Current-Weighted Voltage Interpolation Buffer With Smaller Layout
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Solution Overview
Problem
Existing voltage interpolation buffers in display device driving circuits require both interpolation voltage generation and voltage buffering, leading to increased production costs due to larger layout areas and complex fabrication processes.
Innovation Solution
A current weighted voltage interpolation buffer that adjusts the ratio of bias currents of differential voltage-to-current conversion units to generate interpolation results, eliminating the need for voltage division circuits and reducing layout area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If voltage division circuits with series resistors are used for generating interpolation voltages, then interpolation function is achieved, but layout area increases and production cost increases
Solution Approach 1:
The patent replaces the mechanical/resistive voltage division system with a current-based weighted summation system. Instead of using series resistors to divide voltages, the invention uses differential voltage-to-current conversion units to convert input voltages into currents, which are then weighted by controlling bias current ratios, and finally converted back to voltage. This substitution eliminates the need for large resistance values and reduces layout area significantly.
Solution Approach 2:
The patent changes the fundamental parameter used for voltage interpolation from resistance values to current ratios. By controlling the ratio of bias currents (IB1/IB2) supplied to the differential voltage-to-current conversion units, the weighting factors for input voltages are adjusted. This parameter change allows flexible interpolation control without requiring large physical resistance values, thereby reducing layout area while maintaining the interpolation function.
2Loss of energy
If high resistance values are used in voltage division circuits to reduce current consumption, then power consumption is reduced, but production cost increases due to increased layout area
Solution Approach 1:
The patent replaces the resistive voltage division system with a current-mode system. Instead of relying on high resistance values to limit current, the invention uses controlled current sources (bias currents) to set the operating points of differential voltage-to-current conversion units. The current consumption is directly controlled by the bias current values rather than being determined by large resistance values, thus decoupling power consumption from layout area requirements.
Solution Approach 2:
The patent changes the control parameter from resistance values to bias current ratios. By adjusting the bias currents (IB1 and IB2), the system achieves both current consumption control and interpolation weighting adjustment simultaneously. This eliminates the need for high resistance values and their associated large layout areas, while maintaining efficient current management through active current control.
3Power
If separate interpolation voltage generation unit and voltage buffer are used, then sufficient driving capability is achieved, but device complexity increases
Solution Approach 1:
The patent merges the interpolation voltage generation function and the voltage buffering function into a single integrated circuit structure. The differential voltage-to-current conversion units generate weighted currents from input voltages, and the subsequent current-to-voltage conversion unit simultaneously provides the buffering function with sufficient driving capability. This consolidation eliminates the need for separate interpolation and buffering stages, reducing device complexity while maintaining both interpolation accuracy and driving strength.
Solution Approach 2:
The current-to-voltage conversion unit serves multiple functions: it converts the weighted sum of currents back to voltage for output, provides voltage buffering with sufficient driving capability, and enables the overall interpolation operation. This multi-functional design eliminates the need for separate dedicated interpolation and buffering circuits, thereby reducing device complexity while achieving both interpolation and driving requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for efficient voltage interpolation and buffering while reducing production costs by controlling bias currents, enhancing driving capability and layout efficiency.
Implementation Method 1
a first differential voltage to current conversion unit, coupled to the first voltage input terminal, the first bias current input terminal and the voltage output terminal, for outputting corresponding differential currents through a first current output terminal and a second current output terminal according to the first input voltage, the first bias current and a voltage of the voltage output terminal
Implementation Method 2
a current to voltage conversion unit, coupled to the first differential voltage to current conversion unit, the second differential voltage to current conversion unit and the voltage output terminal, for outputting an interpolation result of the first input voltage and the second input voltage, corresponding to a ratio of the first bias current and the second bias current
Data Source
AI summary
A voltage interpolation buffer for interpolating voltages by adjusting ratio of bias currents includes a first difference voltage to current unit for outputting corresponding difference current according to a first voltage, a first bias current and voltage of a voltage output end, a second difference voltage to current unit for outputting corresponding difference current according to a second voltage, a second bias current and the voltage of the voltage output end, and a current to voltage unit coupled to the first difference voltage to current unit, the second difference voltage to current unit and the voltage output end for outputting a interpolation result of the first voltage and the second voltage corresponding to a ratio of the first bias current and the second bias current according to the difference currents outputted by the first difference voltage to current unit and the second difference voltage to current unit.