Voltage Interpolation Amplifier Circuit With Fewer Differential Pairs
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Solution Overview
Problem
Conventional amplifier circuits with voltage interpolation functions require multiple differential pairs, increasing circuit area and chip size in driver chips for liquid crystal displays, which complicates the reduction of chip size and production cost.
Innovation Solution
An amplifier circuit utilizing a single N-type differential pair and a single P-type differential pair with distinct transconductance values, coupled through an output stage, performs voltage interpolation by weighting input voltages, reducing the number of differential pairs needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple differential pairs are used in the amplifier circuit to achieve voltage interpolation function, then the voltage interpolation capability is improved, but the circuit area and chip size increase
Solution Approach 1:
The patent merges the functions of multiple differential pairs into a single differential pair by combining the voltage interpolation capability with buffer amplifier functionality. This integration allows the circuit to achieve voltage interpolation for multiple reference voltages (Vref1, Vref2, Vref3, Vref4) using fewer circuit elements, thereby reducing circuit area while maintaining the required adaptability
Solution Approach 2:
The amplifier circuit is designed to perform multiple functions simultaneously - it provides voltage interpolation capability while also serving as a buffer amplifier. This multi-functionality allows the circuit to generate interpolated reference voltages and provide adequate driving currents to rear stage circuits using a unified structure, reducing the need for separate dedicated circuits for each function
2Adaptability or versatility
If multiple reference voltage wirings and circuit elements are used in the digital-to-analog converter, then the voltage interpolation function is achieved, but the chip size and production cost increase
Solution Approach 1:
The patent extracts the voltage interpolation function from the digital-to-analog converter block and implements it in the amplifier circuit. By removing the voltage interpolation capability from the DAC and placing it in the amplifier stage, the DAC can focus on its core function of converting digital signals to analog voltages, while the amplifier handles the interpolation and buffering, thereby simplifying the overall device complexity
Solution Approach 2:
The amplifier circuit acts as an intermediary between the digital-to-analog converter and the rear stage circuits. It receives the reference voltages from the DAC, performs voltage interpolation to generate additional reference voltages, and provides buffered output to the rear stage. This intermediary role allows the system to achieve voltage interpolation without increasing DAC complexity
Data Source
AI summary
An amplifier circuit with a voltage interpolation function includes an N-type differential pair and a P-type differential pair. The N-type differential pair includes a first transconductance value, and has a first differential input terminal coupled to a first voltage and a second differential input terminal coupled to a voltage output terminal. The P-type differential pair includes a second transconductance value, and has a first differential input terminal coupled to a second voltage and a second differential input terminal coupled to the voltage output terminal. The N-type differential pair and the P-type differential pair are further coupled to the voltage output terminal through an output stage, and voltages outputted by the voltage output terminal are interpolation results of the first voltage and the second voltage weighted by the first transconductance value and the second transconductance value.