Patent ID: 9083297
Filing Date: 2015-07-14
Classification: H03F,H03G

Abstract:
1. An integrated circuit (IC) including a programmable gain amplifier, the programmable gain amplifier comprising: a first-stage amplifier configured to operate with at least one relatively high power supply voltage in order to accommodate at the input of the first-stage amplifier a relatively large range of input signals, the first-stage amplifier having a in setting that is adjustable from a set of predetermined gain settings separated in relatively coarse increments so as to minimize the number of analog switches that must be implemented with high-voltage active devices in order to set each gain setting; and a second-stage amplifier configured to operate with at least one relatively low power supply voltage, lower than the high power supply voltage in order to minimize the required IC area for the second-stage amplifier, wherein the gain of the second-stage amplifier is adjustable from a set of gain settings separated in relatively small increments between the coarse increments in order to achieve a combined predetermined gain resolution; wherein the gain of the programmable gain amplifier is programmable by adjusting the gain of each of the first-stage and second-stage amplifiers; wherein the first-stage amplifier includes a differential amplifier arrangement; wherein the second-stage amplifier includes a fully differential operational amplifier; and wherein the fully differential operational amplifier includes an internal common-mode feedback loop configured to (1) accept a reference input voltage and (2) force a common mode voltage at the output terminals of the second-stage amplifier to be substantially equal to the reference input voltage.