Patent ID: 8229382

Claim:
A switched-current resistor (SCR) programmable gain array (PGA) for constant-bandwidth gain control, comprising: an inverting amplifier; a feedback resistor forming a feedback loop between an output side and an input side of the inverting amplifier; and a switched current resistor (SCR) array connected in parallel to the feedback resistor, and configured to tune a gain range between a maximum and a minimum, the SCR array comprising: a plurality of switched resistors, each comprising a switch in series with a resistor, wherein a constituent switched resistor of the plurality of switched resistors is connected to another switched resistor in parallel, and wherein when the plurality of switched resistors are switched by a gain-control logic, a plurality of switched current sources and a plurality of grounded resistors are switched correspondingly such that the plurality of switched current sources deliver a transient current, an equivalent of which flows through the plurality of grounded resistors out from the input side of the inverting amplifier, leading to a feedback factor of the PGA being constant.