Patent ID: 9735738
Date: 2017-08-15
CPC Classifications: H03F,H03G

Claim:
1. A low-voltage low-power variable gain amplifier, the amplifier comprising: first differential voltage nodes following differential input voltages at differential input nodes based on a first fixed voltage change; first current branches driving differential output nodes; second current branches paired with respective first current branches to divide, according to a coefficient, a bias current and a difference current representative of the differential input voltages; first floating voltage sources, each one of the first floating voltage sources coupled between respective one of the first differential voltage nodes and respective one of first current branches to provide a first predetermined voltage change; and second floating voltage sources, each one of the second floating voltage sources coupled between respective one of the first differential voltage nodes and respective one of second current branches to provide a second predetermined change in the same direction as the first predetermined voltage change; wherein the first predetermined voltage change and the second predetermined voltage change correspond to the first fixed voltage change in magnitude but in an opposite direction and a difference between the first predetermined voltage change and the second predetermined voltage change sets the coefficient to provide variable gain of the amplifier.