EP-4738701-A1 - DYNAMICALLY-TUNABLE AMPLIFIER

EP4738701A1EP 4738701 A1EP4738701 A1EP 4738701A1EP-4738701-A1

Abstract

An electronic circuit including an amplifier, a first variable capacitance and a second variable capacitance. The amplifier receives an input signal across an inverting input terminal of the amplifier and a non-inverting input terminal of the amplifier. The first variable capacitance is electrically directly connected to the output terminal of the amplifier and the inverting input terminal of the amplifier. The second variable capacitance is electrically directly connected to the output terminal of the amplifier and the non-inverting input terminal of the amplifier.

Inventors

CHUAI, KUN
TONG, HAITAO
LIU, YANG
CUI, DELONG

Assignees

Avago Technologies International Sales Pte. Limited

Dates

Publication Date: 20260506
Application Date: 20251029

Claims (15)

An electronic circuit comprising: an amplifier, the amplifier is configured to receive an input signal across an inverting input terminal of the amplifier and a non-inverting input terminal of the amplifier; a first variable capacitance, the first variable capacitance is electrically directly connected to an output terminal of the amplifier and the inverting input terminal of the amplifier; and a second variable capacitance, the second variable capacitance is electrically directly connected to the output terminal of the amplifier and the non-inverting input terminal of the amplifier.
The electronic circuit according to claim 1, wherein the first variable capacitance comprises a plurality of capacitors; and/or the second variable capacitance comprises a plurality of capacitors.
The electronic circuit according to claim 1 or 2, wherein the output terminal of the amplifier is a non-inverting output terminal of the amplifier; or wherein the output terminal of the amplifier is an inverting output terminal of the amplifier.
The electronic circuit according to any one of the claims 1 to 3, wherein the first variable capacitance is electrically connected between the output terminal of the amplifier and the inverting input terminal of the amplifier.
The electronic circuit according to any one of the claims 1 to 4, wherein the second variable capacitance is electrically connected between the output terminal of the amplifier and the non-inverting input terminal of the amplifier.
The electronic circuit according to any one of the claims 1 to 5, wherein the amplifier is configured to output, in response to amplifying the input signal, an amplified signal onto the output terminal of the amplifier.
The electronic circuit according to claim 6, wherein the amplifier is configured to convert, by amplifying the input signal, the input signal into the amplified signal.
The electronic circuit according to any one of the claims 1 to 7, further comprising: a first inductor, the first inductor is electrically directly connected to the output terminal of the amplifier.
The electronic circuit according to claim 8, further comprising: a second inductor, the second inductor is electrically directly connected to a variable resistance and the first inductor.
The electronic circuit according to claim 9, wherein a pair of mutually-coupled inductors comprises the first inductor and the second inductor.
The electronic circuit according to claim 9 or 10, further comprising: the variable resistance, the variable resistance is electrically directly connected to the output terminal of the amplifier; wherein in particular the electronic circuit comprises at least one of the following features: (A) the variable resistance comprises a plurality of variable resistors; and (B) the electronic circuit further comprises a feedback resistor, the feedback resistor is electrically directly connected to the variable resistance and the non-inverting input terminal of the amplifier.
The electronic circuit according to any one of the claims 1 to 11, further comprising: a capacitor, the capacitor is electrically directly connected to the non-inverting input terminal of the amplifier and the inverting input terminal of the amplifier; wherein in particular the capacitor is electrically directly connected across the inverting input terminal of the amplifier and the non-inverting input terminal of the amplifier.
A device comprising: a load, the load is configured to receive a differential voltage; and an electronic circuit, wherein the electronic circuit comprises: an amplifier, the amplifier is configured to receive an input signal across an inverting input terminal of the amplifier and a non-inverting input terminal of the amplifier; a first variable capacitance, the first variable capacitance is electrically directly connected to an output terminal of the amplifier and the inverting input terminal of the amplifier; and a second variable capacitance, the second variable capacitance is electrically directly connected to the output terminal of the amplifier and the non-inverting input terminal of the amplifier. wherein the amplifier is configured to convert, by amplifying the input signal, the input signal into the differential voltage.
The device according to claim 13, wherein an integrated circuit comprises the electronic circuit.
A system comprising: an input source, the input source is configured to output an input signal; an electronic circuit, wherein the electronic circuit comprises: an amplifier, the amplifier is configured to receive the input signal across an inverting input terminal of the amplifier and a non-inverting input terminal of the amplifier; a first variable capacitance, the first variable capacitance is electrically directly connected to an output terminal of the amplifier and the inverting input terminal of the amplifier; and a second variable capacitance, the second variable capacitance is electrically directly connected to the output terminal of the amplifier and the non-inverting input terminal of the amplifier.

