Patent ID: 9246458
Filing Date: 2016-01-26
CPC Classification: H03F,H03G,H03M

Claim Text:
1. A circuit, comprising: a first differential amplifier having an inverting input, a non-inverting input and an output and having a plurality of selectively enabled current drive sources coupled to the output; a first resistor having a first variable resistance coupled between the output and inverting input of the first differential amplifier; a second resistor having a second variable resistance coupled to the inverting input of the first differential amplifier; a control circuit configured to select the first and second variable resistances to implement a fixed gain at the output and further selectively enable the current drive sources, said control circuit receiving an indication of a downstream programmable gain; wherein the first and second variable resistances are selected scaled inversely with respect to the downstream programmable gain; and wherein the current drive sources are enabled proportionately with respect to the downstream programmable gain.