Adaptable voltage control for a variable gain amplifier
AssigneeBroadcom Corporation
InventorsMario Caresosa, Guangming Yin
Life of this patent
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Abstract
A method and apparatus for adaptively controlling a variable gain amplifier (VGA). The operation of the VGA is separated into a low gain mode and a high gain mode and the mode in which the VGA is currently operating in is adaptively sensed. A threshold voltage is compared to a control voltage of the VGA; if the VGA is currently operating in the low gain mode and the control voltage is higher than the threshold voltage, the VGA is switched from the low gain mode to the high gain mode; and if the VGA is currently operating in the high gain mode and the control voltage is lower than the threshold voltage, the VGA is switched from the high gain mode to the low gain mode.
Claims20
A method for controlling gain of a variable gain amplifier (VGA) having a low gain mode and a high gain mode, the method comprising:
- sensing which mode the VGA is operating in;
- comparing a threshold voltage to a control voltage of the VGA;
- if the VGA is operating in the low gain mode and the control voltage is higher than the threshold voltage, changing the VGA mode from the low gain mode to the high gain mode;
- and
- if the VGA is operating in the high gain mode and the control voltage is lower than the threshold voltage, changing the VGA mode from the high gain mode to the low gain mode.
An apparatus for controlling a variable gain amplifier (VGA) having a low gain mode of operation and a high gain mode of operation, comprising:
- a comparator for comparing a threshold voltage to a control voltage of the VGA and changing state when the control voltage crosses the threshold voltage;
- and
- a control logic for changing effective resistance of a VGA gain resistor when the comparator changes state and changing the mode of operation responsive to the changed effective resistance of the VGA gain resistor.
An electronic circuit for controlling a variable gain amplifier (VGA) having a low gain mode of operation and a high gain mode of operation, comprising:
- means for comparing a threshold voltage to a control voltage of the VGA and changing state when the control voltage crosses the threshold voltage;
- and
- means for changing effective resistance of a VGA gain resistor when the comparator changes state and means for changing the mode of operation responsive to the changed effective resistance of the VGA gain resistor.
Dependencies are inferred from the claim text.