected to the at least one of the gate bias input and the drain supply input and the envelope signal is at least partially determined by an attribute of the input signal to the amplifier. A controller is configured to modify at least one of an amplitude and a phase of the envelope signal to reduce a magnitude of an intermodulation distortion product of the amplifier.

## Claims

### Claim 1

A device, comprising:
an amplifier having an output, and at least one of a gate bias input and a drain supply input, the amplifier being configured to receive an input signal and output an amplified signal at the output of the amplifier;
an input configured to receive an envelope signal, the input being connected to the at least one of the gate bias input and the drain supply input and the envelope signal being at least partially determined by an attribute of the input signal to the amplifier;
a second input configured to receive a second envelope signal having a frequency equal to twice a frequency of the envelope signal, the second input being connected to the at least one of the gate bias input and the drain supply input; and
a controller, the controller being configured to:
modify at least one of an amplitude and a phase of the envelope signal to reduce a magnitude of an intermodulation distortion product of the amplifier, and
modify at least one of a second amplitude and a second phase of the second envelope signal to reduce a second magnitude of a second intermodulation distortion product of the amplifier, the second intermodulation distortion product being different from the intermodulation distortion product.

### Claim 2 (depends on 1)

The device of claim 1, wherein the input signal is a two-tone radio frequency signal having two energy peaks at frequencies f1 and f2.

### Claim 3 (depends on 2)

The device of claim 2, wherein the envelope signal is at a frequency equal to n*(f2−f1).

### Claim 4 (depends on 1)

The device of claim 1, including a second amplifier configured to amplify the envelope signal received at the input.

### Claim 5 (depends on 1)

The device of claim 1, wherein the controller is configured to receive a feedback signal, the feedback signal being at least partially determined by an output signal of the amplifier.

### Claim 6 (depends on 1)

The device of claim 1, wherein the amplifier is a Doherty amplifier.

### Claim 7 (depends on 1)

The device of claim 1, wherein the envelope signal has a frequency equal to a first baseband product of the input signal, and the second envelope signal has a frequency equal to twice the frequency of the envelope signal.

### Claim 8 (depends on 1)

The device of claim 1, wherein the device is formed in a single package.

### Claim 9

A device, comprising:
an amplifier having an output, and at least one of a gate bias input and a drain supply input, the amplifier being configured to receive an input signal and output an amplified signal at the output of the amplifier;
an input configured to receive an envelope signal, the input being connected to the at least one of the gate bias input and the drain supply input and the envelope signal being at least partially determined by an attribute of the input signal to the amplifier;
a variable attenuator connected to the input and configured to modify an attenuation of the envelope signal;
a phase shifter connected to the input and configured to modify a phase shift of the envelope signal;
a second input configured to receive a second envelope signal different from the envelope signal, the second input being connected to the at least one of the gate bias input and the drain supply input, the envelope signal having a frequency equal to a first baseband product of the input signal, and the second envelope signal having a frequency equal to a multiple of the frequency of the envelope signal; and
a controller, the controller being configured to modify at least one of the variable attenuator and the phase shifter to reduce a magnitude of an intermodulation distortion product of the amplifier.

### Claim 10 (depends on 9)

The device of claim 9, wherein the input signal is a two-tone radio frequency signal having two energy peaks at frequencies f1 and f2.

### Claim 11 (depends on 10)

The device of claim 10, wherein the envelope signal is at a frequency equal to n*(f2−f1).

### Claim 12 (depends on 9)

The device of claim 9, including a second amplifier configured to amplify the envelope signal received at the input.

### Claim 13 (depends on 9)

The device of claim 9, wherein the controller is configured to receive a feedback signal, the feedback signal being at least partially determined by an output signal of the amplifier.

### Claim 14 (depends on 9)

The device of claim 9, wherein the amplifier is a Doherty amplifier.

### Claim 15 (depends on 9)

The device of claim 9, wherein the device is formed in a single package.

### Claim 16

A method, comprising:
receiving an envelope signal, the envelope signal being at least partially determined by an attribute of an input signal to an amplifier;
receiving a second envelope signal, the envelope signal having a frequency equal to twice a frequency of the envelope signal;
modifying at least one of an amplitude and a phase of the envelope signal to reduce a magnitude of an intermodulation distortion product of the amplifier, resulting in a modified envelope signal;
modifying at least one of a second amplitude and a second phase of the second envelope signal to reduce a second magnitude of a second intermodulation distortion product of the amplifier, resulting in a second modified envelope signal; and
supplying the modified envelope signal and the second modified envelope signal to at least one of a gate bias input and a drain supply input of the amplifier.

### Claim 17 (depends on 16)

The method of claim 16, wherein the input signal is a two-tone radio frequency signal having two energy peaks at frequencies f1 and f2.

### Claim 18 (depends on 17)

The method of claim 17, wherein the envelope signal is at a frequency equal to n*(f2−f1).

### Claim 19 (depends on 16)

The method of claim 16, wherein modifying at least one of an amplitude and a phase of the envelope signal includes modifying at least one of variable attenuator and phase shifter connected to the at least one of the gate bias input and the drain supply input of the amplifier.