Linear-in-dB variable gain amplifier
AssigneeMediaTek Singapore Pte. Ltd.
InventorsYan Tong, Ying-Tang Chang
Life of this patent
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Abstract
A variable gain amplifier (VGA) with a gain thereof exponential to a control voltage thereof. The variable gain amplifier (VGA) comprises an exponential DC converter, and a linear voltage multiplier. The exponential DC converter receives the control voltage and generates an exponential voltage which is exponential to the control voltage. The linear voltage multiplier is coupled to the exponential DC converter and has a gain proportional to the exponential voltage of the exponential DC converter.
Claims13
A variable gain amplifier (VGA) with a gain thereof exponential to a control voltage thereof, comprising:
- an exponential DC converter receiving the control voltage and generating an exponential voltage which is exponential to the control voltage, and comprising:
- a square law circuit receiving the control voltage and generating first and second currents;
- and
- a current divider receiving the first and second currents and generating the exponential voltage, wherein a current ratio between the first and second currents is exponential to the control voltage, and the exponential voltage is proportional to the current ratio of the first and second currents;
- and
- a linear voltage multiplier coupled to the exponential DC converter and having a gain proportional to the exponential voltage of the exponential DC converter.
A variable gain amplifier (VGA) with a gain thereof exponential to a control voltage thereof, comprising:
- an exponential DC converter, generating an exponential voltage according to a first current and a second current, wherein the exponential voltage is exponential to the control voltage, and a current ratio between the first and second currents is exponential to the control voltage, wherein the exponential DC converter comprises:
- a square law circuit, receiving the control voltage and generating the first and second currents;
- and
- a current divider coupled to the square law circuit, receiving the first and second currents and generating the exponential voltage;
- and
- a linear voltage multiplier coupled to the exponential DC converter, having the gain which is proportional to the exponential voltage of the exponential DC converter.
Dependencies are inferred from the claim text.