Description

BACKGROUND In electronics, an amplifier is circuitry designed to convert an input current into a voltage that is amplified. While converting the input current into the voltage, the amplifier multiplies the input current by an amplifier gain to produce the amplified voltage. BRIEF DESCRIPTION OF DRAWINGS The accompanying drawings, which are incorporated in and form a part of this specification, illustrate examples of the disclosure and, together with the description, explain principles of the examples. FIG. 1 illustrates a functional block diagram of an exemplary system, in accordance with one or more embodiments of the disclosure.FIG. 2 illustrates an exemplary electronic circuit, in accordance with one or more embodiments of the disclosure.FIG. 3 illustrates exemplary configurations for variable capacitances, in accordance with one or more embodiments of the disclosure.FIG. 4 illustrates exemplary configurations for variable resistances, in accordance with one or more embodiments of the disclosure. In the drawings, like reference symbols and numerals indicate the same or similar components. Like elements in the various figures are denoted by like reference symbols and numerals for consistency. Unless otherwise indicated, like elements and method steps are referred to with like reference numerals. DETAILED DESCRIPTION OF THE INVENTION The following describes technical solutions in this specification with reference to the accompanying drawings. Exemplary embodiments are described in detail with reference to the accompanying drawings. The terminology used herein is for describing various examples only, and is not to be used to limit the disclosure. Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains and after an understanding of the disclosure of this application. Terms, such as those defined in commonly used dictionaries, are to be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the disclosure of this application. Although the present technology has been described by referring to certain examples, workers skilled in the art will recognize that changes could be made in form and detail without departing from the scope of the discussion. In general, the frequency response in many high-speed amplifiers is not flat across all frequencies. Instead, a peaking frequency of an amplifier is the frequency at which the amplifier's gain reaches a maximum point before rolling off due to bandwidth limitations. In high-speed amplifiers, factors such as parasitic capacitances and inductances in the amplifier, any feedback resistors in the amplifier, and the overall amplifier characteristics can cause a resonance that increases the amplifier gain at the peaking frequency. Such increasing of the amplifier gain at the peaking frequency is generally referred to as peaking. Peaking typically appears in the frequency response of the amplifier. In the frequency response for some amplifiers, the amplifier gain is highest at the peaking frequency before decreasing as the frequency continues to increase. Peaking quantifies how much the amplifier gain increases at the peaking frequency compared to the flat or nominal gain level of the amplifier. An amount of the peaking is often expressed in decibels (dB) as the difference between a nominal amplifier gain level and the amplifier gain at the peaking frequency. The peaking amount quantifies how much the amplifier gain rises above the nominal or expected gain before it begins to roll off at higher frequencies. Resonance can cause a peak in the frequency response before the gain rolls off at higher frequencies. Resonance is the condition where inductive and capacitive reactances in the amplifier cancel out, thereby causing maximum signal amplification at a resonant frequency. In cases where the resonant frequency coincides with the peaking frequency, both the natural resonance and peaking effects can reinforce each other, leading to a sharp amplification of the input current at the peaking frequency. This sharp amplification can result in distortion in the amplifier. Accordingly, there is a need in the art for an improved amplifier. Referring now to FIG. 1, an example system 100 is illustrated. System 100 may include device 101 and input 102. Those skilled in the art will appreciate there may be additional components in system 100. Device 101 may be any electronic device capable of electronically exchanging information with input 102. Device 101 may be any type of electrically-powered device having computing capability. For example, device 101 may be a computer terminal, a laptop computer, a tablet computer, and/or any other computing device. In some examples, device 101 may be telephone, a mobile phone, a smart phone, a cell phone and/or any other electronic telecommunications