Complementary Variable Gain Amplifier With Shared Current Biasing
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Solution Overview
Problem
Existing variable gain amplifiers in wireless transceivers face challenges in reducing power consumption without compromising gain, noise figure, and linearity performance, as techniques that lower current consumption often degrade these parameters.
Innovation Solution
A variable gain amplifier design featuring cascaded amplifiers with transistors of alternating doping types, where a first amplifier produces a reference current that biases a second amplifier, reducing current consumption while maintaining target performance thresholds through current reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If current consumption is reduced in variable gain amplifier, then power consumption decreases, but gain, noise figure, and linearity performance deteriorate
Solution Approach 1:
The patent combines multiple reference current sources into a single shared current source that serves both the first and second amplifiers. The current mirror circuit allows one reference current to be replicated and distributed to multiple amplifiers, reducing the total number of independent current sources needed and thereby reducing overall power consumption while maintaining proper biasing for all amplifier stages
Solution Approach 2:
The shared reference current source performs multiple functions by simultaneously biasing both the first amplifier and the second amplifier through current mirror replication. This single current source structure serves universal purposes across multiple amplifier stages, eliminating the need for separate dedicated reference current sources for each amplifier and reducing total power consumption
Data Source
AI summary
An apparatus is disclosed for complementary variable gain amplification. In an example aspect, the apparatus includes a variable gain amplifier that includes multiple amplifiers. The multiple amplifiers include at least one first amplifier and at least one second amplifier cascaded together in series. The first amplifier includes a first set of transistors having a first doping type. At least a portion of the first set of transistors is configured to implement a first current mirror. The second amplifier includes a second set of transistors having a second doping type. At least a portion of the second set of transistors is configured to implement a second current mirror. The second current mirror is coupled to the first current mirror.