Patent ID: 9369313
Filing Date: 2016-06-14
CPC Classification: H03F,H04L

Claim Text:
1. A pre-amplifier circuit, comprising: a first differential amplifier having a first output node and a second output node, the first differential amplifier comprising a first differential transistor pair configured to provide a first differential current signal at the first output node and the second output node in accordance with a first pair of differential signals coupled to two control terminals of the first differential transistor pair, respectively, wherein the first differential transistor pair is biased by a first current source; and a second differential amplifier having a third output node and a fourth output node, the second differential amplifier comprising a second differential transistor pair configured to provide a second differential current signal at the third output node and the fourth output node in accordance with a voltage difference between two control terminals of the second differential transistor pair, wherein the second differential transistor pair is biased by a second current source, and at least one adjustable reference voltage circuit is coupled to at least one of the two control terminals of the second differential transistor pair to generate the voltage difference between the two control terminals of the second differential transistor pair; wherein the first output node and the third output node are coupled at a fifth output node and the second output node and the fourth output node are coupled at a sixth output node, wherein the fifth output node is coupled to a first supply voltage via a first resistive element and the sixth output node is coupled to a second supply voltage via a second resistive element.