Programmable gain attenuator with a wide attenuation range and a fine attenuation step size
AssigneeBroadcom Corporation
InventorsTao Wu, Ramon Gomez
Life of this patent
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Abstract
A programmable gain attenuator (PGA) configured to receive a signal at an input and provide an attenuated version of the signal at an output is provided herein. The PGA includes a resistor coupled between a first tap and a second tap, where the first tap is coupled to the input of the PGA. The PGA further includes two sets of switches. The first set of switches is coupled in parallel between the first tap and the output, and the second set of switches is coupled in parallel between the second tap and the output. The attenuation setting of the programmable gain attenuator can be determined by controlling each set of switches.
Claims13
A programmable gain attenuator (PGA) configured to receive a signal at an input and provide an attenuated version of the signal at an output, comprising:
- a resistor coupled between a first tap and a second tap, wherein the first tap is coupled to the input;
- a first set of switches coupled in parallel between the first tap and the output;
- a second set of switches coupled in parallel between the second tap and the output;
- and
- a controller configured to control the first set of switches and the second set of switches such that for a switch turned off in the first set of switches a corresponding switch is turned on in the second set of switches,
- wherein the impedance of each switch in the first set of switches corresponds to an impedance value in a non-uniform impedance profile.
A method for adjusting a gain of a programmable gain attenuator (PGA) configured to receive a signal at an input and provide an attenuated version of the signal at an output, the PGA having a resistor coupled between a first tap and a second tap, a first set of switches coupled in parallel between the first tap and the output, and a second set of switches coupled in parallel between the second tap and the output, the first tap being further coupled to the input, the method comprising:
- receiving a signal to increment an attenuation setting of the PGA by a single attenuation step;
- in response to receiving the signal, turning off a first switch in the first set of switches and turning on a corresponding second switch in the second set of switches;
- and
- selectins;
- the first switch to turn off, in response to receiving, the signal, on a switching order, wherein the switching older is determined based on respective impedances of the switches in the first set, of switches.
Dependencies are inferred from the claim text.