Cascaded Cascode Amplifier Layout for Gain Without Noise Summation
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Solution Overview
Problem
Conventional amplifiers used in wireless communication systems have high power consumption and difficulty in achieving high signal gain while minimizing noise interference, as they rely on differential amplifier structures that sum noise and limit signal gain.
Innovation Solution
The amplifier design incorporates a cascode amplifier circuit structure with two sets of cascode amplifier circuits and a loading circuit, utilizing capacitors for AC coupling and DC blocking, which allows for improved signal gain and reduced noise interference by aligning noise phases for cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If differential amplifier structure is used, then signal gain is improved, but power consumption increases and noise is summed due to opposite phases
Solution Approach 1:
The amplifier is divided into multiple single-ended amplifier stages rather than using a single differential amplifier. Each stage processes signals independently, allowing for better control of power consumption while maintaining signal gain through cascaded configuration.
Solution Approach 2:
Instead of using the conventional differential amplifier approach where noise sums due to opposite phases, the patent inverts the approach by using single-ended amplifiers where noise can be eliminated mutually through proper phase alignment and cancellation techniques.
2Power
If differential amplifier structure is used, then signal gain is improved, but noise generated by transistors is summed due to opposite phases
Solution Approach 1:
The patent inverts the conventional differential amplifier approach by using single-ended amplifiers with proper phase alignment, transforming the noise summation problem into a noise cancellation solution where transistors in different stages eliminate each other's noise through constructive interference of noise cancellation.
Solution Approach 2:
The patent converts the harmful noise generated by transistors into a beneficial effect by arranging the amplifier stages such that the noise from different stages cancels each other out, transforming noise from a harmful factor into a mechanism for noise reduction.
3Power
If gain of gate/source terminal in transistors is amplified, then signal gain is improved, but it becomes difficult to obtain higher signal gain
Solution Approach 1:
The amplifier is segmented into multiple single-ended stages, each contributing to the overall signal gain. This segmentation allows the system to achieve higher total gain by multiplying the gain of individual stages, overcoming the limitation of single-stage gain amplification.
Solution Approach 2:
The patent transitions from a single-dimensional gain amplification approach (amplifying gate/source terminal gain in one transistor) to a multi-dimensional approach by cascading multiple amplifier stages, each adding to the overall gain in a different dimensional aspect of the signal processing chain.
Data Source
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AI summary
An amplifier including a signal input terminal, a signal output terminal, a first and a second cascode amplifier circuits, a capacitor and a loading circuit. The first cascode amplifier circuit includes a first and a second input terminals and a first and a second output terminals. The first input terminal coupled to the signal input terminal receives an input signal. The second cascode amplifier circuit includes a third and a fourth input terminals and a third output terminal. The third input terminal is coupled to the first output terminal, and the third output terminal is coupled to the second input terminal. A terminal of the loading circuit is coupled to the third output terminal, and another terminal of the loading circuit is coupled to the second output terminal. At least one of two terminals of the loading circuit is further coupled to the signal output terminal.