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US 11,463,059 B1Granted
Systems and methods for linear variable gain amplifier
AssigneeMarvell Asia Pte Ltd
InventorsPraveen Prabha, Karthik Raviprakash, Luke Wang, Stephane Dallaire
Life of this patent
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Abstract
The present invention is directed to electrical circuits. In a specific embodiment, the present invention provides variable gain amplifier that includes an impedance ladder and a control circuit. The impedance ladder includes n switches configured in parallel. The control circuit includes a digital-to-analog converter and an amplifier. The control circuit generates n control signals for the n switches. There are other embodiments as well.
Claims18
A variable gain amplifier comprising:
- a first input switch configured to receive a first differential input of the variable gain amplifier;
- a second input switch configured to receive a second differential input of the variable gain amplifier;
- an impedance ladder circuit comprising a plurality of switches configured with a predetermined scale for adjusting a gain of the variable gain amplifier in response to a respective plurality of control signals;
- and
- a control circuit to maintain a gain linearity of the variable gain amplifier, the control circuit configured to (i) receive a control voltage, (ii) apply a gain to the control voltage to generate a ramp voltage configured to ramp each of the respective control signals upward or downward as the control voltage varies, and (iii) generate the respective control signals for the plurality of switches based on the ramp voltage,
- the control circuit comprising (i) a plurality of reference resistors coupled to an output of the control circuit and configured to generate the respective control signals based on the ramp voltage and (ii) first and second reference current sources coupled to the plurality of reference resistors and configured to regulate the respective control signals.
3 more elements
A method of operating a variable gain amplifier, the method comprising:
- receiving, at a first input switch, a first differential input of the variable gain amplifier;
- receiving, at a second input switch, a second differential input of the variable gain amplifier;
- using an impedance ladder circuit comprising a plurality of switches, adjusting a gain of the variable gain amplifier in response to a respective plurality of control signals;
- receiving a control voltage;
- applying a gain to the control voltage to generate a ramp voltage configured to ramp each of the respective control signals upward or downward as the control voltage varies to maintain a gain linearity of the variable gain amplifier;
- generating the respective control signals for the plurality of switches based on the ramp voltage using a plurality of reference resistors coupled to first and second reference current sources configured to regulate the respective control signals.
3 more elements
Dependencies are inferred from the claim text.