US 10,135,404 B2Granted

Calibration of push-pull amplifier to a low second order distortion

AssigneeTelefonaktiebolaget LM Ericsson (publ)

InventorHenrik Sjoland

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Abstract

An integrated circuit comprises a first amplifier circuit with a push-pull amplifier configured to be calibrated to a low second order distortion. The integrated circuit further comprises a second amplifier circuit with at least one push-pull amplifier, wherein a size ratio between sizes of the transistors is adjustable by adjusting the size of at least one transistor device. The size ratio can be consecutively adjusted to a plurality of values, and for each value, a first output signal of a push-pull amplifier with an applied test signal and a second output signal of a push-pull amplifier without applied test signal, are determined. The size ratio for which a difference between the push-pull amplifier output signals is closest to zero is determined, and the push-pull amplifier of the first amplifier circuit is calibrated in dependence of the determined size ratio.

Claims16

Dependent claims

An electronic integrated circuit comprising:

a first amplifier circuit with at least one push-pull amplifier having a complementary pair of transistor devices arranged in series between two supply voltages, wherein the first amplifier circuit is configured to be calibrated to achieve a low second order distortion,
wherein the integrated circuit further comprises a second amplifier circuit with at least one push-pull amplifier having a complementary pair of transistor devices arranged in series between said supply voltages,
wherein a size ratio between effective sizes of said complementary pair of transistor devices of the at least one push-pull amplifier of the second amplifier circuit is adjustable by adjusting the effective size of at least one of its transistor devices;
and
a test signal can be applied on an input terminal of the second amplifier circuit;
and wherein the electronic integrated circuit is configured to:
consecutively adjust the size ratio of the at least one push-pull amplifier of the second amplifier circuit to a plurality of values,
determine for each size ratio a first output signal that is a low pass filtered output signal of at least one of the at least one push-pull amplifier of the second amplifier circuit having an input to which the test signal is applied, and a second output signal that is an output signal of a same or a different one of the at least one push-pull amplifier of the second amplifier circuit without the test signal being applied at an input terminal of the same or the different one of the at least one push-pull amplifier;
determine two adjacent size ratios for which a difference between the first and second output signals has opposite sign;
select one of said two adjacent size ratios;
and
calibrate the at least one push-pull amplifier of the first amplifier circuit in dependence of said selected size ratio.

9 more elements

A method of calibrating a first amplifier circuit of an electronic integrated circuit to achieve a low second order distortion, wherein the first amplifier circuit comprises at least one push-pull amplifier having a complementary pair of transistor devices arranged in series between two supply voltages, wherein the electronic integrated circuit further comprises a second amplifier circuit with at least one push-pull amplifier having a complementary pair of transistor devices arranged in series between said supply voltages, and wherein a size ratio between effective sizes of said complementary pair of transistor devices of the at least one push-pull amplifier of the second amplifier circuit is adjustable by adjusting the effective size of at least one of its transistor devices;

the method comprising the steps of:
consecutively adjusting the size ratio of the at least one push-pull amplifier of the second amplifier circuit to a plurality of values;
determining, for each size ratio, a first output signal that is a low pass filtered output signal of at least one of the at least one push-pull amplifier of the second amplifier circuit when a test signal is applied to an input terminal of the at least one of the at least one push-pull amplifier of the second amplifier circuit, and a second output signal that is an output signal of a same or a different one of the at least one push-pull amplifier of the second amplifier circuit without the test signal being applied at an input terminal of the same or the different one of the at least one push-pull amplifier of the second amplifier circuit;
determining two adjacent size ratios for which a difference between the first and second output signals has opposite sign;
selecting one of said adjacent size ratios;
and
calibrating the at least one push-pull amplifier of the first amplifier circuit in dependence of said selected size ratio.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/533,003Filed 4 Dec 2014
Published: US 2017/0324383 A19 Nov 2017
Granted: 20 Nov 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

H03F 1/3217
Modifications of amplifiers to reduce non-linear distortion: in single ended push-pull amplifiers
H03F 3/193
With semiconductor devices only: with field-effect devices
H03F 3/3028
CMOS common source output SEPP amplifiers: with symmetrical driving of the end stage
H03F 3/3032
With symmetrical driving of the end stage: using two SEPP driving stages