Voltage Generator Ladder Resistor Variable On-Resistance Switching
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Solution Overview
Problem
Conventional voltage generators require increased circuit size to achieve more gray-scales, leading to increased error in output voltage when multiple switches are turned on, particularly in generating ramp voltages.
Innovation Solution
A voltage generator with a ladder resistor circuit and variable on-resistance switching circuits that combine multiple reference voltages to generate a composite output voltage, allowing adjustable ratios and reduced potential difference between reference voltages, thereby minimizing error while reducing circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of resistance elements and switches is increased to increase the number of gray-scales of output voltage, then the number of gray-scales is increased, but the circuit size becomes larger
Solution Approach 1:
The patent merges multiple reference voltages by simultaneously turning on multiple switches to generate intermediate voltages. Instead of using separate resistance elements for each gray-scale level, the invention combines multiple reference voltages through parallel switch connections, reducing the total number of resistance elements and switches needed while achieving higher gray-scale resolution
Solution Approach 2:
The patent introduces variable on-resistance switching circuits that can dynamically adjust their resistance values. This dynamic characteristic allows the switching circuits to optimize the combination of reference voltages in real-time, enabling precise control of output voltage levels without requiring additional static resistance elements, thus reducing circuit size while maintaining high gray-scale capability
2Adaptability or versatility
If the number of switches that are simultaneously turned on is increased to increase the number of gray-scales, then the number of gray-scales is increased, but the error in output voltage becomes larger
Solution Approach 1:
The patent changes the resistance parameter of the switching circuits from fixed to variable. By making the on-resistance adjustable, the system can optimize the weight of each reference voltage in the combination, compensating for cumulative errors that occur when multiple switches are turned on. This parameter change allows precise control of the output voltage even with multiple simultaneous switches activated
Solution Approach 2:
The variable on-resistance switching circuits enable a feedback mechanism where the resistance values can be adjusted based on the actual output voltage levels. This allows the system to compensate for errors in the combined reference voltages by dynamically adjusting the switching circuit resistances, thereby maintaining high precision in the output voltage across all gray-scale levels
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
The solution effectively suppresses the increase in output voltage error and achieves a reduction in circuit size, enabling accurate digital-to-analog conversion and ramp voltage generation with improved differential nonlinearity.
Implementation Method 1
a ladder resistor circuit for generating a plurality of different reference voltages
Implementation Method 2
each of the plurality of switching circuits being connected at one end to a corresponding one of the taps and connected at the other end to an output node, and having a variable on-resistance value
Data Source
AI summary
A ladder resistor circuit generates a plurality of different reference voltages. A plurality of switching circuits correspond to a plurality of taps of the ladder resistor circuit. Each of the plurality of switching circuits is connected at one end to a corresponding one of the taps and connected at the other end to an output node, and has a variable on-resistance value. A control circuit selects continuous n (where n is any integer equal to or greater than 2) of the plurality of switching circuits, turns the n switching circuits on, and sets the respective on-resistance values of the n switching circuits.