Inverter-Based Amplifier Architecture for Low-Voltage Operation
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Solution Overview
Problem
Conventional operational amplifiers require a high supply voltage due to the increasing number of transistors in series, making them unsuitable for operation under low voltage conditions.
Innovation Solution
A low voltage inverter-based amplifier design utilizing a first and second inverter-based amplification module, an inverter-based feedforward module, and an inverter-based common mode detector, constructed using PMOS and NMOS in a CMOS configuration, which reduces the number of cascade MOSs to two, allowing normal operation under low supply voltage without the need for a tail current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of transistors electrically connected in series is increased to achieve higher amplification gain, then the amplification performance is improved, but the supply voltage requirement increases making the amplifier unable to operate under low voltage conditions
Solution Approach 1:
The amplifier is divided into multiple inverter-based amplification modules (first inverter-based amplification module, second inverter-based amplification module) that can be cascaded to achieve higher gain while each module operates independently at low voltage, avoiding the need for high supply voltage
Solution Approach 2:
The inverter-based design allows dynamic operation where the amplification modules can be configured in different stages (first stage, second stage) with feedback mechanisms (inverter-based common mode detector, inverter-based feedforward module) to optimize performance at low voltage conditions
2Power
If conventional operational amplifier design is used with multiple transistors in series, then the amplification capability is achieved, but the device complexity and power consumption increase
Solution Approach 1:
Multiple functions are merged into the inverter-based amplification modules, which provide both amplification and voltage inversion in a single stage, reducing the total number of discrete transistor components needed compared to conventional multi-stage amplifier designs
Solution Approach 2:
The inverter-based amplification modules serve multiple purposes: they provide voltage amplification, signal inversion, and can be configured with feedback mechanisms for gain stabilization, making each module multi-functional and reducing overall device complexity
Data Source
AI summary
A low voltage inverter-based amplifier includes a first inverter-based amplification module, a second inverter-based amplification module, an inverter-based feedforward module, and an inverter-based common mode detector. The first inverter-based amplification module receives an input signal. The second inverter-based amplification module receives the input signal through the inverter-based feedforward module, and receives a first output signal from the first inverter-based amplification module. The inverter-based common mode detector receives an amplified signal from the second inverter-based amplification module, and outputs a feedback signal to the second inverter-based amplification module. Since the first and the second inverter-based amplification modules are both inverter-based, the supply voltage of the low voltage inverter-based amplifier is provided to supply one PMOS and one NMOS for normal operation. Therefore, a number of cascade MOSs of the low voltage inverter-based amplifier is two, and the low voltage inverter-based amplifier can be normally operated under the low supply voltage.