Variable voltage attenuator circuits
AssigneeAnalog Devices, Inc.
InventorsShuyun Zhang, Rob McMorrow
Life of this patent
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Abstract
Methods and circuits are provided for controlling a signal applied to a control terminal of a variable voltage attenuator. In one embodiment, a method comprises detecting an output signal of the variable voltage attenuator, generating a logarithm of the detected output signal of the variable voltage attenuator, and generating the signal applied to the control terminal of the variable voltage attenuator at least partially based on the logarithm of the detected output signal of the variable voltage attenuator.
Claims25
A method of controlling a signal applied to a control terminal of a variable voltage attenuator, the method comprising acts of:
- (A) detecting an output signal of the variable voltage attenuator;
- (B) generating a logarithm of the detected output signal of the variable voltage attenuator;
- and
- (C) generating the signal applied to the control terminal of the variable voltage attenuator at least partially based on the logarithm of the detected output signal of the variable voltage attenuator.
A circuit including a variable voltage attenuator, the variable voltage attenuator comprising an input terminal, an output terminal, and a control terminal, the circuit comprising:
- a first logarithmic signal detector having an input terminal coupled to the output terminal of the variable voltage attenuator;
- and
- a summing element having a first input terminal coupled to an output terminal of the first logarithmic signal detector and an output terminal coupled to the control terminal of the variable voltage attenuator.
A circuit including a variable voltage attenuator, the variable voltage attenuator comprising an input terminal, an output terminal, and a control terminal, the circuit comprising:
- means for detecting an output signal of the variable voltage attenuator;
- means for generating a logarithm of the detected output signal of the variable voltage attenuator;
- and
- means for generating the signal applied to the control terminal of the variable voltage attenuator at least partially based on the logarithm of the detected output signal of the variable voltage attenuator.
A circuit comprising:
- a first input terminal configured to receive an input signal;
- an output terminal configured to output an attenuated input signal;
- and
- a second input terminal configured to receive a set voltage that at least partially determines the attenuation of the attenuated input signal,
- the attenuated input signal having a power such that the power versus the set voltage is linear-in-dB for a range of the set voltage greater than 0.5 V.
Dependencies are inferred from the claim text.